Longest study to date assesses cognitive impairment over time in adults with essential tremor

Essential tremor, a nervous system disorder that causes rhythmic shaking, is one of the most common movement disorders. A new study published in the Annals of Neurology reveals details on the increased risk of mild cognitive impairment (MCI) and dementia that individuals with essential tremor may face.

The research represents the longest available longitudinal prospective study of rates of MCI and dementia in people with essential tremor. The study enrolled 222 patients, 177 of whom participated in periodic evaluations over an average follow-up of 5 years.

Investigators observed a cumulative prevalence of 26.6% and 18.5% for MCI and dementia, respectively. They also noted a cumulative incidence of 18.2% and 11.2% for MCI and dementia, respectively. Each year, 3.9% of patients with normal cognition "converted" to having MCI, and 12.2% of those with MCI "converted" to having dementia.

"We know from related research that the presence of cognitive impairment in patients with essential tremor has meaningful clinical consequences. For example, patients with essential tremor who are diagnosed with dementia are more likely to need to use a walker or wheelchair, to employ a home health aide, and to reside in non-independent living arrangements than are patients with essential tremor without dementia," said corresponding author Elan D. Louis, MD, MS, of the University of Texas Southwestern Medical Center.

"With this in mind, the findings of the present study highlight the importance of cognitive screening and monitoring in patients with essential tremor. Early detection of impairment may provide opportunities for interventions that may slow further cognitive decline and improve the quality of life of patients and their families."