Saccadic oscillations and intrusions preceding the postnatal appearance of congenital nystagmus

Abstract

Saccadic intrusions and oscillations (square wave jerks and oscillations, double saccadic pulses and multiple double saccadic pulses) are rare in infants. They have been observed in both normal adults and those afflicted with central nervous system diseases. The authors recorded saccadic oscillations in a normal 4 _1/2 -month-old infant. Five months later they recorded both saccadic oscillations and congenital nystagmus (CN) waveforms. A complete neurological examination did not show nervous system abnormality.

There is only one report of an adult with documented saccadic oscillations and whose longitudinal evaluation failed to show other abnormalities. Some types of saccadic oscillations may represent a benign condition in infants. The subsequent developing of CN in this patient results in questions regarding the interrelationship of fast eye movement and slow eye movement system abnormalities. The authors hypothesize that the saccadic oscillations precluded the early appearance of the developing CN.

Key Words:

• saccadic oscillations
• square wave oscillations
• saccadic intrusions
• square wave jerks
• congenital nystagmus