OFF-Period Purposeless Groaning in Parkinsonism.

Background: Purposeless groaning is primarily encountered in patients with progressive supranuclear palsy and has also been reported to occur in advanced Parkinson's disease (PD).

Objective: We describe a case of pronounced purposeless groaning occurring as a medication OFF-period nonmotor phenomenon in PD. To our knowledge, this has not been previously reported in the literature.

Methods And Materials: We describe and provide video documentation of a patient with moderately advanced PD and motor fluctuations, in whom OFF-period groaning was reported by the family and observed during clinic consultations to be a prominent feature, occupying approximately 40% of his OFF periods as calculated from his PD diary.

Conclusions: Although rare, OFF-period purposeless groaning in PD can be very disruptive and add significantly to caregiver burden. It is postulated to be a disinhibitory and perseverative behavior related to overactivation of the cingulo-periaqueductal circuit; further study is needed to delineate the underlying pathophysiological mechanisms.