Wearable neuromuscular stimulation system for treatment of dyspnoea

Abstract

The present invention provides a wearable neuromuscular stimulation system for treatment of dyspnoea and / or for increasing VO2 max, comprising a garment configured to be worn about a body of a user; and at least one vibratory stimulation module secured to the garment and comprising a housing enclosing a vibration source mounted such as to focus vibrations generated by the vibration source against the body of the user, reduce variations in vibration strength and / or frequency delivered to the user, reduce external noise and vibration sensation, and reduce variations in power requirements to drive the system.

Description

[0001] WEARABLE NEUROMUSCULAR STIMULATION SYSTEM

[0002] FOR TREATMENT OF DYSPNOEA

[0003] Field of the invention

[0004] The present invention relates to a wearable neuromuscular stimulation system for treatment of dyspnoea including a garment optionally incorporating one or more respiration sensors for detecting inspiration, expiration and breathing patterns. The system is adapted to trigger the delivery of neuromuscular stimulation based on information obtained from the one or more sensors or an alternative means of monitoring breathing to apply a therapy in-phase with breathing via an array of vibration modules disposed about the garment in order to, for example, reduce dyspnoea and / or increase VO2 max.

[0005] Background of the invention

[0006] There is a significant unmet need for improved treatments to relieve the most challenging symptom of Chronic Obstructive Pulmonary Disease (COPD), namely breathlessness. Breathlessness, clinically referred to as dyspnoea, can be particularly debilitating and is central to how COPD progresses. The perception of breathlessness can cause significant anxiety, distress, and leads to the avoidance of physical activity. Over time this leads to a loss of physical fitness, leading to further breathlessness and eventually the need for hospitalisation. COPD is the third leading cause of death in the US, where there are 16 million diagnosed COPD sufferers. Breathlessness in COPD affects an estimated 36 million European and 391.9 million people worldwide. By giving COPD sufferers a tool to help them relieve and control their breathlessness, there is huge potential to significantly improve their quality of life and, longer term, to help reduce healthcare costs and avoid hospitalisations.

[0007] Other conditions than COPD that can cause or contribute to dyspnoea include (but are not limited to) allergies, asthma, respiratory illnesses like Covid 19 or bronchitis or other viral or bacterial infections, inflammation of or around the lungs or heart, Tuberculosis (TB), fluid inside or around the lungs, lung cancers, pulmonary hypertension, pulmonary embolism, obesity, heart failure, arrhythmia, anxiety, certain medications, and the side effects of sleep apnoea.

[0008] In-phase chest wall vibration (CWV) is a known mechanism for reducing the symptom of breathlessness in COPD patients. “In-phase” refers to the way in which vibratory neuromuscular stimulation is applied to discreet locations on the chest during inspiration and during expiration (upper intercostal muscles during inspiration, lower intercostal muscles during expiration). This type of neuromuscular stimulation (which may also be referred to as neurostimulation) has been verified as effective in controlled lab environments and studies have been published to this effect. CWV has also been shown to increase VO2 max during exercise in people with COPD, and has potential in increasing this physiological parameter in any population where this is deemed beneficial, for example in other disease states or to improve athletic performance. In CWV, it is important that vibrations be delivered in a distinct frequency range (60 to 150 Hz), with most of the evidence supporting 100Hz as an optimal vibration frequency. One such system and method is disclosed in International patent application W02010071919A1.

[0009] To deliver the stimulation in-phase, there is a requirement to accurately and reliably detect the onset and end of inspiration and expiration in real time. Various sensors such as respiratory inductive plethysmography (RIP) bands may be repurposed to facilitate the detection of breathing phase and have been used to measure respiration rate and air volumes for several decades, with the primary application being in sleep studies.

[0010] There is however a need for a streamlined, portable, and cost effective means of enabling in-phase neuromuscular stimulation which provides a more consistent and reliable delivery of vibratory stimulation to the body of the patient in order to allow patients to receive this therapy effectively in “real world” settings, for example at home, in a clinic or in an ambulatory setting for prolonged periods while a patient completes activities of daily living or exercise programmes, for example.

[0011] The present invention has therefore been developed with a view to addressing the above mentioned needs in order to provide an improved means of delivering vibratory stimulation therapy to patients suffering from COPD or other respiratory conditions, in addition to any other suitable application in which vibratory neuromuscular or neurostimulation is required.

[0012] Summary of the invention

[0013] According to an aspect of the present invention there is provided a wearable neuromuscular stimulation system for treatment of dyspnoea or for increasing VO2 max comprising a garment configured to be worn about a body of a user; at least one vibratory stimulation module secured to the garment and comprising a housing enclosing a vibration source mounted such as to optimise the delivery of vibration energy to the body of the user, the housing comprising a base on which the vibration source is mounted and an upper enclosure surrounding the vibration source; an isolating element securing the base to the upper enclosure and configured to reduce or eliminate the transfer of vibration from the base to the upper enclosure; and one or more respiration sensors.

[0014] Preferably, the isolating element is configured to facilitate vibrations from the vibration source to propagate in a direction normal to the base. Preferably, the isolating element comprises a resiliently deformable element connecting the base to the upper enclosure.

[0015] Preferably, the resiliently deformable element circumscribes the base.

[0016] Preferably, the resiliently deformable element is at least partially concertina in form.

[0017] Preferably, the housing comprises a keyway into which the resiliently deformable element is secured.

[0018] Preferably, the isolating element comprises an elastomeric material.

[0019] Preferably, the isolating element comprises a spring.

[0020] Preferably, the upper enclosure at least partially comprises a resiliently deformable material.

[0021] Preferably, the housing at least partially comprises a sound absorbent material.

[0022] Preferably, the housing at least partially comprises electromagnetic shielding.

[0023] Preferably, the garment comprises a dock for receiving and retaining the at least one vibratory stimulation module and which is configured to mechanically isolate the vibratory stimulation module from compressive forces generated by tension in the garment.

[0024] Preferably, the dock comprises a relatively inelastic material.

[0025] Preferably, the garment is variable in fit.

[0026] Preferably, the garment comprises one or more tensioners arranged to allow a pressure applied by the garment to the housing to be adjusted.

[0027] Preferably, the garment comprises at least one temperature sensor.

[0028] Preferably, the temperature sensor is configured to monitor the temperature of the vibration source and / or the user.

[0029] Preferably, the neuromuscular stimulation system comprises at least one accelerometer.

[0030] Preferably, the accelerometer is configured to monitor the motion of the vibration source and / or the user. Preferably, the neuromuscular stimulation system comprises a controller operable to drive the vibration source in response to feedback from the one or more respiration sensors.

[0031] Preferably, the controller is operable to modulate the frequency and / or amplitude of vibrations generated by the vibration source.

[0032] Preferably, the controller comprises an algorithm operable to monitor a signal generated by each of the respiration sensors and to compare the signals in order to facilitate a determination of a breathing phase and / or pattern of the user based on the relative values of the generated signals.

[0033] Preferably, the system comprises an array of vibratory stimulation modules controllable independently and / or in groups.

[0034] Preferably, the phases of the two or more of the vibratory stimulation modules can be adjusted.

[0035] Preferably, the vibratory stimulation module is configured to dither the vibrations in order to modulate the vibration frequency.

[0036] Preferably, the vibration source comprises an eccentric rotating mass motor.

[0037] Preferably, the vibration source is operable to produce vibrations in a frequency range of between 50Hz and 150Hz, more preferably between 75Hz and 125Hz, most preferably 100Hz.

[0038] Preferably, the vibration source is operable to produce vibrations in an amplitude range of between 1G and 50G, more preferably between 3G and 20G.

[0039] Preferably, the respiration sensors comprise at least a first sensor arranged on the garment in a first orientation extending, in use, transversely of a chest of the user, and at least a second sensor extending in a second orientation offset to the first orientation.

[0040] Preferably, the respiration sensors are distributed about the garment.

[0041] As used herein, the term “garment” is intended to mean an item or items which can be securely worn about one or more parts of the body, and for example may take the form of a vest or sleeve for location about the torso of a user but equally may be attached to the body via adhesive patches or the like.

[0042] As used herein, the term “vibration source” is intended to mean a mechanical, electromechanical, electromagnetic, electrical or electronic device that is operable to generate a vibration output in response to an electrical input, for example a vibration motor such as an eccentric mass motor or piezoelectric device. As used herein, the term “spring” is intended to mean an element adapted to undergo resilient deformation such as compression and extension in order to isolate one component from another and may include a coil spring, a leaf spring, a torsion spring, an elastomer based spring or other resiliently deformable material, a gas spring or a spring / damper assembly.

[0043] As used herein, the term “VO2 max” is intended to mean the maximum volume of oxygen the body can use during exercise, and is usually an indication of lung capacity, often used by clinicians when assessing Cardiopulmonary Exercise Test results in COPD and other conditions and by athletes and sports physiologists as part of a process of measuring performance.

[0044] Brief description of the drawings

[0045] The present invention will now be described with reference to the accompanying drawings, in which:

[0046] Figure 1 illustrates an embodiment of a wearable neuromuscular stimulation system for treatment of dyspnoea according to the present invention;

[0047] Figure 2 illustrates a perspective view from above of a vibratory stimulation module forming part of the wearable neuromuscular stimulation system shown in Figure 1 ;

[0048] Figure 3 illustrates a perspective view from below of the vibratory stimulation module of Figure 2;

[0049] Figure 4 illustrates a sectioned view of the vibratory stimulation module of Figures 2 and 3 showing a vibration motor contained within a housing, the housing comprising a flexible gasket that secures a base and an upper enclosure together while permitting relative movement therebetween;

[0050] Figure 5 illustrates an enlarged view of the portion labelled as “B” in Figure 4;

[0051] Figure 6 illustrates a perspective view of a base forming part of the housing for the vibration motor;

[0052] Figure 7 illustrates the baseplate of Figure 6 with the vibration motor located thereon;

[0053] Figure 8 illustrates an alternative embodiment of a vibratory stimulation module forming part of the wearable neuromuscular stimulation system shown in Figure 1 ;

[0054] Figure 9 illustrates a sectioned perspective view of the vibratory stimulation module shown in Figure 8;

[0055] Figure 10 illustrates an alternative perspective view of the vibratory stimulation module of Figure 9; Figure 11 illustrates a sectioned elevation of the vibratory stimulation module of Figure 9 and 10;

[0056] Figure 12 illustrates an enlarged view of the portion labelled as “A” in Figure 11 ;

[0057] Figure 13 illustrates a sectioned side elevation of an exemplary vibratory stimulation module secured within a pocket of the wearable neuromuscular stimulation system of the invention;

[0058] Figure 14 illustrates a perspective view of a further alternative embodiment of a vibratory stimulation module forming part of the wearable neuromuscular stimulation system shown in Figure 1 ; and

[0059] Figure 15 illustrates sectioned side elevation of the vibratory stimulation module of Figure 14 illustrating a flexible gasket, of bellows form, securing a base and an upper enclosure of a housing together while permitting relative movement therebetween.

[0060] Detailed description of the invention

[0061] Referring now to Figure 1 of the accompanying drawings there is illustrated a wearable neuromuscular stimulation system for treatment of dyspnoea or for increasing VO2 max, generally indicated as 10, according to an embodiment of the present invention. The system 10 comprises a garment 12 which in the embodiment illustrated is in the form of a vest designed to be worn snugly yet comfortable on the body of the user, and preferably about the torso / chest region in order to monitor the breathing phase of the user and / or deliver neuromuscular stimulation to the chest. The term “breathing phase” is intended to mean a given portion of the breathing cycle of a user, being related to the lung volume of the user at that instance, the breathing phase typically reciprocating between the inspiration phase in which the lung volume is increasing, and the expiration phase in which the lung volume is decreasing, and which is however also intended to cover points or phases intermediate these two extremes. In the embodiment illustrated the garment 12 is of a minimalist design in order to be relatively lightweight and to avoid restricting movement of the user, and to be therefore unobtrusive. The system 10 can therefore be worn for prolonged periods and during ambulatory activity or the like. The system 10 may be water resistant or waterproof. The garment 12 is preferably formed at least in part from elastic material and is further preferably provided with means such as straps or other tensioning elements or the like in order to allow the fit of the garment 12 on the user to be tailored to provide the necessary body conformity. The system 10 could comprise of one or more belts (not shown), using flexible electronics and one or more power sources, connected via a wired or wireless means. It will be appreciated that although the system 10 of the embodiment illustrated is configured for treating dyspnoea and thus designed to be worn about the torso / chest of the user, the system 10 may be configured to be worn about any other region of the body to which neuromuscular stimulation is to be applied. The system 10 is preferably provided with one or more respiration sensors (not shown) preferably disposed about the garment 12 for use in the real time detection of the inspiration and expiration of a user’s breathing, in particular but not exclusively to facilitate the provision of in-phase neuromuscular stimulation to provide relief from the symptoms of Chronic Obstructive Pulmonary Disease (COPD). The respiration sensors may be of any suitable type, for example a sensor which undergoes measurable changes in electrical or electromechanical or electromagnetic properties as the garment 12 expands and contracts in response to the user breathing. While less preferred it will be appreciated that the respiration sensors may be omitted or supplemented by the use of alternative means of achieving the real time detection of the user’s breathing phases, for example a respiration mask which may be operable directly or indirectly to actuate the in-phase neuromuscular stimulation effected by the garment 12, or a remote sensor such as LIDAR, RADAR, ultrasonic or capacitive sensors in a chair or bed or an audio sensor placed near the throat or from a photoplethsmographic signal.

[0062] In the embodiment illustrated it is preferred that the array of the respiration sensors (not shown) are located on or distributed about the garment 12 so as to be positioned at various locations about the chest when the garment 12 is worn as intended. The garment 12 may be formed from any suitable material or combination of materials, and for example may be partially or wholly formed from an elastic fabric material such as bamboo charcoal blend. Other materials could include a blend of cotton, elastane, spandex, Lycra, polyester, nylon or modal blends, where the resulting blend is elastic. In addition one or more regions of the garment 12 may comprise relatively inelastic material such as cotton denim (without spandex or elastane), wool mix, 100 percent cotton or linen, polyester (non-stretch) in order to provide mechanical isolation for the vibration modules from tensile forces seen by the garment 12 during fitting, as described in detail hereinafter.

[0063] It is beneficial for the respiration sensors (not shown) to be positioned at different locations or levels of the chest, for example for monitoring different disease states and accurately monitoring or sensing breathing phases, movements or patterns. For example the array of sensors may comprise sensors oriented to extend, when the garment 12 is worn about the chest of the user, transversely or laterally across the chest of the user, and preferably across the upper and lower chest region. Additional vertically and diagonally extending sensors are preferably also employed to measure different regions of chest expansion / contraction.

[0064] By combining and analysing the resulting signals from the respiration sensors and / or respiration mask (not shown) if utilised, it is possible to detect many different breathing patterns. In particular the use of respiration sensors integrated into the garment 12 allows for a three dimensional mapping of breathing mechanics specific to the wearer of the garment 12. The combination of signals obtained from the array of respiration sensors and / or respiration mask allows reliable and accurate detection of respiratory phase during periods of atypical breathing patterns such as dynamic hyperinflation, when respiratory rates may be elevated and relative changes in chest circumference from breath to breath reduced. A simultaneous change in electrical properties of sensors placed at different locations on the garment 12 provides a reliable signal to indicate chest expansion and therefore inspiration.

[0065] The system 10 preferably comprises a local controller (not shown), preferably integrated into the garment 12, and which receives signals from the respiration sensors and / or the respiration mask or associated equipment. The controller runs an algorithm that monitors the signal generated by each of the respiration sensors and / or mask, for example comparing the signals from two or more of the sensors, from which comparison various determinations regarding the breathing phase or pattern of the user can be determined.

[0066] The output signal from the respiration sensors and / or mask can then be used to actuate an array of vibratory stimulation modules 14 illustrated in Figures 2 to 7 and 14 and which are also disposed about the garment 12, each at a location which corresponds to an anatomical site to which neuromuscular stimulation is to be effectively applied in order to treat a particular condition. For example in the embodiment illustrated where the system 10 is configured for treating dyspnoea the vibratory stimulation modules 14 are positioned on the garment 12 to apply vibratory stimulation to the upper and lower intercostal muscles that form part of and move the chest wall. As noted above the garment 12 has an adjustable and / or stretch fit in order to accommodate different sized users and to allow for a closely conforming fit in order to both effectively monitor breathing phase and to efficiently deliver vibratory stimulation as required. In use the garment 12 is applied to the user and is then adjusted in tightness / fit to ensure good contact with the region of the body to be treated, with the user ultimately deciding on the fit that is comfortable. This will likely vary from person to person and may vary for the same user depending on the circumstances, such as a particular activity being undertaken, type of clothing being worn over or under the garment 12, environment conditions, etc. As a result there may be significant variation in the fit of the garment 12, which will then have an impact of the intensity of the vibratory stimulation that will be applied by the vibratory stimulation modules 14, impacting the efficacy of the treatment.

[0067] In particular, the use of a flexible, fabric garment 12 to retain the vibratory stimulation modules 14 can introduce variabilities in how vibration energy is transferred to the intended target (the body). The tightness with which the garment 12 is applied can affect the total energy in the system 10 - tighter restraint of the garment 12 and, therefore, vibration modules 14 can reduce the vibration energy. Similarly, anything making contact with an outer surface of the garment 12 can affect energy in the system 10. Both of the above scenarios are likely during use of the present invention. The more energy that is taken out of the system 10, the more power is required to keep the vibrations generated by the vibration modules 14 in the desired frequency / amplitude range. This can be monitored by the controller.

[0068] This can be compensated for by monitoring the vibrations and utilizing software to adjust the amount of power being supplied to the vibration modules 14. However, the vibration modules 14 then have to operate over a wider range of voltages, thus resulting in a higher or more variable power requirement and potentially temperature rise, which can be managed by the controller.

[0069] Furthermore, as the garment 12 preferably comprises a soft shell, vibrations propagate outwards as well as inwards towards the body. This makes the vibrations potentially as perceptible on the outside as on the inside of the garment 12, being the actual target of vibration delivery. It is therefore possible, if contact is made with the exterior of the garment 12, to feel the vibration to the same extent as can be felt on the inside. Notably with an eccentric rotating mass (ERM) as the vibration source, vibrations propagate in all directions around the axis the mass is rotating on, but with any vibration source, there will be vibrations outwards as well as inwards due to the backwards / forwards motion.

[0070] It is thus an object of the invention that vibrations are only perceivable on the inner side of the garment 12 such as to be as discreet and as quiet as possible. It is therefore desirable to use as small a vibration source as possible, and as little power as possible, to achieve the desired effect.

[0071] The vibratory stimulation modules 14 comprises a housing 16 enclosing a vibration source in the form of a vibration motor 18, the housing 16 being suitably secured to the garment 12 and through which housing 16 vibratory stimulation is transmitted to the anatomical site from the vibration motor 18. The vibration source or motor 18 may be of any suitable form, for example a mechanical, electromechanical, electromagnetic or electronic device that is operable to generate a vibration output in response to an electrical input. The vibration motor 18 may for example comprise a piezoelectric element (such as PVDF (polyvinylidene fluoride), linear actuator such as a Linear Resonant Actuator (LRA - such as using a spring mass system driven by an AC voltage to create a linear oscillation), speaker such as a voice coil actuator driven by a Class D amplifier, a coin vibration motor (pancake motor) or, as illustrated in Figures 2 to 7, an eccentric rotating mass based motor. The delivery frequency and amplitude can be adjusted, as can the switching and relative timing of the individual delivery devices. As an example, pulse width modulation (PWM) which involves rapidly switching a voltage signal on and off leading to pulses of varying widths, can be used to control the average voltage and the motor speed. For this case, the duty cycle is adjusted by varying the on time, and thus a higher average voltage for greater on time, and vice versa. For treating dyspnoea it is the amplitude and frequency of vibration that is important, not the type of vibration motor 18 employed, as the amplitude dictates the strength of vibration experienced by the user and correct frequency range is required for effective therapy.

[0072] Vibration produced by an eccentric rotating mass is an example of “Driven Harmonic Vibration”, meaning there is an external driving force causing the vibration. The excitation input is the rotation of the eccentric mass around the central motor shaft. A DC voltage controls the speed of the motor (the two are directly proportional) and therefore the frequency of the generated vibration. Eccentric rotating mass motors work over a range of voltages. As the applied voltage is increased, the vibration frequency increases proportionally, and vibration amplitude will also increase. When modelling such a vibration motor:

[0073] Fo = mra>2where:

[0074] Fo is the amplitude of the centrifugal force, m is the mass of the eccentric mass, r is the distance from the motor shaft to the centre of the eccentric mass a) is the angular velocity of the motor.

[0075] The driving current of the eccentric rotating mass motor is proportional to the torque ‘load’ seen by the motor. As vibration energy is taken out of the system 10, the torque required to continue spinning the eccentric mass will increase, as will the current.

[0076] Strength of vibration is referred to as vibration amplitude (a), which is measured in acceleration, G (acceleration caused by earth gravitational pull), and is dependent on the centripetal force (Fc) and the mass of the body the motor is attached to, the target mass (M).

[0077] Fc=Ma

[0078] For the wearable neuromuscular stimulation system 10 of the invention the amplitude of vibration is important as it dictates the strength of vibration experienced by the user. When utilising a vibration motor 18, in particular one containing moving parts such as an eccentric rotating mass motor, it is necessary to encase the vibration motor 18 inside the housing 16 to protect the vibration motor 18 and the user, primarily to ensure consistent operation. This does however have an impact on the operation of the system 10. As the vibration motor 18 is encased in the housing 16, vibrations can be transferred in any direction and into anything touching the housing 16, both on the inner and outer sides of the garment 12. The flexible garment 12 provides a degree of constraint to the vibration motor 18 on one side and the body of the user provides constraint on the other side. This configuration can give rise to variations in the current required to drive the vibration motor 18 and / or variations in the strength of the vibrations experienced by the user, given the variations in the fit of the garment and other external influences.

[0079] For example, an object (such as a hand) contacting the outer garment 12 over one of the vibratory stimulation modules 14 may reduce displacement of the vibratory stimulation module 14, meaning less vibration energy is extracted. This may alter the current required to drive the vibration motor 18. In addition the object, if placed with sufficient pressure against the vibratory stimulation module 14, may affect the strength of vibrations experienced by the user, as it may begin to contribute to M, the target mass. When the garment 12 is applied more tightly to the user the vibration stimulation modules 14 are more tightly constrained to the body of the user and may cause the body to contribute to M, the target mass, altering the strength of vibrations experienced by the user. This would also have the effect of reducing displacement, altering current requirements for a given speed of rotation of the vibration motor 18.

[0080] In empirical testing it has been observed that the above effects can have an impact on vibration frequency (due to changes voltage and therefore changes in velocity of motor spin), which is a critical requirement to provide accurate and effective levels of vibration.

[0081] The wearable neuromuscular stimulation system 10 addresses the above shortcomings by designing the housing 16 to focus the vibrations generated by the vibration motor 18 in a direction towards the respective anatomical site on the body of the user, and to isolate as much as possible the transmission of vibrations and to a lesser extent noise, to the surrounding garment 12. The housing 16 comprises a base 20, preferably rigid in form, on which the vibration motor 18 is securely mounted, and an upper enclosure 22 extending from the base 20 to surrounding and enclose the vibration motor 18. The base 20 is preferably planar in form and comprising a relative rigid material such as a polymer or the like. The base 20 is connected to the upper enclosure 22 by means of an isolating element in the form of a flexible gasket or skirt 24 which partially or fully circumscribes and is substantially coplanar with the base 20. The skirt 24 may for example be over-moulded on the base 20. The outer perimeter of the skirt 24 is secured at or adjacent a lower rim of the upper enclosure 22, and in the embodiment illustrated is suitable captured within a keyway or channel 24 provided on an inner wall of the upper enclosure 22. The flexible skirt 24 is configured to allow the base 20 to undergo movement relative to the upper enclosure 22 in a direction substantially normal to the plane of the base 20. The flexible skirt 24 may be formed from any suitable material providing the necessary resilience to allow the base to oscillate relative to the upper enclosure 22 in response to operation of the vibration motor 18, and may for example be a silicone or rubber or the like.

[0082] By isolating the base 20 from the upper enclosure 22, the flexible skirt 24 significantly reduces dissipation or transfer of the vibration energy from the vibration motor 18 to the upper enclosure 22 from where it would be lost, improving efficiency of the vibration delivery to the chest of the user. In other words by reducing losses of the vibrational energy generated in directions that do not face towards the body the vibratory stimulation module 14 effectively focuses or optimises the vibrational energy directed towards and thus delivered to the body of the user. As the base 20 can vibrate substantially independently of the upper enclosure 22, the provision of the isolating skirt 24 also reduces the effects on vibration strength experienced by the user, and on power to maintain a constant vibration frequency, when the garment 12 is applied at different tightness levels and when objects such as hands make contact with the upper enclosure 22 through the outer shell of the garment 12. The flexible skirt may also be configured to provide a sealing function between the base 20 and the upper enclosure 22. Referring now to Figures 8 to 12 there is illustrated a vibratory stimulation module, generally indicated as 114, according to an alternative embodiment of the invention. In this alternative embodiment like components have been accorded like reference numerals and unless otherwise stated perform a like function.

[0083] The vibratory stimulation module 114 again comprises a housing 116 having a preferably rigid base 120 on which is securely mounted a vibration motor 118, the housing 116 further comprising an upper enclosure 122 extending from the base 120 and surrounding the vibration motor 118. In this embodiment the housing 116 is cylindrical in shape but it will be appreciated that any other suitable shape may be employed. The base 120 and upper enclosure 122 are connected by an isolating element in the form of a pair of coil springs 124 which allow the base 120 to vibrate relatively independently of the upper enclosure 122. This again allows the vibratory stimulation module 114 to focus the vibrations from the vibration motor 118 towards the anatomical site directly below the base 120, reducing losses to the surroundings, in particular the upper enclosure 122. The pair of springs 124 are configured and / or arranged to allow the base 120 to undergo movement relative to the upper enclosure 122 in a direction substantially normal to the plane of the base 120. Referring in particular to Figures 11 and 12 the base 120 preferably comprises a stepped outer rim 140 which is seated about a corresponding radially inwardly extending shoulder 142 at the lower rim of the upper enclosure 122 in order to prevent separation of the base 120 and upper enclosure 122. A shock absorber in the form of a elastomer such as rubber or foam or virgin PTFE or FFKM, FKM, EPDM or silicone o-ring 144 is preferably provided between the rim 140 and shoulder 142, and may also provide a sealing function between the base 120 and the upper enclosure 122.

[0084] Referring to Figure 12 the garment 12 may comprise pockets 28 for receiving and retaining the vibratory stimulation modules 14, 114. The pockets 28 are preferably formed integrally with the garment 12, but may for example be comprised of a relatively rigid or inelastic dock 32 for receiving the vibratory stimulation module 14, 114, which dock 32 is secured to the adjacent, relatively elastic material of the garment 12. In this way the stiffer material will serve to isolate the vibratory stimulation module 14, 114 from tensile forces experienced by the garment 12 as it is tightened to fit the user. This isolation further acts to reduce the variability in forces applied to the exterior of the housing 16, 116 as hereinbefore described, thus reducing variability in the strength / amplitude of the vibrations applied to the user and reducing variations in power requirements as the system 10 attempts to maintain a consistent vibration frequency.

[0085] Referring now to Figures 14 and 15 there is illustrated a vibratory stimulation module, generally indicated as 214, according to a further alternative embodiment of the invention. In this alternative embodiment like components have been accorded like reference numerals and unless otherwise stated perform a like function.

[0086] The vibratory stimulation module 214 comprises a housing 216 having a preferably rigid base 220 on which is securely mounted a vibration motor 218, the housing 216 further comprising an upper enclosure 222 extending from the base 220 and surrounding the vibration motor 218. The housing 216 comprises a substantially box shaped enclosure open on the side facing the base 220, but it will again be appreciated that any other suitable shape may be employed. The base 220 and upper enclosure 222 are connected by an isolating element in the form of a flexible or resiliently deformable gasket 224 which may for example be concertina or bellows in form as shown in the embodiment but which may be of other suitable forms. The gasket 224 may be formed from any suitable material or combination of materials, and for example may be silicone, TPE, rubber, polyurethane, PVC Polyolefin Elastomer (POE), and various other elastomers. The gasket 224 allows the base 220 to vibrate relatively independently of the upper enclosure 222 in order to allow the vibratory stimulation module 214 to focus the vibrations from the vibration motor 218 towards the anatomical site directly below the base 220, reducing losses to the surroundings, in particular the upper enclosure 222 and the surrounding garment 12 when mounted thereon.

[0087] The gasket 224 thus effectively defines a spring between the base 220 and the upper enclosure 222, while simultaneously avoiding the requirement for additional sealing therebetween. The concertina or bellows configuration of the gasket 224 allows the base 220 to undergo movement relative to the upper enclosure 222 in a direction substantially normal to the plane of the base 220. It will be appreciated that the gasket 224 may comprise a large number of different profiles, shapes and / or cross sections which will enable this functionality, that is to allow movement of the base 220 relative to the upper enclosure 22to the vibrations of the base 220 induced by the vibration motor 218. The concertina form illustrated may include more or less folds or convolutions than shown. The gasket 224 may facilitate the relative movement between the base 220 and the upper enclosure by mechanical design, namely the array of folds of the concertina, potentially allowing the gasket 224 to be formed from a relatively rigid material while still achieving deformation, or the gasket 224 may be formed from an inherently flexible material such as the above referenced elastomers.

[0088] The gasket 224 may be secured to the base 220 and / or the upper enclosure 222 by any suitable means. For example the connection may be achieved by over moulding the gasket 224 onto the respective part, adhering the gasket 224 in place, ultrasonic or thermal welding at the interface between the gasket 224 and the base 220 and / or the upper enclosure 222, a mechanical interlock between the gasket 224 and the base 220 and / or the upper enclosure 222, and / or a snap fit or compression fit. Referring in particular to Figures 15 the gasket 224 may be suitably secured an outer rim 240 of the base 220 as hereinbefore described, and the upper enclosure 22 may comprise a radially outwardly extending shoulder 242 circumscribing the lower rim of the upper enclosure 222 against which the gasket 224 may abut and be sealed.

[0089] The vibratory stimulation modules 14, 114; 214 may be provided with additional features to augment the functionality hereinbefore described. For example a pressure sensor (not shown) and / or a temperature sensor (not shown) and / or an accelerometer or Inertial Measurement Unit IMU (not shown) may be associated with one or more of the vibratory stimulation modules 14, 114; 214 in order to allow the controller (not shown) to receive feedback regarding the level of tightness of the garment 12 and / or the temperature at which the vibration source 18; 118; 218 is operating. Accelerometers (not shown) could for example be positioned on the garment 12 in order to gain insights on user activity and / or to assist in filtering out movement artefacts. Accelerometers could be placed on one or more suitable locations on the garment, for example the centre of the upper back. In addition or alternatively, accelerometers could be located on or in associated with the vibratory stimulation modules 14; 114; 214 in order to monitor the force and frequency of vibrations. This may be beneficial if attempting to gain insights on the type of tissue the vibration module 14; 114; 214 is positioned against, and to act as a check that vibration is being delivered correctly, for example to monitor actual versus applied vibration frequency in real time. The system 10 may also include one or more temperature sensors (not shown) operable to monitor the temperature of the wearer and / or any other component of the system 10, such as the individual vibratory stimulation modules 14, 114; 214. Such data may be useful for informing the user on the correct / optimum fit of the garment 12, allowing power adjustments to be made to the vibration motors 18, 118, 218 or to provide an alarm signal when the garment 12 is overtightened, under tightened, or operating at an elevated temperature, which may adversely affect operation. It may also help to detect abnormal changes in the wearer’s temperature, or if the garment 10 has been removed from the body (along with the absence of a respiration signal).

[0090] Maintaining a relatively stable and appropriate level of vibration to provide the desired therapeutic benefit of treating breathlessness or increasing VO2 max is an important aspect of the present invention, whilst also maintaining user comfort. In addition to the mechanical design of the vibratory stimulation module 14; 114; 214 to stabilize vibration delivery even in the presence of external forces on the housing 16; 116; 216, active control of vibration delivery can be provided by a feedback mechanism using a local or remote processor (not shown), using digital signal processing and / or Machine Learning or Al to correct for any variation outside a threshold level. During the course of the activities of daily living, including exercise, a pressure or strain sensor (not shown) provided on or about the housing 16; 116; 216 can be used to map an expected pressure level versus a detected level, and act via the processor to adjust the frequency and or intensity of the one or more vibration motors 18; 118; 218 to meet an expected level. Depending on the placement of the garment 12, the adjustment may only apply to one or more of the vibration motors 18; 118; 218, as the deviation from expected values may be location dependent.

[0091] The changes may be designed to have an equal aide to side variation, such as for two lower vibration motors 18; 118; 218 (i.e., to adapt their behaviour to feel at a similar level to each other, even with unequal external influences that would otherwise cause one to have an apparent greater perceptible vibration than the other) and / or and an equal up to down sensation, such that one side is balanced to the other side (such as for left or right side vibration motors 18; 118; 218).

[0092] The changes in the intensity may be made over one or more respiratory cycles, so as to avoid abrupt or readily apparent changes in the intensity of the vibration, in order that wearing the garment 12 remains comfortable. The changes can be cued based on detections of the inspiratory and expiratory cycles, and count of breaths elapsed and or time elapsed (such as over twelve breaths at a detected breathing rate of twelve breaths per minute or over sixty seconds).

[0093] Hysteresis may be employed such that the variations do not appear to oscillate, particularly where the pressure sensors (not shown) are not immediately co-located with the vibration motors 18; 118; 218.

[0094] The pressure sensors could be within or attached to the housing 16; 116; 216, and filter out the vibration source, or sample when the sources are not in operation. The sensors could also be based on digital filtering of the respiration sensors, such as to capture the equivalent frequency bands (e.g., a respiratory sensor might be sampled at a higher than usual rate - for example 256 Hz rather than 64 Hz, such that a 100 Hz vibration signal can be recovered).

[0095] The vibratory stimulation modules 14; 114; 214 may also be provided with sound insulation (not shown) on the housing 16; 116; 216 preferably on an interior surface thereof, in order to absorb any sound or vibration energy that may be directed away from the body of the wearer. By implementing a sound absorbent material in the outer housing 16; 116; 216, it is possible to further reduce the sound produced by the system 10. The material may also help conduct or dissipate any heat from the vibration source outward.

[0096] A variety of materials can be used in the housing 16; 116; 216 to provide sound absorption, such as open cell foam, melamine, polyurethane, or a mass adding material such as dense rubber or mass loaded vinyl (MLV). The “on” time of the vibration motors 18, 118; 218 is managed such that they do not overheat, and can be sealed. In some designs, a temperature sensor and / or humidity sensor may be co-located with the vibration source(s).

[0097] A cable seal is used, such that vibration cannot easily escape the enclosure around the cable entry point to the vibration motor 18, 118; 218. Where two sources or motors 18, 118; 218 are to be activated at the same time, a small delay or ramping may be introduced such that the stall / start-up current draw is staggered rather than coinciding.

[0098] The housing 16, 116; 216 may also be at least partially formed from a resilient deformable material, or a shape memory material such as nitinol, which would allow the housing 16, 116; 216 to deform in response to tension in the garment 12 without impacting on the operation of the vibration motor 18, 118; 218, and which would then return to the unstressed shape once the tension has been sufficiently removed. For example the housing 16, 116; 216 may be generally rigid or semi-rigid but have an upper or surrounding layer of a resiliently deformable material.

[0099] In a wearable device, efficient consumption of power is paramount. By reducing the variations in the motor torque required to maintain the correct vibration frequency, it is possible to utilise a vibration motor 18; 118; 218 that is optimally selected or designed to meet power requirements and maximise efficiency. This allows the use of a motor that is as small as possible and runs at correct speeds on the least power. In an exemplary embodiment the vibration motor 18; 118; 218 operates on a 5V input and generates vibrations at 100 Hz [+ / - 10Hz] and at amplitudes of between 3g and 20G. It will of course be understood that these are exemplary values which may be varied as required.

[0100] The wearable system 10 of the present invention provides a simple and low cost, yet reliable means of delivering neuromuscular stimulation therapy. The system 10 is compact, lightweight and discreet, allowing a user to wear the garment 12 in most conventional settings and thus enjoy the benefits of in-phase CWV at any time or place. The use of the vibratory stimulation modules 14, 114; 214 to focus vibrations ensures that power consumption is optimised, extending the operating window of the system 10 and providing the user with the requisite therapy for prolonged periods of time.

Claims

Claims1 . A wearable neuromuscular stimulation system for treatment of dyspnoea or increasing VO2 max comprising a garment configured to be worn about a body of a user; at least one vibratory stimulation module secured to the garment and comprising a housing enclosing a vibration source mounted such as to optimise the delivery of vibration energy to the body of the user, the housing comprising a base on which the vibration source is mounted and an upper enclosure surrounding the vibration source; an isolating element securing the base to the upper enclosure and configured to reduce or eliminate the transfer of vibration from the base to the upper enclosure; and one or more respiration sensors.

2. A wearable neuromuscular stimulation system according to claim 1 in which the isolating element is configured to facilitate vibrations from the vibration source to propagate in a direction normal to the base.

3. A wearable neuromuscular stimulation system according to any preceding claim in which the isolating element comprises a resiliently deformable element connecting the base to the upper enclosure.

4. A wearable neuromuscular stimulation system according to claim 3 in which the resiliently deformable element circumscribes the base.

5. A wearable neuromuscular stimulation system according to any claim 3 or 4 in which the resiliently deformable element is at least partially concertina in form.

6. A wearable neuromuscular stimulation system according to any of claims 3 to 5 in which the housing comprises a keyway into which the resiliently deformable element is secured.

7. A wearable neuromuscular stimulation system according to any preceding claim in which the isolating element comprises an elastomeric material.

8. A wearable neuromuscular stimulation system according to any preceding claim in which the isolating element comprises a spring.

9. A wearable neuromuscular stimulation system according to any preceding claim in which the upper enclosure at least partially comprises a resiliently deformable material.

10. A wearable neuromuscular stimulation system according to any preceding claim in which the housing at least partially comprises a sound absorbent material.11 . A wearable neuromuscular stimulation system according to any preceding claim in which the housing at least partially comprises electromagnetic shielding.

12. A wearable neuromuscular stimulation system according to any preceding claim in which the garment comprises a dock for receiving and retaining the at least one vibratory stimulation module and which is configured to mechanically isolate the vibratory stimulation module from compressive forces generated by tension in the garment.

13. A wearable neuromuscular stimulation system according to claim 12 in which the dock comprises a relatively inelastic material.

14. A wearable neuromuscular stimulation system according to any preceding claim in which the garment is variable in fit.

15. A wearable neuromuscular stimulation system according to claim 14 in which the garment comprises one or more tensioners arranged to allow a pressure applied by the garment to the housing to be adjusted.

16. A wearable neuromuscular stimulation system according to any preceding claim in which the garment comprises at least one temperature sensor.

17. A wearable neuromuscular stimulation system according to claim 16 in which the temperature sensor is configured to monitor the temperature of the vibration source and / or the user.

18. A wearable neuromuscular stimulation system according to any preceding claim comprising at least one accelerometer.

19. A wearable neuromuscular stimulation system according to claim 18 in which the accelerometer is configured to monitor the motion of the vibration source and / or the user.

20. A wearable neuromuscular stimulation system according to any preceding claim comprising a controller operable to drive the vibration source in response to feedback from the one or more respiration sensors.21 . A wearable neuromuscular stimulation system according to claim 20 in which the controller is operable to modulate the frequency and / or amplitude of vibrations generated by the vibration source.

22. A wearable neuromuscular stimulation system according to claim 20 or 21 in which the controller comprises an algorithm operable to monitor a signal generated by each of the19 respiration sensors and to compare the signals in order to facilitate a determination of a breathing phase and / or pattern of the user based on the relative values of the generated signals.

23. A wearable neuromuscular stimulation system according to any of claims 20 to 22 comprising an array of vibratory stimulation modules controllable independently and / or in groups.

24. A wearable neuromuscular stimulation system according to claim 23 in which the phases of two or more of the vibration sources can be adjusted.

25. A wearable neuromuscular stimulation system according to any preceding claim in which the vibratory stimulation module is configured to dither the vibrations in order to modulate the vibration frequency.

26. A wearable neuromuscular stimulation system according to any preceding claim in which the vibration source comprises an eccentric rotating mass motor.

27. A wearable neuromuscular stimulation system according to any preceding claim in which the vibration source is operable to produce vibrations in a frequency range of between 50Hz and 150Hz, more preferably between 75Hz and 125Hz, most preferably 100Hz.

28. A wearable neuromuscular stimulation system according to any preceding claim in which the vibration source is operable to produce vibrations in an amplitude range of between 1G and 50G, more preferably between 3G and 20G.

29. A wearable neuromuscular stimulation system according to any preceding claim in which the respiration sensors comprise at least a first sensor arranged on the garment in a first orientation extending, in use, transversely of a chest of the user, and at least a second sensor extending in a second orientation offset to the first orientation.

30. A wearable neuromuscular stimulation system according to any preceding claim in which the respiration sensors are distributed about the garment.

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