A psychogenic condition in adults, causing nodding of the head from clonic spasms of the sternomastoid muscles. A similar nodding occurs in babies, with the head turning from side to side.
A head-shaking motion is observed in various medical conditions and is commonly found in infants, where it’s referred to as spasmus nutans. In these cases, it’s entirely normal, harmless, and typically resolves within the first year of life. In older children, involuntary head movements can be attributed to conditions like St. Vitus’s dance or habit spasms of nervous origin. Involuntary head movements are also observed in conditions like tremors associated with old age, Parkinson’s disease, and instances of alcohol or tobacco poisoning.
One identified by the repetitive movement of nodding the head.