Isolated head tremor: part of the clinical spectrum of essential tremor? Data from population-based and clinic-based case samples.

Essential tremor (ET) still remains a clinical diagnosis. Nonetheless, it is misdiagnosed in 30 to 50% of cases. There are a number of areas of diagnostic uncertainty. One of these is isolated head tremor, on which published data are limited and at variance. We studied the prevalence of isolated head (i.e., neck) tremor in ET in two population-based studies (Turkey and New York) and a large clinical sample (New York); these 583 ET cases all received the same detailed tremor examination. Head tremor with mild arm tremor occurred in a very small percentage of cases in each sample (1.9-3.1%, overall 2.7%). Nearly all of them were women. Head tremor in the complete absence of arm tremor was not observed in any cases (0.0%). These clinical data may be of value to clinicians in practice settings and researchers in phenotyping efforts in the emerging field of ET genetics.