Every year, one in ten people die of a stroke globally making it the second-leading cause of death. Survivors suffer impaired mobility and struggle to execute daily tasks that most of us take for granted. Since they need lifelong support which can be very expensive, it is important to help them perform physical activities on their own as this will improve their quality of life and ability to do everyday tasks.
“One of the ways to achieve this is through sensory-motor exercises that can induce the functional recovery in chronic stroke survivors and improve their brain's ability to reorganise itself in response to sensory input, experience and learning," says Dr Tania Zastron who recently obtained a doctorate in Sport Science at Stellenbosch University.
As part of her study, Zastron developed a cost-effective and simple task-specific eight-week sensory-motor training (SMT) programme to determine whether exercise can improve the connectivity strength between different affected areas of the brain as well as functional recovery in chronic stroke survivors.
She points out that of the 71 men and women who were approached to participate in the study, only 22 met the inclusion criteria which included being 18 years or older; having had a stroke six or more months (chronic stroke) prior to the intervention; being able to maintain standing balance for 30 seconds; having the ability to walk 7 metres independently; and physician approval for participation. These 22 individuals completed three 45 to 60-minute sessions per week over the eight-week period and had an average age of 70 years. Zastron randomly divided them into two groups, i.e. a SMT group and an attention-matched control group (CON). The CON group was used to ensure the results found in the experimental group were not merely because they received some form of attention.
The SMT completed task-specific balance training focused on manipulating the visual system, as well as parts of the sensory system concerned with balance and spatial orientation (vestibular) and the conscious perception of touch, pressure, pain, temperature, position, movement and vibration (somatosensory). The CON group listened to educational talks regarding various lifestyle topics for the same duration as the SMT group.
Both interventions were delivered by experienced biokineticists at centres close to the participants' homes.
Zastron says participants in the SMT group did balance exercises which included, among others, head nods, trunk leans, reaching, catching, throwing, single leg stance, weight shifting, walking (normal, high knees, butt kicks, sideways, backwards), tandem walking, weight shifts with stepping, agility ladders, line walking; sit-to-stands, walking with direction and obstacles, reaching and walking, 360° turns and sitting on an exercise ball and reaching.
She adds that these exercises were performed under sensory-manipulated conditions, for example using dimmed lights, moving of the visual surroundings, using dark glasses, asking participants to close their eyes and changing the surface area underneath their feet, head tilts, etc.
These type of exercises are important because a stroke critically disturbs the balance within the different structures in the brain, says Zastron.
“After the central nervous system has been injured, brain reorganisation lays the foundation for motor learning, acquiring new skills as well as functional recovery."
Zastron says her research showed that the SMT programme indeed works.
“Participants showed improved postural sway or balance when standing on a foam pad with their eyes open, reduced somatosensory dependence, improved turning performance while walking, as well as improvements in perceived physical and social functioning. Their fear of falling also decreased.
“The brain activation results showed that there was increased connectivity strength between parts of the brain responsible for motor learning (the improvement of motor skills through practice, which are associated with long-lasting changes in neurons), motor control (the way in which the nervous system produce movement) and postural balance.
“Overall, the SMT programme led to a higher perceived level of physical functioning, which in turn increased the participants' self-efficacy and created a state of improved functioning in daily living and overall well-being."
Zastron says with improved postural control comes improved functional mobility because the individual is able to change and maintain his or her posture better while moving from one position to another.
“It has been reported that turning is one of the most frequent activities to cause a fall in stroke survivors. Therefore, if turning performance improves with SMT, it can reduce the risk of falling in chronic stroke survivors."
She adds that the findings of her study highlight the importance for stroke survivors to participate in balance training programmes.
“The use of balance training under sensory-manipulated conditions should be encouraged in the rehabilitation procedure for chronic stroke survivors. Exercise may be a cost-effective and simple way to help these individuals live independently."
Zastron says SMT programmes are important because studies have shown that globally 70 million stroke survivors will be living with disability by 2030.
She points out that risk factors for strokes include, among others, hypertension, smoking, diabetes, enlargement and thickening of the walls of the heart's main pumping chamber and an abnormal heart rhythm.
“Research shows that an individual's risk of a stroke increases by 22% when overweight and 64% when obese. Given estimations that 20 million people worldwide will die of a stroke by 2030, we must do everything in our power to reduce the risks."
Zastron says that apart from stroke survivors, people with neurological disorders such as Parkinson's and Alzheimer's diseases could benefit from her training programme.
She adds that, in terms of future research, it would be valuable to investigate whether improvements are retained at all as well as how long effects are maintained after stroke survivors have finished the balance training programme.