Reversible Dropped Head Syndrome after Hemispheric Striatal Infarction

Abstract

We report a rare case of transient "dropped head syndrome" (DHS) after acute ischemic stroke. A 64-year-old man noticed a sudden onset of mild weakness in his left hand and also difficulty in preventing his head from dropping onto his chest without weakness of the neck extensor muscles. Magnetic resonance images showed acute ischemic changes at the right putamen and caudate nucleus. Surface electromyography (EMG) performed 3 days after the stroke showed that both trapeziuses were hypertonic at rest, whereas the activity of the sternocleidomastoids was gradually increased on passive head lifting, indicating dystonia of the neck muscles. His dropped head fully improved by 9 days after the stroke. Re-examination by surface EMG 30 days after the stroke showed no hypertonic activity in the neck muscles. DHS is characterized by an abnormal ante-fixed posture of the neck, usually observed in patients with neurodegenerative disorders such as multiple system atrophy and Parkinson disease. This is the first case of reversible DHS after acute ischemic stroke, and the accumulation of similar cases will be important to elucidate the mechanisms underlying the development of DHS and stroke-associated movement disorders.