THURSDAY, March 31 (HealthDay News) -- For people with the movement disorder dystonia, starting deep brain stimulation therapy early in the course of the disease provides better results, according to a new study.

Dystonia is a potentially crippling disorder that causes muscles to contract, resulting in involuntary twisting of affected areas of the body. Deep brain stimulation is approved in the United States for certain treatment-resistant dystonias.

The study included 44 patients, aged 10 to 59 years, with generalized dystonia who received a deep brain stimulation device, which consists of electrical leads implanted in the brain and an electrical pulse generator placed near the collarbone. The device controls abnormal nerve signals that cause uncontrolled muscle contractions in people with the disorder.

After receiving the device, all of the patients experienced overall improvement in their ability to control muscles and movements (motor function). After one year, there were significant improvements in all ratings of affected body regions and functions such as speech, with the exception of three patients whose symptoms worsened somewhat between years one and three.

Additional improvements were seen after three years, according to the study published in the March issue of the Journal of Neurology.

The investigators also found that patients who were over the age of 27 years when they received the device had an additional 10 percent average improvement between years one and three. Before receiving the device, 32 patients were taking prescription drugs, but one year after getting the device that number fell by 52 percent, and after three years it fell by 80 percent.

"Our data suggest that patients who begin treatment earlier in the disease process may expect a better general outcome than those with longer disease duration. Also, age at surgery appears to influence the time necessary to achieve the best clinical response, meaning that older patients need more time before reaching their potential benefit," senior author Dr. Michele Tagliati, director of the Movement Disorders Program at Cedars-Sinai Medical Center, said in a journal news release.

Tagliati and other study authors have financial ties with Medtronic Inc., which makes deep brain stimulation devices.

More information

We Move has more about dystonia.