AP-HP, Hôpital Trousseau, Service de neuropédiatrie, 26, rue du Dr Arnold Netter, 75571 Paris Cedex 12, France, Centre de référence neurogénétique, mouvements anormaux de l’enfant, Hôpital Trousseau, Service de neuropédiatrie, 26, rue du Dr Arnold Netter, 75571 Paris Cedex 12, France
Spasmus nutans (SN) is a benign syndrome occurring in early infancy. It consists of a triad of symptoms: head nodding, nystagmus and anomalous head position. The age of onset is three to 18 months, sometimes until two years (average: seven months). Head nodding consists of slow head tremor, usually of the no-no type. Head nodding may also be of the yes-yes type or rotatory. The nystagmus is acquired, typically asymmetric, disconjugate, horizontal, sometimes unilateral, pendular and of small amplitude and high frequency. Head tilting is less constant, observed in about 40% of cases. Psychomotor development is often normal. The pathogenesis is unknown. SN is a self-limiting benign entity, which resolves spontaneously within one to two years after onset. Normal complete ophthalmologic and neurological examination, as well as MRI and electroretinography, are necessary to confirm the diagnosis. Children with SN must be carefully monitored to ensure that SN remains isolated and gradually disappears.