The “Head Snap”: A Subtle Clinical Feature During the Finger–Nose–Finger Maneuver in Essential Tremor

BACKGROUND: Essential tremor is characterized by several hyperkinetic movements, including arm and head tremors. We report another movement of the head in patients with essential tremor, which we term the “head snap.” This was observed as a jerking motion of the head in some patients while they performed the finger–nose–finger maneuver. METHODS: We compared the prevalence of the head snap in essential tremor patients vs. Parkinson's disease patients. We also assessed the clinical correlates of the head snap. RESULTS: Ten (20%) of 50 essential tremor patients exhibited a head snap of any severity (rating ≥0.5) vs. 0 of 50 Parkinson's disease patients (p = 0.001). Patients with head snap had more severe arm tremor on Archimedes spiral drawings (p = 0.019) and were more likely to have head tremor (p = 0.03) than those without it. CONCLUSIONS: This sign could be a useful aid in the clinical diagnosis of tremor.