Clinical reasoning: Psychomotor regression in the young.

SECTION 1 A 38-year-old right-handed man was referred for investigation of a 20-year history of progressive behavior change and involuntary movements. Symptom onset was in his late teens. Up until that time he had achieved age-appropriate motor and cognitive milestones and had completed normal schooling. There was no family history of dementia or movement disorders. Initially, family members noted deterioration in his gait, which became increasingly imbalanced and clumsy. By the age of 20, speech and cognitive difficulties emerged. His speech was dysarthric with reduced output. By 25 years of age, he was noted to be inattentive at work. A decline in short-term memory and safety awareness was also noted by coworkers. After several episodes of inappropriate behavior, he was referred to psychiatric services. By age 30, he was deemed unfit for work. Over the next 8 years, further symptoms emerged: involuntary movements of his upper limbs, dysphagia, and episodes of apparent collapse after raucous laughter. At age 38, he was admitted to the hospital after an episode of unwitnessed collapse, presumed to be a seizure. Head CT confirmed a subdural hematoma requiring evacuation. After recovery, his examination demonstrated generalized chorea, past-pointing and dysarthria, limb and gait ataxia, and impaired vertical gaze eye movements. His MiniMental State Examination score was 14/30, with 0/3 recall at 5 minutes.