[Spasmus nutans: apropos of 16 cases]

Spasmus nutans is a syndrome occurring in early childhood. It consists of a triad of symptoms: head nodding, ocular oscillations and anomalous head position. Ophthalmologic and neurological findings are otherwise normal. This syndrome is benign and has spontaneous resolution.

Sixteen patients with spasmus nutans seen from 1980 to 1995 were retrospectively studied. Their present status was evaluated by clinical examination or questionnaire.

The age at onset ranged from 1 to 15 months (average 7 months). Thirteen of 16 patients were referred for head nodding, which was a constant manifestation; its direction was horizontal, vertical or rotatory. Nystagmus was present in 14 infants. It was acquired, asymmetrical, bilateral (or unilateral in three cases), rapid, fine, pendular and horizontal. Both head nodding and nystagmus were intermittent. Anomalous head position was present in seven cases, consisting of head tilt or a chin upon/chin down posture. Neuroimaging (13 cases) was always normal. The follow-up in 12 children (up to 2 years) showed a complete resolution of the syndrome in 6 months to 6 years (average 2.5 years).

The diagnosis was established by the constancy of the characteristic triad and the elimination of the other causes of nystagmus. Isolated head nodding had to be distinguished from bobble head syndrome. In several reported cases, electronystagmography recordings have suggested that head nodding is a compensatory process against nystagmus and that the head tilt allows transient resolution of the nystagmus.

Spasmus nutans is a self-limiting benign clinical entity. Normal complete ophthalmologic and neurological examination, as well as magnetic resonance imaging (MRI) are necessary to confirm the diagnosis.