Abstract
Purpose:
Gaze apraxia is difficulty in initiating and executing saccades, evident as abnormally long latencies and/or subnormal saccade amplitude. The purpose of the current study was to determine the prevalence and severity of gaze apraxia in children with different severities of cerebral palsy (CP).
Methods:
Horizontal and vertical visually evoked saccade testing was conducted by clinical observation in 131 children with CP. Stimuli were positioned ± 20° from central gaze as the child viewed binocularly. OKN fast-phases were quantified using large-field stripe motion and laboratory eye movement recordings in an additional 19 CP children. Responses were compared to a control group of 32 normal children.
Results:
Gaze apraxia prevalence for CP children was 55%. Prevalence was linked to severity of CP (Gross Motor Function Classification Systems [GMFCS] level 1 = mildest to 5 = most severe). Gaze apraxia was detected in 23% of GMFCS 1 children. Prevalence increased systematically with increasing GMFCS levels (chi square, p < .01) to 87% at GMFCS 5. OKN fast-phase frequency and amplitude in CP children across all GMFCS levels was 36% of control values.
Conclusions:
Gaze apraxia, evident as saccadic or OKN fast-phase dysfacility, is evident in over one-half of children with CP. The prevalence of the apraxia increases with severity of CP. The apraxia degrades visual function, which is dependent upon prompt and accurate foveation of targets at different locations.
Keywords: 522 eye movements •
525 eye movements: saccades and pursuits