Abstract
Purpose:
Global motion perception is thought to be particularly susceptible to atypical development and therefore may provide a sensitive measure of neurological function in young children. The aim of this study was to assess global motion perception in a cohort of two-year old children born at risk of neonatal hypoglycaemia by utilizing the optokinetic reflex.
Methods:
Random-dot-kinetogram stimuli (250 dots, dot speed 8°/sec) were used to measure motion coherence thresholds in 275 children born with risk factors for neonatal hypoglycaemia including; small or large for gestational age, child of a diabetic mother and pre-term delivery (≥35 weeks gestation). Data were also collected from 11 adult volunteers. Motion coherence was varied using the method of constant stimuli and detection of global motion was determined by observing the optokinetic reflex (OKR), and also behavioural responses in adults. Standard age-appropriate optometry tests were also performed.
Results:
Motion coherence thresholds were successfully measured in 261 (95%) children, which compared favourably with success rates for standard age-appropriate clinical tests (such as Cardiff cards, LANG I&II stereo test, Frisby stereo test). As expected, motion coherence thresholds were higher for 2-year old children (mean 42.0±13%) than for adults (mean (3.2± 1%), and were in good agreement with previous studies on global motion perception infants and older children. Motion coherence thresholds were significantly correlated with stereoacuity (R=0.22, p=0.002) in children. In addition, motion coherence thresholds assessed using OKR were significantly correlated with behavioural thresholds in adults (R = 0.67, p = 0.047), suggesting that OKR is indicative of perceived global motion.
Conclusions:
Motion coherence thresholds measured using OKR eye movements reflect behavioural responses in adults. This method can be applied to two-year old children born at risk of abnormal neurodevelopment.
Keywords: 611 neuro-ophthalmology: cortical function/rehabilitation •
465 clinical (human) or epidemiologic studies: systems/equipment/techniques •
522 eye movements