Low-cost personalised instrumented clothing with integrated FES electrodes for upper limb rehabilitation

Stroke is the leading cause of adult disability in the UK. Every year 150,000 strokes occur and 54,000 of these fail to regain upper limb function, resulting in yearly personal and societal care costs of £5.5bn. These numbers will increase with the aging population; by 2040 the number of people over 65 is expected to grow by 67%. The government has termed this situation 'a ticking time bomb' and has called for innovative technology that Persons with Stroke (PwS) can use in their own homes.

Functional Electrical Stimulation (FES) of muscles is a technology that has been shown to help PwS re-learn lost skills by enabling them to practice and regain lost arm movement, and in-so-doing create new nerve connections in their brain. FES works by stimulating muscles with electrical pulses via electrodes placed on the skin. Unfortunately, commercial FES systems are not suitable for intensive daily use as they are rigid and uncomfortable, and not able to assist PwS in performing the necessary precise movements because only a limited number of muscles are stimulated.

In our previous research we have developed a prototype FES array on a conventional wearable fabric enabling the FES to be worn as normal clothing to achieve rehabilitation. The FES array thus is flexible, breathable and comfortable to wear, and can be scaled up to cover as many muscles as are needed. A range of precise hand functions including pinching, pointing and hand opening have been achieved by stimulating an optimised selection of electrode elements in the array. The stimulation is controlled using advanced software called "iterative learning control" which mimics the way the brain learns new skills. This controller can potentially achieve highly accurate movement by learning the optimal stimulation pattern over multiple attempts at a task.

Our project will use printing to fabricate customised FES garments to precisely fit the individual's arm and specific needs. The customised FES array design will be generated by scanning the arm using a commercial 3D scanner and processing the image using software developed in this project. Each FES array will be printed on standard everyday fabric and then integrated into a piece of clothing (e.g. cuff/armband, sleeve, long sleeved T-shirt). The resulting garment will be very comfortable to wear and convenient to use every day. The FES clothing will be operated using a wireless control system combined with sensors which automatically adjust the FES to enable precise activities, such as assisting eating, washing and dressing.

We will work closely with an expert user group consisting of PwS and their carers, FES engineers and healthcare professionals to produce a detailed device specification. This will provide the device requirements in terms of comfort, robustness, stimulation function and cost criteria. Following development, the device will be tested against this specification and refined throughout the project to ensure it fully meets the needs of PwS.

Our technology will bring affordable, effective physical therapy into the homes of PwS, allowing them to practice goal-orientated functional activities at home without needing a carer or therapist. It thereby increases the intensity of rehabilitation without an increase in clinical contact time. This will lead to better outcomes, such as reduced impairment, greater restoration of function, improved quality of life and increased social activity. This in turn will translate to greater independence leading to less dependence on carers, and the possibility of return to work.

The first application of the technology will be with PwS with upper limb impairments followed by those with lower limb impairments. The technology can also potentially be further applied to treat other neurological conditions such as spinal cord injuries and multiple sclerosis.

Stroke is the second highest cause of disability in the UK. Stroke survivors receive rehabilitation at home, but about 60% of Persons with Stroke (PwS) fail to regain upper limb function. Clinical evidence supports the use of Functional Electrical Stimulation (FES) to restore upper limb function in PwS. However, existing commercial FES devices are not highly effective due to significant limitations:

1) Too few muscles are stimulated.
2) Their large non-selective electrodes cause imprecise movement.
3) Imprecise movement also occurs because the FES controller is not adjusted using movement sensor feedback.
4) Devices are bulky and expensive, or difficult to set-up.

In previous research, we demonstrated the concept of screen printing fabric-based FES; in this project we further address the above limitations by combining recently developed technologies to implement the following advantages:

1) Electrode arrays printed directly on fabric, using bespoke inks, will provide high muscle selectivity scalable to all the appropriate limb muscles.
2) Direct write printing and 3D scanning will allow rapid fabrication of low cost personalised designs matching the users' physiology.
3) Intelligent control using movement sensors will automatically adjust the FES to enable precise functional movements (e.g. repositioning objects).

Clothing is defined in this project as any fabric-based item (e.g. cuff/armband, sleeve) worn on the body.

The device specification will be defined by an Expert User Group (EUG) consisting of PwS, carers, FES engineers and healthcare professionals. The FES array and control/sensor technologies will be refined to meet this specification (milestone 1). These components will be integrated into candidate clothing designs with wireless electronics and training software, and evaluated (milestone 2). This project delivers a practical, comfortable, high performance solution for cost effective rehabilitation.

1. Persons with Stroke and other neurological conditions: The stroke survivors living in the UK are the direct beneficiaries of our research. The FES clothing can be adapted to also treat hand/arm disabilities resulting from other neurological conditions such as cerebral palsy, head injury, spinal cord injury, and multiple sclerosis. The use of FES clothing increases the intensity of rehabilitation without an increase in clinical contact time. This leads to better outcomes, such as reduced impairment, greater restoration of function, improved quality of life and increased social activity.

2. NHS: FES clothing is a comfortable to wear and convenient to use rehabilitation device which impaired people can use by themselves at home. It will transfer hospital based professional care to home based self-care, and therefore, will reduce NHS costs by saving healthcare professionals' time and other hospital resources.

3. Industry: bringing business to the whole supply chain; increasing the FES market demand by improving performance; benefiting other industry sectors such as rehabilitation for other neurological conditions.

4. Research communities in the related fields: novel fabrication and control system design of medical devices, rehabilitation, smart fabrics, remote healthcare. These will benefit from the highly transformative platform technology (e.g. direct write printing, fabric electrode, iterative learning control system) developed in this work.

5. UoS: The FES clothing technology IP developed in this project will be protected, as appropriate, by the University of Southampton. We anticipate that this will create an opportunity to license to medical device companies or form a spin-out company.