Cogan Syndrome Or Infantile Saccade Initiation Delay Syndrome (ISID)

ISID is usually associated with several additional neurological and developmental deficiencies. 

Signs and Symptoms

A characteristic symptom of Cogan syndrome/ISID is the inability to initiate saccades on command. Even thought the velocity of the saccades appears normal, saccades can be prolonged and hypometric. Head thrusts, frequent blinking, developmental delay, ataxia and clumsiness are also frequently observed in patients with ISID. 


MRI scans of the brain can appear normal in patients with ISID, indicating that the defects in the brain may be below the detection limit. A detailed examination of ocular motor function is essential for the diagnosis of ISID. The best way to diagnose an impairment of saccades is by videooculographie.

Observable ocular motor disorders

  • Impaired initiation of saccades
  • Saccadic smooth pursuit


Strupp M, et al. (2014) Central ocular motor disorders, including gaze palsy and nystagmus. J Neurol 261(2):542-558. PubMed

Salman MS & Ikeda KM (2013) The syndrome of infantile-onset saccade initiation delay. Can J Neurol Sci 40(2):235-240. PubMed