Estimates of the prevalence of essential tremor (ET) are probably low because screening questionnaires have been used. The authors estimated the prevalence of ET in Mersin Province, Turkey, in 2,253 individuals aged >or=40 years, all of whom were examined by study neurologists. There were 89 ET cases (prevalence = 4.0%, 95% CI = 3.2 to 4.8%). The prevalence of ET may be higher than previously estimated. This is important when defining the extent of the health care problem.

The discrepancy in RLS prevalence studies (including the authors') suggests that prevalence varies among different races, thus supporting a genetic predisposition.

The objectives of the present study were to estimate the prevalence of recurrent headaches in schoolchildren (ranging from 2nd to 5th degrees) in Mersin city of Turkey and to determine the sensitivity, specificity, positive predictive value and positive likelihood ratio of the diagnostic headache characteristics in children with migraine and Tension Type Headache (TTH) using neurologist's diagnosis as the gold standard. The stratified sample of study was composed of 5562 children. The prevalence of recurrent headache was 49.2% (2739 of 5562) and the prevalence of current headache was 31.3% (859 of 2739). TTH was more common than migraine (24.7% vs. 10.4%). The most sensitive headache characteristic for migraine was 'severity of pain' and the most sensitive definitive symptom is 'duration of headache' in children with TTH. IHS-based symptom definition criteria are highly beneficial in diagnosis of childhood headache, if used together with detailed clinical assessment.

We present the clinical findings of a group of largely undiagnosed and untreated population-dwelling ET cases that would not otherwise have come to neurological attention. Approximately one-half reported functional difficulty and psychiatric symptoms were over-represented in these ET cases compared with matched controls. These findings suggest that ET, as it exists in the population, is not a completely benign entity.

Headache is a common health problem among schoolchildren in Mersin, which merits increased attention and detailed multicentre epidemiological and clinical studies.