Related Experiment Video
Updated: Apr 16, 2026
Investigating the Deployment of Visual Attention Before Accurate and Averaging Saccades via Eye Tracking and Assessment of Visual Sensitivity
Published on: March 18, 2019
Infantile-onset saccade initiation delay (congenital ocular motor apraxia)
1Winnipeg Children's Hospital and Section of Pediatric Neurology, Department of Pediatrics and Child Health, College of Medicine, Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada, msalman@hsc.mb.ca.
Insights
Congenital ocular motor apraxia, characterized by saccade initiation delay, often presents with head thrusts in infants. This condition primarily affects horizontal eye movements, with vertical saccade issues being rare but indicative of brain abnormalities.
Area of Science:
- Neuroscience
- Ophthalmology
- Pediatrics
Background:
- Infantile-onset saccade initiation delay, or congenital ocular motor apraxia, is a condition typically emerging in early infancy.
- Key features include difficulties initiating horizontal saccades (eye movements) and saccade hypometria, with normal saccadic velocity.
Purpose of the Study:
- To describe the clinical presentation and neuroimaging findings associated with infantile-onset saccade initiation delay.
- To differentiate the typical presentation from rarer forms and associated neurological disorders.
Main Methods:
- Clinical case review and analysis of characteristic ophthalmological findings.
- Correlation of ocular motor abnormalities with brain Magnetic Resonance Imaging (MRI) findings.
Main Results:
- Horizontal saccade initiation delay and hypometria are characteristic; isolated vertical saccade impairment is rare and suggests supratentorial abnormalities.
- Associated features can include developmental delay, hypotonia, ataxia, and abnormal optokinetic responses, often linked to cerebellar or midbrain-hindbrain malformations.
- Disorders like Joubert syndrome and ataxia telangiectasia present with broader saccade impairments and distinct neuroimaging findings.
Conclusions:
- Congenital ocular motor apraxia has a distinct presentation involving horizontal saccade deficits, with vertical saccade abnormalities pointing to specific brain lesions.
- Neuroimaging is crucial for identifying underlying causes, differentiating from other neurodevelopmental disorders, and understanding the spectrum of saccadic eye movement dysfunction.
Abstract:
Infantile-onset saccade initiation delay, also known as congenital ocular motor apraxia, typically presents in early infancy with horizontal head thrusts once head control is achieved. Defective initiation of horizontal saccades and saccade hypometria with normal saccadic velocity are characteristic findings. Isolated impairment of vertical saccades is rare. Impaired smooth ocular pursuit may be seen. Other relatively common features include developmental delay, hypotonia, ataxia, or clumsiness. Brain MRI may be normal or show a diverse range of abnormalities, most commonly involving the cerebellum. Defective slow phases of the optokinetic response are commonly associated with brain MRI abnormalities. Isolated defect of vertical saccade initiation may indicate supratentorial brain abnormalities on MRI. Joubert syndrome, a developmental midbrain-hindbrain malformation, and ataxia telangiectasia are both commonly associated with defective volitional and reflexive saccade initiation, saccade hypometria, and head thrusts. Both horizontal and vertical saccades are impaired in these two disorders.
