AU738837B2

AU738837B2 - Method and device for waking people before the occurrence of REM-sleep within a short nap

Info

Publication number: AU738837B2
Application number: AU28855/97A
Authority: AU
Inventors: Karim Daghbouche
Original assignee: JETLOG CORP
Current assignee: JETLOG CORP
Priority date: 1996-04-06
Filing date: 1997-03-26
Publication date: 2001-09-27
Anticipated expiration: 2017-03-26
Also published as: AU2885597A; DE59702342D1; DE19614790C2; ATE196372T1; EP0838046A1; WO1997038359A1; DE19614790A1; JPH11508369A; EP0838046B1

Abstract

When it is impossible to overcome fatigue with the appropriate amount of sleep, an individual's concentration and performance are restricted according to the extent of their fatigue. The object of the novel method and novel device is to prevent involuntarily occurring sleep by causing the tired user to experience a high degree of revitalization in a short amount of time thanks to sleep induced in an autonomously controlled manner and similarly induced waking. In order to overcome fatigue in a controlled manner, the waking time is made dependent on the muscle tone of an extremity, this muscle tone decreasing significantly at a moment which is considered favourable from the physical and mental aspects and is therefore used as a timer for a waking device. The novel method and the novel device are suitable for use in situations in which no time and no suitable place are available for conventional sleep but the extent of fatigue demands sleep.

Description

Method and device for waking people before the occurrence of REMsleep within a short nap Abstract When it is not possible to provide the appropriate amount of sleep to overcome fatigue, an individual's concentration and performance will be restricted according to the extent of the fatigue. The object of the novel method and novel device is to prevent sleep occurring involuntarily by ensuring that the tired individual experiences a high degree of revitalization in a short amount of time thanks to sleep induced in an individually controlled manner and similarly induced individually controlled waking. In order to overcome fatigue in a controlled manner, the time point of waking is made dependent on the muscle tension of a body extremity. The muscle tension decreases significantly at a point in time which is considered favorable from physical and mental viewpoints and is then used to control a waking device.

The novel method and the novel device are suitable for use in situations in which no time and no suitable place are available for conventional sleep but the extent of fatigue demands sleep nonetheless.

Description Application of the invention The invention relates to a method and device for waking people before the occurrence of REM-sleep within a short nap. The said device wakes up the sleeping person when a particular sleeping phase has been detected provided that an individually adjustable duration of sleep has been exceeded.

The aim of the invention is to improve the living conditions by increasing the effectiveness of sleep, in particular sleep undertaken during the daytime.

Present state of the art Methods to wake a sieeping person are known where the REM sleeping phase is detected using sensors and used to trigger awakening in order to simplify awakening and make it more pleasant (compare JP 01 212565 A).

Furthermore, in DE 42 09 336 Al, the cycle time of the REM sleeping phase is determined and the time point of awakening is arranged to coincide with a REM phase.

The sleeping phases are determined from physiological data such as eye movement, brain waves, pulse rate, respiratory rate, body or head temperature, body movement and/or the level of metabolism.

Methods and devices are known whereby, to ensure awakening is more pleasant, the REM sleeping phase is determined by detecting body movements using a vibration sensor located under the mattress of the bed (compare JP 59 023284 A).

Methods and devices are known which utilize the different waking and sleeping phases of the person.

They are used to control devices which coordinate the wake up signal of an interconnected alarm to coincide with the actual or calculated waking or sleeping phase of the person to be awakened (compare EP 0 496 196 Al).

This too involves measurement of body related data such as body temperature and/or body movements of the sleeping person and/or brain waves (EEG) signals.

Electromyographic methods and devices are known from the medical field of sleep physiology where measurement of the physiological signal of muscle tension is used to ensure that a sleeping person is only awakened in a light sleeping phase (NREM 1 and 2) (compare US 4 228 806). Since the muscle tension drops slightly when entering a deep sleeping phase (NREM 3 and US 4 228 806 proposes among other things that awakening of the person should be dependent on a slight drop of muscle tension, whereby the waking device is not yet triggered by the drop in muscle tension but, rather more, the awakening is delayed until the muscle tension rises again.

Devices and methods are not known which awaken a sleeping person from a particular sleeping phase as a result of to an absence corresponding drop of the muscle tension in a body's extremity.

Standard methods of sleep physiology measure the muscle tension using an electromyographic method (EMG). EMG is not used to detect the REM sleeping phase, although in this sleeping phase the muscle tension is practically zero compared to the waking state and all other sleeping phases. The explanation is that when reaching the REM sleeping phase, the EMG channel does not drop to zero but indicates instead the superimposed electrocardiogram signal (ECG) of to the pulse rate (compare e.g. Koella, Werner Die Physiologie des Schlafes: Eine Einfihrung; Fischer, Stuttgart, New York; 1988, p.28).

In accordance with the invention, the measurement of muscle tension is independent of body movements since the presence of muscle tension does not necessary imply body movement. In addition it is significant that the muscle tension drops to zero during the REM sleeping phase, whereby no body movements are possible in this sleeping phase except for occasional twitches. Furthermore, the correct waking time at the start of the REM phase can be determined unambiguously without complex technical measures, since with the exception of muscle tension none of the other physiological parameters such as pulse rate are measured due to their mutual interference; the wake up signal is arranged to occur at the exact point in time when muscle tension drops to zero.

Background of the invention The invention has the aim of improving the living conditions and performance of homo sapiens by ensuring a physical and mentally favorable process of sleep and in particular by awakening the person at a favorable point in time.

The invention has the aim of improving the concentration and performance of homo sapiens by ensuring a high degree of revitalization in a short amount of time without interrupting a physically or mentally favorable sleeping phase.

The invention has the aim of improving the utilization of favorable conditions of work, e.g. flexible working hours, and minimizing the negative effects of unfavorable conditions of work, e.g. long working hours, long on-call periods or shift work.

In addition the invention has the aim of satisfying safety aspects in private, public and professional life by preventing the person from falling asleep unintentionally. This is achieved by an individually controlled process of falling asleep and an individually controlled awakening.

Summary of the invention In view of the foregoing it is the primary object of the present invention to provide a device and method which ensures a high degree of revitalization through sleep in a short amount of time without needing to interrupt a physically or mentally favorable sleeping phase. This is achieved as follows with a device and series of steps as described in patent claims 1 and While the person is still awake, a body extremity is brought from a relaxed to a non-relaxed state in order to increase the muscle tension.

The muscle tension is measured by a sensor and causes the switch to go to position zero The muscle tension drops significantly when the sleeping person enters the REM sleeping phase.

The significant decrease of the muscle tension causes the body extremity to relax.

The relaxation of the body extremity causes the sensor to immediately go to the one state.

The one state of the switch triggers the wake up signal. Conversely, the wake up signal is inhibited when the switch state is zero The sleeping phase is thus dependent on the REM or NREM sleeping stages, whereby the duration of sleep is restricted to the NREM phase.

In one embodiment of the invention, the method is implemented in devices which are provided with sensors having two switching states which are positioned at a suitable distance to a body extremity a finger) and which are able to output a wake up signal, for example by causing a mobile telephone to ring.

The invention is based on the fact that significant differences in the muscle tension can be used to determine the sleeping phase (REM or NREM), since the muscle tension is practically zero during the REM phase and the latter thus differs significantly from the NREM phase. In addition, the invention is based on the fact that the REM phase starts fairly quickly during the sleeping process of an average healthy homo sapiens, in particular when sleeping during the day and because a sufficient number of sleeping phases have been experienced for physical and mental revitalization when the first REM phase starts.

The invention has a practical application since in every society, particularly in highly technical societies, situations occur where sleep is necessary to maintain performance and concentration after the onset of tiredness, but this sleep cannot take place for personal or social reasons or for reasons connected with work. This results in a reduction of performance and concentration of the person and thus to reduced productivity and a reduction in safety, particularly in professional life.

The invention satisfies the need for sleep in such situations since it allows the tired homo sapiens a period of sleep which is sufficiently long in duration for the degree of fatigue but short enough to satisfy the respective situation, this being achieved with a method and device which has a low degree of technical complexity, low weight and small external dimensions and while ensuring user-friendliness and reliability in operation.

Example of the invention To illustrate the invention one embodiment of the invention will now be discussed in more detail.

Reference will be made to figures 1 and 2 which show schematic diagrams of a device which implements the method.

As shown in figures 1 and 2, a device which implements the method of awakening a sleeping person during a particular sleeping phase consists of a sensor with two switching states (2a 2b), a unit to output an alarm signal (4a 4b), and a body (3a 3b) to integrate the sensor with two switching states and the alarm unit.

For reasons of simplicity, mechanical or electrical sources of energy and mechanical or electrical connections/switches between the sensor with the two switching states and the alarm unit have not been shown in the figures.

In the first stage, a body extremity (la) causes the sensor with two switching states to attain a switching state (2a) which inhibits the alarm unit (4a) (Figure 1).

Provided that the sleeping person is sleeping in the NREM phase, muscle tension keeps the body extremity in this position, preventing the alarm from being triggered (Figure 1).

In the second step, the sleeping person reaches the REM phase, causing the muscle tension to drop to such an extent that the body extremity of the sleeping person goes to the relaxed position (1 b), thereby causing the sensor with the two switching states to immediately switch to another position (2b) and thus trigger the alarm unit to output an alarm signal (4b) (Figure 2).

The alarm signal can be tactile, electrical, optical or preferentially use an acoustic signal.

The novel device and the novel method to awaken a sleeping person from a particular sleeping phase can be used in any body position and thus in a wide range of situations, e.g. sleeping while seated.

EDITORIAL NOTE FOR APPLICATION NO. 28855/97 THE CLAIMS PAGE IS NUMBERED PAGE 1

AND

THE FOLLOWING DRAWING PAGE IS NUMBERED PAGE 6

Claims

1. Method for waking people before the occurrence of REM-sleep within a short nap, whereby sensor signals are utilized to detect the appropriate time point of awakening, whereby due to this utilization the waking stimulation will occur, wherein the mentioned utilization contains the muscle tension's drop as sensor signal.

2. A method of claim 1, wherein the mentioned, the drop of the muscle tension as sensor signals containing utilization, is determined through muscle tension of the muscle tension of a body extremity.

3. Method of claim 2, wherein muscle tension is determined from a finger.

4. Method of claim 1, wherein the waking signal consists of a tactile, electric, optic, or acoustic signal.

Device to implement the method of claim 1, by means containing a sensor for a method for waking people before the occurrence of REM-sleep within a short nap, whose signals are transferred to a utilization unit as well to an alarm unit to initiate the waking stimulus, wherein the mentioned utilization unit contains a switch who receives the drop of the muscle tension as sensor signal and who triggers the alarm unit by this switch.

6. Device to claim 5, wherein the alarm unit is triggered by a mechanical or electromechanical switch.

7. Device to claim 5, wherein the alarm unit is triggered by an electrical or electronic switch.

8. Device to claim 5, wherein a photoelectric sensor is used to detect the muscle tension.