Senescent Saccades: Effects of Aging on Their Accuracy, Latency and Velocity

Abstract

The effects of aging on horizontal saccades were investigated by infrared oculography in young, middle-aged and elderly normal subjects. Saccades were elicited in response to three target conditions: 1) predictable amplitude direct and timing; 2) unpredictable amplitudes and directions at regular intervals; and 3) unpredictably timed targets of predictable amplitude and direction. Peak velocities were significantly reduced in the elderly when target amplitude and direction were predictable. Latencies were prolonged in the elderly under all conditions. Saccadic accuracy was significantly decreased in elderly subjects; the amplitudes of primary saccades were reduced and hypometric saccades were frequent. The results indicate that the diagnosis of saccadic dysfunction in disease should be qualified by the age of the patient and by the target task.

Key Words:

• saccades
• aging
• hypometric saccades
• slow saccades
• saccadic delay