Then researchers learned that the brains of Parkinson s patients were deficient in dopamine, a neurotransmitter that carries signals between neurons. In the late 1960s, they found that oral doses of a dopamine precursor, L-dopa, could ease the deficiency, mitigating symptoms. That killed off most surgery for the disease. Unknown to most doctors, however, a noted Swedish surgeon named Lars Leksell had found that by knocking out part of the pallidum not usually targeted, he could dramatically improve all Parkinson s symptoms. He says he has now performed about 350 pallidotomies with similar results.
Younger patients do particularly well.
Medical textbooks say brain surgery can help the tremor of Parkinson s but not the freezing. Rethinking that in light of the new pallidotomy results, scientists theorize that lack of dopamine incites furious firing by certain neurons that normally help suppress undesired movement. That causes Parkinson's patients to freeze up. An Emory University team in Atlanta has begun a federally funded study to answer these questions, but its results aren't expected for years. A report on 126 patients given pallidotomies by Dr. Iacono is expected to be published soon.