"Off" gait freezing and temporal discrimination threshold in patients with Parkinson disease

Objective: To investigate the relationship between temporal discrimination threshold (TDT) and "off" period gait freezing (OGF) in patients with fluctuating Parkinson disease (PD). Methods: TDT values were measured at the dorsum of the toes in 11 control subjects and 22 patients with PD with a wearing-off phenomenon (16 patients with OGF and 6 patients without OGF). Results: During the L-dopa "off" period, TDT values increased abnormally in both patient groups but were significantly higher in patients with OGF than in those without OGF. A positive correlation was found between the severity of OGF and TDT values measured by different point stimulation. In patients with OGF, a single dose of L-dopa treatment normalized TDT values and ameliorated OGF. Conclusions: Dopa-responsive abnormal discriminative sensory processing may be a possible cause of "off" period gait freezing observed in patients with fluctuating Parkinson disease.