Behavioral symptoms associated with essential tremor.

As the complexity and heterogeneity of ET emerge, greater interest has been taken in the nonmotor manifestations of this disease. The fact that the motor manifestations reflect widespread anatomic pathology (e.g., cerebellum, basal ganglia) suggests that the nonmotor aspects might be a manifestation of an illness that affects multiple areas of the nervous system. Therefore, nonmotor aspects of the disease might reflect the presence of disease pathology in a particular area of the brain. Alternatively, nonmotor aspects could be the result of the tremor itself and the effects that it has on disability, mood, and personality. Finally, some of the nonmotor aspects could reflect the possibility that individuals with these disorders have a shared predisposition for ET and that a common mechanism underlies both. Further work is needed to define the extent of the nonmotor manifestations, their presence or absence in the predisease state, and their progression over time. These studies will further our insights into the mechanisms and anatomic pathology of ET and help us to develop a broader understanding of issues that are important in treating the individuals with this disease.