[Neuropsychiatric disturbances in essential tremor]

This review focuses on the neuropsychiatric manifestations (personality disturbances, depressive symptoms, cognitive impairment and dementia), which have been described in this last decade in patients with essential tremor. We compared the data derived from the Neurologic Disorders in Central Spain (NEDICES) study, a prospective population-based survey, with those derived from the literature. The traditional view of essential tremor as a mono-symptomatic condition characterized by action tremor is now changing. First, it is known that many patients also have other motor manifestations apart from tremor (e.g., ataxic gait). Second, in the last years, the presence of a variety of non-motor neuropsychiatric features has been described. Mild cognitive changes (especially executive dysfunction) have been documented in several independent studies. Further, two population-based studies have demonstrated an association between essential tremor with mild cognitive impairment and dementia. Psychiatric manifestations include specific personality traits, anxiety, social phobia, and depressive symptoms. Taking together, the neuropsychiatric dysfunction pattern and the new data on neuropathology of essential tremor suggest that this disease is a neurodegenerative cerebellar disorder and let us to question the classical concept of essential tremor as a benign mono-symptomatic disorder.