Teaching NeuroImage: tremor in aqueductal stenosis and response to endoscopic third ventriculostomy.

Marc W. Halterman, MD, PhD G. Edward Vates, MD, PhD Garrett Riggs, MD, PhD Idiopathic aqueductal stenosis (AS) may account for up to 59% of cases presenting with triventricular noncommunicating hydrocephalus.1 The clinical presentations associated with triventricular hydrocephalus differ depending on age at onset and the acuity of obstruction. Acute syndromes include Parinaud’s syndrome (vertical gaze restriction, lid retraction, and pupillary abnormalities), the rostral midbrain syndrome (upward gaze palsy, retraction nystagmus, pyramidal and extrapyramidal signs), and deficits in arousal. In the very young, chronic diencephalic compression can produce the bobble-head doll syndrome (high frequency head movements, limb ataxia, tremor, and cognitive deficits). Resolution of transtentorial pressure gradients by CSF diversion typically produces rapid improvement.2 We describe an adult patient with upper extremity tremor due to decompensated hydrocephalus from AS, who demonstrated improvement following endoscopic third ventriculostomy.