Congenital Ocular Motor Apraxia: Clinico-Radiological Analyses

b Background: Congenital ocular motor apraxia (COMA) is characterized by impaired voluntary saccades and abnormal head thrusts. However, mechanism of this disorder remains to be elucidated. Methods: This study analyzed the eye movements and imaging findings in 16 patients with COMA, who had been recruited from 2003 to 2009 at the Neuro-Ophthalmology Clinic of Seoul National University Bundang Hospital. Results: All the children showed impaired saccades and smooth pursuit in the horizontal direction. One of them also exhibited impaired vertical saccades and smooth pursuit. Eight children showed excessive blinks in association with an attempt to generate saccades. The typical head thrust usually developed around the age of eight months and had resolved by the age of 6-7 years. History of spasmus nutans was confirmed in seven children. Fourteen children showed cerebellar vermian hypoplasia, mostly in the inferior portion, and five of them also had dysgenesis of the corpus callosum. The severity of cerebellar vermian hypoplasia was correlated with developmental delay, as determined by the age of independent walking. Conclusion: Cerebellar vermian hypoplasia is a frequent finding in COMA. Dysfunction of the oculomotor vermis may responsible for the impaired saccades and smooth pursuit in COMA. The occasional association of COMA with spasmus nutans indicates a common pathophysiology of these benign developmental disorders. J Korean Neurol Assoc 28(1):27-32, 2010