Background: A recent consensus statement introduced the term “ET plus”. Although investigators have quantified the prevalence of ET plus in cross-sectional studies, patients with ET plus have not been tracked longitudinally; hence, there is no understanding of its stability over time.Methods: We present prospective, longitudinal phenotypic data on an ET cohort that was followed regularly at 18-month intervals (T1, T2, T3, T4) for up to 64 months. We assigned an ET or ET plus diagnosis to each case at each time interval.Results: There were 201 participants at baseline. The proportion with ET plus increased from 58.7% at baseline to 72.1% at T4 (p = 0.046). Of 172 (85.6%) who received a diagnosis of ET plus at one or more time intervals, the diagnosis was unstable (e.g., with reversion) in 62 (36.0%). We also assessed the stability of the clinical features of ET plus. Rest tremor was the most unstable clinical feature of ET plus; it was present in 59 participants, among whom it reverted from present to absent in 23 (39.0%). By contrast, for “memory impairment” (i.e., either mild cognitive impairment or dementia), the proportion who reverted from present to absent was only 21.3%.Conclusion: These data support our two a priori hypotheses: (1) the prevalence of ET plus would increase progressively, as it likely represents a more advanced stage of ET, and (2) the ET plus diagnosis would not be stable over time, as cases would fluctuate with respect to their phenotypic features and their assigned diagnoses.
The Essential Tremor Centralized Brain Repository is the largest repository of prospectively collected essential tremor (ET) brains (n = 231). Hence, we are uniquely poised to address several questions: What proportion of ET cases has Lewy pathology (LP)? What is the nature of that pathology and how does it relate to other comorbidities? Each brain had a complete neuropathological assessment, including α-synuclein immunostaining. We created a 10-category classification scheme to fully encapsulate the patterns of LP observed. Four metrics of cerebellar pathology were also quantified. Mean age at death = 89.0 ± 6.4 years. Fifty-eight (25.1%) had LP and 46 (19.9%) had early to late stages of Parkinson disease (PD). LP was very heterogeneous. Of 58 cases with LP, 14 (24.1%) clinically developed possible PD or PD after a latency of 5 or more years. There was a similar degree of cerebellar pathology in ET cases both with and without LP. In summary, 1 in 4 ET cases had LP—a proportion that seems higher than expected based on studies among control populations. Heterogeneous LP likely reflects clinical associations between ET and PD, and ET with Alzheimer disease-type neuropathology. These data further our understanding of ET and its relatedness to other degenerative diseases.
Background: Patients with essential tremor (ET) have an increased risk of cognitive impairment, yet little is known about the predictors of cognitive decline in these patients. Exposures to infectious agents throughout the lifespan may impact the later development of cognitive impairment. For example, high Infection exposure has been associated with lower cognitive performance in Alzheimer's and Parkinson's disease. However, this predictor has not been examined in ET.Objectives: To determine whether a higher baseline infection burden is associated with worse cognitive performance at baseline and greater cognitive decline over time in an ET cohort.Method/Design: 160 elderly non-demented ET participants (80.0 ± 9.5 years) underwent an extensive cognitive evaluation at three time points. At baseline, participants completed an infection burden questionnaire (t-IBQ) that elicited information on previous exposure to infectious agents and number of episodes per disease. Analysis of covariance and generalized estimated equations (GEEs) were used.Results: Overall, infection burden was not associated baseline cognitive performance. Adjusted GEE models for repeated measures yielded a significant time interaction between moderate infection burden at baseline and better performance in the attention domain over time (p = 0.013). Previous history of rubella was associated with faster rate of decline in visuospatial performance (p = 0.046).
Conclusion:The data were mixed. Moderate self-reported infection burden was associated with better attention performance over time. Self-reported history of rubella infection was related to lower visuospatial performance over time in this cohort. Follow-up studies with additional design elements would be of value.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.