Effects of Physostigmine on Swallowing and Oral Motor Functions in Patients with Progressive Supranuclear Palsy: A Pilot Study

The purpose of this pilot study was to investigate whether cholinergic stimulation reduces swallowing and oral motor disturbances in patients with progressive supranuclear palsy (PSP). A controlled, double-blind crossover trial of physostigmine, a centrally active cholinesterase inhibitor, and placebo was conducted. Patients were randomized to a 10-day crossover placebo-controlled double-blind trial of physostigmine at their previously determined best dose administered orally every 2 hr, six times per day. Patients were evaluated with ultrasound imaging of the oropharynx and an oral motor examination at baseline and during the third or fourth days of each study phase (placebo and drug). Under the double-blind placebo-controlled conditions, patients showed no statistically significant improvement in oral motor functions or swallow durations. Because patients with PSP have increased sensitivity to cholinergic blockade compared with control subjects, studies with newer, more potent cholinergic stimulating agents need further exploration. Suggestions for future research include the evaluation of newer direct cholinergic agonists in the treatment of the less-impaired PSP patients who may have a greater number of cholinergic neurons preserved and the evaluation of combined therapies.