Sensory conduction study in fisher syndrome: patterns of abnormalities and their clinical correlation

To report sensory conduction findings in patients with typical Fisher syndrome (FS) and to determine if a specific pattern of sensory conduction abnormalities was present in such patients.

We retrospectively reviewed results of sensory conduction studies of 55 FS patients and compared them with those obtained from 83 age- and sex-matched healthy volunteers.

Mean median and ulnar sensory nerve action potential (SNAP) amplitudes were lower in FS patients than in normal subjects, whereas sural SNAP amplitudes were not different between the two groups. Abnormal median/ulnar sensory responses (reduced SNAP amplitude or absent response) were more frequently observed than abnormal sural response. Normal sensory conduction results were found in 31 (56%) patients. Of the 24 (44%) patients with abnormal sensory findings, 18 (33%) had a sural-sparing pattern of abnormalities. Patients with impaired sensation had lower median and ulnar SNAP amplitudes than those without.

Abnormal median and ulnar sensory responses were the most frequent sensory findings in FS. Findings of the sural-sparing pattern of abnormalities suggest distal sensory nerve involvement in these patients.