Aiding rehabilitation after stroke

Why is new technology needed for stroke rehabilitation?

Worldwide over 13 million people [1] will have a stroke each year and it is a leading cause of death and disability. A stroke happens when the blood flow to any part of the brain is blocked by a clot or bleeding. The resulting lack of oxygen and nutrients causes brain cells to die.

The impact of stroke depends on which area of the brain is damaged. It can cause paralysis down one side of the body, loss of muscle movement, difficulty talking or swallowing, memory loss and emotional problems.

Rehabilitation following stroke focuses on assisting the brain to create new pathways so that unaffected areas can be used to regain control over the body using physiotherapy and speech therapy.

Physiotherapy can improve function and reduce disability, but recovery can be slow and is often incomplete.

Bionics Institute researchers are focused on developing a device with the aim of boosting physiotherapy to speed up recovery and the potential for a fuller recovery following stroke.

How can electricity help rehabilitation?

It is well established that physiotherapy treatment following stroke can be boosted by applying electrical or magnetic stimulation to the affected brain regions.

Technology using transcranial magnetic stimulation (TMS) is currently in use, but the equipment is bulky and can only be used in a clinic.

Bionics Institute researchers are in the early stages of developing a small, implantable device with the aim of providing electrical stimulation for therapy at home and in the clinic that could increase both the speed and effectiveness of rehabilitation

How will the Bionics Institute device work?

Bionics Institute researchers are in the early stages of developing a medical device called the Minimally Invasive Therapeutic Implant (MiTi).

The aim of the small implant, designed to be positioned under the scalp, is to use embedded electrodes to stimulate the part of the brain responsible for controlling body movement.

Eventually, it could be used to boost treatment provided during physiotherapy appointments and while the patient is carrying out exercises at home.

In addition, our researchers have shown that the relationship between muscle function, stroke severity and brainwave activity can be used to assist with the overall management of patients following a stroke.

Our team is also developing an additional brain activity recording function in the device that may be able to detect adverse events and provide clinicians with the prognostic information needed to optimise ongoing treatment.

Next steps

Our researchers have confirmed the effectiveness of the device in a small pilot study at the acute stage of stroke, in collaboration with researchers from the Florey Institute.

Work is underway to ensure the implant is safe for long-term use and develop a prototype for clinical studies.

The research team

Bionics Institute researchers:

A/Prof Chris Williams, Dr Matt Petoe, Alexia Saunders, Owen Burns and A/Prof Graeme Rathbone.

External researchers:

Professor Clive May

Clinical collaborator:

Associate Professor Michael Murphy.

More information for researchers

Our primary target for neurostimulation is the motor cortex following ischemic stroke of the middle cerebral artery. The MiTi device is designed to deliver sub-threshold neurostimulation to the spared cortices at the periphery of a motor cortex lesion. Neurostimulation has been shown to enhance mechanisms of reorganisation in peri-infarct circuitry, generating a functional advantage when used as an adjuvant to physiotherapy. The device also includes monitoring of cortico-cortico evoked responses, or transcallosal inhibition between hemispheres, which can provide prognostics for the clinical team, or for closed-loop control of therapy

Publications

Benovitski, Y. B., Lai, A., McGowan, C. C., Burns, O., Maxim, V., Nayagam, D. A. X., Williams, C. E. (2017). Ring and peg electrodes for minimally-Invasive and long-term sub-scalp EEG recordings. Epilepsy Research, 135, 29-37. doi:https://doi.org/10.1016/j.eplepsyres.2017.06.003

Byblow, W. D., Stinear, C. M., Barber, P. A., Petoe, M. A., & Ackerley, S. J. (2015). Proportional recovery after stroke depends on corticomotor integrity. Annals of neurology, 78(6), 848-859. doi:10.1002/ana.24472

Stinear, C. M., Petoe, M. A., & Byblow, W. D. (2015). Primary motor cortex excitability during recovery after stroke: implications for neuromodulation. Brain Stimulation: Basic, Translational, and Clinical Research in Neuromodulation, 8(6), 1183-1190. doi:10.1016/j.brs.2015.06.015

Williams, C. E., & Gluckman, P. D. (1990). Real-time spectral intensity analysis of the EEG on a common microcomputer. J Neurosci Methods, 32(1), 9-13.

Williams, C. E., Gunn, A. J., Mallard, C., & Gluckman, P. D. (1992). Outcome after ischemia in the developing sheep brain: an electroencephalographic and histological study. Ann Neurol, 31(1), 14-21. doi:10.1002/ana.410310104