New research offers hope for rehabilitation

Jun 15, 2009 10:51 GMT  ·  By
A host of new therapies aimed at helping people with stroke-induced paralysis regain control of their affected arms have been published in the latest issue of the Journal of Neurophysiology
   A host of new therapies aimed at helping people with stroke-induced paralysis regain control of their affected arms have been published in the latest issue of the Journal of Neurophysiology

One of the most often met consequences of strokes is paralysis, either of a limb, or of an entire half of the body. In the most severe cases, the entire body could be rendered immobile, though these occurrences are a bit rarer. Now, researchers from the Rehabilitation Institute of Chicago, supported by the American Physiological Society (APS), say that a host of treatments and therapies could potentially help those with hand paralysis overcome their inabilities. A study detailing their techniques appears in the latest issue of the Journal of Neurophysiology.

One of the key findings that the team made is the fact that active muscle-stretching exercises could help patients with stroke-induced heart paralysis regain their abilities of gripping an object. On the other hand, this therapy increases the difficulty that patients experience when attempting to release an object, according to the scientists. Conversely, when the affected arm is supported by a platform, releasing an object becomes a lot easier, but gripping it can be very difficult.

In their experiments, the scientists used ten people with severe paralysis in their hands, owed to strokes, as well as five individuals who were healthy, and acted as a control group. All participants were instructed to grip a metal cylinder in front of them each time they heard an auditory signal, to squeeze it as strongly as they could, to hold it as long as the sound played, and to release it as soon as it stopped. In order to assess the amount of effort each of the participants made, the team used an electromyogram, a device able to record the activity inside the muscles.

One of the most unfortunate discoveries that the experts made was that the stroke victims seemed to have their ability to grip and release an object impaired in both of their hands, despite the fact that only one brain hemisphere was affected by the attack. Also, the ten paralysis victims took a longer time in letting go of an object than they took to grab it (1.9 seconds as opposed to five seconds). In the control group, members took on average 0.2 seconds to grip, and 0.4 to release it.

The researchers concluded that active-passive bilateral therapy, in which both the paretic and non-paretic hands are used together, so as to restore the natural balance between the two brain hemispheres, worked together in combination with regular methods of restoring function in the paralyzed hand. Trans-cranial magnetic stimulation and trans-cranial direct current stimulation – in which the neurons are stimulated with electrical current – also proved to be an effective way of reducing the time needed for recovery.