Objective: To evaluate the usefulness of the somatosensory-evoked potential (SEP) in differentiating progressive supranuclear palsy (PSP) from other movement disorders.
Materials and methods: The median nerve SEPs were studied in patients with PSP, Parkinson's disease and essential tremor, and in healthy controls.
Results: The amplitudes of the median nerve SEPs were enlarged only in patients with PSP. In four of the 10 patients with PSP, giant SEPs were elicited either unilaterally or bilaterally.
Conclusions: The enlargement of the SEP in PSP may be useful for early differentiation of PSP, and this enlargement suggest a disease-specific dysfunction in the sensory processing mechanism of PSP which distinguishes it from other movement disorders.