EFFECT OF AGING ON SMOOTH-PURSUIT EYE-MOVEMENT

Examination of smooth pursuit eye movement is useful for detecting cen tral nervous system disorders. It is important to take patient's age i nto consideration when evaluating smooth pursuit eye movement. The pur pose of the present study was to clarify the effect of aging on smooth pursuit eye movement. Thirty healthy volunteers (three groups of 10 v olunteers, in their fifties, sixties, and seventies and over, respecti vely) served as subjects, and 10 healthy young volunteers (23 to 33 ye ars old: mean age 26) served as controls. The pursuit target was drive n by sinusoidal waveform with various amplitudes and frequencies. Targ et peak velocities ranged from 12.6 to 94.2 degrees/s. Eye movement si gnals were recorded d.c. EOG and pursuit gain (ratio of eye peak veloc ity to target peak velocity) was measured by a computer. Pursuit gain decreased with increasing target frequency and velocity in all age gro ups. This tendency was more remarkable in the older groups than in the young controls; in particular, it was more frequently seen at a frequ ency of 0.5 Hz. On the other hand, there was no significant relationsh ip between pursuit gain and the target amplitude. In the group in thei r seventies and over, pursuit gain was saturated at about 60 degrees/s .