Alternating hemiplegia of childhoood and oculomotor anomalies

Background : Alternating hemiplegia of childhood is a syndrome which begins in the first year of life. It is characterized by repeated attacks of uni- or bilateral hemiplegia or hemiparesia. In most cases paroxysmal manifestat ions are observed: movements or distony attacks, episodic nystagmus, abnorm al eye movements and disturbance of the neurovegatative system, predominant ly in the first year of life. Analysis: In half of the cases, neurological anomalies begin during the neo natal period with a non characteristic aspect. Typical attacks take place a fter one year of life, sometimes associated with partial epilepsy. In a qua rter of cases, the oculomotor anomalies have been known since early life. T he diagnosis is made prior to one year on the basis of associated oculomoto r anomalies and other symtoms without EEG arguments for epilepsy. Paroxysma l nystagmus is always found. One eye is affect in most cases, generally wit h horizontal and seldom with vertical movements of large variable pendular amplitude. One eye with nystagmus and the other with mydriasis is sometimes reported. Most attacks last from 30 sec to 3 min. Paroxysmal strabismus de scribed in half of the cases seems to be generally unilateral internuclear transitory ophthalmoplegia. Finally, ocular deviations on the hemiparetic s ide are described. They are generally unique or sometimes associated with h ead deviation. Spontaneous blinking is reduced. Conclusion : Alternating hemiplegia of childhood is a non-epileptic sporadi c, paroxysmal manifestation of unknown pathogenesis. Prognosis is poor. The presence of oculomotor signs suggests the diagnosis.