WO2005064311A1

WO2005064311A1 - Measuring skin deflection

Info

Publication number: WO2005064311A1
Application number: PCT/GB2004/005403
Authority: WO
Inventors: Eric Abel; Robin Christopher Brodie
Original assignee: University Court Of The University Of Dundee
Priority date: 2003-12-27
Filing date: 2004-12-24
Publication date: 2005-07-14
Also published as: GB0330069D0

Abstract

The present invention relates to apparatus for measuring skin deflection and to a corresponding method. In particular, but not exclusively, the present invention relates to apparatus for measuring skin deflection where a torsional load is applied to the skin, and to a corresponding method.

Description

MEASURING SKIN DEFLECTION The present invention relates to apparatus for measuring skin deflection and to a corresponding method. In particular, but not exclusively, the present invention relates to apparatus for measuring skin deflection where a torsional load is applied to the skin, and to a corresponding method. Scleroderma is a connective tissue disease which causes the skin to thicken and tighten as the disease progresses. This is caused by a tethering of the skin to underlying structures such as subcutaneous fat, and prevents free movement of the skin at surface, reducing skin elasticity. One proposed method for isolating and assessing scleroderma skin is disclosed in the paper "Scleroderma skin scoring method" by Kalaleh MB, which involves manual palpation and visual inspection of the skin using a skin score system. However, this method is only semi- quantitative and is highly susceptible to observer bias, such that results obtained using this method are often inaccurate and unreliable. Numerous-- alternative quantitative techniques have been proposed to investigate the mechanical properties of skin in vivo . These proposals include techniques for assessment of scleroderma by torsional skin testing, where the skin is loaded by an applied torsional load and the resulting angular displacement is measured, such as disclosed in the papers "Scleroderma by non- invasive techniques", Kalis B et al and "Scleroderma: torsional stiffness re-visited" by Knight L.R et al . In the paper by Knight L.R et al , a device is disclosed comprising a fixed frame and spindle turned by a free weight to drive a loading shaft, which turns the skin.

A final displacement is read off a scale on the frame after a given time. The papers "In vivo measurement of the stratum corneum elasticity" by De Rigal J et al and "Influence of ageing on the in vivo extensibility of human skin at a low stress" by Leveque J.L et al both disclose fixed frame devices using an in-line motor to impart a torsional load, connected to a rotation sensor for measurement of angular displacement. US patent 4,396,025, assigned to L'Oreal, discloses a hand-held device which measures angular skin displacement when a torsional load is applied by electric motor, and skin recovery when the torque is removed, by disengaging a measurement shaft from a drive motor. The results from tests carried out following these methods demonstrate that torsional loading of the skin is an effective method for assessing skin involvement in scleroderma. However, the proposed devices and methods suffer from disadvantages. For example, each of the above devices and methods suffer from general disadvantages with the result that none of the devices or methods have been adopted for skin assessment in scleroderma clinics. These include poor portability of proposed apparatus; lack of versitility for testing different skin sites; the need to hold a patient in a certain position for testing; time to set up the proposed apparatus; the length of time needed to analyse and compare results; the need for associated equipment such as an external power supply, computer and/or volt meter; and the likelihood of user error. A particular further disadvantage with all of the previously proposed devices and methods is that there are differences in the pressure force applied to the skin fro one test procedure to another, or indeed through out a particular test procedure. This affects results considerably and is a major cause of error. For example, considering US 4,396,025 in more detail referring to the attached prior art sketch Fig. A, the disclosed device D includes a casing C and a fixed shaft FS rotatably mounted in the casing C and driven by a motor M. The shaft FS is fixed relative to the casing C such that the pressure force exerted on skin S during a test is dependent upon the force F that an operator exerts on the patient through the device D, which can cause errors in measurements taken. It is amongst the objects of embodiments of the present invention to obviate or mitigate at least one of the foregoing disadvantages. It is also amongst the objects of embodiments of the present invention to provide a non-invasive torsional skin testing apparatus that can be used on a wide range of body sites for skin tests; to provide test results which are useful for comparisons in scleroderma; to provide an easily portable device; and to provide apparatus which allows tests to be performed quickly and the results easily understood for clinical use. According to a first aspect of the present invention, there is provided apparatus for measuring skin deflection comprising: a housing; a load member for applying a torsional load to the skin, the load member mounted for movement relative to the housing in a direction towards and away from the skin; and a device for measuring deflection of the skin in response to the applied torsional load. Mounting the load member for movement relative to the housing in this fashion facilitates independent movement of the load member separately from the housing. The load member may be telescopic. It will be understood that a torsional load applied to skin is a rotational force exerted over a defined surface area of the skin, generated by rotating the load member relative to the skin. Preferably, the load member is a floating load member. Thus the load member may be mounted for sliding movement relative to the housing in said direction towards and away from the skin. It will therefore be understood that, in use, the apparatus may be arranged such that the only pressure force exerted by the load member on the skin in a direction towards the skin is that due to the weight of the load member resting on the skin, under gravity. This pressure force may be independent of any force transmitted through the housing or any other part of the apparatus and thus the pressure force exerted on the measured skin is consistent, irrespective of the skin type, body location or other parameters/variables. The load member may be mounted for movement in said direction between opposite extreme positions, which may be retracted and extended positions. The apparatus may be adapted to exert an engagement or restraining force upon the load member, preferably through frictional contact, when in one or both of the extreme positions, preferably in the extended position. This may facilitate location of the load member adjacent the skin. Preferably, the load member is adapted to apply a substantially constant torsional load on the skin. The invention therefore offers advantages over prior proposals by ensuring that there is little or no fluctuation in the applied load over time, facilitating accurate measurement of the skin deflection. The apparatus may further comprise a driver operatively associated with the load member, for exerting a drive force on the load member. The driver may therefore be adapted to drive the load member to generate the torsional load, the torsional load applied to the skin by the load member. Preferably, the drive member is adapted to exert a substantially constant drive force on the load member; this may facilitate generation and application of a substantially constant torsional load on the skin, with the advantages discussed above. The driver may comprise a spring, in particular, a constant force spring for exerting a substantially constant drive force on the load member, for application of a substantially constant torsional load on the skin.

Accordingly, the invention may provide a simple, relatively cheap apparatus which provides improved skin deflection measurements when compared to prior proposals. In alternative embodiments, the driver may comprise an electromechanical or electrical device or mechanism, such as a solenoid or motor. The apparatus may further comprise a control mechanism or the like for controlling operation of the driver. Where the driver comprises a spring, the driver may be adapted to be loaded or stressed by the control mechanism, and the control mechanism may also be adapted to control application of the drive force on the load member. The control mechanism may comprise a restraint or lock for locking the driver, in particular, where the driver comprises a spring, for restraining the spring in a loaded or stressed configuration. Releasing the lock may therefore allow exertion of the drive force on the load member . The load member may be movable relative to the driver, or the load member and the driver may be movable together, relative to the housing. The load member may comprise a shaft, rod or the like, and the apparatus may comprise a load transfer assembly for transferring a drive force to the load member. The load transfer assembly may be for transferring a drive force between the driver and the load member, and may comprise one or more load transfer elements formed on or coupled to each of the driver and the load member, each of which may take the form of a spline, tooth, pin, follower, groove, gear or the like. Preferably, the driver comprises a pin and the load member a plurality of splines or a groove, the pin adapted to engage between adjacent splines or in the groove. This allows transfer of a rotational drive force to the load member whilst permitting movement of the load member in said direction towards and away from the skin. A circumferential width of a gap between the splines or of the groove may reduce towards one or both ends of the load member. This may provide a friction between the driver and the load member, for example, when the load member is an extended position and may assist in location of the load member adjacent the skin. The load member may include a detachable portion, such as a head or end adapted for contact with the skin, and the detachable portion may carry an adhesive, adhesive tape or the like for securing to the skin. The detachable portion may thus be separated from a main part of the load member, which may facilitate operation of the apparatus. For example, the detachable portion may be located in contact with the skin, and the main part of the load member then connected to the detachable portion. The detachable portion may be pivotally mountable relative to the main part of the load member and may be pivotable about an axis extending perpendicularly to a longitudinal axis of the load member main part. This may allow the detachable portion to tilt, ensuring it is perpendicular to the skin and minimising or avoiding any tendency for the portion to move out of contact with the skin on rotation. The main part of the load member and the detachable portion may be couplable by load transfer elements which may form part of the above load transfer assembly, and may also take the form of a groove/pin or the like. The device for measuring deflection of the skin may be adapted to measure angular rotation of the load member, and may comprise a potentiometer or the like. The potentiometer may provide a voltage output indicative of the measured deflection, and the apparatus may comprise an output, such as a display, screen or the like, for displaying the output voltage, the measured deflection, or a value indicative of a selected parameter, such as elasticity of the skin. Where a value indicative of a selected parameter is output, the value may be calculated based upon the measured deflection, and the apparatus may include a suitable processor for calculating the respective values. Additionally or alternatively, the device may comprise a mechanical or other component for measuring deflection of the skin, such as a pointer coupled to the load member, and a scale associated with the pointer for providing an indication of the deflection of the load member. The load member may be adapted to be secured, preferably temporarily, to the skin. The load member may be adapted to be secured by an adhesive, or an adhesive backed member coupled to the load member. The apparatus may further comprise a flexible base, which may be integral with the housing or a separate component 'adapted to be coupled to the housing. This facilitates shaping of the base to conform to a local skin area/body part. The base may be adapted to be held in abutment with the skin by the user, or may be adapted to be secured, preferably temporarily, to the skin. The housing may define an opening, the load member mounted for movement with respect to the opening. The opening may be adapted to define an area of skin to be tested and the load member may be mounted for movement relative to the opening. Preferably, the apparatus is for measuring skin deflection in order to determine at least one parameter of the skin, the parameter selected from the group comprising skin elasticity, skin thickness, skin hardness, connectivity between epidermis and/or dermis layers and underlying structures, and the like. The apparatus may take the form of medical apparatus for use in a diagnostic method, for example, in the diagnosis of skin conditions such as scleroderma. As discussed above, scleroderrna is a condition tending to cause a thickening/hardening of the skin, with an associated decrease in elasticity and thus a decrease in deflection for a given torsional load, measured using the present invention. Alternatively, the apparatus may be adapted to measure skin deflection for cosmetic purposes. For example, the apparatus may be adapted to be used to determine changes in skin deflection before, during and/or following use of a cosmetic product, to determine relative effects of use of the product on skin parameters such as elasticity. The apparatus is preferably adapted to be hand-held. The apparatus may be disposable and may be adapted for single use, or may be adapted for multiple uses. According to a second aspect of the present invention, there is provided apparatus for measuring skin deflection comprising: a load member for applying a substantially constant torsional load to the skin; and a device for measuring deflection of the skin in response to the applied torsional load. Preferably, the apparatus comprises a housing and the load member is mounted for movement relative to the housing in a direction towards and away from the skin. Further features of the apparatus are defined above. According to a third aspect of the present invention, there is provided a method of measuring skin deflection comprising the steps of: providing a housing and a load member mounted for movement relative to the housing; allowing movement of the^' load member relative to the housing in a direction towards and away from the skin; locating the load member in contact with the skin; applying a torsional load to the skin using the load member; and measuring the deflection of the skin in response to the applied torsional load. According to a fourth aspect of the present invention, there is provided a method of measuring skin deflection comprising the steps of: applying a substantially constant torsional load to the skin; and measuring the deflection of the skin in response to the applied torsional load. An embodiment of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figs 1, 2 and 3 are top, side and end views, respectively, of apparatus for measuring skin deflection in accordance with a preferred embodiment of the present invention, shown in a test configuration; Fig. 4 is a side view of the apparatus of Figs. 1-3 shown in a storage configuration; Fig. 5 is an exploded perspective view of the apparatus in the test configuration of Figs. 1-3; Figs. 6 and 7 are cross-sectional side views of the apparatus in the test configuration of Figs. 1-3, taken along line X-X of Fig. 1, and showing the apparatus at different stages in use; Fig. 8 is an enlarged view of a driver assembly forming part of the apparatus of Figs. 1-3; and Fig. 9 is an enlarged view of a load member forming part of the apparatus of Figs. 1-3. Turning firstly to Figs 1-3, there are shown top, side and end views, respectively, of apparatus for measuring skin deflection in accordance with a preferred embodiment of the present invention, the apparatus indicated generally by reference numeral 10. The apparatus is shown in Figs. 1-3 'in a test or deployed configuration, and in Fig. 4 in a storage configuration. Fig. 5 is an exploded perspective view of the apparatus 10, whilst Figs. 6 and 7 are cross- sectional side views taken along line X-X of Fig. 1, and showing the apparatus 10 at stages in use during a procedure to measure skin deflection. Fig. 8 is an enlarged view of a driver assembly forming part of the apparatus of Figs. 1-3, and Fig. 9 is an enlarged view of a load member forming part of the apparatus of Figs. 1-3. The apparatus 10 generally comprises a housing 12, a load member 14 for applying a torsional load to the skin 16 and a device 18 for measuring deflection of the skin 16 in response to the applied torsional load. The apparatus 10 has a particular utility for locating and assessing skin affected by the skin thickening and hardening disease scleroderma, as will be described in more detail below. In general, a torsional load is applied to the skin 16 using the load member 14 and a corresponding deflection of the skin in response to the applied torsional load is measured using the deflection measuring device 18. As discussed above, scleroderma tends to cause a thickening and tightening of the skin with a resultant loss in elasticity. Accordingly, skin affected by scleroderma will experience a smaller deflection in response to a given applied torsional load than skin unaffected by scleroderma. It will be understood that references herein to application of a torsional load are to application of a rotary, twisting force on the skin. The apparatus 10 and the corresponding method of measuring skin deflection will now be described in more detail with particular reference to Figs. 5 to 9. The housing 12 forms an outer housing of the apparatus 10 and includes two housing sections 20 and 22. This facilitates assembly of the apparatus 10 and disassembly for maintenance purposes, if required. Within the housing 12 is mounted a driver assembly 24; the load member 14, which in the illustrated embodiment takes the form of a slotted shaft; the deflection measuring device 18, which in the embodiment shown takes the form of a potentiometer; a battery 26; a switch 28; and a mechanism for controlling operation of the driver assembly 24, which includes a lever arm 30 and a trigger 32. An output display for displaying information relating to the measured skin deflection is mounted on support arms

34 and 36, which are pivotally mounted to the respective housing sections 20, 22 by appropriate rivets 37 (one shown) , and are pivotable between storage configurations (Fig. 4), and deployed configurations (Figs. 1-3, 5 and 6). The apparatus 10 is thus moveable between a compact storage configuration and a deployed, test configuration. A flexible .base 38 of a material having a high coefficient of friction, typically a rubber, elastomeric or fabric material, is coupled to the housing 12 at front and back edges 39, 41 and includes an opening 40 which aligns with a corresponding opening in the underside of the housing, the housing opening formed by cut-out portions 42 (one shown) in the housing sections 20, 22 when the housing sections are coupled together. The load member shaft 14 is mounted for movement relative to the housing 12 in a direction towards and away from the skin, as indicated by the arrow Y-Y' in Figs. 6 and 7. The shaft 14 is movable between a fully extended position (Fig. 6) and a retracted position (Fig. 7) protruding from the housing 12. Moveably mounting the shaft 14 in the housing 12 in this fashion allows the shaft 14 to move independently of the housing 12. The shaft 14 is thus a floating shaft and, in use, the only pressure force exerted by the load member on the skin in the direction Y (towards the skin) is that due to the weight of the load member resting on the skin, under gravity. The shaft 14 includes a detachable portion in the form of a head or end attachment 44 which is brought into contact with the skin 16 to exert a torsional load on the skin. The shaft 14 includes upper slots 15 for engaging a driver pin 58, which will be described below, and lower slots 17 for receiving the attachment 44. Specifically, the attachment 44 carries pins 45 which are received in the slots 17, for transferring a rotational load from the shaft 14 to the attachment 44. The attachment 44 is temporily secured to the skin 16, preferably using a disposable adhesive tape or pad, but alternatively using a suitable adhesive. The shaft 14 is then coupled to the attachment 44 and a torsional load exerted on a portion of the skin 16 which, in use, is exposed in the opening 40 of the flexible base 38. By providing the shaft 14 as a floating shaft, any pressure force exerted on the skin 16 outwith the opening 40 does not affect the measurement of deflection of the skin exposed in the opening 40. Also, the shaft 14 applies a substantially constant torsional load to the area of skin 16 exposed in the opening 40, and this facilitates accurate measurement of the skin deflection as the torsional load remains constant over a defined test period. This is achieved by providing a driver assembly 24 which exerts a substantially constant drive force on the shaft 14. The driver assembly 24 includes a constant force drive spring 25, shown in Fig. 8, which is held on a take- up spool 46 which is mounted in the housing 12 by a bearing 48 and a locking screw 50. The other end of the spring is coupled to a driver shaft housing 52 by a screw 54 (Fig. 5) . As shown in Fig. 6, the driver shaft housing 52 includes an inner shaft 56 and the load member shaft 14 is mounted on the driver housing inner shaft 56, for sliding movement relative to the driver inner shaft. A pin 58 on the inner shaft 56 (Fig. 8) is located extending into the shaft 14 upper slots 15. In this fashion, rotation of the driver shaft housing 52 by the constant force drive spring is transferred to the load member shaft 14. Engagement of the pin 58 in the upper slots 15 allows the sliding movement of the load member shaft 14 towards and away from the skin in the directions Y, Y' shown in Figs. 6 and 7. The width of the gap between the slot 15 flanks reduces towards an upper end of the shaft 14, to provide a frictional force between the slot 15 flanks and the pin 58. This assists in locating the load member shaft 14 on the skin 16 by facilitating engagement of the shaft 14 with the attachment head 44. The housing 12 is then moved down, and the pin 58 moves out of the reduced width portion of the slots 15 and the shaft 14 is then fully floating. The potentiometer 18 includes a potentiometer shaft 60 mounted to the top of the driver shaft housing 52. Rotation of the driver shaft housing 52 carries the potentiometer shaft 60, turning a wiper (not shown) which provides a variable resistance, to produce a varying output voltage depending upon the rotational position of the potentiometer shaft 60. The potentiometer 18 is coupled to a display 62, which is mounted in casing parts 64 and 66 on the respective support arms 34, 36 to output the voltage readings of the potentiometer 18, which correspond to the measured deflection of the skin 16. The potentiometer 18 and the display 62 are powered by the internal battery 26, and the switch 28 serves for enabling and disabling the system when required. The lever arm 30 is connected to the driver shaft housing 52, as best shown in Fig. 6, and is moveable in a slot 68 (Figs. 3/5) in the housing 12. Movement of the lever 30 from left to right in Fig. 3 partially rotates the driver shaft housing 52, stressing and thus loading the constant force drive spring 25. The trigger 32 includes a catch which restrains the lever 30 in this position where the spring is stressed and, when it is desired to exert a torsional load on the skin 16, the trigger 32 is depressed, such that the catch releases the lever 30 and the spring then urges the driver shaft housing 52 (and thus the inner shaft 56 and load member splined shaft 14) in the opposite rotational direction, exerting the substantially constant torsional load on the skin 16. The procedure for measuring skin deflection using the apparatus 10 is as follows . The support arms 34, 36 are moved from the storage configuration of Fig. 4 to the deployed configuration of Figs. 1-3, 5 and 6. The attachment 44 is then located on the skin 16, ready for coupling to the shaft 14. The lever arm 30 is then moved to load the constant force spring 25. The action of this movement operates the switch 28, thus providing power to the electric circuitry. The shaft 14 is then moved to its fully extended position of Fig. 6 and is connected to the attachment 44, the shaft pin 58 engaging in the lower shaft slots 17. Application of a force through the housing then moves the housing 12 down relative to the shaft 14 until the flexible base 38 is brought into contact with the skin 16

(Fig. 7) . The side edges 70, 72 are then held down against the skin, to conform the base with the shape of the particular body part. In this position, the shaft 14 is fully floating. It will be understood that the apparatus 10 is best suited to use in a vertical orientation, however, as the attachment head 44 is secured to the skin 16 using an adhesive, the apparatus may be utilised at an angle from the vertical. As noted above, the load in the spring 25 is retained by the trigger 32, which restrains the lever arm 30 and, when it is desired to carry out a test procedure, the trigger 32 is depressed, releasing the lever 30. This rotates the load member shaft 14, exerting a torsional load on the skin 16. The degree of rotation and thus deflection of the skin 16 is measured by the potentiometer 18, which displays an appropriate output on the display 62. On disengaging the shaft 14 from the attachment 44, residual force in the spring 25 rotates the driver shaft housing 52 further and presses it against the switch 28, turning off the device. By coupling the attachment 44 to the shaft 14 through the pin/slot arrangement, the attachment 44 can tilt in the slots 17. This ensures the attachment 44 is perpendicular and avoids any tendency for the attachment adhesive to peel free during rotation. The display 62 may give more than one reading, for example a reading a very short time after release of the trigger 32, which would give a measure of the stiffness of the skin 16, and a reading at a later time, which would give a measure of the viscous property of the skin 16. Timing and logic circuitry may be included that will show the first reading, hold it for short time (for example, several seconds) , as required (to allow the operator to note the reading) then to display a second reading at, for example, 10 or 15 seconds after the start of the test, which can also be noted. It will be understood that the apparatus 10 may be used on the skin of any body part or area, such as the torso, arms, legs, face or the like and has uses other than in the testing for scleroderma. In particular, the apparatus 10 may have cosmetic uses, for example, to determine the success of a particular cosmetic product. The invention provides a compact apparatus which can be used in a hand-held fashion and which is sufficiently small to be used one-handed. Also, the apparatus does not require any additional equipment to carry out a test procedure as it incorporates an internal power supply, measuring and output devices . Various modifications may be made to the foregoing within the scope of the present invention. For example, the load transfer assembly may comprise a plurality of load transfer elements formed on or coupled to each of the driver and the load member, each of which may alternatively take the form of a tooth, pin, follower, groove, gear or the like. The potentiometer may provide an output indicative of a selected parameter, such as elasticity of the skin. Where a value indicative of a selected parameter is output, the value may be calculated based upon the measured deflection, and the apparatus may include a suitable processor for calculating the respective values. Additionally or alternatively, the device may comprise a mechanical or other component for measuring deflection of the skin, such as a pointer coupled to the load member, and a scale associated with the pointer for providing an indication of the deflection of the load member. The base may be adapted to be held in abutment with the skin by the user, or may be adapted to be secured, preferably temporarily, to the skin. The apparatus may include a mechanism for exerting a pressure force on the skin through the load member. The mechanism may be adapted to exert a force of a predetermined value to provide consistency of results. The pressure force may be matched to the force exerted through the load member under gravity in a vertical orientation, and may be selectively applicable, for example, when the load member is angled from the vertical. The flexible base of the housing may be sprung to conform the base to the skin, using strip springs or the like. The display may be mounted on or may form part of the main housing rather than the support arms; the apparatus may not include the support arms .

REFERENCES

Kalaleh MB, Suttany GL, Smith EA, Huffstutter JE, Loadholt CB, LeRoy EC. A modified Scleroderma Skin Scoring Method. Clin Exp Rheu atol 1986;4:367-369.

Kalis B, de Rigal J, Leonard F, Leveque JL, Riche 0, le Corre Y, de Lacharriere O. In Vivo Study of Scleroderma by Non-Invasive Techniques. British Journal of Dermatology 1990;122:785-791.

Knight LR, Smeathers JE , Isdale AH, Helliwell PS. Evaluating the Cutaneous Involvement in Scleroderma: Torsional Stiffness Revisited. Rheumatology 2001/40:128- 132.

De Rigal J, Leveque JL. In Vivo Measurement of the Stratum Corneum Elasticity. Bioeng . Skin 1985;1:13-23.

Leveque JL, de Rigal J, Agache PG, Monneur C. Influence of Ageing on the In Vivo Extensibility of Human Skin at a Low Stress. Arch Dermatol Res 1980;269:127-135.

Claims

CLAIMS 1. An apparatus for measuring skin deflection comprising: a housing,- a load member for applying a torsional load to the skin, the load member mounted for movement relative to the housing in a direction towards and away from the skin_/ and a device for measuring deflection of the skin in response to the applied torsional load.

'

2. The apparatus according to claim 1 wherein the load member is telescopic.

3. The apparatus according to either of claims 1 or 2 wherein the load member is a floating load member.

4. The apparatus according to any preceding claim wherein, in use, the apparatus is arranged such that the only pressure force exerted by the load member on the skin in a direction towards the skin is that due to the weight of the load member resting on the skin, under gravity.^'

5. The apparatus according to any preceding claim adapted to exert an engagement or restraining force upon the load member when in one or both of an extreme positions.

6. The apparatus according to any preceding claim wherein the load member is adapted to apply a substantially constant torsional load on the skin.

7. The apparatus according to any preceding claim further comprising a driver operatively associated with the load member, for exerting a drive force on the load member.

8. The apparatus according to claim 7 wherein the driver comprises a constant force spring for exerting a substantially constant drive force on the load member, for application of a substantially constant torsional load on the skin.

9. The apparatus according to claim 7 wherein the driver is an electromechanical or electrical device.

10. The apparatus according to any preceding claim, further comprising a control mechanism for controlling operation of the driver.

11. The apparatus according to claim 10 wherein the control mechanism comprises a restraint or lock for locking the driver in a loaded or stressed configuration.

12. The apparatus according to any preceding claim, wherein the apparatus comprises a load transfer assembly for transferring a drive force to the load member.

13. The apparatus according to claim 12, wherein the load transfer assembly is for transferring a drive force between the driver and the load member, and comprises one or more load transfer elements formed on or coupled to each of the driver and the load member, each of which may take the form of a spline, tooth, pin, follower, groove, gear or the like .

14. The apparatus according to any preceding claim, wherein the driver comprises a pin and the load member a plurality of splines or- a groove, the pin adapted to engage between adjacent splines or in the groove.

15. The apparatus according to any preceding claim wherein the load member includes a detachable portion, such as a head or end . adapted for contact with the skin, and the detachable portion may ^• carry an adhesive, adhesive tape or the like for securing to the skin.

16. The apparatus according to claim 15 wherein the detachable portion is pivotally mountable relative to the main part of the load member and may be pivotable about an axis extending perpendicularly to a longitudinal axis of the load member main part .

17. The apparatus according to any preceding claim, adapted to measure angular rotation of the load member.

18. The apparatus according to claim 17, wherein the angular rotation is measured by a potentiometer.

19. The apparatus according to claim 18, wherein the potentiometer provides a voltage output indicative of the measured deflection, and the apparatus further comprises an output, such as a display, screen or the like, for displaying the output voltage, the measured deflection, or a value indicative of a selected parameter, such as elasticity of the skin.

20. The apparatus according to claim 19 wherein the value indicative of a selected parameter may be calculated based upon the measured deflection, and the apparatus may include a suitable processor for calculating the respective values.

21. The apparatus according to any preceding claim further comprising a mechanical or other component for measuring deflection of the skin, such as a pointer coupled to the load member, and a scale associated with the pointer for providing an indication of the deflection of the load member.

22. The apparatus according to any preceding claim wherein the load member is adapted to be releasably secured to the skin.

23. The apparatus according to any preceding claim further comprising a flexible base, which may be integral with the housing or a separate component adapted to be coupled to the housing.

24. The apparatus according to claim 23 wherein the housing defines an opening, the load member being mounted for movement with respect to the opening.

25. The apparatus according to any preceding claim wherein the apparatus is for measuring skin deflection in order to determine at least one parameter of the skin, the parameter selected from the group comprising skin elasticity, skin thickness, skin hardness, connectivity between epidermis and/or dermis layers and underlying- structures, and the like.

26. The apparatus according to claim 25 for use in the diagnosis of skin conditions such as scleroderma.

27. The apparatus according to claim 25 for use in measuring sin deflection for cosmetic purposes.

28. An apparatus for measuring skin deflection comprising: a load member for applying a substantially constant torsional load to the skin; and a device for measuring deflection of the skin in response to the applied torsional load.

29. The apparatus according to claim 28 further comprising a housing and the load member is mounted for movement relative to the housing in a direction towards and away from the skin.

30. A method of measuring skin deflection comprising the steps of : providing a housing and a load member mounted for movement relative to the housing; allowing movement of the load member relative to the housing in a direction towards and away from the skin; locating the load member in contact with the skin; applying a torsional load to the skin using the load member; and measuring the deflection of the skin in response to the applied torsional load.

31. A method of measuring skin deflection comprising the steps of : applying a substantially constant torsional load to the skin; and measuring the deflection of the skin in response to the applied torsional load.