“This research shows it is possible to ‘prime’ the brain to be more receptive to rehabilitation exercises, allowing it to re-learn how to control fine movement,” says Associate Professor Winston Byblow in the Department of Sport and Exercise Science who led the research along with PhD student and physiotherapist Suzanne Ackerley.
“Upper limb impairment is very common following a stroke, and can have a major impact on people’s quality of life and level of independence. But because many stroke survivors also need speech-language therapy and help re-learning to walk, rehabilitation of the arm and hand often becomes a lower priority.
“It’s significant that everyone who took part in our research had their stroke at least six months before they began the rehabilitation programme. This shows that with new techniques like brain stimulation it is still possible to benefit from rehabilitation some time after the initial injury, which challenges a lot of conventional thinking” says Dr Byblow.
The latest study, published in the journal Stroke, is part of an ongoing research programme led by Dr Byblow and Dr Cathy Stinear in the Department of Medicine, whose work has already seen a new arm rehabilitation device being trialled in selected rehabilitation centres in New Zealand. While the researchers have focused on the upper limb, the new combination of brain stimulation with rehabilitation may also prove effective for other parts of the body.
The current study involved ten people with persistent impairment of the upper limb at least six months after a stroke. The researchers delivered bursts of magnetic stimulation across the skull to parts of the brain that control upper limb movement. Since the stimulation was painless, participants were unable to tell the difference between real or placebo treatments given on successive weeks.
The stimulation or placebo was given just before participants began practising a standard rehabilitation exercise that involves gripping and lifting an object with the index finger and thumb – a task that requires manual dexterity as well as coordination of muscles along the entire arm. After magnetic stimulation, participants showed substantial improvements in the task they had practised, more efficiently applying force with their weak hand. After placebo stimulation, their performance worsened due to fatigue.
The combination therapy has shown such promise that a new clinical trial, funded by the Neurological Foundation of New Zealand, is underway in Auckland to determine whether brain stimulation can provide long-lasting benefits when combined with physical therapy over several days. Anyone with residual hand and arm weakness 6 to 36 months after stroke who would like to take part in the study can contact Dr Cathy Stinear on 09 373 7599 extension 83779 or firstname.lastname@example.org.
The research also provided important new insights into how the two sides of the brain contribute to recovery.
People with poor upper limb recovery after a stroke have an imbalance in their brains, with reduced activity in the side damaged by stroke and excess activity in the healthy side, and it has been widely believed that re-balancing this activity will assist recovery. Since different types of magnetic stimulation can be used to “turn up” or “turn down” activity in one side of the brain, the current study allowed this idea to be tested.
While either approach improved participants’ ability to do the task they had practiced during rehabilitation, when activity in the healthy side of the brain was “turned down” they did slightly less well in tests of upper limb activities they had not practised. No change in these other tests was seen when the damaged side of the brain was “turned up” or the placebo treatment given.
“The idea of re-balancing the brain has been pushed by many researchers, but our results show that the affected side of the brain is contributing to recovery in some way,” says Dr Byblow. “It is often assumed that we should focus on the healthy side of the brain during rehabilitation but studies like ours show that it’s not that simple. There’s a lot of untapped potential on the damaged side of the brain, and it isn’t just about ‘turning down’ the healthy side to force the affected side to work harder.”
The researchers will be giving a free public lecture at the Christchurch Art Gallery from 6-7:15pm on Thursday 15 July as part of the Neurological Foundation appeal week.