Physician-authored summaries and commentary on the most important medical research, provided by the NEJM Group, a division of the Massachusetts Medical Society.
© Massachusetts Medical SocietyAugust 2024
A longitudinal study tracked conversion rates to mild cognitive impairment and dementia.
Cognitive impairment has been shown to occur in many essential tremor cohorts. What has been lacking is a better understanding of conversion to mild cognitive impairment and potentially dementia. These authors conducted neuropsychological testing and divided their cohort of 222 patients with essential tremor (mean age, 79 years) into those with normal cognition, mild cognitive impairment or dementia at baseline. Evaluations were repeated for 177 of the patients at 18, 36, 54 and 72 months.
The cumulative prevalence of dementia was 18.5%. The annual conversion rate from essential tremor with normal cognition to essential tremor with mild cognitive impairment was 3.9%, and the conversion rate from essential tremor with mild cognitive impairment to essential tremor with dementia was 12.2%. Compared with historical data, the conversion rate from mild cognitive impairment to dementia was three times that seen in the general population and similar to the rate in patients with Parkinson’s disease. The cumulative prevalence of mild cognitive impairment was 26.6%, which is about twice what is observed in the general population.
Comment: This important study showed a conversion rate from mild cognitive impairment to dementia in patients with essential tremor that was similar to the rate in historical controls with Parkinson’s disease. The findings add to the collective evidence that essential tremor is commonly associated with cognitive changes, including the possibility of dementia. The reason practitioners should be aware that essential tremor is more than a motor disorder is that development of dementia doubles the mortality rate.
Michael S. Okun, MD, Adelaide Lackner Professor and Chair of Neurology and Executive Director, Fixel Institute for Neurological Diseases, University of Florida McKnight Brain Institute, Gainesville, USA.
Ghanem A, et al. Prevalence of and annual conversion rates to mild cognitive impairment and dementia: prospective, longitudinal study of an essential tremor cohort. Ann Neurol 2024; 95: 1193-1204.
This summary is taken from the following Journal Watch title: Neurology.