WO2009029996A1

WO2009029996A1 - Patient monitoring system

Info

Publication number: WO2009029996A1
Application number: PCT/AU2008/001324
Authority: WO
Inventors: Basil C. Bautovich
Original assignee: Conseng Pty Ltd
Priority date: 2007-09-05
Filing date: 2008-09-05
Publication date: 2009-03-12

Abstract

Described herein are monitoring systems for beds and the like, along with various methods for monitoring patients. In some embodiments, a system is configured to generate an alert signal responsive to a user attempting to exit a bed, and configured not to generate an alert signal responsive to a user approaching the bed.

Description

PATIENT MONITORING SYSTEM

FIELD OF THE INVENTION

[01] The present invention relates to a monitoring system.

[02] The invention has been developed primarily for use as a monitoring system for an individual in a bed - for example, a hospital patient or nursing home patient - and will be described hereinafter with reference to this application. However, it will be appreciated that the invention is not limited to this particular field of use and is also suitable for monitoring more than one individual or other individuals such as children, domestic animals and the like whether in a bed, chair, cot or other support surface, or a room, or other defined zone such as a doorway between two rooms.

BACKGROUND OF THE INVENTION

[03] Any discussion of the prior art throughout the specification should in no way be considered as an admission that such prior art is widely known or forms part of the common general knowledge in the field.

[04] In many cases, individuals such as patients in a hospital or a nursing home require constant physical care and attention from caregivers. Due to costs and resource limitations there are typically many more patients requiring care than there are caregivers - such as nurses or other health service professionals - in any given organisation. Therefore, it is not always possible to administer personal physical care and support to each and every patient that may warrant such attention.

[05] Known methodologies that attempt to ameliorate this problem include the use of personal monitoring systems, video surveillance systems, pressure sensitive mats on a bed surface, physical barriers to patient movement, or the like. These types of methodologies have a number of disadvantages. For example, it is necessary for physical barriers to be fixed in place, involving cost both at the stage of provisioning and, if the barrier is no longer required or needs to be moved, at the stage of removal or relocation. There is also the additional risk of the patient becoming entrapped or imprisoned by the barrier, or injured when attempting to defeat the barrier. Video surveillance systems, on the other hand, are usually expensive and still require the caregiver to constantly monitor the patient, albeit remotely. If the caregiver is distracted - be that legitimately or otherwise - the surveillance will be compromised. This then increases the risk of a patient being left wholly without care, or increases the time for care to be provided. In some instances this can result in the patient being injured, or further injured, before a caregiver has the opportunity to take any action.

[06] Other known devices are individual monitoring systems. For example, the devices disclosed in:

• PCT application number PCT/AU2004/000135. The embodiments of the monitoring system include spaced apart components mounted to the foot and the head of a bed for generating a field that extends along a periphery of the bed.

• US Patent 6,166,644. The embodiments disclose a portable unit that is responsive to at ) least two separate and distinct actuators for providing an alarm signal.

[07] Disadvantages of the known devices include:

• Being relatively prone to providing false alarms indicating that the individual is attempting to leave the bed.

• Requiring considerable manual intervention by the carer to disable the alarm function so 5 that legitimate passage from the bed is able to be affected.

• Being subject to the carer forgetting to have the system activated after being disabled. SUMMARY OF THE INVENTION

[08] It is an object of the present invention to overcome or at least ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

0 [09] According to a first aspect of the invention there is provided a monitoring system for indicating movement of an individual through a gateway between a first zone in which the individual is located and a second zone, the system including: a transmitter for providing a field that extends across at least some of the gateway; a first detector for generating, in response to the individual entering the field, a »5 movement signal indicative of movement of the individual through the gateway; a second detector for generating a reference signal in response to a body being disposed within a third zone adjacent to the field; and an alarm that is responsive to one or both of the movement signal and the reference signal for selectively generating an alert signal. [10] In an embodiment, the third zone extends across at least some of the gateway.

[11] In an embodiment, the third zone and the field collectively extend across the gateway.

[12] In an embodiment, the third zone and the field overlap across the gateway.

[13] In an embodiment, the gateway extends between two spaced apart posts.

[14] In an embodiment, the first zone includes a boundary that is defined at least in part by a support surface for the individual that extends between the posts, and the second zone surrounds the support surface.

[15] In an embodiment, the gateway extends along part of the boundary.

[16] In an embodiment, the boundary has a substantially linear portion and the gateway i extends along the portion.

[17] In an embodiment, the boundary includes a plurality of substantially linear portions and the gateway extends along one of the linear portions.

[18] In an embodiment, the boundary is substantially rectangular.

[19] In an embodiment, the posts define at least part of a bed head and a bed foot ; respectively.

[20] In an embodiment, the posts define at least part of respective opposed chair arms.

[21] In an embodiment, the third zone extends from a first end that is at or adjacent to one of the posts and terminates at a second end intermediate the posts, and the field extends from the second end to a third end at or adjacent to the other of the posts.

) [22] In an embodiment, the second end is closer to the one of the posts than the other of the posts.

[23] In an embodiment, the distance between the first end and the second end is about half the distance between the second end and the third end.

[24] In an embodiment, the first detector and the second detector define a compound detector, i [25] In an embodiment, the compound detector is disposed at or adjacent to one of the posts. [26] In an embodiment, the compound detector is mounted to one of the posts.

[27] In an embodiment, the alarm is responsive to the movement signal for generating the alert signal. [28] In an embodiment, the alarm is responsive to the reference signal for preventing the generation of the alert signal.

[29] In an embodiment, the field and the third zone coextend across at least part of the gateway.

[30] In an embodiment, the field and the third zone are substantially co-terminus. [31] In an embodiment, the third zone is disposed in the second zone. [32] In an embodiment, the third zone is immediately adjacent to the field.

[33] In an embodiment, the alarm is responsive to the movement signal for generating the alert signal.

[34] In an embodiment, the alarm is responsive to the reference signal for preventing the generation of the alert signal.

[35] In an embodiment, the field and the third zone coextend across at least part of the gateway.

[36] In an embodiment the support surface extends along a plane and the first field is substantially parallel with the plane.

[37] In an embodiment, the plane is substantially horizontal and the first field is disposed above the plane. Preferably, the first field is disposed above the plane by no more than about 200 mm.

[38] In an embodiment, the plane is substantially horizontal and the first field is disposed below the plane. Preferably, the first field is disposed above the plane by no more than about 200 mm.

[39] In an embodiment the support surface includes an edge and the first field is substantially parallel with the edge. Preferably, the first field is spaced from the edge outwardly of the support surface. More preferably, the first field is spaced from the edge at least about 100 mm outwardly of the support surface. Even more preferably, the first field is spaced from the edge by no more than about 250 mm.

[40] According to a second aspect of the invention there is provided a method for indicating movement of an individual through a gateway between a first zone in which the individual is located and a second zone, the method including: providing a field that extends across at least some of the gateway; generating, in response to the individual entering the field, a movement signal indicative of movement of the individual through the gateway; generating a reference signal in response to a body being disposed within a third zone adjacent to the field; and being responsive to one or both of the movement signal and the reference signal for selectively generating an alert signal.

[41] According to a third aspect of the invention there is a monitoring system for indicating the presence of a body in a detection zone, the system including: a housing; a transmitter mounted to the housing for providing a field that defines the detection zone; a detector mounted to the housing for generating, in response to the body entering the field, a detection signal indicative of the presence of the body in the detection zone; a lockout control that extends from the housing and which is manually moveable between a lockout configuration and an operable configuration; and at least one monitor control that extends from the housing, wherein the monitor control is manually operable, when the lockout control is in the operable configuration, to selectively adjust one or more characteristics of the monitor.

[42] In an embodiment, the lockout control and the at least one monitor control are spaced apart from each other.

[43] In an embodiment, the at least one monitor control and the lockout control extend from the housing and away from each other.

[44] In an embodiment, the housing includes a first surface from which the at least one monitor control extends and a second surface from which the lockout control extends.

[45] In an embodiment, the first and second surfaces define part of continuous surface. [46] In an embodiment, the first surface is spaced apart from the second surface. [47] In an embodiment, the first surface is adjacent to the second surface.

[48] In an embodiment, at least some of the first surface is inclined away from the second surface.

[49] In an embodiment, at least some of the first surface is opposite to the second surface. [50] In an embodiment, the lockout control is biased toward the lockout configuration.

[51 ] According to a fourth aspect of the invention there is provided a method for constructing a monitoring system for indicating the presence of a body in a detection zone, the method including: providing a housing; mounting a transmitter to the housing for providing a field that defines the detection zone; mounting a detector to the housing for generating, in response to the body entering the field, a detection signal indicative of the presence of the body in the detection zone; providing a lockout control that extends from the housing and which is manually moveable between a lockout configuration and an operable configuration; and providing at least one monitor control that extends from the housing, wherein the monitor control is manually operable, when the lockout control is in the operable configuration, to selectively adjust one or more characteristics of the monitor.

[52] According to a fifth aspect of the invention there is provided a monitoring system for indicating movement of individuals through respective gateways, the system including: a monitoring unit associated with each individual, each monitoring unit having:

(a) a transmitter for providing a field that extends across at least some of the respective gateways;

(b) a first detector for generating, in response to the individual entering the respective field, a movement signal indicative of movement of the individual through the gateway; and

(c) a second detector for generating a reference signal in response to a body being disposed within a third zone adjacent to the field; and an alarm that is selectively responsive to the movement signal and the reference signal for selectively generating an alert signal.

[53] According to a sixth aspect of the invention there is provided a method for indicating movement of individuals through respective gateways, the system including: a monitoring unit associated with each individual, each monitoring unit having: (a) a transmitter for providing a field that extends across at least some of the respective gateway; (b) a first detector for generating, in response to the individual entering the respective field, a movement signal indicative of movement of the individual through the gateway; and

(c) a second detector for generating a reference signal in response to a body being disposed within a third zone adjacent to the field; and an alarm that is selectively responsive to the movement signals and the reference signals for selectively generating an alert signal.

[54] One embodiment provides a monitoring system for a bed, the system being configured to generate an alert signal responsive to a user attempting to exit the bed, and configured not to generate an alert signal responsive to a user approaching the bed.

[55] One embodiment provides a monitoring system wherein the system recognises a user approaching the bed by the breakage of an outer region of a monitored field prior to the breakage of an inner region of the monitored field.

[56] One embodiment provides a monitoring system for a bed, wherein the bed is configured to operate in a first mode in which a longitudinally extending bedrail hinders a patient from exiting the bed, and a second mode wherein the bedrail does not hinder the patient from exiting the bed, the system including: a support member mountable with respect to the bed; a transmitter for providing a field, the transmitter being supported by a transmitter housing that is movably mounted with respect to the support member; wherein transmitter housing is movable between a first position wherein field monitors a gateway through which the patient passes when exiting the bed as operated in the first mode, and a second position , wherein field monitors a second gateway through which the patient passes when exiting the bed as operated in the second mode.

[57] One embodiment provides a system wherein the bed includes a mattress, and wherein in the first position the field is provided above and transversely inwards from the bedrail, and wherein in the second position the field is provided above and transversely outwards from and generally parallel with the side of the mattress.

BRIEF DESCRIPTION OF THE DRAWINGS

[58] Preferred embodiments of the invention will now be described with reference to the accompanying drawings in which: [59] Figure 1 is a schematic top view of a nursing-home bed that is subject to monitoring with a monitoring system of one embodiment of the invention;

[60] Figure 2 is a sectional view taken along line 2-2 of Figure 1 ;

[61 ] Figure 3 is a schematic front view of a monitoring unit used in the system of Figure 1 ;

> [62] Figure 4 is a schematic top view of the unit of Figure 3;

[63] Figure 5 is a schematic side view of the unit of Figure 3;

[64] Figure 6 is a schematic representation of the circuitry of the monitoring unit of Figure 3;

[65] Figure 7 is a schematic top view of a nursing-home bed that is subject to monitoring with a monitoring system of another embodiment of the invention;

) [66] Figure 8 is a schematic representation of the circuitry of the monitoring unit of Figure 7;

[67] Figure 9 is a schematic representation of a monitoring system including a plurality of monitoring units selected from the units illustrated in the above figures; and

[68] Figure 1OA is a schematic representation, not to scale, of specific placements of a field for a bed.

5 [69] Figure 1OB is schematic representation, again not to scale, of specific placements of a field for a bed having bedrails.

[70] Figure 11 is view similar to that of Figure 2, showing a monitoring system according to another embodiment;

[71] Figure 12 shows the monitoring system of Figure 2 in a second configuration appropriate ) for use in conjunction with a bedrail;

[72] Figures 13 A to 13D illustrate a monitoring unit having a movable transmitter housing.

[73] Figure 14 provides an exploded perspective view of a support member according to one embodiment.

[74] Figure 15 schematically illustrates a bed assembly according to one embodiment.

5 [75] It will be appreciated that corresponding reference numerals are used to denote corresponding features in different embodiments and that the drawings are not to scale. -Si- PREFERRED EMBODIMENTS OF THE INVENTION

[76] Referring to Figures 1 to 6 there is illustrated a monitoring system 1 for indicating movement of an individual (not shown) through a gateway 2 (which will be described in more detail below). The gateway is between a first zone 3 - which is bounded by the broken line best shown in Figures 1 and 2 — that substantively directly overlies a bed 4 in which the individual is located and a second zone in the form of a room 5 in which bed 4 is located. As best shown in Figure 6, system 1 includes a monitoring unit 9 having an infrared transmitter 10 for providing an infrared field 11 that extends across about 60% of gateway 2. A first detector, in the form of an infrared detector 12 generates, in response to the individual entering field 11, a movement signal indicative of movement of the individual through gateway 2. A second detector, which in this embodiment is also defined by detector 12, generates a reference signal in response to a body (not shown) being disposed within a third zone 13 that is immediately adjacent to field 11. An alarm, in the form of a processor 14, is responsive to one or both of the movement signal and the reference signal for selectively generating an alert signal.

[77] Bed 4 extends longitudinally between a tubular metal bed head 21 and a spaced apart tubular metal bed foot 22. Bed head 21 include a pair of transversely spaced apart generally parallel and vertical tubular bedposts 23 and 24, while foot 22 includes a further pair of correspondingly transversely spaced apart bedposts 25 and 26. Bed 4 also includes a generally rectangular metal tube bed frame 27 that is suspended horizontally between the bedposts and maintained a fixed distance above the underlying surface. In this embodiment the underlying surface is a substantially planar floor 28. In other embodiments the bed head, bed foot and frame are made from other materials or combinations of materials such as metal, wood, composites, laminates, or meshes.

[78] Frame 27 supports a generally rectangular single bed mattress 29 which extends substantially horizontally and longitudinally between a first end 31 that is adjacent to bed head 21 and a second end 32 that is adjacent to foot 22 and generally parallel with end 31. The mattress also extends transversely between two opposite and generally parallel sides 33 and 34. Ends 31 and 32 and sides 33 and 34 collectively define a substantially rectangular horizontal support surface 35 for the individual. As illustrated in Figures 1 and 2, bed 4 also includes a pillow 36 that, in normal use, is disposed adjacent to bed head 21 and upon which the individual rests their head. It will be appreciated that additional or other pillows or other support aids are also available for use with bed 4. Moreover, as would be appreciated by those skilled in the art, AQ- bed 4, and mattress 29 in particular, is typically covered by one or more removable sheets, blankets, waterproof liners or other sheet materials.

[79] Unit 9 is releaseably secured to bedpost 24 vertically above the plane of surface 35 and extends transversely outwardly from the bedpost, hi this embodiment, the placement is such that transmitter 10 generates field 11 at about 150 mm above surface 35 and about 150 mm transversely offset from and generally parallel with side 34. hi other embodiments alternative placements of unit 9 are used to provide different positioning of field 11. It will be appreciated by those skilled in the art that the placement of unit 9 will also be determined by the nature and type of radiation used to establish field 11. For some fields will be relatively uniformly dispersed along gateway 2 - such as that illustrated in Figure 1 - while others will disperse transversely with increasing longitudinal displacement from unit 9. For example, for some transmitters zone 13 is about 10 mm in diameter immediately adjacent to end 45 and field 11 is about 60 mm in diameter adjacent to end 47, where there is a substantially uniform transition between the two. Where there is a considerable divergence it is usual to align with edge 34 the adjacent edge of field 11 and zone 13. In some embodiments this alignment is affected by physically rotating unit 9 about a vertical axis that passes through bedpost 24. hi other embodiments, however, the alignment of transmitter 10 is adjusted relative to unit 9 so that no physical movement of unit 9 is required. It has been found in practice that allowing a rotation of transmitter 10 by about ±10° usually provides for sufficient adjustment. However, in other embodiments more or less adjustment is accommodated.

[80] System 1 includes a like unit 9 (not shown) that, in use, is mounted to bedpost 23 for providing a further field 11 that is parallel with and offset from side 33. This like unit has been omitted from Figures 1 and 2 for the sake of clarity. In other embodiments, the like unit 9 is not included and bed 4 has a bedrail or other physical barrier that extends along side 33. hi further embodiments, the like unit 9 is not required as side 33 is adjacent to a wall or other barrier, hi still further embodiments an alternative form of unit 9 is used to provide the required pairs of field 11 and zone 13 adjacent to edges 33 and 34.

[81] As best shown in Figures 1 and 2, zone 3 extends upwardly from surface 35 and defines a volume in which the individual would typically occupy when making use of bed 4. Zone 3 includes a boundary that is generally rectangular when viewed from above, which is represented by the broken line indicated by reference numeral 3. Part of this boundary, which in this embodiment is a linear part 39, is parallel with side 34 and extends along gateway 2. -41-

[82] In the event the individual progresses from surface 35 of bed 4, there is a need to move from zone 3 - that is, to cross the boundary of zone 3 - and into the surrounding room 5. Bed head 21 and foot 22 provide a barrier to the progress of the individual from bed 4 into room 5, which makes gateway 2 the path of least resistance for movement between zone 3 and room 5. Accordingly, normal movement of the individual between zone 3 and room 5 will result in movement across part 39 of the boundary of zone 3. This part 39 is longitudinally coextensive with gateway 2, in that they both extend longitudinally between bedposts 24 and 26. It will be appreciated that a second gateway is defined between bedposts 23 and 25 and a further linear part 40 of the boundary of zone 3 is longitudinally coextensive with that second gateway.

[83] It will be appreciated by those skilled in the art that the Figure 1 embodiment is primarily for use with individuals such as hospital patients and the elderly, who in normal circumstances are unlikely to attempt to progress from zone 3 to room 5 other than through gateway 2. For those more active individuals, use is also made of one or more additional like units 9 that provide respective fields 11 which extend along the boundary of zone 3 adjacent to bed head 21 and foot 22.

[84] Zone 13 extends longitudinally along part of gateway 2 from a first end 45 that is adjacent bedpost 24 to a second end 46 that is intermediate bedposts 24 and 26. In this embodiment, ends 45 and 46 are longitudinally spaced apart by about 800 mm, however, in other embodiments, alternative spacing is used. It has been found for elderly and other less mobile individuals that ends 45 and 46 are usually spaced apart longitudinally within a range of about 700 mm to 900 mm.

[85] It will be appreciated that zone 13 is adjacent to bed head 21 and, hence, adjacent to the head of the individual when lying conventionally within bed 4. The field 11 , however, is adjacent to the legs and torso of the individual.

[86] For more elderly individuals the usual technique for moving from bed 4 to room 5 is to first lie on their side while facing gateway 2. Next, the individual will move one or both or their lower limbs over edge 34, which typically results in the feet or lower legs entering into field 11. Consequently, the alert signal is generated by processor 14 and the alarm signal is provided to the relevant carer. However, it will still be at least a few more seconds, and for less mobile individuals upward of thirty seconds, before that individual makes the final move to progress from bed 4. The individual is most at risk of a fall during both the final move from bed 4 and when moving about room 5 unassisted. Accordingly, system 1 provides the carer with advance 42- notice of movement through gateway 2 to provide a better chance of the carer being present during the time where the individual is most at risk of a fall.

[87] In other embodiments unit 9 is connected to bedpost 26 rather than bedpost 24 to provide zone 13 and field 11 in the illustrated configuration. In further embodiments, a separate unit 9 is connected to each of bedposts 24 and 26, one for providing field 11 and the other for providing zone 13. In still further embodiments, another unit 9 is releaseably engaged with bedpost 24 about 150 mm above the illustrated unit 9 for providing an additional zone 13 and field 11.

[88] In additional embodiments there are more than one field 11 or more than one zone 13.

[89] Mattress 29 is about 2 metres long and bed head 21 and foot 22 are correspondingly spaced apart longitudinally.

[90] Field 11 extends longitudinally from end 46 to a third end 47 that is adjacent to post 26. Collectively, zone 13 and field 11 extend across all of gateway 2 and, as such, the usual movement of the individual through the gateway will result in the individual entering field 11 or zone 13. It has been found that, particularly with more elderly individuals and ill individuals who use the technique described above for rising from bed 4, rarely will zone 13 be entered during normal movement to and from bed 4. Rather, it has been found that substantially always the individual will move into and through field 11, at least prior to moving into zone 13. For some individuals, particular those that are more mobile, it is often necessary to contain zone 13 to the lower end of the range of about 700 mm to 900 mm to best ensure that field 11 is entered, or entered prior to zone 13 being entered, during the normal movement of the individual from bed 4. In more extreme cases zone 13 is less than 700 mm.

[91] Unit 9 includes a generally rectangular plastics prismatic housing 49 for securely containing the electronic elements used by unit 9. This housing is sealed and tamper resistant.

[92] As best shown in Figure 6, transmitter 10 is disposed within housing 49 and includes a controller 51 for communicating with processor 14 via a communications bus 52. Controller 51 is responsive to commands from processor 14 for driving a radiating element 53 to generate a pulsed infrared beam - which is schematically illustrated by arrows 54 - that emanates in the direction from the housing via a generally rectangular window 55 that is substantially transparent to infrared radiation. Element 53 is mounted directly against window 55 to minimise any reflections of the beam by that window. In this embodiment window 55 is of red acrylic. In other embodiments, however, alternative materials are used. 43-

[93] Beam 54, in this embodiment, defines both field 11 and to zone 13. It will be appreciated that in other embodiments separate beams are used to respectively define field 11 and zone 13.

[94] Detector 12 includes an infrared sensor 57 that is mounted directly against window 55 for receiving reflected infrared radiation from beam 54. A controller 58 is responsive to sensor 57 receiving such reflected radiation for generating a range signal that is indicative of the distance from window 55 that the reflections occurred. Controller 58 also communicates with processor 14 via a communications bus 59 for receiving commands from the processor and for providing the range signal to the processor. The range signal defines either the reference signal or the movement signal. That is, if the range signal indicates that the reflections occurred within field 11, processor 14 interprets the range signal as the movement signal. Conversely, if the range signal indicates that the reflections occurred within zone 13, processor 14 interprets the range signal as the reference signal. In other embodiments having more than one field 11 or more than one zone 13, processor 14 is responsive to the range signal to determine the field or zone in which the reflections occurred.

[95] In alternative embodiments, transmitter 10 provides a diffuse infrared beam and detector 12 includes two sensors 57 disposed adjacent to window 55 and on opposite sides of element 53. In this alternative embodiment the range information is obtained via a triangulation calculation, rather than from time of flight calculation. Diffuse infrared beams are preferred in some embodiments due to generally not dispersing significantly as the longitudinal distance from window 55 increases.

[96] Detector 12 is disposed adjacent to edge 34 and transmitter 10 is disposed next to detector 12 but on the opposite side to edge 34. This has been found to provide more reliable detection of movements of the individual. In other embodiments, however, transmitter 10 is adjacent to edge 34 and detector 12 is disposed next to transmitter 12 but on the opposite side to edge 34. In further embodiments, transmitter 10 and detector 12 are aligned vertically - in that they are stacked vertically one on the other.

[97] If the individual is lying on surface 35 of bed 4 and attempts to move through gateway 2, the individual will normally enter field 11 only, or will enter field 11 prior to entering zone 13, as has been discussed above. This will result in some reflection of beam 54 in field 11. Sensor 57 will detect the reflections and controller 58 will derive the movement signal indicative of the individual entering field 11. Processor 14 is responsive to the movement signal for generating 44- the alert signal that is communicated externally of unit 9 via a communications port 60. In some embodiments port 60 is combined with a wireless transmitter (not shown) for transmitting the alert signal to a remote receiver.

[98] In this embodiment system 1 includes a nurse-call system (not shown) and port 60 facilitates connection of unit 9 to that call system. In other embodiments, system 1 does not include a nurse-call system and is comprised primarily of unit 9, which includes an inbuilt speaker (not shown) that is responsive to the alert signal for sounding an audible alarm. In some embodiments the audible alarm is a pre-recorded voice command directed to the individual to encourage him or her to remain on bed 4,

[99] In this embodiment room 5 is a room within a nursing home of other health care facility. In such facilities it is usual to have a plurality of beds - typically in separate rooms for nursing homes - all of which include one or more units 9. These units 9 are each interfaced with the nurse-call system to allow a reduced number of nurses or carers to provide a greater level of timely assistance to the individuals.

[100] The alert signal in this embodiment is provided to the nurse-call system and results in a remote warning signal being generated for the allocated carer of the individual. This warning signal includes a visual and/or audible alarm at a central operator console. In other embodiments the nurse-call system includes pagers that are provided to the allocated carer or carers and the warning signal takes the form of the relevant pager or pagers vibrating and sounding the warning signal. In other embodiments use is made of one or more alternative wireless devices such as a cellular telephone, a PDA, a PABX system with wireless functionality, or a combination of these devices.

[101] In other embodiments unit 9 makes use of alternate transmitters and receivers that operate at frequencies outside the infrared spectrum.

[ 102] When used in nursing homes or other multiple bed facilities, the warning signal is indicative not only of an alert signal, but the location of the unit 9 that generated the alert signal. This allows the allocation of the warning signal to the subset of carers who are on duty for the corresponding location. In some embodiments, the carer has to provide confirmation that he or she will be responding to the warning signal and, if the confirmation is not provided within a given timeframe — typically about 2 minutes — the warning signal is re-issued to the subset of carers or more broadly to other carers. In other embodiments, the alert signal is only able to be cancelled at unit 9. Moreover, and as will be described below, unit 9 includes a lockout function 45- for reducing the risk of the individual intentionally or inadvertently disabling unit 9 or cancelling an alert signal. Accordingly, carers will be encouraged to seek out the individual and the unit 9.

[103] Another example of the operation of unit 9 is where the body of a carer or other person

> enters zone 13 to physically tend to the individual in bed 4. The presence of the body in zone 13 will result in some reflection of beam 54, which will be detected by sensor 57. Controller 58 will, in turn, generate the range signal and provide this to processor 14. As the range signal will define a reference signal — as the reflection was determined to have originated in zone 13 — processor 14 will not generate the alert signal. Accordingly, the carer is able to access the

) individual when in bed 4 without having to disable system 1 to prevent a "false" alarm.

[104] In this embodiment detector 12 is a digital device, in that it provides on bus 59 a series of data packets representing the reference signal and the movement signal. These data packets are derived from an A/D converter (not shown) within controller 58 that samples the output of sensor 57 at a predetermined rate. That is, there is a plurality of successive sample periods,

< wherein in each sample period a single sample is taken. In the absence of a sufficient amount of beam 54 being detected by sensor 57 as being reflected during a given sample period, controller 59 does not provide a reference signal or a movement signal for that period. In some embodiments, however, periodic communications occur between controller 58 and processor 14 during that period to check for the presence of controller 58 or other such routine maintenance

) functions.

[105] When the individual progresses into field 11, controller 59 will provide the movement signal to processor 14 for most, if not all, the sample periods in which the individual remains in the field. Whilst in this embodiment processor 14 is responsive to the first movement signal for generating the alert signal, in other embodiments, processor 14 requires five movement signals

> in consecutive sample periods before issuing an alert signal. This mechanism is used to reduce the risk of false alarms being generated. In other embodiments, an alternate number of movement signals within consecutive sample periods are required by processor 14. For example, in one such embodiment, processor 14 requires four movement signals in five consecutive sample periods, hi other embodiments alternate mechanisms are used.

) [ 106] It will be appreciated that each movement signal usually includes different range information depending upon the extent of the movement of the individual within the field and the accuracy of the range determination. In some embodiments the range information is monitored to determine the extent and speed of longitudinal movement of the individual. For example, in one such embodiment, processor 14 is responsive to thresholds for considerable or fast longitudinal movement for changing the status of the alert signal.

[107] Processor 14 is programmable, and in this embodiment is programmable to allow adjustment of the longitudinal extent of either or both of field 11 and zone 13. Moreover, processor 14 is programmable to reverse the location of field 11 and zone 13. In other embodiments the programmable nature of processor 14 allows other functionalities to be realised through the execution of other computer code.

[108] It will be understood by those skilled in the art that processor 14 includes one or more memory devices, power supply circuitry, ports, communications busses and other components that have not been shown in the figures for the sake of clarity.

[109] In this embodiment transmitter 10 and detector 12 are collectively defined by an infrared time of flight sensor made by Sick AG and having the product designation DS30. In other embodiments alternative sensors are used.

[110] Bed 4 is usually arranged such that bed head 21 is parallel with and adjacent to a wall in room 5, with both edges 33 and 34 spaced apart from the adjacent walls to allow the individual to enter and exit the bed through either gateway. This also provides the carer or carers to freer access to the individual whilst in bed 4. Accordingly, units 9 are preferentially releasably fixed to bed head 21 to minimise the risk of inadvertent contact with either the individual or the carer. In other embodiments foot 22 is parallel with and adjacent to a wall and, in such circumstances, units 9 are preferentially releasably fixed to foot 22. In other embodiments use is made of only one unit 9, in that field 11 and zone 13 are defined only along one side of bed 4. This is able to occur particularly for those individuals that demonstrate only leaving bed 4 through the same gateway 2. This is common in nursing homes where habits are deeply ingrained for some individuals. Moreover, in some circumstances, edge 33 of bed 4 is adjacent to and parallel to a further one of the walls defining room 5. This is usually reserved for those individuals who require additional care, attention and encouragement to only make use of gateway 2.

[Ill] In other embodiments bed 4 is disposed within room 5, which is a room in a domestic residence. Port 60 is linked to a telephone line and is configured in the event of an alert signal to dial a preset number to alert a carer of an attempt by the individual to move from bed 4. In other embodiments unit 9 includes wireless connectivity to a communications network and the alert signal is communicated via that network to a remote carer. For example, in some 47- embodiments, the communications network is a cellular telephone network and the wireless connectivity includes a cellular telephone chipset and associated circuitry that is disposed within housing 49.

[112] These and other forms of connectivity for units 9 are discussed in co-pending and commonly owned Australian patent application no. 2006252036 filed on 11 December 2006, the disclosure of which is incorporated herein by way of cross-reference.

[113] While system 1 is described as applied to a bed, it will be appreciated by those skilled in the art, with the benefit of the teaching herein, that system 1 or a like system is also applicable to monitoring the individual in other situations such when using a chair, a lounge or other furniture, or for monitoring a door that is available for use by the individual. For example, in one embodiment, a unit 9 is mounted to a wall to define a corresponding field 11 and zone 13 that are aligned with the edge of a bathtub, where zone 13 is usually adjacent to the taps that allow water to be supplied to the bathtub. In the event the individual attempts to move into or from the bathtub the carer is alerted and is able to attend the scene to reduce the risk of a fall. Moreover, the releasable fixing and unit 9, together with its portable nature, particularly when combined with the wireless connectivity, facilitates a relocation of the unit to accommodate a wide variety of circumstances. This allows greater monitoring of the individual with a lesser number of units 9, in that it does not require for each situation a dedicated unit.

[114] It will also be appreciated that the longitudinal extent of both field 11 and zone 13 is adjustable to allow ease of use of unit 9 in the different applications referred to above.

[115] Reference is now made to Figure 7 and Figure 8 where there is illustrated an alternative embodiment of the invention in the form of a system 65, where corresponding features are denoted by corresponding reference numerals. In this embodiment, system 65 includes a monitoring unit 66 having a transmitter in the form of two generally like transmitters 10 and 61 for respectively generating field 11 and defining zone 13. Zone 13 is defined by a pulsed infrared beam 68 that is coextensive with field 11. In other embodiments, field 11 extends less than fully across gateway 2.

[116] Unit 66 also includes two detectors 12 and 69 that are alternated between transmitters 10 and 67. The detectors 12 and 69 are responsive to a body being in field 11 or zone 13 respectively for providing the movement signal and the reference signal. It will be appreciated that in this embodiment, transmitter 67 and detector 69 are collectively defined by an infrared time of flight sensor made by Sick AG and having the product designation DS30. In other 48- embodiments alternative sensors are used. Moreover, in some embodiments the two transmitter/detector pairs — that is, transmitter 10 and detector 12, on the one hand, and transmitter 67 and detector 69, on the other — are defined by different types of sensors.

[117] In other embodiments, both detectors are disposed between the transmitters.

[118] Field 11 extends from a first end 67 that is adjacent to unit 66, to end 47, which is adjacent to bedpost 26. Zone 13 extends from end 45, which is adjacent to unit 66, to end 46, which is adjacent to bedpost 26. That is, field 11 and zone 13 are longitudinally coextensive and both extend longitudinally across substantially all of gateway 2. Moreover, zone 13 is on the opposite side of field 11 to bed 4 and is not disposed within zone 3.

[119] In use, if the individual attempts to pass through gateway 2, he or she will enter field 11 and then zone 13. This will result in the sequential generation of the movement signal and the reference signal. Processor 14 is responsive to the sequence of the generation of those signals for determining if the alert signal is to be generated, hi this instance, the movement signal will precede the reference signal and, as such, processor 14 will generate the alert signal.

[120] In some instances processor 14 receives a movement signal - in response to the individual moving into field 11 - but no subsequent reference signal as a result of the individual halting the attempt to progress through gateway 2. If the movement signal persists for a predetermined period without the reference signal having being provided to processor 14 - that is, if the individual remains within field 11 without entering zone 13 - the alert signal is varied to downgrade the alarm signal to a lower level. In some embodiments the predetermined period is about 10 seconds, while in other embodiments the predetermined period is about 30 seconds. Preferably, the duration of the predetermined period is adjustable.

[121] If the movement signal persists for less than the predetermined period without the reference signal being generated, processor 14 cancels the alert signal. That is, the sequencing of the generation of the movement signals, and the absence of a reference signal, indicates that the individual, while advancing beyond the boundary of zone 3, returned prior to any substantive excursion into the surrounding room 5.

[122] Should a carer approach bed 4, either to tend to the bed or the individual using the bed, the carer will first enter zone 13 and then field 11. This will result in the sequential generation of the reference signal and the movement signal. In this instance, the reference signal will precede the movement signal and, as such, processor 14 will not generate the alert signal. 49-

Following from this, once zone 13 and field 11 are determined to be clear of one or more bodies for a predetermined time, processor 14 enables system 1 for normal operation. That is, after a delay in having detected a body within field 11 or zone 13, system 1 is automatically reset for normal operation. In some embodiments, the delay is about half a second prior to the automatic reset occurring. There are also embodiments that require first field 11 and then zone 13 to be clear of the body prior to the automatic reset. That is, this sequence of a clear field 11 and then a clear zone 13 indicates that the body is moving away from bed 4.

[123] In some embodiments one or both of the reference signal and the movement signal include range data indicative of the distance of the body from window 55. This range data is provided to the nurse-call system - and in particular to a central database (not shown) - for allowing ongoing assessment and analysis of the bodies moving through gateway 2. This allows for further fine tuning of the dimensions of field 11 and zone 13 to best suit the individual concerned, the carers involved and the requirements of the facility in which bed 4 is located. For example, in some instances there is a need to attach, from time to time, specific medical measurement equipment to bed 4 at specific locations to assess the medical condition of the individual. If it is found that this falls within a certain volume of field 11 that the individual does not access when progressing through gateway 2, it is possible to trim the field — by manual adjustment of controls provided on unit 9 - to no longer extend into that volume. More typically, however, the effect is achieved through adjustment of the software executed by processor 14. That is, the software is adjusted such that the zone is redefined to exclude the certain volume referred to above. Processor 14 is then responsive, once again, to the range data contained within the range signal provided by detector 12 to categorise the range signal as a movement signal if the relevant reflections have been determined to emanate from the redefined zone 14.

[124] The above selective generation of the alert signal by processor 14 allows for monitoring of the individual, while also allowing a carer to fully tend to the individual without having to disable unit 9. This is a significant advantage over prior art system that have to be disabled, for there is no need for the carer to re-enable unit 9 to ensure its correct operation.

[125] In alternative embodiments, one or more of the transmitter/detector pairs are defined by alternative sensors such as a diffuse infrared sensor, an ultrasonic sensor, a laser based sensor, or other sensors detecting a change in an electromagnetic or similar field that undergoes changes of one or more characteristics when disturbed by a human body or part of human body entering the field. That is, the transmitter provides a relatively well-defined field or zone adjacent to the gateway that is typically not visible at least to the individual. The detectors used are required to detect some change or changes in the properties of the field or zone due to the presence of a body such as the individual in that field or zone to allow the alert signal to be selectively generated. Examples of diffuse infrared sensors used in some embodiments include that manufactured by Sick AG and designated by model number WT14. A further example of a diffuse infrared sensor is manufactured by Sick AG and designated by model number WT34. For example, in the Figure 7 embodiment, field 11 is able to be provided by a WT34 sensor and zone 13 is able to be provided by a WT 14 sensor.

[126] A particular advantage of the specific infrared detectors referred to above is that there is need only to mount unit 9 to one side of gateway 2. That is, there is no need for a reflector or receiver at the opposite end of the gateway. However, in other embodiments use is made of monitoring units that have spaced apart components mounted at or adjacent to opposite ends of the gateway.

[127] A further advantage of infrared sensors is that the beams provided are not visible to the human eye. This makes it more difficult for the individual being cared for to quickly understand the system. In the embodiments described above further steps are taken to make the monitoring less invasive, less detectable by the individual, and less prone to intentional defeat. This includes, for example, ensuring that any and all displays on the monitors, during normal use, face away from the patient. Such displays include one or more, or a combination of LEDs, LCD displays or the like. This has the added advantage of allowing a carer to inspect the status of the monitor without having to necessarily engage with the individual. This latter feature is advantageous for those individuals with sleep disorders who, while requiring constant monitoring, are highly susceptible to being disturbed.

[128] It will be appreciated that in those embodiments where unit 9 includes two transmitter/detector pairs, the alignment of the zone 13 is less critical than the alignment of field 11. Accordingly, if two different types of transmitter/detector pairs are used, it has been found most advantageous to have the transmitter that provides the beam that disperses most to define zone 13, while the other is used to define field 11. For example, if one transmitter/detector pair makes use of a diffuse beam and the other pair makes use of a pulsed beam, the former is used to define field 11 and the latter zone 13. [129] In some embodiments, processor 14 is remote from unit 9. Furthermore, in other embodiments, processor 14 is part of a computer or computer network. In a specific embodiment, processor 14 is part of a server in a network that provides the nurse-call system referred to above.

[130] In further embodiments use is made of more than two beams and a field or zone other than or in addition to field 11 and zone 13 to provide more detailed information about the movement of the individual and/or the carer. This information is processed by processor 14 or another processor in communication with processor 14, for providing additional functions or diagnosis for the individual, the carer or the facility in which the individual is placed.

[131] Housing 49 includes a substantially planar and generally rectangular top face 75 and a like-shaped but opposite and spaced apart bottom face 76. A substantially planar generally rectangular front face 77 extends between faces 75 and 76 and supports window 55. Housing 49 also includes a rear face 78 and two opposite side faces 79 and 80, all of which extend between faces 75 and 76. A control panel 81 extends between faces 75, 76, 77 and 80 and includes a display in the form of three aligned LEDs 82, 83 and 84. Panel 81 also includes an array of controls in the form of two manually operable tactile buttons 85 and 86. Face 80 also supports a further control in the form of a generally circular manually operable tactile lockout button 87.

[132] In other embodiments one or more of the controls or display are omitted. However, in further embodiments additional or alternative displays or controls are included.

[133] LED 82 is a single colour LED - usually a yellow coloured LED - that provides a visual indication to the carer of the predetermined time required for a body to be within field 11 before an alert signal will be generated. The carer is able selectively to adjust this time via ADJUST button 85 in combination with the operation of button 87 as described below.

[134] LED 83 is a single colour LED - usually a red coloured LED - that is illuminated by processor 14 following the generation of an alert signal. This LED remains illuminated until unit 9 is turned OFF by selective operation of ON/OFF button 86 in combination with the operation of button 87 as described below.

[135] LED 84 is a single colour LED - usually a green coloured LED - that is illuminated by processor 14 to indicate that unit 9 is operating to provide field 11 and zone 13. This LED remains illuminated while unit 9 is turned ON, regardless of whether or not an alert signal has been generated. [136] LEDs 82, 83 and 84 and buttons 85, 86 and 87 are all electrically connected to processor 14 by wiring 88.

[137] Button 87 is biased outwardly into a disable configuration and is able to be manually depressed inwardly to face 80 to move to an enable configuration. Once the manual force applied to button 87 is removed, the button returns to the disable configuration.

[138] Whilst buttons 85 and 86 are easily accessible and easily manually operable, processor 14 is not responsive to those buttons unless, simultaneously, button 87 is in the enable configuration. This has been found to be an effective barrier to preventing the individual from operating or adjusting unit 9 without authorisation from the carer.

[139] It will be appreciated that face 80 and face 81 are inclined with respect to each other. In other embodiments, face 80 and face 81 are normal to each other.

[140] Button 87 is mounted to a face of unit 9 other than the face to which buttons 85 and 86 are mounted. However, in some embodiments all the buttons are mounted to the same face. If so, it is preferred that button 87 is spaced apart from the remaining buttons to reduce the risk of inadvertent operation of buttons 85, 86 and 87.

[141] In another embodiment, button 87 is mounted to face 78 to facilitate one-handed operation of unit 9 by the carer. That is, the carer is able to depress button 87 with either the thumb or index finger of one hand, and simultaneously selectively depress one of buttons 85 and 86 with the other of the index finger and the thumb of the same hand. That is, in some embodiments, button 87 is disposed on or mounted to a face that is opposite to the face to which one or more of the remaining buttons are disposed, hi some instances button 87 is disposed on face 78 to better obscure the button from view of the individual.

[142] The embodiments of the invention described above are monitoring systems for monitoring an individual. Other terms used to describe the systems are personal monitoring systems, through-beam monitoring systems, movement detection systems and the like. The systems of the embodiments illustrated in the drawings are adjustable in that they offer flexibility in application to a range of individuals, facilities, and situations. This adjustability also allows the systems to be specifically tuned for use with an individual having known characteristics, requirements, or idiosyncrasies.

[143] The embodiments referred to above are mains powered, and unit 9 includes power supply circuitry (not shown) for converting the mains voltage to a low DC voltage. This DC voltage is used by the relevant electronic components included within unit 9. In other embodiments more than one DC voltage is provided by the power supply circuitry. In further embodiments, unit 9 is battery powered.

[144] Reference is now made to Figure 9 where there is illustrated a further system 91 for monitoring an individual, where corresponding features are denoted by corresponding reference numerals. System 91 is installed in an aged-care facility 92 and includes a network 93 that communicates selectively with a plurality of units 9. Typically, units 9 are all intended for use with respective individuals and are often disposed within separate rooms within facility 92.

[145] Units 9 are all connected to network 93 by respective data cables. In some embodiments, alternative cables are used to also supply power to units 9.

[146] Network 93 includes a communications bus 94, a database 95, a server 96 and a wireless communication point 97 for allowing wireless communication between network 93 and a plurality of wireless handsets 98 (only one shown) that are used by respective carers within facility 92.

[147] It will be appreciated that in other embodiments network 93 is alternatively or additionally configured with servers, databases, communications buses and communications points, or otherwise.

[148] In this embodiment, server 96 executes software to be responsive to the signals provided by units 9. If an alert signal is generated by one of units 9, server 96 causes a warning signal to be communicated to handset 98 via point 97. The warning signal includes data indicative of the type of alarm being raised, and the location of the unit 9 that provided the alert signal.

[149] Server 96 is also responsive to the signals that provide range data, and for storing the range data in database 95, to build a profile for each user. This profile is periodically analysed to assess the respective monitoring needs of the individuals, and the costs of providing those needs. That analysis will assist the facility in planning for present and future staffing needs, and the best location for the patients within the facility. Moreover, in some embodiments, the analysis is one input into the fees levied to the patient for use of the facility.

[150] Server 96 is responsive to the profile for developing a configuration file for each individual, so that a unit 9 is able to be quickly commissioned for that individual. That is, when a new unit 9 is connected to network 93 it will be associated with the profile of an individual, and server 96 then downloads to processor 14 of unit 9 a configuration file that specifies the required set-up information for unit 9. The set-up information will include, for example, the predetermined delay, the ends of the relevant zones, and other information.

[151] In some embodiments the units 9, when initially switched OFF via button 86, first have processor 14 perform a shutdown routine, where part of the routine includes uploading the most recent set-up information held on unit 9 for storage and backup in database 95. In other embodiments unit 9, when initially switched ON via button 86, first has processor 14 perform an initialisation routine, where part of the routine includes downloading from network 93 the most recent set-up information held on database 95.

[152] In other embodiments a different number of units 9 are used, whilst in further embodiments facility 92 is spread over more than one continuous site.

[153] In some embodiments, one or more of units 9 include a unique identifier and a GPS module for providing a position indicator. When processor 14 generates an alert signal, that signal includes data unique identifier and the position indicator. Server 96 is responsive to the alert signal for providing handset 98 with not only a warning signal, but also some location information or direction information. Handset 98 processes and presents this information to the carer to facilitate their passage to the relevant unit 9.

[154] The above embodiments are described primarily with reference to monitoring an individual who is supported in a bed or chair, where the individual is in a nursing home or hospital ward. The embodiments are also applicable for use in "home care" situations such as where elderly individuals continue to live in a home environment either on their own or with others such as relatives or family. In these embodiments, the alarm is able to be provided either within the home and/or externally to a cellular telephone of one or more family members and/or to an external party such as an agency that provides emergency assistance or care assistance.

[155] Another specific application of the embodiments of the invention is to patient beds for use in pre and post-operation rooms where patients are respectively placed prior to and following from surgery in an operating theatre. The patients often have to wait in these rooms for a considerable time and require some form of supervision for it is important that the patients remain at rest in the respective beds. The use of an embodiment of the invention to aid in that supervision is able to reduce the reliance upon constant human surveillance of the patients.

[156] Reference is now made to Figure 1OA where there is illustrated schematically a cross section of mattress 29 where corresponding features are denoted by corresponding reference numerals. It has been found by the inventor that to reduce the risk of false alarms being provided by the monitoring unit of the invention the fields should be spaced apart from the support surface such as surface 35. More particularly, there is illustrated a first generally rectangular placement zone 101 that has a height of about 200 mm and a width of about 150 mm. This zone is laterally outwardly from side 33 by about 100 mm and extends upwardly from the plane 102 of surface 35. It has been discovered by the inventor that, for use with an individual's regular bed, the placement of field 11 within zone 101 provides for high levels of reliable operation and low levels of false alarms. While placement of field 11 outside of zone

101 does not provide as ideal operating performance, it is in some embodiments an acceptable compromise.

[157] In the preferred embodiments, the field provided by unit 9 (or a like unit) all falls within the bounds of zone 101 or zone 103, as the case may be. This is inclusive of any spread of the field as the distance from unit 9 increases. In other embodiments, however, not all of the "spread" field will fall within zone 101 or 103.

[158] The placement of the field, as mentioned above, allows the individual being monitored with some freedom of movement within zone to allow normally expected activities to occur without an alarm signal being generated, but to detect correctly when the individual is actually attempting to move from surface 35 and into room 5. For example, it is not unusual for a patient when sleeping, particularly in warmer weather, to allow a foot to hang over the edge of surface 35 and adjacent to side 33 of mattress 29. Moreover, it is also not unusual for a patient while adjusting their position on surface 35 to move any sheets, blankets or other coverings along or over side 33 and 34.

[159] There are beds that include a plurality of adjacent movable platforms that are able to be collectively or individually controlled by a carer or a patient to incline with respect to each other. The control is often by way of a hand controller that selectively drives electric motors or other similar drive means to move the platforms relative to each other and the remainder of the bed. The mattress is mounted across the platforms and is deformed from a generally flat configuration as the platforms move relative to each other. Usually, there is a central part of the mattress that remains relatively stationary during this movement, and it is that part where plane

102 is taken.

[160] In other embodiments, such as specialist beds for pre and post-operations rooms, field 11 is preferentially disposed within zone 103, which is also illustrated in Figure 1OA. This zone is the same size as and directly underlies zone 101. While adequate performance will be obtained with field 11 in zone 101, it is often desirable to not have any instrumentation blocking access to the patient and, hence, the relevant transmitter is placed below surface 35 such that field 11 falls within zone 103.

[161] Some beds include one or more bedrails. It will be appreciated by those skilled in the art that bedrails, such as those in use in hospital wards, extend longitudinally across a respective gateway, and are in some cases movable between a storage (for example lowered or collapsed) configuration and an operative (for example raised) configuration. When in the raised configuration the bedrail is intended to provide a barrier to movement of the patient through the gateway. In some cases, when in a lowered configuration, the bedrail is nested out of the way of the patient or use, and access though the gateway is relatively free.

[162] Some embodiments of the present invention provide monitoring systems specifically adapted for use in situations where bedrails are present. Some such embodiments include a monitoring unit similar to those discussed above in conjunction with other embodiments, although the positioning of the transmitter is varied to account for the presence of a raised bedrail. For example, a monitoring unit may include a transmitter that is mounted to a support frame that, in turn, is mounted to the bed head or a wall or other surface adjacent to the bed head. The transmitter defines a field that extends parallel with the top of the bedrail but which is about 100 mm above the bedrail, or slightly less than less than about 100 mm above the bedrail. In some such embodiments, the field is also offset laterally and inwardly from the bed rail by about 50 mm. Inward lateral offset is particularly useful where a field is actively monitored at a lower portion of the bed (i.e. towards a patient's legs and feet). In such an embodiment, a patient is able to reach out of bed with his/her arms without necessarily causing an alarm. However, if the patient sufficiently lifts his/her legs towards the bedrail, an alarm signal is generated. Due to the positioning of the transmitter, such an alarm signal is beneficially initiated prior to the patient's legs actually moving over the bedrail. In other embodiments, the field is offset laterally and outwardly from the bed rail by about 100 mm.

[163] In some embodiments, a monitoring unit is configured such that the transmitter is movably mounted to the support frame to allow configuration for applications with and without raised bedrails. That is, the unit is mounted to a bed (or relative to a bed) by way of the support frame, and the transmitter is subsequently able to be moved between a first position where it is configured to operate with a raised bedrail (as generally discussed in the preceding paragraph) and a second position where it is configured to operate in absence of a bedrail (generally as discussed further above). Some exemplary embodiments in this vein are discussed below.

[164] Figures 11 and 12 illustrate a monitoring system 200 for a bed 201. Bed 201 is generally the same as bed 4 as described in the examples of Figures 1-6, although reference numerals denoting detailed features have presently been omitted for the sake of clarity. Central to the present embodiment, bed 201 includes a bedrail 202, which is movable between a stored configuration (shown in Figure 11) and an operative configuration (shown in Figure 12). The manner of movement between the stored and operative configurations varies between embodiments, optionally including rotation about a horizontal axis parallel with the side of the bed, upward sliding, or attachment/detachment.

[165] System 200 includes a monitoring unit 210. Unit 210 is mounted to bed 201 by way of a support frame 211. A transmitter housing 212 is mo vably mounted with respect to frame 211. Transmitter housing 212 includes a generally rectangular window 213 that is substantially transparent to infrared radiation, and contains a transmitter for providing an infrared field, and detectors for monitoring that field, generally as discussed further above.

[166] The movable mounting of housing 212 to support frame 211 allows the housing to be moved between the configurations illustrated in Figures 11 and 12, which is ideally performed such that the transmitter is positioned to provide a field suitable for applications with and without bedrails. Specifically, the present embodiment allows for the unit to be position in accordance with a first and second configuration.

[167] In the first configuration, shown in Figure 11, the transmitter is disposed upwardly and laterally outwardly from the mattress of bed 201. The precise positioning of the transmitter when the unit is provided in the first configuration is optionally as considered further above, for example such that transmitter generates a field at about 150 mm above the mattress and about 150 mm transversely outwards from and generally parallel with the side of the mattress or bed. It will be appreciated that other modes of positioning are implemented for further embodiments.

[168] In the second configuration, shown in Figure 12, the transmitter is disposed upwardly and laterally inwardly from the mattress of bed 201, such that the transmitter is disposed upwardly and laterally inwardly from the top 215 of bedrail 202. In some embodiments, this defines a field that extends parallel with the top of the bedrail but which is about 100 mm above the bedrail, or slightly less than less than about 100 mm above the bedrail (in many conventional situations this positions the field about 400 mm above the top of the mattress). In some -2S- embodiments the field is also offset laterally and inwardly from the bedrail by about 50 mm. In some embodiments a side of housing 212 is substantially aligned with the side of the mattress.

[169] In some embodiments, movement between the first and second configurations includes rotation and/or translation. The manner in which the physical device is configured to allow such movement varies between embodiments. In this embodiment, the rotation of the transmitter is through just over 90°, while in other embodiments alternative rotations are used, typically between about 70° and 120°. hi still further embodiments, use is made of translations or other movements to progress the transmitter to the lowered position.

[170] Figures 13 A to 13C illustrate, in more detail, a monitoring unit that is particularly adapted for bedrail applications. In particular, a monitoring unit 250 includes a support member 251, which allows mounting of unit 250 to a bed head or the like, for example by way of a clamp. In some embodiments member 251 is integrally formed with a component of a bed. An arm 252 is at its proximal end movably mounted to member 251, and at its distal end fixedly mounted to a transmitter housing 253. Transmitter housing 253 includes a generally rectangular window 254 that is substantially transparent to infrared radiation. The housing additionally contains a transmitter for providing an infrared field, and detectors for monitoring that field, generally as discussed further above.

[171] In overview, arm 252 is movable between two stable configurations, shown in Figures 13 A and 13D. The configuration of Figure 13 A is particularly appropriate for applications without an operative bedrail (for example where a bedrail is stored or non-existent). The configuration of Figure 12D is particularly appropriate for applications where a bedrail is present in an operative configuration. In this manner, unit 250 is generally suitable to take on the role of unit 210 of Figures 11 and 12.

[ 172] In the configuration of Figure 13 A, arm 252 is mounted to member 251 by way of a pair of hinge pins 260 and 261. In the manner illustrated, only the heads of these pins are visible. It will nevertheless be appreciated that the pins are each movable within respective slots 262 and 263.

[173] In the configuration of Figure 13, the relative positioning of pins 260 and 261 within respective slots 262 and 263 prevents rotation of arm 252, thereby to rotationally lock the arm in place. However, by sliding arm 252 towards housing 251, as shown in Figure 13, rotation is permitted given that pin 261 is able to escape slot 263 via an opening 264. During this rotation, pin 260 remains within its respective slot 262. [174] Rotation continues until pin 261 is received by an opening 265 of a further slot 266, as best shown in Figure 13 C. Arm 252 is then slid in the opposite direction to that which it was slid prior to the rotation, thereby to lock the arm in the configuration shown in Figure 13 D, and hence configure unit 252 for application with an operative bedrail. The process is reversible to return the unit to the configuration of Figure 13 A, for example to re-configure the device for operation in conjunction with a lowered bedrail.

[175] As noted, the example of Figures 13 A to 13D is provided for the sake of illustration only. It will be appreciated that various details that may be present in physical implementations have been omitted for the sake of simplicity. For instance, additional locating formations are optionally provided within slots 262, 263 and/or 266 thereby to increase the stability of the configurations shown in Figures 13 A and 13D. In some cases, slot 266 is omitted in favour of another means for maintaining the arm in the configuration of Figure 13D.

[176] In another embodiment, a single arc-shaped slot provides the functionality of slots 263 and 266. Furthermore, in some embodiments alternate locking devices, such as thumbwheels, are provided so as to do away with the need to slidably progress the arm in and out of positions where rotation is inhibited.

[177] In other embodiments, a monitoring unit is mounted directly to the bedrail and is movable with the bedrail as it progressed between the raised and lowered configurations. It will be appreciated by those skilled in the art, form with the benefit of the teaching herein, that the monitoring unit for mounting to a bedrail has to be configured robustly to accommodate the greater forces it will likely have to endure during normal use.

[178] Figure 14 illustrates a support member 280 according to one embodiment, shown by way of an exploded view. Member 280 is specifically adapted for use in bedrail application, such as those described in relation to Figures 11 to 13D. That is, member 280 allows a transmitter to be located in two positions, being for bedrail and πon-bedrail use respectively.

[ 179] Support member 280 includes three major components: a clamp body 281 , a clamp wrap 282, and a mounting bracket 283.

[180] In overview, clamp body 283 allows support member 280 to be mounted to a bed head or the like. In the orientation shown, member 280 is positioned for mounting to the left side of a vertically extending bed head (as viewed from the foot of the bed). However, member 280 is equally well adapted for mounting to the right side of a vertically extending bed head (as viewed from the foot of the bed) by flipping member 280 about a horizontal axis generally parallel with arrow 289.

[181] Clamp body 281 includes a clamp member 284 that extends (or retracts) under the influence of handle 285 into a clamp area 286. In practice, the clamp body is positioned at the desired height on a vertically extending bed head such that the bed head is received in area 286, and clamped in position by turning handle 285 in a clockwise direction until the force exerted by clamp member 284 is adequate to support the weight of member 280 and a transmitter housing supported by member 280.

[182] Clamp wrap 282 is provided primarily for aesthetic purposes, although it will be appreciated that is serves functional purposes as well, some of which being discussed further below.

[183] A transmitter housing, such as a transmitter housing described in respect of previous embodiments, is mountable to bracket 283. In this instance, the transmitter housing is mounted to the bracket by way of a stud 288, which in the present embodiment is an M8 stud, allowing the housing to be secured by way of a nyloc nut and nylon washer. The transmitter housing is mounted such that the beam extends generally in the direction shown by arrow 289, which is parallel with the longitudinal axis of bracket 283. This presently places the housing in a horizontal configuration, appropriate for use without a bedrail. It will be appreciated that in the illustrated orientation the transmitter would be positioned for monitoring of the left side of the bed (as viewed from the foot of the bed). However, by flipping member 280 about a horizontal axis generally parallel with arrow 289, member 280 could be just as easily mounted to the other side of a bed head such that the transmitter would be positioned for monitoring of the right side of the bed (as viewed from the foot of the bed) .

[184] Bracket 283 is movably mounted to body 281 by way ofa pair of hinge pins 290. These extend through apertures 291 in bracket 283, allowing rotational movement to allow horizontal and vertical positioning ofa transmitter housing. Apertures 291 are also elongate so as to permit some sliding movement. Bracket 283 is stable in two positions. In one position, suited for non- bedrail applications, bracket 283 is slid inwardly with respect to body 281, and held in place by a rare earth magnet 292 (which is in this embodiment located in or adjacent body 281 and held in place by wrap 282). In this position, pins 293 abut in recesses 294 to restrict rotation of the bracket. Bracket 283 is then able to be outwardly slid (by way ofa force exceeding that attraction provided by magnet 292), and subsequently rotated. Upon rotation upwardly and inwardly through 90 degrees, the bracket is able to settle in the other stable position under the influence of gravity. In this position the transmitter housing would be vertical, and appropriately positioned for bedrail applications. Precise transmitter positions for bedrail and non-bedrail applications are preferably as discussed above in relation to previous examples.

[185] Although embodiments considered above generally assume a monitoring unit that is mounted to a bed, or relative to a bed, as an aftermarket accessory, in some embodiments a monitoring unit in integrated with a component of a bed. For example, in some embodiments a monitoring unit is integrated into a bed head. Such an embodiment is schematically illustrated in Figure 15. In particular, a bed assembly 300 includes a base 301, mattress 302, and bed head 303. Bed head 303 is partially hollow, thereby to contain a monitoring system, such as one of the monitoring systems described above. Such a monitoring system includes an infrared transmitter and one or more detectors, these being communicable with the outside world via a window 304 formed in bed head 303. In the illustrated example windows 304 are provided at each side of the bed head, thereby to allow for the generation of fields for each side of the bed (optionally being about 400 mm above the top surface 305 of mattress 302 and about 50 mm transversely inward from and generally parallel with side 306 of mattress 302). It will be appreciated that this is particularly appropriate for bedrail applications. However, it will also be appreciated that an alternate arrangement is readily provided for non-bedrail applications, based on field positioning information provided above.

[186] In some embodiments (not shown) an integral monitoring system is adjustable for bedrail and non-bedrail applications. In some such embodiments two windows 304 are provided for each transmitter, these corresponding to appropriate locations for the provision of fields for bedrail and non-bedrail applications.

[187] In some embodiments, rather than integrating a monitoring unit with a bed head, a bed head is manufactured with receiving formations that receive and maintain respective monitoring units. For example, a receiving formation is provided at the rear of a bed head, just behind a window 304, such that an appropriately sized monitoring unit is able to be inserted for operation as discussed herein.

[188] Reference is now made to Figure 1OB, whish provides a view similar to that of Figure 1OA, but is specifically directed towards bedrail applications. Figure 1OB illustrates schematically a cross section of mattress 29 where corresponding features are denoted by corresponding reference numerals. A bedrail 110 is also shown, this being provided in an -33- operative position. The bedrail has a height above the surface 35 of mattress 29 of A mm. The value of A varies between embodiments, depending on the nature of bedrail present. Bedrails typically range in height from between 100 mm and 300 mm, although there are exceptions to this generalisation. In some cases a bedrail also extends below surface 35, although that is ignored for the present purposes. Bedrail 110 is also is spaced from side 33 of the mattress by a dimension "B mm). This dimension is often in the order of 50 mm. However, there are instances where dimension B is approximately zero. Indeed, in some cases dimension B is negative (i.e. where a bedrail is inwardly offset from the side of the mattress).

[189] In bedrail applications, it has been found by the inventor that to reduce the risk of false alarms being provided by the monitoring unit of the invention the fields should be spaced apart from the support surface such as surface 35. More particularly, there is illustrated a generally rectangular placement zone 111 that has a height of about 200 mm and a width of about 200 mm (or greater than 200 mm depending of the width of bedrail 110).

[190] Zone 111 is upwardly offset from surface 35 by about A mm, although in some embodiments it is upwardly offset from surface 35 by about (A + 50) mm or (A + 100) mm, so as to allow a patient to reach out of bed to some extent. Zone 111 extends between a laterally inward offset from bedrail 110 of about 100 mm and a laterally outward offset from bedrail 110 of about 100 mm. In some embodiments, only one of a lateral inward or laterally outward offset is considered. It has been discovered by the inventor that, for use in bedrail applications, the placement of field 11 within zone 111 provides for high levels of reliable operation and low levels of false alarms. While placement of field 11 outside of zone 111 does not provide as ideal operating performance, it is in some embodiments an acceptable compromise.

[191] In the preferred embodiments, the field provided by unit 9 (or a like unit) all falls within the bounds of zone 111. This is inclusive of any spread of the field as the distance from unit 9 increases. In other embodiments, however, not all of the "spread" field will fall within zone 111.

[192] The placement of the field, as mentioned above, allows the individual being monitored with some freedom of movement within zone to allow normally expected activities to occur without an alarm signal being generated, but to detect correctly when the individual is actually attempting to move from surface 35 and into room 5.

[193] In some embodiments, a unit 9 is movable for use in both bedrail and non-bedrail applications, as discussed above. In such embodiments, the field provided by unit 9 (or a like unit) all optionally falls within the bounds of either zone 110 or zone 111. This is inclusive of any spread of the field as the distance from unit 9 increases. In other embodiments, however, not all of the "spread" field will fall within these zones.

[194] Unless specifically stated otherwise, as apparent from the following discussions, it is appreciated that throughout the specification discussions utilizing terms such as "processing", "processing system", "computing", "calculating", "determining", "analysing" or the like, refer to the action and/or processes of a computer or computing system, or similar electronic computing device, that manipulate and/or transform data represented as physical, such as electronic, quantities into other data similarly represented as physical quantities.

[195] In a similar manner, the term "processor" may refer to any device or portion of a device that processes electronic data, for example, from registers and/or memory to transform that electronic data into other electronic data that, for example, may be stored in registers and/or memory. A "computer" or a "computing machine" or a "computing platform" may include one or more processors.

[196] The methodologies described herein are, in one embodiment, performable by one or more processors that accept computer-readable (also called machine-readable) code containing a set of instructions that when executed by one or more of the processors carry out at least one of the methods described herein. Any processor capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken are included. Thus, one example is a typical processing system that includes one or more processors. Each processor may include one or more of a CPU, a graphics processing unit and a programmable DSP unit. The processing system further may include a memory subsystem including main RAM and/or a static RAM and/or ROM. A bus subsystem may be included for communicating between the components. The processing system further may be a distributed processing system with processors coupled by a network. If the processing system requires a display, such a display may be included, for example, a liquid crystal display (LCD) or a cathode ray tube (CRT) display. If manual data entry is required, the processing system also includes an input device such as one or more of an alphanumeric input unit such as a keyboard, a pointing control device such as a mouse and so forth. The term "memory unit" or "memory" as used herein, if clear from the context and unless explicitly stated otherwise, also encompasses a storage system such as a disk drive unit. The processing system in some configurations may include a sound output device and a network interface device, for example. The memory subsystem thus includes a computer-readable earner medium that carries computer-readable code (for example, software) including a set of instructions to cause performing, when executed by one or more processors, one of more of the methods described herein. Note that when the method includes several elements, for example, several steps, no ordering of such elements is implied, unless specifically stated. The software may reside in the hard disk, or may also reside, completely or at least partially, within the RAM and/or within the processor during execution thereof by the computer system. Thus, the memory and the processor also constitute computer-readable carrier medium carrying computer-readable code.

[ 197] Furthermore, a computer-readable carrier medium may form, or be includes in a computer program product.

[198] In alternative embodiments, the one or more processors operate as a standalone device or may be connected, for example, by being networked to another processor or other processors. In such a networked deployment, the one or more processors may operate in the capacity of a server or a user machine in a server-user network environment, or as a peer machine in a peer- to-peer or distributed network environment. The one or more processors may form a personal computer (PC)₅ a tablet PC, a set-top box (STB), a Personal Digital Assistant (PDA), a cellular telephone, a web appliance, a network router, switch or bridge, or any machine capable of executing a set of instructions (sequential or otherwise) that specify actions to be taken by that machine.

[199] Where a figure only illustrates a single processor and/or a single memory that carries the computer-readable code, those in the art will understand that many of the components described above are included, but not explicitly shown or described to reduce the risk of obscuring the inventive aspect. For example, while only a single machine is illustrated, the term "machine" shall also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein.

[200] Thus, one embodiment of each of the methods described herein is in the form of a computer-readable carrier medium carrying a set of instructions - for example, a computer program - that are for execution on one or more processors. For example, the one or more processors that are part of an apparatus for determining the award of a set of prizes. Thus, as will be appreciated by those skilled in the art, embodiments of the present invention may be embodied as a method, an apparatus such as a special purpose apparatus, an apparatus such as a data processing system, or a computer-readable carrier medium, for example, a computer program product. The computer-readable carrier medium carries computer readable code including a set of instructions that when executed on one or more processors cause a processor or processors to implement a method. Accordingly, aspects of the present invention may take the form of a method, an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of carrier medium (for example, a computer program product on a computer- readable storage medium) carrying computer-readable program code embodied in the medium.

[201] The software may further be transmitted or received over a network via a network interface device. While the carrier medium is shown in an exemplary embodiment to be a single medium, the term "carrier medium" should be taken to include a single medium or multiple media (for example, a centralized or distributed database and/or associated caches and servers) that store the one or more sets of instructions. The term "carrier medium" shall also be taken to include any medium that is capable of storing, encoding or carrying a set of instructions for execution by one or more of the processors and that cause the one or more processors to perform any one or more of the methodologies of the present invention. A carrier medium may take many forms, including but not limited to, non- volatile media, volatile media and transmission media. Non- volatile media includes, for example, optical, magnetic disks and magneto-optical disks. Volatile media includes dynamic memory, such as main memory. Transmission media includes coaxial cables, copper wire and fibre optics, including the wires that comprise a bus subsystem. Transmission media also may also take the form of acoustic or light waves, such as those generated during radio wave and infrared data communications. For example, the term "carrier medium" shall accordingly be taken to included, but not be limited to, solid-state memories, a computer product embodied in optical and magnetic media, a medium bearing a propagated signal detectable by at least one processor of one or more processors and representing a set of instructions that when executed implement a method, a carrier wave bearing a propagated signal detectable by at least one processor of the one or more processors and representing the set of instructions a propagated signal and representing the set of instructions and a transmission medium in a network bearing a propagated signal detectable by at least one processor of the one or more processors and representing the set of instructions.

[202] It will be understood that the steps of methods discussed are performed in one embodiment by an appropriate processor (or processors) of a processing - that is, a computer - system executing instructions - that is, computer-readable code - stored in storage. It will also be understood that the invention is not limited to any particular implementation or programming technique and that the invention may be implemented using any appropriate techniques for implementing the functionality described herein. The invention is not limited to any particular programming language or operating system.

[203] Reference throughout this specification to "one embodiment" or "an embodiment" means that a particular feature, structure or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, appearances of the phrases "in one embodiment" or "in an embodiment" in various places throughout this specification are not necessarily all referring to the same embodiment, but may. Furthermore, the particular features, structures or characteristics may be combined in any suitable manner, as would be apparent to one of ordinary skill in the art from this disclosure, in one or more embodiments.

[204] Similarly it should be appreciated that in the above description of exemplary embodiments of the invention, various features of the invention are sometimes grouped together in a single embodiment, figure, or description thereof for the purpose of streamlining the disclosure and aiding in the understanding of one or more of the various inventive aspects. This method of disclosure, however, is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects He in less than all features of a single foregoing disclosed embodiment. Thus, the claims following the Detailed Description are hereby expressly incorporated into this Detailed Description, with each claim standing on its own as a separate embodiment of this invention.

[205] Furthermore, while some embodiments described herein include some but not other features included in other embodiments, combinations of features of different embodiments are meant to be within the scope of the invention and form different embodiments, as would be understood by those in the art. For example, in the following claims, any of the claimed embodiments can be used in any combination as would be understood by a skilled addressee given the benefit of the teaching herein.

[206] Furthermore, some of the embodiments are described herein as a method or combination of elements of a method that can be implemented by a processor of a computer system or by other means of carrying out the function. Thus, a processor with the necessary instructions for carrying out such a method or element of a method forms a means for carrying out the method or element of a method. Furthermore, an element described herein of an apparatus or system embodiment is an example of a means for carrying out the function performed by the element for the purpose of carrying out the invention.

[207] In the description provided herein, numerous specific details are set forth. However, it is understood that embodiments of the invention may be practiced without these specific details. In other instances, well-known methods, structures and techniques have not been shown in detail in order not to obscure an understanding of this description.

[208] As used herein, unless otherwise specified the use of the ordinal adjectives "first", "second", "third", etc., to describe a common object, merely indicate that different instances of like objects are being referred to and are not intended to imply that the objects so described must be in a given sequence, either temporally, spatially, in ranking, or in any other manner.

[209] In the claims below and the description herein, any one of the terms comprising, comprised of or which comprises is an open term that means including at least the elements/features that follow, but not excluding others. Thus, the term comprising, when used in the claims, should not be interpreted as being limitative to the means or elements or steps listed thereafter. For example, the scope of the expression a device comprising A and B should not be limited to devices consisting only of elements A and B. Any one of the terms including or which includes or that includes as used herein is also an open term that also means including at least the elements/features that follow the term, but not excluding others. Thus, including is synonymous with and means comprising.

[210] Thus, while there has been described what are believed to be the preferred embodiments of the invention, those skilled in the art will recognize that other and further modifications may be made thereto without departing from the spirit of the invention and it is intended to claim all such changes and modifications as fall within the scope of the invention. For example, any formulas given above are merely representative of procedures that may be used. Functionality may be added or deleted from the block diagrams and operations may be interchanged among functional blocks. Steps may be added or deleted to methods described within the scope of the present invention.

[211] Although the invention has been described with reference to specific examples, it will be appreciated by those skilled in the art that the invention is be embodied in many other forms.

Claims

THE CLAIMS DEFINING THE INVENTION ARE AS FOLLOWS:

1. A monitoring system for a bed, the system being configured to generate an alert signal responsive to a user attempting to exit the bed, and configured not to generate an alert signal responsive to a user approaching the bed.

2. A monitoring system according to claim 1 wherein the system recognises a user approaching the bed by the breakage of an outer region of a monitored field prior to the breakage of an inner region of the monitored field.

3. A monitoring system for indicating movement of an individual through a gateway between a first zone in which the individual is located and a second zone, the system including: a transmitter for providing a field that extends across at least some of the gateway; a first detector for generating, in response to the individual entering the field, a movement signal indicative of movement of the individual through the gateway; a second detector for generating a reference signal in response to a body being disposed within a third zone adjacent to the field; and an alarm that is responsive to one or both of the movement signal and the reference signal for selectively generating an alert signal.

4. A system of according to claim 3 wherein the third zone extends across at least some of the gateway.

5. A system according to claim 4 wherein the third zone and the field collectively extend across the gateway.

6. A system according to claim 5 wherein the third zone and the field overlap across the gateway.

7. A system according to claim 4 or claim 5 wherein the gateway extends between two spaced apart posts.

8. A system according to claim 7 wherein the first zone includes a boundary that is defined at least in part by a support surface for the individual that extends between the posts, and the second zone surrounds the support surface.

9. A system according to claim 8 wherein the gateway extends along part of the boundary.

10. A system according to claim 8 wherein the boundary has a substantially linear portion and the gateway extends along the portion.

11. A system according to claim 8 wherein the boundary includes a plurality of substantially linear portions and the gateway extends along one of the linear portions.

12. A system according to claim 11 wherein the boundary is substantially rectangular.

13. A system according to claim 8 wherein the posts define at least part of a bed head and a bed foot respectively.

14. A system according to claim 8 wherein the posts define at least part of respective opposed chair arms.

15. A system according to claim 8 wherein the third zone extends from a first end that is at or adjacent to one of the posts and terminates at a second end intermediate the posts, and the field extends from the second end to a third end at or adjacent to the other of the posts.

16. A system according to claim 15 wherein the second end is closer to the one of the posts than the other of the posts.

17. A system according to claim 16 wherein the distance between the first end and the second end is about half the distance between the second end and the third end.

18. A system according to any one of claims 15 to 17 wherein the first detector and the second detector are defined by a compound detector.

19. A system according to claim 18 wherein the compound detector is disposed at or adjacent to one of the posts.

20. A system according to claim 19 wherein the compound detector is mounted to one of the posts.

21. A system according to claim 20 wherein the alarm is responsive to the movement signal for generating the alert signal.

22. A system according to claim 21 wherein the alarm is responsive to the reference signal for preventing the generation of the alert signal.

23. A system according to claim 3 wherein the field and the third zone coextend across at least part of the gateway.

24. A system according to claim 23 wherein the field and the third zone are substantially co- terminus.

25. A system according to claim 23 or claim 24 wherein the third zone is disposed in the second zone.

26. A system according to any one of claims 3 or claims 23 to 25 wherein the third zone is immediately adjacent to the field.

27. A system according to claim 25 wherein the alarm is responsive to the movement signal for generating the alert signal.

28. A system according to claim 27 wherein the alarm is responsive to the reference signal for preventing the generation of the alert signal.

29. A system according to claim 3 wherein the field and the third zone coextend across at least part of the gateway.

30. A system according to claim 1 wherein the transmitter is movably mounted respect to a support member.

31. A system according to claim 30 wherein the transmitter is movable between a first position for indicating movement of the individual through the gateway and a second position for indicating movement of the individual through another gateway.

32. A method for indicating movement of an individual through a gateway between a first zone in which the individual is located and a second zone, the method including: providing a field that extends across at least some of the gateway; generating, in response to the individual entering the field, a movement signal indicative of movement of the individual through the gateway; generating a reference signal in response to a body being disposed within a third zone adjacent to the field; and being responsive to one or both of the movement signal and the reference signal for selectively generating an alert signal.

33. A monitoring system for indicating the presence of a body in a detection zone, the system including: a housing; a transmitter mounted to the housing for providing a field that defines the detection zone; a detector mounted to the housing for generating, in response to the body entering the field, a detection signal indicative of the presence of the body in the detection zone; a lockout control that extends from the housing and which is manually moveable between a lockout configuration and an operable configuration; and at least one monitor control that extends from the housing, wherein the monitor control is manually operable, when the lockout control is in the operable configuration, to selectively adjust one or more characteristics of the monitor.

34. A system according to claim 33 wherein the lockout control and the at least one monitor control are spaced apart from each other.

35. A system according to claim 33 or claim 34 wherein the at least one monitor control and the lockout control extend from the housing and away from each other.

36. A system according to any one of claims 33 to 35 wherein the housing includes a first surface from which the at least one monitor control extends and a second surface from which the lockout control extends.

37. A system according to claim 36 wherein the first and second surfaces define part of continuous surface.

38. A system according to claim 36 wherein the first surface is spaced apart from the second surface.

39. A system according to claim 36 wherein the first surface is adjacent to the second surface.

) 40. A system according to claim 36 wherein at least some of the first surface is inclined away from the second surface.

41. A system according to claim 36 wherein at least some of the first surface is opposite to the second surface.

42. A system according to claim 36 wherein the lockout control is biased toward the lockout configuration.

43. A system according to claim 33 wherein the transmitter is movably mounted respect to a support member.

44. A system according to claim 43 wherein the transmitter is movable between a first position for indicating the presence of a body in the detection zone and a second position for indicating the presence of a body in another detection zone.

45. A method for constructing a monitoring system for indicating the presence of a body in a detection zone, the method including: providing a housing; mounting a transmitter to the housing for providing a field that defines the detection zone; mounting a detector to the housing for generating, in response to the body entering the field, a detection signal indicative of the presence of the body in the detection zone; providing a lockout control that extends from the housing and which is manually moveable between a lockout configuration and an operable configuration; and providing at least one monitor control that extends from the housing, wherein the monitor control is manually operable, when the lockout control is in the operable configuration, to selectively adjust one or more characteristics of the monitor.

46. A monitoring system for indicating movement of individuals through respective gateways, the system including: a monitoring unit associated with each individual, each monitoring unit having:

47. A method for indicating movement of individuals through respective gateways, the system including: a monitoring unit associated with each individual, each monitoring unit having:

(a) a transmitter for providing a field that extends across at least some of the respective gateway;

48. A monitoring system for a bed, wherein the bed is configured to operate in a first mode in which a longitudinally extending bedrail hinders a patient from exiting the bed, and a second mode wherein the bedrail does not hinder the patient from exiting the bed, the system including: a support member mountable with respect to the bed; a transmitter for providing a field, the transmitter being supported by a transmitter housing that is movably mounted with respect to the support member; wherein transmitter housing is movable between a first position wherein field monitors a gateway through which the patient passes when exiting the bed as operated in the first mode, and a second position , wherein field monitors a second gateway through which the patient passes when exiting the bed as operated in the second mode.

49. A system according to claim 48 wherein the bed includes a mattress, and wherein in the first position the field is provided above and transversely inwards from the bedrail, and wherein in the second position the field is provided above and transversely outwards from and generally parallel with the side of the mattress.