Case number: 80

A twist of the head

Author: Raed Benbehani, Raj Heran

This 8-month old boy was referred for abnormal head and eye movements.

The onset is uncertain, but dates back at least to when he started sitting.
Labour and delivery were uncomplicated, at full term. The mother has noticed that he seems a bit limp and has trouble supporting his head and neck at times.

On exam he seems to fix and follow visual objects but shows intermittent abnormalities when attempting to make horizontal saccades, as shown in the video. There is no nystagmus.

T1 axial MR images are shown:

  case80T1a   case80T1d   case80T1c
  case80T1b   case80T1g   case80T1f

Question: What is the diagnosis?

View Diagnosis

Cogan’s congenital oculomotor apraxia

This condition is characterized by impaired voluntary horizontal saccades, intact smooth pursuits and abnormal head jerks by which the child utilizes the VOR to enable fixation. Vertical saccades are not affected. The child typically uses head thrusts to drive the eyes in the opposite direction over the target, to allow for the controversively rotated eye to fixate the desired target. The absence of the fast phase of optokinetic nystagmus when the child is held and rotated can affirm the diagnosis. The condition is present since birth but does not manifest until six month of age when the child gains head and neck control. Isolated congenital oculomotor apraxia is usually sporadic but other forms can be inherited in an autosomal recessive or dominant manner.

The ocular motility abnormalities can be isolated or associated with neurologic manifestations such as developmental and motor delay, cerebellar ataxia, speech abnormalities, incoordination and hypotonia.
Congenital oculomotor apraxia can also be part of syndromes such as Ataxia telangectasia, Krabbe disease and Joubert syndrome.

Neuro-imaging abnormalities have been well described in congenital oculomotor apraxia and include most commonly cerebellar vermis hypoplasia, particularly in the inferior portion, as in this case. The fourth ventricle is often seen pointing at the level of cerebellar peduncles on axial images.
Vermian hypoplasia is also a feature of Joubert Syndrome, but in this condition the superior vermis is more severely involved: on imaging, there is superior convexity of the fourth ventricle and abnormal orientation of the superior cerebellar peduncles and deep interpeduncular fossa , giving rise to the classic “molar-tooth” sign. Other clinical features like neonatal tachypnea and retinal dystrophy usually distinguish Joubert syndrome from congenital ocular motor apraxia.
Other neuro-imaging abnormalities associated with congenital oculomotor apraxia include posterior fossa tumors and cysts, absence of the corpus collosum, cortical migration abnormalities like pachygyria and supratentorial heterotopia, periventricular leukomalacia and leukodystrophy.

Congenital oculomotor apraxia tends to improve with time although the associated developmental and learning difficulties may require multidisciplinary assistance for speech and learning difficulties are often needed.


  1. Whitsel EA, Castillo M, D’Cruz O. Cerebellar vermis and midbrain dysgenesis in oculomotor apraxia: MR findings. AJNR Am J Neuroradiol. 1995;16:831-4.
  2. Sargent MA, Poskitt KJ, Jan JE. Congenital ocular motor apraxia: imaging findings. AJNR Am J Neuroradiol. 1997;18:1915-22