Assistive device for alleviating symptoms of movement disorders

Abstract

A wearable assistive device for alleviating the symptoms of a movement disorder is disclosed. The assistive device comprises a main body for wearing against a user's skin, means for vibrating the main body against the skin of the user when the device is being worn by the user, circuitry for controlling the assistive device, an internal power source for powering the assistive device, and means for activating and deactivating the assistive device. The circuitry is configured to control vibration provided by the means for vibrating, by switching the vibration on and off periodically at a periodic frequency of 1,35Hz.

Description

[0001] Assistive Device for Alleviating Symptoms of Movement Disorders

[0002] The present invention relates to an assistive device, and associated methods, for alleviating symptoms of movement disorders. The present invention has particular, but not exclusive, relevance to a wearable device for alleviating symptoms such as the involuntary movements such as tics, tremors, dyskinesias and / or the like associated with disorders such as Parkinson’s disease, Tourette syndrome, Tics, Tremor, and / or the like.

[0003] Movement disorders are neurological conditions that adversely affect the ability of an individual to control their movement. There are many different types of movement disorders, and many different types of symptoms associated with them. Whilst movement disorders are often associated with involuntary movements such as tics, tremors, spasms, jerking, shaking, etc., they can also affect the ability of the affected individual to make and control voluntary movements including, for example, the ability to control the muscles and organs required for coherent speech.

[0004] The most common movement disorders include Parkinson’s Disease (PD) which, it is estimated, is suffered by over 10 million people globally, including approximately 1 million people in the US, and 153,000 people in the UK, living with the disease. Parkinson’s disease is a progressive neurodegenerative disorder characterized by bradykinesia (slow movement), resting tremors, muscle rigidity, and postural instability. Other common movement disorders include, for example: Essential Tremor (ET) which causes involuntary, rhythmic shaking, typically in the hands, head, or voice; Dystonia, that causes involuntary muscle contractions that lead to abnormal postures or repetitive movements; Tourette Syndrome involving motor and vocal tics, such as blinking, head jerking, or involuntary sounds; and the like.

[0005] There are a number of different treatments available to help manage the symptoms of movement disorders depending on the specific condition, severity, and underlying cause.

[0006] Medication the primary technique used to treat the underlying condition and in so doing reduce the associated involuntary movements and / or lack of voluntary movement control. For example, dopaminergic drugs (e.g., Levodopa, dopamine agonists) may be used for Parkinson’s disease to help replenish dopamine levels that have been reduced by the loss of dopamine-producing neurons, in the region of the brain (substantia nigra (SN)) that is crucial for motor control, that is associated with Parkinson’s. Moreover, anticholinergics (e.g., Trihexyphenidyl) are sometimes used to help reduce tremors and rigidity in Parkinson’s disease and dystonia. In other cases, beta-blockers (e.g., Propranolol) can help control essential tremor, and botulinum toxin (Botox) injections may be used in the context of dystonia, tics, and some tremors to reduce muscle contractions.

[0007] Nevertheless, the use of medication has a number of limitations. In the case of Parkinson’s disease, for example, Levodopa can lose effectiveness as the disease progresses due to ongoing dopamine neuron degeneration. As a result, patients need higher doses to alleviate symptoms, increasing the risk of side effects (e.g., nausea, dizziness, hallucinations, and / or confusion). Similarly, the beneficial effects of medication typically reduce over time as the medication ‘wears-off’ leading to the return of symptoms before the next dose. Long-term use of medication such as Levodopa can also, in itself, lead to the development of involuntary uncontrolled, jerky movements. Moreover, the effects of using medication can be unpredictable with associated swings between mobility and immobility in a relatively short space of time.

[0008] Because of these limitations, treatment for movement disorders such as Parkinson’s disease often involves a combination of medication, lifestyle modifications, and advanced therapies.

[0009] Deep brain stimulation (DBS) is one such therapeutic technique that may be used to help regulate abnormal movement-related signals and thus alleviate the symptoms of movement disorders such as Parkinson’s disease, essential tremor, and dystonia. However, DBS involves surgical implantation of electrodes into the brain and is thus invasive, carries surgical risks such as brain bleeds and infection, and can require further ‘revision’ circuitry to deal with hardware issues such as lead displacement, battery failure, or system malfunctions. It has also been found that whilst DBS can be effective for some symptoms (e.g., tremors, rigidity, and dyskinesias) it is less effective for freezing of gait, balance issues, and cognitive symptoms. In some cases, it can also lead to a worsening of speech and swallowing issues. DBS also requires regular adjustment and maintenance such as frequent reprogramming of stimulation settings, and ongoing battery management and / or replacement. DBS is also costly, not always covered by medical insurance, and so is not accessible to all patients.

[0010] Wearable technology is increasingly being used to monitor, manage, and assist individuals with movement disorders like Parkinson’s disease, essential tremor, dystonia, and others. These devices help track symptoms, improve mobility, and provide feedback for treatment adjustments.

[0011] Existing wearable technology includes symptom monitoring wearables include a number of motion sensors for tracking tremors, bradykinesia, dyskinesias, and gait changes. However, these wearables are relatively complex and, in general, cannot always detect subtle symptoms accurately. The data produced also tends to be complex, requiring expert interpretation leading to limited real-time feedback for patients.

[0012] Existing wearable technology also includes assistive wearables designed to counteract involuntary movements, such as tremors, and / or improve motor function.

[0013] One such assistive wearable, for example, comprises a glove like wearable device that fits over the hand, wrist, and forearm. The device utilises gyroscopic stabilisation that helps stabilise the hand and thus reduce hand tremors. Whilst this device is effective at providing hand stabilisation, however, it is relatively bulky and does not help to alleviate involuntary movements elsewhere in the body. Moreover, because of the underlying gyroscopic technology, the device is expensive, which thus excludes a large proportion of potential users from being able to obtain one.

[0014] Other assistive wearables comprise watch like wearable devices that are designed to provide vibratory haptic feedback to the wearer. Such feedback has been found to be effective in temporarily reducing, or even eliminating, involuntary movements in some individuals that suffer from movement disorders. One wearable assistive device, for example, has several small vibration sources arranged, when the device is worn, around the wrist of a user. Each vibration source is arranged to provide vibratory haptic feedback to the wearer with at a different respective vibration pattern. Another similar device provides haptic feedback that cycles through several different vibration patterns automatically. Yet another wrist worn wearable device is configured to both sense the tremors of a wearer, and to provide vibratory stimulation to the wearer that is adapted based on sensor feedback to provide a personalised therapeutic experience along with feedback via an associated app. All of these devices are, however, relatively complex including, for example, various combinations of: multiple vibration actuators, control circuitry, sensor circuitry, communication circuitry etc. This relative complexity increases the power consumption of the device, thus shortening battery lifetime for a given battery size, or increasing the battery size for a given battery lifetime. Available devices can also be difficult, for someone who is experiencing involuntary movements such as tremors, to use. The available wrist worn devices are also relatively expensive (from several hundred to several thousand dollars), making them unavailable to a large proportion of potential users.

[0015] Moreover, the vibration patterns used in current devices can begin to cause discomfort I irritation to users after prolonged use.

[0016] The present invention aims to provide an assistive device for alleviating symptoms of movement disorders that overcomes, or at least partially ameliorates, one or more of the above issues.

[0017] In one example, described in more detail below, there is provided a wearable assistive device for alleviating the symptoms of a movement disorder, the assistive device comprising: a main body for wearing against a user’s skin; means for vibrating the main body against the skin of the user when the device is being worn by the user; circuitry for controlling the assistive device; an internal power source for powering the assistive device; and means for activating and deactivating the assistive device; wherein the circuitry is configured to control vibration provided by the means for vibrating, by switching the vibration on and off periodically at a periodic frequency of 1 ,35Hz. The means for vibrating may, for example, comprise a motor having a shaft on which is provided an eccentric rotating mass configured for providing the vibration when the motor is powered.

[0018] The circuitry may, for example, comprise a timer circuit that is configured to control the vibration provided by the means for vibrating.

[0019] The timer circuit may, for example, comprise a 555-timer integrated circuit configured to control the vibration provided by the means for vibrating.

[0020] The means for activating and deactivating the assistive device may, for example, comprise a user operable switch for activating the assistive device when the assistive device is off, and for deactivating the assistive device when the assistive device is on.

[0021] The circuitry may, for example, comprise a latching circuit for activating the assistive device and maintaining the device in an on state if the switch is operated when the assistive device is off, and for deactivating the assistive device and maintaining the device in an off state if the switch is operated when the assistive device is on.

[0022] The user operable switch may, for example, comprise a push button.

[0023] The assistive device may, for example, be configured for operation by means of the user operable switch for activating and deactivating the assistive device, without having another mechanism for receiving additional user input for controlling operation of the device.

[0024] The assistive device may, for example, comprise a charging port, and the circuitry may, for example, comprise a charging circuit configured for charging the internal power source when the charging port is connected to a compatible external power source.

[0025] The wearable assistive device may, for example, be configured to be worn on a wrist of the user. The main body may, for example, comprise a first portion defining a first recess, and a second portion defining a second recess, the first portion and the second portion being mutually configured for coupling to one another to bring the first recess and the second recess together to form a chamber for housing the means for vibrating, the circuitry, and the internal power source when the assistive device is assembled.

[0026] The circuitry may, for example, be provided on (e.g., a single side of) a circuit board, and the first portion may be configured for holding the circuit board in the first recess when the assistive device is assembled.

[0027] The circuit board may, for example, comprise first connecting portions for forming an electrical connection to electrical terminals of the means for vibrating, and the first portion and the second portion may be mutually configured for holding the means for vibrating and the circuit board against one another with the first connecting portions in electrical contact with the electrical terminals of the means for vibrating.

[0028] The circuit board may, for example, comprise second connecting portions for forming an electrical connection to electrical terminals of the internal power source, and the first portion and the second portion may be mutually configured for holding the internal power source and the circuit board against one another with the second connecting portions in electrical contact with the electrical terminals of the internal power source.

[0029] The second portion may, for example, be configured for holding the means for vibrating, and the internal power source, in the second recess when the assistive device is assembled.

[0030] The assistive device may, for example, be configured for switching the vibration on and off periodically at only a single periodic frequency.

[0031] In one example, described in more detail below, there is provided a wearable assistive device for alleviating the symptoms of a movement disorder, the assistive device comprising: a main body for wearing against a user’s skin; means for vibrating the main body against the skin of the user when the device is being worn by the user; circuitry for controlling the assistive device; an internal power source for powering the assistive device; and means for activating and deactivating the assistive device; wherein the circuitry is configured to control vibration provided by the means for vibrating, by switching the vibration on and off periodically at a periodic frequency, and wherein the means for vibrating comprises a motor having a shaft on which is provided an eccentric rotating mass configured for providing the vibration when the motor is powered.

[0032] An exemplary device incorporating the innovative concepts to which this disclosure relates, variations of that device, and associated methodologies will now be described, by way of example only, with reference to the accompanying drawings in which:

[0033] Figure 1 is a three-dimensional view of an assistive device for alleviating symptoms of movement disorders;

[0034] Figure 2 is a simplified exploded view of the assistive device of Figure 1 ;

[0035] Figure 3 shows a number of different views of a circuit board for the assistive device of Figure 1 ;

[0036] Figure 4 is a three-dimensional view of a cover portion for the assistive device of Figure 1 ;

[0037] Figure 5 shows a number of different views of a base portion for the assistive device of Figure 1 ;

[0038] Figure 6 is a simplified block schematic of an example circuit for controlling the assistive device 10; and

[0039] Figure 7 is a simplified circuit schematic of an exemplary timing circuit that may form part of the circuit shown in Figure 6.

[0040] Overview

[0041] The assistive device will now be described in general overview, by way of example only, with reference to Figures 1 and 2. Referring firstly to Figure 1 , which is a three-dimensional view of the assistive device for alleviating symptoms of movement disorders, the assistive device is shown generally at 10. The assistive device 10 is a watch-like electronic wearable device comprising a main body 20 and a strap 30-1 , 30-2 (30).

[0042] Turning to Figure 2, which is a simplified exploded view of the assistive device 10, the main body 20 comprises a base portion 20-1 , and a cover portion (or ‘lid’) 20-2, that are mutually configured for forming an internal chamber for housing, and / or coupling to, the other components of the assistive device 10.

[0043] Those other components include: a circuit board 40 on which circuitry for controlling the assistive device 10 is fabricated (not illustrated); a battery 42 for providing electrical power for powering the assistive device 10; a motor 44 configured to act as a source of vibratory haptic feedback to a wearer of the assistive device 10; and a push button 46 for operating the assistive device 10.

[0044] A power connector 48 (or ‘charging port’) is attached to the circuit board 40 and is electrically connected to the circuitry on that the circuit board 40, for allowing that circuitry to be connected to an external source of power for charging purposes. A battery power connector 50 is also arranged on the circuit board 40 for electrically connecting the circuitry on that the circuit board 40, to the battery 42, for the purposes of powering the circuitry when the assistive device 10 is assembled. In the illustrated example, the battery 42 is a lithium-ion rechargeable battery but it will be appreciated that any suitable battery with a relatively small form factor could be used. As will be described in more detail later, an electronic switch (not visible in Figure 2) is also provided on the circuit board 40. The electronic switch is electrically connected to the circuitry and is configured for activating and deactivating the assistive device 10 when operated.

[0045] The push button 46 and main body 20 are mutually configured for coupling to one another, when the assistive device 10 is assembled, for movement of the push button 46 when pressed to engage with and operate the electronic switch to activate or deactivate the assistive device 10. The base portion 20-1 comprises a pair of strap attachment portions 22-1 , 22-2 (22) configured for attachment of the strap 30 to the main body 20.

[0046] The strap 30 comprises two separate parts - a fastening part 30-1 and an adjustment part 30-2. Each strap part 30-1 , 30-2 comprises a respective main body attachment portion 32-1 , 32-2 (32) for attaching that strap part 30-1 , 30-2 to the corresponding strap attachment portion 22 provided on the base portion 20-1 of the main body 20. Each main body attachment portion 32 and the corresponding strap attachment portion 22 are mutually configured for fixing to one another means of a respective pin 34-1 , 34-2 (34). Specifically, when each strap part 30 is respectively attached to the main body 20, each pin 34 respectively extends through an elongate transverse hole provided at the end of the corresponding main body attachment portion 32, and the opposing ends of each pin 34 respectively extend into corresponding holes 24-1 , 24- 2 (24) provided in the corresponding strap attachment portion 22. The fastening part 30-1 comprises a stud 36 and the adjustment part 30-2 comprises a plurality of holes 38. Each hole 38 is configured for respectively engaging with the stud 36 to provide a different corresponding strap length when securing the strap 30 to the wrist of a wearer.

[0047] Beneficially, as described in more detail later, the motor 44 is a small form factor direct current (DC) motor that is configured to generate harmonic vibration by means of an eccentric rotating mass (ERM). The ERM a small weight that is is attached to the shaft of the motor 44 in a position other than that of the center of mass of the weight (e.g., because the weight itself is asymmetric or because it is connected off- centre / non-coaxially to the shaft). As the shaft of the motor 44 rotates, and the ERM with it, the centripetal force holding the ERM to the shaft is asymmetric results in a net centrifugal force in the direction of the centre of mass of the ERM which translates into harmonic vibrations. The force produced is a function of the distance between the centre of mass and the shaft of the motor, the angular velocity of the motor, and the mass of the ERM. Accordingly, the frequency, magnitude and hence the perceived intensity of the vibration is dependent on the speed at which the motor shat rotates and can thus be regulated by the voltage applied to the motor. It will be appreciated that the use of an ERM based vibration motor is particularly beneficial because of its extremely small form factor, its simplicity (and hence reliability), the ease with which it can be integrated into a device with relatively simple control circuitry, and its relative low cost. ERMs are also capable of producing a range of vibration intensity, from relatively weak to strong vibrations. This allows the intensity of the vibration produced by the assistive device 10 to be calibrated appropriately to ensure that the vibration is strong enough to be sensed by the nerves of the wearer, and hence provide the desired therapeutic effects, whilst avoiding being so strong that it represents an undue distraction - for example, drawing the focus of the wearer to the device and away from the very activity that they were using the assistive device 10 to help them to engage in.

[0048] Moreover, whilst the presence of additional vibration motors is not precluded, by using only a single motor rather than several, the size, complexity, and manufacturing cost of the assistive device 10 is minimised thus making the assistive device 10 more accessible to a wide range of potential users.

[0049] Other sources of vibration, such as linear resonant actuators (LRAs), could potentially be used to provide a similar effect, and might be considered by those in the art to be preferable because of their faster response times, potential for more refined vibration intensity and frequency control, and consistent performance. Nevertheless, LRAs tend to be more expensive, require more complex control circuitry, and have a relatively narrow range of vibration frequencies within which they can operate efficiently and the use of ERM based vibration has been found to be effective at alleviating the symptoms of a range of movement disorders including Parkinson’s disease.

[0050] Beneficially, as described in more detail later, the circuitry is preconfigured to switch the vibration on and off with a specific ON-OFF duty cycle that has been deliberately optimised to be effective to as broad a range of different users as possible. Specifically, the circuitry of the assistive device 10 is configured to switch the vibration on and off at a frequency of 1.35Hz (within reasonable tolerances of, for example, 10%), which corresponds to 81 beats per minute (or 73 to 89 beats per minute when the 10% tolerance is applied). This frequency has been found to be particularly effective at alleviating the symptoms of various movement disorders in as large a proportion of different wearers as possible. Whilst the specific reasons for this efficacy are not certain, it is believed that the proximity of this optimised frequency to the centre of the typical range of heart rates for a human (typically 60 to 100 beats per minute) may be a factor. In effect, controlling the vibration in this way creates a tapping sensation as the assistive device 10 switches periodically between vibrating and not vibrating.

[0051] Whilst understanding of the precise mechanisms behind the assistive device’s effectiveness is currently limited, it appears that the various conditions it benefits generally involve dysfunction of the basal ganglia - a brain region responsible for subconscious, automatic sensorimotor control.

[0052] Whilst earlier studies of similar phenomenon suggested that users may benefit by consciously focusing on the vibration signals, in a process known as "cueing", the inventors believe that such a conscious focus may simply trigger goal-directed behaviour, which influences the basal ganglia indirectly through alternate neural pathways.

[0053] In contrast, for example, the assistive device 10 has been found to be more effective when the user is able to ignore the vibrations entirely at the conscious level. It is believed this allows the somatosensory stimulation to act directly on the subconscious processes governed by the basal ganglia. In effect, the assistive device 10 is functioning as a ‘pacemaker for the brain’; supporting the regulation of neural activity via rhythmic sensory input to the basal ganglia. By allowing conscious attention to be diverted away from the vibratory stimulus, the effect remains within the subconscious sensorimotor system rather than being rerouted by conscious attention.

[0054] Initial data supports this theory, though in cases of anxiety or heightened stress, consciously engaging with the vibrations may still offer therapeutic benefits. Additionally, anecdotal evidence suggests a possible entrainment effect - with some evidence of sustained improvement even when the assistive device is no longer in use after several weeks. This may point to longer-term changes in brain activity, potentially driven by subtle, unconscious neural re-patterning that bypasses the kind of conscious scrutiny that might otherwise inhibit such change.

[0055] Preconfiguring the assistive device 10 with a single optimised on-off frequency without, for example, providing a mechanism for selecting, or automatically switching, between different on-off frequencies and / or patterns of on-off switching, the cost of the assistive device 10 helps to minimise the cost and complexity of the assistive device 10. Moreover, by operating at a single optimised on-off frequency without switching between different on-off frequencies and / or using patterns of on-off switching can help to allow a user to divert their conscious focus to other activities, and to reduce / prevent discomfort / irritation that might otherwise be experienced by a user after prolonged use. This is because the consistent nature of the vibration, and the relatively low frequency used (that is close to that of a normal heartbeat), results in the vibration rapidly passing into a user’s sub-conscious as they continue with their normal activities. Nevertheless, the use of a mechanism for switching between different specific on-off patterns and / or on-off frequencies is not precluded.

[0056] Moreover, configuring the assistive device 10 for operation using a single push button 46 to activate and deactivate the assistive device 10 (e.g., without providing any other additional mechanism for receiving user input for controlling operation of the device), also helps to keep the cost and complexity of the assistive device 10 to a minimum whilst allowing for simple operation that ensures that the assistive device 10 can be operated relatively easily even by an individual affected by a movement disorder, such as Parkinson’s disease, that can make it difficult to operate more complex small devices with several small, multifunctional, buttons or the like.

[0057] The various components of the assistive device 10 will now be described, by way of example only, with reference to Figures 3 to 5.

[0058] Circuit Board

[0059] Figure 3 shows a number of different views of the circuit board 40 of the assistive device 10. Figure 3(a) is a view of a first surface 40a of the circuit board 40 (the surface that faces the wrist of the wearer of the assistive device in use).

[0060] As seen in Figure 3(a), the circuit board 40 is generally rectangular in shape, having two short edges 40b, 40c, and two long edges 40d, 40e. However, the circuit board 40 has a short narrower portion 40f at one end and longer wider portion 40g at the other. Figure 3(b) is a view of the first short edge 40b of the circuit board 40. Figure 3(c) is (c) a view of the second short edge 40c of the circuit board 40, opposite the first short edge 40b shown in Figure 3(b). Figure 3(d) is a view of the first long edge 40d of the circuit board 40.

[0061] In the illustrated example the narrower portion 40f terminates at the second short edge 40c, and the wider portion 40g terminates at the first short edge 40b - although it will be appreciated that this need not be the case. The presence of the narrower portion 40e results in an asymmetry that helps to ensure that, during assembly, the circuit board 40 can only be inserted into the main body 20 one way round, hence reducing the possibility for erroneous assembly.

[0062] Referring to Figure 3 the surface 40a shown in (a) is on the ‘underside’ of the circuit board that is closest to the user when the assistive device 10 is worn. Whilst not shown in Figure 3 it will be appreciated that, beneficially, all of the circuitry for controlling the assistive device 10 may be provided on the first surface 40a of the circuit board 40 visible in Figure 3(a). Configuring the circuitry on a single side of the circuit board is beneficial as doing so further reduces the cost of manufacture. Nevertheless, at least some of the circuitry for controlling the assistive device 10 may be provided on a second surface of the circuit board 40, that is not visible in Figure 3(a).

[0063] The power connector 48 is provided on the first surface 40a of the circuit board 40 adjacent, and extending over, the second short edge 40c. In the illustrated example the power connector 48 is a universal serial bus (USB) type-C (USB-C) connector. Nevertheless, whilst the use of a USB-C type connector is particularly advantageous because of its small form factor, it will be appreciated that the connector could be any suitable connector for connection to an external power source. The battery power connector 50 is a surface mount connector that is provided on the first surface 40a of the circuit board 40 adjacent the first long edge 40d of the circuit board 40. The battery power connector 50 comprise a pair of resilient electrodes 50a that extend away from the first surface 40a and that are configured to, when the assistive device 10 is assembled, engage with and push resiliently against corresponding negative and positive battery terminals to form the electrical connection between the circuitry on that the circuit board 40 and the battery 42. The use of such an arrangement is beneficial as it simplifies manufacture of the circuit board 40 and the assembly of the assistive device 10; hence reducing manufacturing costs.

[0064] The electronic switch (mentioned in the overview above) is shown at 52 and is provided on the first surface 40a adjacent the first short edge 40b. The electronic switch 52 has an integral button for operating the switch that extends over the first short edge 40b. The electronic switch 52 may be any suitable form of switch - for example, a surface mount tactile switch or the like. As described in more detail later the electronic circuitry provided on the circuit board includes a latching switch circuit that when the switch is operated: activates and latches on (if the assistive device 10 is currently off); and deactivates and latches off (if the assistive device 10 is currently on).

[0065] A pair of motor contacts 54 are also provided on the on the first surface 40a of the circuit board 40 for connecting to corresponding electrical terminals of the motor 44 when the assistive device 10 is assembled. Each motor contact 54 respectively comprises a region or ‘pad’ of conductive material (e.g., solder, copper, or the like) that is formed on the first surface 40a. The motor contacts 54 have a shape and size that are configured to, when the assistive device 10 is assembled, engage with the corresponding electrical terminals of the motor 44 to form an electrical connection between the circuitry on that the circuit board 40 and the motor 44. The use of such an arrangement is beneficial as it allows the assistive device 10 to be assembled without requiring the motor 44 to be soldered in place, thus simplifying manufacture of the circuit board 40 and the assembly of the assistive device 10; hence reducing manufacturing costs further. Cover Portion

[0066] Figure 4 is a three-dimensional view of the cover portion 20-2 of the main body 20 of the assistive device 10. As seen in Figure 4, the cover portion 20-2 is shown with the circuit board 20-2 located in the cover portion 20-2, in a position that the circuit board 20-2 will remain in, when the assistive device 10 is fully assembled.

[0067] The cover portion 20-2 of the main body 20 has a perimeter wall 56 configured to provide a recess into which the circuit board 40 can be clipped when assembling the assistive device 10. To facilitate the clipping of the circuit board 20-2 into the cover portion 20-2, a plurality of circuit board clips 58 are provided, inside the recess, along the perimeter wall 56 on two sides of the cover portion 20-2. The circuit board clips 58 are configured for engaging with the two long edges 40d, 40e, of the circuit board 40. Specifically, in the illustrated example, a set of three clips 56 are provided for engaging at different locations along the first long edge 40d of the circuit board 40 and a set of three clips 56 are provided for engaging at different locations along the second long edge 40e of the circuit board 40. Each set of three clips 58 respectively comprises one clip 58 configured for engaging with the narrower portion 40f of the circuit board 40 and two clips for engaging with the wider portion 40g of the circuit board 40. A plurality of deformable ribs (or ‘crush ribs’) 60 are also provided, inside the recess, along the perimeter wall 56, on another side of the cover portion 20-2. The deformable ribs 60 are configured for engaging with the first short edge 40b of the circuit board 40 to help control the position of the circuit board 40 during assembly.

[0068] The perimeter wall 56 of the cover portion 20-2 comprises a first cut-away portion 62a and a second cut-away portion 64a.

[0069] The first cut-away portion 62a is formed in part of the perimeter wall 56 that extends adjacent the second short edge 40c of the circuit board 40 when the assistive device 10 is assembled. The first cut-away portion 62a is configured to receive, and extend partially around, the part of the power connector 48 that extends over the second short edge 40c of the circuit board 40. The first cut-away portion 62a is further configured to form, together with the base portion 20-1 of the main body 20 when the assistive device 10 is assembled, an aperture for providing access to connect a power source to the power connector 48.

[0070] The second cut-away portion 64a is formed in part of the perimeter wall 56 that extends adjacent the first short edge 40b of the circuit board 40 when the assistive device 10 is assembled. The second cut-away portion 64a is configured to receive, and extend partially around, the push button 46 for operating the assistive device 10. The second cut-away portion 64a is further configured to form, together with the base portion 20-1 of the main body 20 when the assistive device 10 is assembled, an aperture through which the push button 46 extends to allow operation of the assistive device 10 by a user.

[0071] The parts of the perimeter wall 56 that extend adjacent the long edges 40d, 40e of the circuit board 40, when the assistive device 10 is assembled, each include a portion that is configured to provide a respective elongate resilient clip 66 for clipping the cover portion 20-2 to the base portion 20-1 to form the main body 20. Each resilient clip 66 is sufficiently elastically deformable to allow the clip to flex when the cover portion 20-2 is correctly positioned and pressed against the base portion 20-1 to facilitate the clipping action. As seen in Figure 4 to help ensure that the resilient clips 66 are not too rigid, each resilient clip 66 includes a plurality of slots 66a. Whilst not visible, the part of the perimeter wall 56 that extends adjacent the first short edge 40b of the circuit board 40, when the assistive device 10 is assembled, may also include one or more portions that that are configured to provide one or more further resilient clips for clipping the cover portion 20-2 to the base portion 20-1 to form the main body 20.

[0072] One end of each part of the perimeter wall 56 that extends adjacent a long edge 40d, 40e of the circuit board 40 is respectively provided with a first part 68a of a poka- yoke mechanism for inhibiting assembly of the cover portion 20-2 and the base portion 20-1 with an incorrect relative orientation. In the illustrated example, the first part 68a of the poka-yoke mechanism provided in the cover portion 20-2 comprises a slot 68a respectively provided near the same end of each corresponding part of the perimeter wall that extends adjacent a long edge 40d, 40e of the circuit board 40. These slots 68a are configured for engagement with corresponding protrusions in a perimeter wall of the base portion 20-1 , when the cover portion 20-2 and the base portion 20-1 are correctly oriented relative to one another and are clipped together. It will, nevertheless, be appreciated that this arrangement is purely exemplary, and any suitable poka-yoke mechanism may be implemented for inhibiting erroneous assembly.

[0073] Base Portion

[0074] Figure 5 shows a number of different views of the base portion 20-1 of the main body 20 of the assistive device 10.

[0075] Figure 5(a) is a three-dimensional view of the base portion 20-1 . Figure 3(b) is a plan view of the base portion 20-1 shown in Figure 3(a). Figure 3(c) is a cross-sectional view through the base portion 20-1 along the line F-F shown in Figure 3(b). Figure 3(d) is a cross-sectional view through the base portion 20-1 along the line H-H shown in Figure 3(b). Figure 3(e) is a cross-sectional view through the base portion 20-1 along the line G-G shown in Figure 3(b).

[0076] As seen in the different views shown in Figure 5, the base portion 20-1 is illustrated with the battery 42, motor 44, and push button 46 in the different respective positions that they will take when the device is assembled.

[0077] The base portion 20-1 of the main body 20 has a perimeter wall 76 configured to provide a recess into which the battery 42 and motor 44 may be located when assembling the assistive device 10. To facilitate the clipping of the battery 42 into the base portion 20-1 , a plurality of battery clips 78 are provided, inside the recess, along the perimeter wall 76 on two sides of the base portion 20-1 that run generally parallel to the two long edges 40d, 40e of the circuit board 40 when the device is assembled. Specifically, in the illustrated example, a first set of three clips 76 are provided on one side of the base portion 20-1 and are configured for engaging at different locations along a first edge of the battery 42, whilst a second set of three clips 76 are provided on the other side of the base portion 20-1 and are configured for engaging at different locations along a second edge of the battery 42 opposite the first edges. A plurality of deformable ribs (or ‘crush ribs’) 80 are also provided, inside the recess, along the perimeter wall 76, on another side of the base portion 20-1 that runs generally parallel to the second short edge 40c of the circuit board 40 when the device is assembled. The deformable ribs 80 are configured for engaging with another edge of the battery 42 to help control the position of the battery 42 during assembly. Specifically, the battery clips 78 and deformable ribs 80 are mutually configured to position the battery 42 at a location in which the electrical terminals 42a of the battery 42 are positioned to engage with the corresponding resilient electrodes 50a of the battery power connector 50 provided on the circuit board 40, when the assistive device 10 is assembled.

[0078] A motor alcove 82 is formed on a floor of the recess formed by the perimeter wall 76 and is configured for receiving the motor 44 snugly at the correct location in the main body 20 when the assistive device 10 is assembled. Specifically, the motor alcove 82 is configured to receive the motor 44 at a location in which the electrical terminals 44a of the motor 44 are positioned to engage with the corresponding motor contacts 54 provided on the circuit board 40 when the assistive device 10 is assembled. The motor alcove 82 is also configured such that, when the assistive device 10 is assembled, the shaft of the motor extends from the motor alcove 82 and the ERM 44b provided on that shaft is free to rotate, within the main body 20, when the shaft is driven by the motor 44.

[0079] The perimeter wall 76 of the base portion 20-1 comprises a first cut-away portion 62b and a second cut-away portion 64b.

[0080] The first cut-away portion 62b is formed in part of the perimeter wall 76 that extends adjacent the second short edge 40c of the circuit board 40 when the assistive device 10 is assembled. The first cut-away portion 62b is configured to receive, and extend partially around, the part of the power connector 48 that extends over the second short edge 40c of the circuit board 40. The first cut-away portion 62b is further configured to form, together with the corresponding first cut-away portion 62a of the cover portion 20-2, when the assistive device 10 is assembled, the aperture for providing access to connect a power source to the power connector 48.

[0081] The second cut-away portion 64b is formed in part of the perimeter wall 76 that extends adjacent the first short edge 40b of the circuit board 40 when the assistive device 10 is assembled. The second cut-away portion 64b is configured to receive, and extend partially around, the push button 46 for operating the assistive device 10. The second cut-away portion 64b is further configured to form, together with the corresponding second cut-away portion 62b of the cover portion 20-2, when the assistive device 10 is assembled, an aperture through which the push button 46 extends to allow operation of the assistive device 10 by a user.

[0082] A set of guides 84 are provided internally on the floor of the recess formed by the perimeter wall 76. The guides 84 are mutually configured, with corresponding guide portions 46a of the push button 46, for engaging with one another to guide reciprocal movement of the push button 46 into and out of the main body 20 (as indicated by arrow A) when the push button 42 is pushed and released. In the illustrated example, to facilitate the reciprocal movement (A) of the push button 46, the push button 42 is provided with a resilient leg 46b that is configured to engage against an external surface of the motor alcove to provide tactile reliant resistance to movement of the push button 42 when pressed into the main body 20, and to provide a spring force for returning the push button 42, out of the main body 20, to the original position when released. Nevertheless, it will be appreciated that the presence of a resilient leg 46b may not be necessary or may be omitted or replaced with an alternative mechanism.

[0083] The push button 46, guides 84, guide portions 46a, and resilient leg 46b are mutually configured such that when the push button 46 is pressed during operation it engages with the integral button of the electronic switch 52 to activate, or deactivate, the assistive device 10.

[0084] The parts of the perimeter wall 76 that extend adjacent the long edges 40d, 40e of the circuit board 40, when the assistive device 10 is assembled, each include an elongate recess 86 that is configured to engage with a respective elongate resilient clip 66 of the cover portion 20-2, when clipping the cover portion 20-2 to the base portion 20-1. Specifically, when engaged, part of the elongate resilient clip 66 is received in the elongate recess 86 to secure the cover portion 20-2 to the base portion 20-1. Whilst not visible, the part of the perimeter wall 76 that extends adjacent the first short edge 40b of the circuit board 40, when the assistive device 10 is assembled, may also include one or more recesses that that are configured to engage with one or more further resilient clips provided on the cover portion 20-2, when clipping the cover portion 20-2 to the base portion 20-1

[0085] One end of each part of the perimeter wall 76 that extends adjacent a long edge 40d, 40e of the circuit board 40 is respectively provided with a second part 68b of the poka-yoke mechanism for inhibiting assembly of the cover portion 20-2 and the base portion 20-1 with an incorrect relative orientation. In the illustrated example, the second part 68b of the poka-yoke mechanism provided in the base portion 20-1 comprises a protrusion 68b respectively provided near the same end of each corresponding part of the perimeter wall 76 that extends adjacent a long edge 40d, 40e of the circuit board 40. These protrusions 68b are configured for engagement with the corresponding slots 68a in the perimeter wall 56 of the cover portion 20-2, when the cover portion 20-2 and the base portion 20-1 are correctly oriented relative to one another and are clipped together. It will, nevertheless, be appreciated that this arrangement is purely exemplary, and any suitable poka-yoke mechanism may be implemented for inhibiting erroneous assembly.

[0086] A circuit for controlling the assistive device 10, that may be fabricated on the circuit board 40, will now be described, by way of example only, with reference to Figures 6 and 7.

[0087] Control Circuitry

[0088] Figure 6 is a simplified block schematic of an example control circuitry the assistive device 10. As seen in Figure 6, the control circuitry is shown generally at 600 with the battery 42 and motor 44 of the assistive device 10 connected, as they would be when the assistive device 10 is assembled.

[0089] The control circuitry 600 comprises a charging circuit 610, a latching switch circuit 620, and a timing circuit 630.

[0090] The charging circuit 610 is electrically connected to the power connector 48 for disconnectable electrical connection to an external source of DC power 650. In the illustrated example, the external source of DC power 650 is a 5V DC power supply providing a potential difference of 5V been a first (more positive or ‘5V’) power rail 652, and a second (less positive or ‘OV’) power rail 654.

[0091] The charging circuit 610 is configured for supplying current from the external source of DC power 650 to the battery 42, to charge the battery 42 when the power connector 48 is connected to the external source of DC power 650 and the battery 42 is depleted. As illustrated in Figure 6, one or more light sources (e.g., light emitting diodes (LEDs)) 656 may be connected into the charger circuit 610 for indicating one or more corresponding charging statuses of the battery (e.g., fully depleted, partially depleted, fully charged, charging and / or the like). It will be appreciated that where one or more LEDs 656 (or the like) are provided, the cover portion 20-2 of the main body 20 may be adapted to allow the light from the LEDs 656 to be visible to a user.

[0092] The charging circuit 610 may take any suitable form that will be familiar to those skilled in the art and, in the interests of conciseness, will not be described in detail.

[0093] The latching switch circuit 620 is configured, when the switch 52 on the circuit board 40 is operated, for connecting / disconnecting a negative terminal (M-) of the motor 44, and a first output connection 630a of the timing circuit 630, to / from the negative terminal of the battery 42 (via resistor R1) (and to / from the second (‘0V’) power rail 654 of the external source of DC power 650, if connected).

[0094] Specifically, when the switch 52 is operated and the negative terminal (M-) of the motor 44, and a first output connection 630a of the timing circuit 630, are not connected to the negative terminal of the battery 42, the latching switch circuit 620 connects them and maintains that connection until the switch 52 is operated again. Similarly, when the switch 52 is operated and the negative terminal (M-) of the motor 44, and the first output connection 630a of the timing circuit 630, are connected to the negative terminal of the battery 42, the latching switch circuit 620 disconnects them and maintains that disconnected state until the switch 52 is operated again.

[0095] Accordingly, when the switch 52 is operated the motor 44 1 timing circuit 630 become connected and operational if they are currently disconnected and inactive. Similarly, when the switch 52 is operated the motor 44 I timing circuit 630 become disconnected and inactive if they are currently connected and operational.

[0096] The latching switch circuit 620 may take any suitable form that will be familiar to those skilled in the art and, in the interests of conciseness, will not be described in detail.

[0097] The timing circuit 630 is configured, when operational, to provide power intermittently to drive the motor 44 and hence cause the assistive device 10 to vibrate. Specifically, the timing circuit 630 is configured to switch between: a first state in which a second output connection 630b provides a positive voltage to the positive terminal (M+) of the motor that is sufficient for driving the motor 44; and a second state in which the second output connection 630b does not provide a positive voltage to the positive terminal (M+) of the motor that is sufficient for driving the motor 44.

[0098] Specifically, the timing circuit is configured to switch the motor 44 (and hence the vibration) on and off at a frequency of 1.35Hz (within reasonable tolerances of, for example, 10%), which corresponds to 81 beats per minute (or 73 to 89 beats per minute when the 10% tolerance is applied).

[0099] The timing circuit 630 may take any suitable form that will be familiar to those skilled in the art. One possible example of such a timing circuit 630 will now be described with reference to Figure 7, which is a simplified circuit schematic of one example of such a timing circuit 630.

[0100] As seen in Figure 7, the exemplary timing circuit 630 comprises a dedicated timer integrated circuit (IC) 632. As those skilled in the art will be aware such dedicated timer ICs are widely available commercially - the dedicated timer IC 632 may, for example, comprise a conventional ‘555’ timer IC or the like. The dedicated timer IC 632 is configured by the timing circuit 630 to provide a substantially square wave output 634 at the desired frequency (e.g., 1 ,35Hz in this example). This square wave output 634 is provided to a base terminal of a bipolar junction transistor 636 (via an appropriately valued base resistor, R2), for switching that transistor 636 between (at the frequency of the square wave output 634): an on state in which current can flow between the collector and emitter of that transistor 636; and an off state in which current cannot flow between the collector and emitter of that transistor 636. The base resistor, R2, may have any suitable value for limiting the corresponding base current depending on the transistor used.

[0101] The first output connection 630a of the timing circuit 630 is connected to the emitter of the transistor 636, and second output connection 630b of the timing circuit 630 is connected to the collector of the transistor 636. The second output connection 630b of the timing circuit 630 I transistor collector terminal is also connected, via an appropriate emitter resistor R3 to the positive terminal of the battery 42. The emitter resistor, R3, may have any suitable value for limiting the corresponding current flowing though the transistor when in the on state.

[0102] When the transistor 636 is in the off state, therefore, the emitter terminal - and hence second output connection 630b - rises in voltage towards that of the positive battery terminal. Accordingly, the motor 44 and corresponding vibration is turned on. Contrastingly, when the transistor 636 is in the on state, the emitter terminal - and hence second output connection 630b - drops in voltage towards that of the first output connection 630a (and hence that of the negative battery terminal). Accordingly, the motor 44 and corresponding vibration is turned off.

[0103] Summary

[0104] It can be seen, therefore, that the assistive device 10 described above is an electronic wearable device that creates a tapping sensation at a specific frequency and intensity. The assistive device 10 has been found to have a positive impact on humans suffering from a range of symptoms arising from conditions such as Parkinson’s disease, Tourette syndrome, Tics and Tremor. The assistive device 10 makes beneficial use of an ERM motor to create intermittent vibration with an on-off frequency controlled using a simple timer IC chip, such as the so-called ‘555 timer’ which is a widely available, and well-known timer chip, to regulate the on / off duty cycle frequency. The intensity of vibration is controlled via voltage regulation and power output. The assistive device 10 is designed to be rechargeable with simple operation that helps to ensure that those with Parkinson’s disease and other similar movement disorders can operate the assistive device 10 easily. Beneficially, the device uses a specific frequency of 1.35 Hz that reflects 81 beats per minute. The heart rate for a normal individual ranges between 60-100 beats per minute and it is believed that the efficacy of the device is partly due to the regulatory nature of the frequency, along with the sensory input that is received in the brain.

[0105] The intensity of the vibration is calibrated to be sufficient for the signals to be received but not too strong that it fully diverts attention to the device. Thus, the device beneficially does not draw undue focus by the wearer.

[0106] The selection of the specific optimum frequency of operation and the appropriate selection of components, especially of the ERM based vibration mechanism, allows for a simple circuit design to be implemented, in a very compact package, that can be manufactured at extremely low cost. Hence, the assistive device 10 can be priced at a level that makes it accessible to a significantly larger proportion of potential users than current devices can be. The simplicity of operation, via a single push button 46, makes the device easy to operate even by those who experience very severe involuntary movements - thus making the device even more accessible.

[0107] As those skilled in the art will appreciate, whilst a detailed example has been described above, a number of modifications and alternatives can be made to the above example whilst still benefiting from the innovative concepts embodied therein.

[0108] For example, whilst the assistive device is described as being powered by a rechargeable battery a simpler device could be powered by a replaceable battery such as a coin cell or the like. Where the replaceable battery is not a rechargeable battery the circuitry may be further simplified to omit the charging circuitry.

[0109] Whilst the assistive device is described as being operated by a single push button the device could be configured for operation by another form of mechanical switch such as a single slide switch or the like. Moreover, the push button or other switch may be configured to self-latch mechanically in which case the circuitry could be further simplified to omit the latching switch circuit or to use a simpler switch circuit. Whilst the example assistive device described above is configured to be worn on the wrist it will be appreciated that the assistive device could be configured to be worn elsewhere on a user’s body.

[0110] Various other modifications will be apparent to those skilled in the art and will not be described in further detail here.

Claims

Claims1. A wearable assistive device for alleviating the symptoms of a movement disorder, the assistive device comprising: a main body for wearing against a user’s skin; means for vibrating the main body against the skin of the user when the device is being worn by the user; circuitry for controlling the assistive device; an internal power source for powering the assistive device; and means for activating and deactivating the assistive device; wherein the circuitry is configured to control vibration provided by the means for vibrating, by switching the vibration on and off periodically at a periodic frequency of 1.35Hz.

2. The wearable assistive device of claim 1 , wherein the means for vibrating comprises a motor having a shaft on which is provided an eccentric rotating mass configured for providing the vibration when the motor is powered.

3. The wearable assistive device of claim 1 or 2, wherein the circuitry comprises a timer circuit that is configured to control the vibration provided by the means for vibrating.

4. The wearable assistive device of claim 1 or 2, wherein the timer circuit comprises a 555 timer integrated circuit configured to control the vibration provided by the means for vibrating.

5. The wearable assistive device of any of claims 1 to 4 wherein the means for activating and deactivating the assistive device comprises a user operable switch for activating the assistive device when the assistive device is off, and for deactivating the assistive device when the assistive device is on.

6. The wearable assistive device of claim 5, wherein the circuitry comprises a latching circuit for activating the assistive device and maintaining the device in an on state if the switch is operated when the assistive device is off, and for deactivating the assistive device and maintaining the device in an off state if the switch is operated when the assistive device is on.

7. The wearable assistive device of claim 5 or 6, wherein the user operable switch comprises a push button.

8. The wearable assistive device of claims 5, 6, or 7 wherein the assistive device is configured for operation by means of the user operable switch for activating and deactivating the assistive device, without having another mechanism for receiving additional user input for controlling operation of the device.

9. The wearable assistive device of any preceding claim, wherein the assistive device comprises a charging port, and the circuitry comprises a charging circuit configured for charging the internal power source when the charging port is connected to a compatible external power source.

10. The wearable assistive device of any preceding claim, wherein the wearable assistive device is configured to be worn on a wrist of the user.11 . The wearable assistive device of any preceding claim, wherein the main body comprises a first portion defining a first recess, and a second portion defining a second recess, the first portion and the second portion being mutually configured for coupling to one another to bring the first recess and the second recess together to form a chamber for housing the means for vibrating, the circuitry, and the internal power source when the assistive device is assembled.

12. The wearable assistive device of claim 11 , wherein the circuitry is provided on a circuit board, and the first portion is configured for holding the circuit board in the first recess when the assistive device is assembled.

13. The wearable assistive device of claim 11 or 12, wherein the circuit board comprises first connecting portions for forming an electrical connection to electricalterminals of the means for vibrating, and the first portion and the second portion are mutually configured for holding the means for vibrating and the circuit board against one another with the first connecting portions in electrical contact with the electrical terminals of the means for vibrating.

14. The wearable assistive device of claim 11 , 12 or 13, wherein the circuit board comprises second connecting portions for forming an electrical connection to electrical terminals of the internal power source, and the first portion and the second portion are mutually configured for holding the internal power source and the circuit board against one another with the second connecting portions in electrical contact with the electrical terminals of the internal power source.

15. The wearable assistive device of any of claims 11 to 14, wherein the second portion is configured for holding the means for vibrating, and the internal power source, in the second recess when the assistive device is assembled.

16. The wearable assistive device of any preceding claim, wherein the assistive device is configured for switching the vibration on and off periodically at only a single periodic frequency.

17. A wearable assistive device for alleviating the symptoms of a movement disorder, the assistive device comprising: a main body for wearing against a user’s skin; means for vibrating the main body against the skin of the user when the device is being worn by the user; circuitry for controlling the assistive device; an internal power source for powering the assistive device; and means for activating and deactivating the assistive device; wherein the circuitry is configured to control vibration provided by the means for vibrating, by switching the vibration on and off periodically at a periodic frequency, andwherein the means for vibrating comprises a motor having a shaft on which is provided an eccentric rotating mass configured for providing the vibration when the motor is powered.

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