Essential tremor (ET), a neurological disorder characterized by involuntary, rhythmic shaking of the hands and head, is one of the most common movement disorders, affecting an estimated 2.2% of the United States population. While ET is often explained as a motor condition, a new study published in the Annals of Neurology details a potential link between essential tremor and an increased risk of cognitive impairment, including mild cognitive impairment (MCI) and dementia.
The study, conducted over six years, resulted in the longest available longitudinal prospective study reporting rates of MCI and dementia in people with essential tremor. Enrolled participants included 222 patients, average age 79, all of whom were diagnosed with essential tremor. Participants underwent periodic neuropsychological tests for cognitive function over an average five-year period. The researchers’ conclusion pointed to a cumulative prevalence of MCI and dementia in this group, with nearly double the MCI rate compared to the general population and triple the dementia rate.
Moreover, the study found high annual conversion rates from normal cognition to MCI (3.9%) and from MCI to dementia (12.2%). This data implies that individuals with essential tremor face a higher risk of progressing to more severe cognitive impairment over time.
Notably, the study also revealed that the prevalence of cognitive impairment in essential tremor patients falls between those associated with normal aging and the more severe rates observed in Parkinson’s disease patients. This finding underscores the importance of early cognitive screening and monitoring for individuals with essential tremor.
While the reasons behind this link are not fully understood, the implications may help patients and family caregivers prepare for their future long-term care needs.
“We know from related research that the presence of cognitive impairment in patients with essential tremor has meaningful clinical consequences,” said corresponding author Elan D. Louis, MD, MS, of the University of Texas Southwestern Medical Center. “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 nonindependent living arrangements than are patients with essential tremor without dementia. 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.”
