Subthalamic deep brain stimulation versus best medical therapy for L-dopa responsive pain in Parkinson's disease.

Pain is a frequently observed non-motor symptom of patients with Parkinson's disease. In some patients, Parkinson's-related pain responds to dopaminergic treatment. In the present study, we aimed to elucidate whether subthalamic deep brain stimulation has a similar beneficial effect on pain in Parkinson's disease, and whether this effect can be predicted by a pre-operative l-dopa challenge test assessing pain severity. We prospectively analyzed 14 consecutive Parkinson's patients with severe pain who underwent subthalamic deep brain stimulation. In 8 of these patients, pain severity decreased markedly with high doses of l-dopa, irrespective of the type and localization of the pain symptoms. In these patients, subthalamic deep brain stimulation provided an even higher reduction of pain severity than did dopaminergic treatment, and the majority of this group was pain-free after surgery. This effect lasted for up to 41 months. In the remaining 6 patients, pain was not improved by dopaminergic treatment nor by deep brain stimulation. Thus, we conclude that pain relief following subthalamic deep brain stimulation is superior to that following dopaminergic treatment, and that the response of pain symptoms to deep brain stimulation can be predicted by l-dopa challenge tests assessing pain severity. This diagnostic procedure could contribute to the decision on whether or not a Parkinson's patient with severe pain should undergo deep brain stimulation for potential pain relief.