HAPTIC STIMULATION APPARATUS
20180280227 ยท 2018-10-04
Inventors
- James QUEST (Petersfield Hampshire, GB)
- Stephen Paul SMITH (Petersfield Hampshire, GB)
- Adam PAWLAK (Petersfield Hampshire, GB)
- Howard Morgan CLARKE (Petersfield Hampshire, GB)
- Cheryl Diane METCALF (Petersfield Hampshire, GB)
Cpc classification
A61H2230/625
HUMAN NECESSITIES
A61H2201/5002
HUMAN NECESSITIES
A61H2201/5005
HUMAN NECESSITIES
A61H9/0078
HUMAN NECESSITIES
A61H23/0218
HUMAN NECESSITIES
International classification
Abstract
Transducers for applying stimulation to a patient include a Peltier device (8), a pneumatically inflatable Finger bladder (4) and an LRA or ERM (6), and are connected to a controller. In a passive mode stimulation can be provided in the absence of feedback from the patient. In an active mode, the addition of movement detection enables additional visual images to encourage a response from a patient, increasing the range or rehabilitation provided to the patient.
Claims
1-23. (canceled)
24. A transducer for applying stimulation to a user, comprising a housing holding:a Peltier device for providing heating and/or cooling, an inflatable chamber having a diaphragm for applying pressure to the user, the air pocket having a pneumatic air inlet and outlet, and a linear resonance actuator (LRA) or eccentric rotating mass (ERM) for providing vibration wherein the Peltier device is located approximately centrally on the diaphragm with a top surface of the Peltier device designed to be in contact with a user and a bottom surface located on the diaphragm.
25. The transducer of claim 24, wherein the LRA/ERM is held within the inflatable chamber.
26. The transducer of claim 24, further including a transistor for temperature measurement.
27. The transducer of claim 24, wherein the transducer is sized for securement to the pad of a user's finger.
28. The transducer of claim 24, further including a motion tracking sensor.
29. The transducer of claim 28, wherein the sensor for motion tracking is selected from one or more of accelerometers, magnetometers, gyroscopes, compasses.
30. The transducer of claim 24, further including a material which changes resistance as it bends.
31. A stimulation device for a patient, comprising: a plurality of transducers as claimed in claim 24, each transducer mounted on a housing and having means for securement to a patient; a corresponding plurality of pneumatic tubing for connection to the inlets and outlets of the inflatable chambers and wiring for the Peltier devices and the LRA/ERM; and a controller connectable to the plurality of transducers and including: a plurality of ports for connection of pneumatic tubing to the transducers; a plurality of ports for connection of power supply wiring to the transducers; a power supply; and a microcontroller for controlling the operation of the transducers.
32. The stimulation device of claim 31, wherein the plurality of transducers comprises at least two transducers sized for securement to the fingers of a user.
33. The stimulation device of claim 31, wherein the plurality of transducers further includes an additional transducer comprising a Peltier device and an LRA or ERM.
34. The stimulation device of claim 31, further including a strap to secure the tubing and wiring to the body or the user.
35. The stimulation device of claim 31, further including a shoulder bag holding the controller.
36. The stimulation device of claim 31, further including means for attaching the controller to a forearm of a user.
37. The stimulation device of claim 31, further including a vdu connectable to the microcontroller.
38. The stimulation device of claim 33, wherein the microcontroller is adapted to control the vdu to display images and activate the transducers independently.
39. The stimulation device of claim 38, wherein the microcontroller is adapted to detect movement and display images on the vdu relating to detected movement.
40. A method of providing stimulation to a patient, the method comprising: attaching the transducers of the stimulation device according to claim 31 to a patient; and providing stimulation to the patient through the transducers.
41. The method of claim 40, wherein the stimulation is provided in a predetermined pattern.
42. The method of claim 40, further including providing images on the vdu corresponding to the pattern of stimulation provided.
43. The method of claim 40, further including the step of detecting movement by the patient.
44. The method of claim 43, further including the step of providing images on the vdu corresponding to the movement detected.
45. The method of claim 44, wherein the images exaggerate the detected movement.
Description
[0050] To help understanding of the invention, specific embodiments thereof will now be described by way of example and with reference to the accompanying drawings, in which:
[0051]
[0052]
[0053]
[0054]
[0055]
[0056]
[0057]
[0058] The device uses an array of transducers which are attachable to a user on various parts of the body, particularly the hands. Each transducer can provide stimulation in the form of all of pressure, vibration and temperature change.
[0059]
[0060] In the embodiment shown in
[0061] The Peltier device 8 is attached to the diaphragm 10 above the air pocket 4 such that as the air pocket is inflated, the Peltier device is urged against a user, especially against a pad of the finger. This provides a hard surface which is urged against the user when the air pocket is inflated, creating a stronger feeling of pressure for a user. A thermistor 9 is provided on the Peltier device to detect the temperature and to ensure that any increase or decrease in temperature resulting from the Peltier device does not exceed the safe range for skin, namely 2 C.-45 C.
[0062] As shown in
[0063] In typical use a plurality of such devices 1 are held at different positions against the skin of a user.
[0064] Where the use is for the treatment of stroke patients, or other patients with sensory disorders, individual devices 1 may be attached to for example their fingers, using e.g. Velcro or elastic attachment. Individual devices may then be connected to a central controller (as discussed later). Velcro straps are particularly suitable as they can be adjusted to ensure a snug fit which varies according to finger sizes.
[0065] Where the use is gaming or training/simulation, a plurality of the devices 1 may be connected into or onto an item of clothing, for example a glove. Patients suffering from sensory disorders will typically not be able to put on a glove and thus the provision of a modular system described above is indicated for this disability. However, under particular circumstances where they are able to put on a glove, this can also be used in the treatment of such patients.
[0066] In an alternative embodiment shown in
[0067] Again this device 101 may be attached to a user using Velcro straps, or by incorporation into clothing.
[0068] In a further embodiment 201 shown in
[0069] In this device 201, the ERM/LRA 206 is provided on the diametrically opposite side of the device to the air pocket 204, with pneumatic inlet 205, and Peltier device 208 and thermistor 209. The EMR/LRA is positioned to act against the nail of the finger of the user, while the air pocket, on which is mounted the Peltier device 208 and thermistor 209, is positioned to act against the pad 218 of the finger. The thimble will have a hard plastic over cover 202 and a lining of silicon 203, or other flexible plastic material, into which the air pocket and Peltier device are set.
[0070] While the combination of vibration, pressure and temperature can be used to provide a range of stimulation to a user, a device in which there is no ability to provide pressure is also provided. Such a device 301 will be useful in positions where it cannot be held sufficiently tightly against the body for an increase in pressure to be felt for example when used on the palm of the hand. Such a device is shown in
[0071] For use on a stroke patient, as shown in
[0072] For use in applying stimulation to the hand, typically 5 devices 1, 101, 201 as described above are applied to the fingers, including the thumb. In addition, a further device 1, 101, 201, or 301 is provided for attachment to the palm. The device is provided against the muscle adjacent the thumb. Typically this device excludes the option of the application of pressure.
[0073] Each of the devices has a power connection 30, and a pneumatic connection 32 where appropriate, for connection to a power source 34, and for a pneumatic system 36. The pneumatic system may be a closed loop pressurized reservoir system with the flow of the air from the pneumatic system into each device being controlled by a solenoid 38. These in turn are connected to a microcontroller 40, which controls the activation of the stimulation in the transducers 1, 101, 201, 301.
[0074] The wires 30 and tubes 32 from the devices 1, 101, 201, 301 may be provided within woven sheath to keep them together and protect them from damage. Alternatively the may be held to the user with Velcro straps or allowed to drape.
[0075] As shown in
[0076] In an alternative, the transducers can be placed within an item of clothing, typically a glove, with all of the wires and tubes fixed to the item of clothing.
[0077] The power source 34, pneumatic system 36, solenoid 38 and microcontroller 40 may be provided in a bag (not shown) for ease of use. The bag may be a shoulder bag or a back pack for wearing by the user, or may be a hand bag for containing these elements together. In another embodiment, not shown, these elements are attached to the forearm of the patient using straps.
[0078] For the treatment of stroke patients the stimulation may be applied independently of any other activity, for example when the patient is going about their normal routine, or when they are watching the television. As set out above the treatment is by application of combinations of pressure, temperature increase and/or decrease and vibration.
[0079] The pressure is applied by inflation of the air pocket 4, 104, 204. As described above, a Peltier device 8, 108, 208 is attached to a diaphragm 10, 110, 210 on the top of the air pocket and by inflating the air pocket, the Peltier device is urged again the limb of the patient wearing the device 1, 101, 201.
[0080] As shown in
[0081] Typically the solenoids may be latching solenoids 38 and may be controlled by the microcontroller 40 via an H-bridge driver IC 42. The advantage of using such a system is that a short pulse of power to the latching solenoid will switch it to latch on mode, which will hold the pressure within the air pocket, unless released or leakage failure, without the need to constant application of power. This reduces power consumption, extending the life of the battery. Typically the power pulse to switch the solenoid to latch on will be 10-15 ms.
[0082] To release the pressure from the device the solenoid can be switched to latch off mode, but a further pulse of power, again of a duration of approximately 10-15 ms. To switch the solenoid to latch off mode, the polarity of the power source applied is the opposite to that applied to achieve latch on mode. Switching to latch off mode exhausts that air pocket through the solenoids exhaust outlet.
[0083] Using this system the pressure in each device 1, 101, 201 can be controlled separately to achieve the same or different pressures, and to hold the pressure for the same or different time periods.
[0084] The temperature stimulation is applied using the Peltier device 8, 108, 208, 308, which is a thermoelectric device that generates the presence of heating or cooling at an electrified junction of two different conductors. Thus when the Peltier device is driven in one direction, it produces a heating process on one surface and a cooling process on the other surface; similarly when the Peltier device is driven in the opposite direction, it produces a cooling effect on the first surface (which had previously been heated) and a heating effect of the other surface. When no current is passed through the device, it returns to the ambient temperature. Thus if such a device is placed against the skin of a patient, the upper surface can be heated or cooled, or allowed to remain at ambient temperature dependent on the current flow through the device. This is again achieved using an H-bridge and driver ICs 44 controlled by the microcontroller.
[0085] The vibration is generated by creating different waveforms to simulate different everyday sensations (for example typing or a cat), using a LRA or ERM.
[0086] The LRA comprises a small disc containing a small mass, a wire coil, a spring and a permanent magnet. When a current is passed through the coil it generates a magnetic field, which moves the mass causing a vibration to be generated.
[0087] The ERM comprises a small motor with an off-centre mass connected to its shaft. When this rotates a vibration is generated.
[0088] Different vibration waveforms, created by driving the LRA or ERM in different ways, using pulse width modulation, can be used to simulate different sensations. Different sensations can be simulated by driving different waveforms to these LRA and ERM devices. The LRA/ERM is controlled by a drive IC 46, which may be programmed to control them to generate in excess of 100 different waveforms. Communication between the microcontroller 40 and the ICs 46 is via I.sup.2C switch 48. All the driver ICs have the same I.sup.2C address, so they are all connected via an I.sup.2C switch 48.
[0089] The microcontroller 40 in turn may be controlled from a computer (not shown). This may be in the form of a smart phone or tablet, using Bluetooth 50 to communicate.
[0090] In some embodiments motion sensing may also be provided on the transducers.
[0091] These may be in the form of a combination of accelerometers and magnetometers, gyroscopes and compasses which can provide position and orientational information. Such device may be provided on the transducers 1, 101, or may be provided on the straps which are used to hold the transducers in position. In other embodiments the motion sensing devices may be incorporated into the item of clothing, where this is used to hold the transducers against the body of a user. In addition a strip of material which changes resistance when bent may be provided for securement to a user's fingers, for detecting bending of the finger.
[0092] In an alternative, a motion tracking system such as Leap Motion or Wii motion may be used.
[0093] To provide stimulation to a user, different levels and combinations of the pressure, vibration and temperature are used to create different effects. These can be used whether the apparatus is being used to treat stroke patients, for user for training or games.
[0094] The skin contains four types of mechanoreceptors which are used to detect touch in different ways, and use of the three types of stimulation in the device 1, 101, 201 all four types of mechanoreceptors can be activated. Two are fast receptors and two are slow receptors. Their details are as follows:
TABLE-US-00001 Name Reaction to: Type Meissner's corpuscles Touch, pressure (dynamic) Fast Pacinian corpuscles Deep pressure, vibration (dynamic) Fast Merkel's disks Touch, pressure (static) Slow Ruffini's corpuscles Stretching of skin Slow
[0095] The skin also contain thermoreceptors which react to changes in temperature.
[0096] As discussed above, pressure is applied by the inflation of an air pocket via a solenoid, the air pocket inflating in less than 1 second. This enables rapid inflation of the air pocket.
[0097] Alternative, the solenoid can be pulsed on and off at a fast rate such that only a fraction of the air needed to inflate the air pocket is allowed through during each on phase. As a result the air pocket can be filled slowly, or only partial filling of the air pocket can be achieved, resulting in the application of a lower pressure.
[0098] Typically the reservoir pressure will be between 3 psi and 9 psi. This will enable a significant amount of pressure to be provided to a user, or any level of pressure desired.
[0099] Thermistors are used to prevent the Peltier device from increasing or decreasing the temperature of the skin by more than 10 C. from ambient temperature. The thermistors form part of a hardware controlled safety circuit that monitors the ambient skin temperature on the back of the hand. There is a thermistor positioned between the Peltier device and the fingertip to monitor the stimulation temperature. Assuming ambient temperature to be 25 C. this will ensure that the no damage to the skin will result.
[0100] Generally the Peltier device will be used to change the temperature of the skin by up to 3 C., either up or down, in less than 2 seconds, and by up to 10 C. in less than 5 seconds. It has been found that there is a better temperature change perception when pressure is applied at the same time.
[0101] The vibration stimulation can be used to create the largest number of different effects on the skin.
[0102] An LRA can be vibrated with pulse width modulation (PWM) pulses, self-defined waveforms or pre-defined waveforms, determined by the drive IC, and the form can be chosen to create different effects.
[0103] An un-calibrated system can be driven with a standard square wave up between 4 KHz and 20 Hz, with a duty cycle of 20-50%. For example a single click sensation can be created using a short burst of 10-100 ms, containing the square wave. Similarly a double click sensation can be achieved by creating two bursts of approximately 20-100 ms duration, with a gap of approximately 75-500 ms between them. A hum could be created using a long burst of the square wave.
[0104] The performance and efficiency of the LRAs can be improved with slight changes to the waveforms. This may also give slight changes to the sensations created. The waveform now consists of periodic bursts (of 20 KHz square wave). The frequency of these bursts can be a rate of between 80-350 Hz. Each burst being approximately 3.4 ms in duration.
[0105] Varying the duration of each burst and the intervals between them can also give the sensation of the vibration ramping (speeding) up and down.
[0106] For use with patients the apparatus can be used in either a passive mode or an active mode.
[0107] In passive mode the apparatus is attached to the hand of a user and stimulation applied irrespective on any response made by the user. Pre-programmed patterns of stimulation can be applied to the user which can be chosen by a doctor, physiotherapist or other practitioner, or the user themselves. Generally in this mode the sensory neural pathways only will be stimulated and not the motor pathways. In particular the stimulation will be directed to the Pacinian corpuscles, which lie deep within the skin. As treatment progresses other sensory receptors may be targeting by using the device to simulate light touch, pressure, stretching and temperature change. This mode would be used in patients who have severely affected sensory perception and/or motor impairment.
[0108] In active mode the apparatus provides active feedback to information provided in a screen, for example a TV, PC, or tablet. In this mode the microcontroller 40 will be connected to a computer, for example a PCT or tablet. This may be wired or wireless. As discussed above, this may be via a Bluetooth module 50. The computer will in turn be connected to the screen as describe, and again this may be wired or wireless. This mode requires active participation from the patient who will be provided with sensory feedback appropriate to the activity shown on the screen. The user will experience a tailored virtual environment, whereby the physical movement a user is capable of in the real world may be accentuated to produce an exaggerated visual representation for the virtual world, and will include all the appropriate sensory feedback via the transducers, to provide an immersive and realistic environment. This mode is useful for patients with moderate to minor sensory perception and motor impairment.
[0109] A system of goal-setting may be built into the virtual environment, whereby when a user can consistently achieve a goal set for him, the difficulty will be increased. This ability to manipulate the parameters of an environment is specific to virtual environments and is very useful for the rehabilitation of patients. In addition, providing an engaging, adaptable environment for patients and gamifying their rehabilitation makes seemingly repetitive therapy an enjoyable and motivating experience, thus providing the intensity to promote sensorimotor neuroplasticity that is required for recovery.
[0110] The device can be used for training in a very similar way to the active mode set out above.
Evaluation Study
[0111] An evaluation study has been carried out on a number of unimpaired participants using the device as set out above providing sensations to the thumb, fingers and palms. All participants were right handed and the device was attached to their right hand. The age range of the participants was 26-58, with a male: female ratio of 1:3.
Haptic Device Evaluation
[0112] The haptic device was attached to the participant's right hand providing sensations to the volar aspect of the palm, distal phalanx of the thumb, index, middle and little fingers.
[0113] Four distinct phases were completed during the evaluation: [0114] Phase 1: Did you feel something? And, what did you feel? [0115] This phase was designed to test whether the participant could feel the type of sensation applied by the haptic device. Table 1 below shows the sequence of testing:
TABLE-US-00002 Index Vibration Pressure Cold Hot Thumb Hot Vibration Cold Pressure Little Pressure Middle Cold Hot Pressure Vibration Palm Vibration Cold Hot [0116] Phase 2: Using the vibration haptic actuator, we adjusted the frequency and amplitude in order to determine perceptual thresholds of the devices. Three profiles (click, buzz, hum) were pre-programmed at three amplitudes (low, medium and high). [0117] Phase 3: Static sensory testing: The hand was held as if holding a cylinder such as a drinking cup. The haptic devices were activated according to a set sensory profile of combined sensations chosen with the aim of mimicking a range of objects (hot mug, tennis ball, cold can, clay pot, woven basket, empty tin, glass of water, wooden pencil pot). Participants were asked to describe the sensations initially using free language. They were then provided with a prompt sheet of descriptive words to help focus their descriptions. Finally, participants were asked to describe the sensations with reference to photographs of several objects (see full study protocol in Appendix A). The participant was unaware that the intended object was depicted on the photograph sheet. [0118] Overall, the outcome from this phase was to ascertain: [0119] How much the participant feels like they are interacting with an actual object when using the device? [0120] If the stimulation feels like interacting with any of the objects pictured and why? [0121] Participants were then asked to repeat the process, but this time while moving their fingers and hand position. The exact protocol of free language description, word prompt sheet and visual prompt sheet were again used. [0122] Phase 4: Dynamic sensory testing to replicate surface texture of objects: Haptic sensations (vibration profiles) were applied whilst the participant moves their index finger horizontally as if exploring the surface of a table. Sensations were applied that were intended to mimic sandpaper, corrugated cardboard and rattan. Participants were also instructed to repeat the movements slowly and fast in order to assess whether or not this changes perception. This process was then repeated while the participant moved their index finger vertically, as if touching the surface of a wall.
Summary of Results
[0123] Phase 1 For the individual sensations, vibration was always perceived although some people had difficulty locating a place of origin on the hand/fingers. Pressure was generally accurately perceived but some people also felt a sensation of rushing air. Pressure, in this phase, was often described as a flick or a squeeze. Hot/cold were less reliably perceived but helped by combining them with pressure. [0124] Phase 2 Many people couldn't feel the low amplitude in any of the 3 frequencies. The results from this phase were hugely variable. People perceived sensation to be originating from different fingers, or even in the space between the fingers or in the palm. Wearers were able to distinguish between mid-high amplitudes, and they could feel that high was stronger. [0125] Phase 3 [0126] Stationary The inclusion of temperature, when coupled with a suitable visual prompt, leads the wearer to associate the sensation with a specific object (hot mug/cold coke can). The perception of temperature fading was reported as feeling unrealistic by some wearers, but others thought that it was akin to a thin metal where you transfer your own heat to it, so become less aware of the surface temperature. [0127] Vibration was the most contentious sensation with primarily two dichotomous outcomes; wearers whose responses were objects don't vibrate, to wearers who related vibration to a surface texture. Some participants found the inclusion of vibration as unpleasant. [0128] The profile of the woven basket often resulted in a perception of a dynamic interaction, where an object contained moving liquid, or there was something moving within it. This object was often described as being pliable whereas, the clay pot and the glass of water sensations were often described as solid objects. [0129] Dynamic Wearers found the addition of moving the hand and fingers as changing the perception from there's something in my hand to there can't be because my fingers wouldn't be able to pass through it. Other feedback concluded that objects that were initially perceived as solid changed to pliable by introducing movement. When moving the hand from supination to pronation, wearers indicated that they could feel the weight of an object being held. [0130] Phase 4 Sandpaperincreasing or decreasing speed was not an important factor in determining the surface texture of the virtual object. The surface texture was perceived as consisting of small undulations or bumps. It was reported to be most like the corrugated cardboard to wearers. A resistance to slip or friction was also reported. Direction of movement did not impact perception. [0131] Cardboardregular undulations were perceived, but reportedly too subtle to be the corrugations on the cardboard. Leather or woollen fabric was often identified instead. Niggles, dimples, dots, etc., were repeatedly used to describe this sensation. Speed seemed to be more important to perception, but direction did not. [0132] Rattanthere was less uniformity that the [last one] corrugated cardboard. This sensation was less consistently identified as a single surface, but texture was definitely present. Wearers were more convinced of the sensation when moving vertically, and then able to correlate it to a woven basket.
General Comments:
[0133] Auditory: The majority of wearers commented on the sound of the device influencing their perception of the virtual objects to the extent that they were unsure if the sensation was physical or auditory in origin. Some suggested wearing headphones or playing music to disguise the noise. However, coupling physical sensations, irrespective of auditory influences, with a more realistic virtual environment, i.e. a game, were reported possibly as being more like grasping an object.
[0134] Physical: Some people were aware of a constant light vibration during wear, which would indicate some feedback from the cabling (but may also be a factor of the noise on occasion). The wrist support also affected the movement available and realism of the interaction with the virtual objects. The cabling on the back of the hand was also reported as restricting the movement. Some wearers reported missing the sensation on the ring finger.
[0135] Influencers: People were particularly intrigued by the warm and cold sensations. Coupling the temperature with the pressure sensation seemed to be the most realistic sensation akin to feeling an object. Preliminary results suggest that the dynamic Phase 4 surface textures are promising for interacting with a virtual world.
CONCLUSIONS
[0136] This study has concluded as follows: [0137] The device produces realistic sensations based on the combination of vibration, pressure and temperature and manipulation of these to create texture, i.e. sandpaper, corrugated cardboard and rattan at least are effective. [0138] The inclusion of temperature has the most potential for generating a realistic interaction within a virtual world. [0139] Surface texture was most convincing during dynamic exploration.
[0140] Thus this evaluation has demonstrated that the device can provide realistic stimulation for stroke patient and create realistic sensations for use in virtual simulators.