Some therapies for stroke rehabilitation are extremely effective – but only for some patients. A group of researchers set to figure out why that is, and based on the results, how to get higher rates of effectiveness for each type of therapy.
At Sinai Post Acute Care Center for Rehabilitation, we’re always interested in stroke rehabilitation research that might help us as we provide top rehab services for our patients.
Therapies that aid in stroke rehabilitation
Some of the most popular and effective rehab efforts for stroke involve some form of electro-magnetic therapy, where nodes are placed on parts of the head and stimulate various points in the nervous system. These can be wildly powerful in some patients, and completely ineffective in others, with every type of response in between. However, it doesn’t seem that evaluators have been adequately determining before the treatment which patients it might work for and which ones it probably wouldn’t.
Researchers from The Institute for Cognitive Neuroscience, National Research University Higher School of Economics, and The Max Planck Institute for Human Cognitive and Brain Sciences, presented this dilemma and their findings in “Predicting the Response to Non-Invasive Brain Stimulation in Stroke,” published in Frontiers in Neurology.
They discuss the Neuromodulatory non-invasive brain stimulation (NIBS) techniques that are frequently used in stroke rehabilitation today. Some examples are transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS). These show a range of effectiveness among patients.
The writers compare it to earlier stroke rehabilitation models such as thrombolysis, where rates of effectiveness were mixed until researchers developed systems and protocols to determine which patients it would be effective for, and rates of effectiveness increased.
They put the factors that would indicate the potential of the patient’s response to NIBS into two categories: their general health factors, and their specific stroke factors.
General health factors are age, gender, medications, and overall health. The specific stroke factors include severity of injury, how big and where the lesions are, and how long from stroke until treatment, as well as others.
How to make the determination
Stroke rehabilitation clinicians agree that some therapies work for different patients, and it’s time to collect the necessary data that will help ascertain the right treatment per patient.
They say that previously, the interhemispheric competition model was used as a basis for therapy, which posits that the unaffected brain hemisphere suppresses the affected hemisphere, and that therapy should involve suppressing the unaffected side to allow the affected side to repair. While this has shown to be productive in certain cases, it has not generally shown high results. The other model is the vicariation model, which says that the unaffected hemisphere compensates for the affected side, a completely different way of understanding what’s going on.
There’s a metric used to determine which of these models is exhibiting in individual patients, and the results of the metric can help in determining which patients can benefit from NIBS. Patients who show the first model usually do not stand to benefit from NIBS, whereas patients who show the second are more likely to respond positively to NIBS.
Why this isn’t already used is because it’s not so clear how to apply the metric. There’s some promise, including brain imaging of white matter and behavioral testing, both of which seem to indicate a clear response to the proposed metric, but the researchers say that there still needs to be much research into how to apply the metric to get the proper outcomes.