Bringing Back the Sense of Touch

Stimulation, drugs can help stroke victims improve fingertip sensitivity

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THURSDAY, July 3, 2003 (HealthDayNews) -- Skin stimulation and drug treatment may help stroke victims or the elderly button their shirts and perform other daily tasks that require delicate finger movement.

That good new comes from a German study in the July 4 issue of Science.

It may even aid professional piano players or improve a blind person's ability to read Braille.

The study found finger stimulation and drugs can temporarily reorganize parts of the brain. This stimulation process, called coactivation, shuffles brain synapses that link neurons. The stimulated area of the brain becomes more sensitive as more neurons are recruited by the brain to process tactile information relayed from the fingers.

Amphetamine drugs doubled stimulation-induced gains in tactile activity, the study found.

"We are at the beginning of an era where we can interact with the brain. We can apply what we know about brain plasticity to train it to alter behavior. People are always trying to find ways to improve learning. What we tested was unconscious skill learning. How far could this carry to cognitive learning? That remains to be seen," researcher Hubert R. Dinse says in a news release.

To induce coactivation, study participants wore an 8-millimeter disc for three hours that stimulated a patch of skin on the tips of their right index fingers. To measure changes in the test tactile acuity, the researchers reduced the distance between two pins pressing against the skin on the participants' right index fingers.

At a specific distance, people are no longer able to detect two distinct pressure points on the tips of their index fingers. By monitoring changes in that minimum distance, the researchers were able to measure tactile acuity and perceptual learning.

The coactivation method used in this study doesn't require active participation by the subject. That makes it an attractive treatment approach.

"In past experiments, we tested coactivation in people between 65 and 90 years old. The coactivation temporarily improved tactile acuity with little harassment to the subjects. According to our new findings, certain drugs can enhance the effects of coactivation. The drug component makes this coactivation approach even more promising," Dinse says.

More information

Here's where you can learn more about stroke.

SOURCE: American Association for the Advancement of Science, news release, July 3, 2003


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