J G Nutt1, T G Nygaard. 1. Department of Neurology, OP 32, Oregon Health Sciences University, 3181 SW Sam Jackson Park Rd, Portland, OR 97201-3098, USA.
Abstract
BACKGROUND: Dopa-responsive dystonia (DRD) is similar to Parkinson disease in that both disorders have impaired dopamine synthesis and respond to levodopa treatment. Dopa-responsive dystonia differs in that dopamine storage is intact in contrast to Parkinson disease in which it is markedly reduced. OBJECTIVE: To examine the short- and long-duration responses to levodopa dosing in subjects with DRD. METHODS: The response to brief infusions of levodopa was examined in 4 subjects with DRD and the effects of withdrawal of levodopa for 3 to 7 days studied in the 3 subjects receiving long-term levodopa therapy. Motor function was measured with tapping speed, Unified Parkinson's Disease Rating Scale motor score, and global dystonia score. RESULTS: The short-duration response to levodopa dosing seems to develop more slowly and persists longer in subjects with DRD than in subjects with Parkinson disease. Withdrawal of levodopa leads to a gradual decline in tapping speed and reemergence of dystonia over several days, similar to the rate of decay of motor function in Parkinson disease. The short- and long-duration responses were not clearly differentiated in DRD. CONCLUSIONS: This pilot study suggests that retained dopamine storage in DRD may prolong the short-duration response and blur the distinction of the short- and long-duration responses. The decline in motor function in DRD on withdrawal of long-term levodopa therapy resembles that in Parkinson disease, suggesting that a long-duration response, if it exists in DRD, is unrelated to dopamine storage.
BACKGROUND:Dopa-responsive dystonia (DRD) is similar to Parkinson disease in that both disorders have impaired dopamine synthesis and respond to levodopa treatment. Dopa-responsive dystonia differs in that dopamine storage is intact in contrast to Parkinson disease in which it is markedly reduced. OBJECTIVE: To examine the short- and long-duration responses to levodopa dosing in subjects with DRD. METHODS: The response to brief infusions of levodopa was examined in 4 subjects with DRD and the effects of withdrawal of levodopa for 3 to 7 days studied in the 3 subjects receiving long-term levodopa therapy. Motor function was measured with tapping speed, Unified Parkinson's Disease Rating Scale motor score, and global dystonia score. RESULTS: The short-duration response to levodopa dosing seems to develop more slowly and persists longer in subjects with DRD than in subjects with Parkinson disease. Withdrawal of levodopa leads to a gradual decline in tapping speed and reemergence of dystonia over several days, similar to the rate of decay of motor function in Parkinson disease. The short- and long-duration responses were not clearly differentiated in DRD. CONCLUSIONS: This pilot study suggests that retained dopamine storage in DRD may prolong the short-duration response and blur the distinction of the short- and long-duration responses. The decline in motor function in DRD on withdrawal of long-term levodopa therapy resembles that in Parkinson disease, suggesting that a long-duration response, if it exists in DRD, is unrelated to dopamine storage.
Authors: Christopher Bishop; Jessica A George; William Buchta; Adam A Goldenberg; Mohamed Mohamed; Sando O Dickinson; Satie Eissa; Karen L Eskow Jaunarajs Journal: Eur J Neurosci Date: 2012-07-05 Impact factor: 3.386
Authors: Shan H Siddiqi; Natalia K Abraham; Christopher L Geiger; Morvarid Karimi; Joel S Perlmutter; Kevin J Black Journal: Front Pharmacol Date: 2016-01-06 Impact factor: 5.810