Non-motor features of essential tremor, Updated review of evolving aspects

Abstract

Essential tremor (ET) is defined as an action tremor syndrome with a duration of more than three years in both upper limbs with or without tremor in other areas and with no other neurological signs. ET's non-motor characteristics add to the evidence of clinical variability in ET, a disease with a wide range of pathological and etiological characteristics. Problems in frontal-executive function, comparable to Parkinson's disease (PD), were one of the most common patterns of cognitive affection in ET. ET individuals who started tremor after the age of 65 were 64 to 70% more likely than control subjects to develop dementia, but ET cases who started tremor before the age of 65 have an equal chance to develop dementia as controls. Depression rates were considerably higher in ET than controls and more severe depression is found. A strong evidence linking anxiety and ET. Many studies have documented sleep disturbances in ET.