Long-term follow-up of levodopa responsiveness in generalized dystonia.
OBJECTIVE
To assign an accurate diagnosis to patients with dystonia based on the presence of sustained levodopa responsiveness and to determine whether motor fluctuations occur in patients with dystonia who are withheld from levodopa.


METHODS
Patients with generalized dystonia who responded to treatment in the 1970s with levodopa/carbidopa were surveyed by phone and then examined during a 3-day levodopa holiday. Functional imaging with fluorodopa positron emission tomography was performed on a subset of patients.


RESULTS
In the phone interview, 4 of 7 patients with a diagnosis of dopa-responsive dystonia reported the wearing-off effect a short while (within 4-8 hours) after missing a dose of levodopa. Five patients with dopa-responsive dystonia were examined repetitively during levodopa withdrawal, and 3 developed recurrent symptoms of dystonia as the drug was withheld. In each case, worsening of dystonia did not occur until 29 hours or more after levodopa withdrawal, providing evidence for a response profile similar to the long duration response described in Parkinson disease. No significant changes were seen in the dystonia scores of the 3 patients with idiopathic torsion dystonia who were withheld from levodopa.


CONCLUSIONS
We suggest that the subjective feeling of wearing off experienced by our patients with dopa-responsive dystonia may have been for one of the nonmotor effects of levodopa, such as mood elevation. Our data provide objective evidence for the often-repeated assertion that motor fluctuations (analogous to those in levodopa-treated patients with Parkinson disease) do not occur in patients with dopa-responsive dystonia.
Department of Neurology, University of Texas Southwestern Medical School, Dallas 75235-9036, USA.
R B
RB
Dewey
M D
MD
Muenter
A
A
Kishore
B J
BJ
Snow
D000978:Antiparkinson Agents / Q000627:therapeutic use*; D004305:Dose-Response Relationship, Drug; D004421:Dystonia / Q000175:diagnosis / Q000188:drug therapy*; D005500:Follow-Up Studies; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use*; D012720:Severity of Illness Index; D013997:Time Factors; D014055:Tomography, Emission-Computed
D000978:Antiparkinson Agents; D007980:Levodopa