[Diurnal observation of antecollis in Parkinson's disease to determine the dopamine agonist dose: A case report].

A 50-year-old man was diagnosed with Parkinson's disease at the age of 43 years. The patient was hospitalized because of frozen gait and tendency to fall and showed abnormal postures of marked antecollis and stooped posture. The angle of the abnormal posture dramatically fluctuated, and the fluctuation coincided with the motor symptoms over the course of a 24-hour period. Treatment with rotigotine was started, and diurnal fluctuations in the gait disorder and abnormal posture were recorded. The time recorded in the Timed Up & Go test decreased after treatment with rotigotine in a dose-dependent manner, particularly early in the morning. The angle of the abnormal posture improved with a 4 mg/24 hr dose of rotigotine but worsened with a dose of 8 mg/24 hr. Because abnormal posture is a known side effect of dopamine agonists such as rotigotine, it is possible that high-dose rotigotine worsened the abnormal posture, whereas the low-dose improved the abnormal posture because of undertreatment. This case highlights the importance of observing the diurnal fluctuation in abnormal posture for developing a strategy for the treatment of Parkinson's disease.