Normal square wave jerks in differing age groups.

This report details the characteristics of normal square wave jerks (SWJ) over a broad age range. Sixty normally sighted subjects, categorized into three age groups (35-49 yr, 50-64 yr, and 65-89 yr) underwent electrooculographic (EOG) examination to investigate the characteristics of normal SWJ. The frequency, duration, and amplitude of SWJ per minute were calculated in three clinically used test conditions: 1) with a fixation point in a lighted room; 2) with eyes closed and 3) in darkness without a fixation point. Results were compared over age and conditions as well as with the scores of 50 normal young subjects (20-37 yr). SWJ were recorded in all conditions, with the highest number found with closed eyes and in darkness for all age groups. Contrary to earlier findings, no statistical differences in frequency of SWJ per minute due to age were observed. These findings describe a range of normalcy for these three EOG conditions from which pathology can be inferred.