Mild Cognitive Impairment Subtypes in a Cohort of Elderly Essential Tremor Cases

Abstract

Objective Individuals with essential tremor (ET) exhibit a range of cognitive deficits generally conceptualized as “dysexecutive” or “fronto-subcortical,” and thought to reflect disrupted cortico-cerebellar networks. In light of emerging evidence that ET increases risk for Alzheimer’s disease (AD), it is critical to more closely examine the nature of specific cognitive deficits in ET, with particular attention to amnestic deficits that may signal early AD. Method We performed a cross-sectional analysis of baseline data from 128 ET cases (age 80.4 ± 9.5 years) enrolled in a longitudinal, clinical-pathological study. Cases underwent a comprehensive battery of motor-free neuropsychological tests and a functional assessment to inform clinical diagnoses of normal cognition (ET-NC), mild cognitive impairment (MCI) (ET-MCI), or dementia (ET-D). ET-MCI was subdivided into subtypes including: amnestic single-domain (a-MCI), amnestic multi-domain (a-MCI+), non-amnestic single-domain (na-MCI), or non-amnestic multi-domain (na-MCI+). Results 91 (71.1%) cases were ET-NC, 24 (18.8%) were ET-MCI, and 13 (10.2%) were ET-D. Within MCI, the a-MCI+ subtype was the most common (13/24; 54.2%) followed by a-MCI (4/24; 16,7%), na-MCI+ (4/24; 16.8%), and na-MCI (3/24; 12.5%). Cases with amnestic MCI demonstrated lower recognition memory z-scores (−2.4 ± 1.7) than non-amnestic groups (−0.9 ± 1.2) (p=0.042). Conclusions Amnestic MCI, defined by impaired memory recall but associated with lower memory storage scores, was the most frequent MCI subtype in our study. Such impairment has not been explicitly discussed in the context of ET and may be an early hallmark of AD. Results have implications for the prognosis of specific cognitive deficits in ET.

Essential tremor: diagnosis and management

“…Impairments of attention and working memory were commonly seen. A 2017 cross sectional analysis of 128 older patients with essential tremor found that both amnestic and non-amnestic mild cognitive impairment (MCI) subtypes were represented (n=24); amnestic MCI, single and multi-domain, represented about 70% (n=17) of cases 68. Multi-domain amnestic MCI was the most common subtype (n=13; 54%) Five neuropsychological tests that are sensitive to mild cognitive deficits in patients with essential tremor (as defined by a Clinical Dementia Rating of 0.5) are the California Verbal Learning Test II Total Recall, Logical Memory II, Verbal-Paired Associates I, category Switching Fluency, and Color-Word Inhibition 69…”

Graph theory analysis of resting‐state functional magnetic resonance imaging in essential tremor

“…Study Group et al, 2006b;Benito-León, Louis, Mitchell, & Bermejo-Pareja, 2011;Bermejo-Pareja et al, 2007;Cersonsky et al, 2018;Collins et al, 2017), depressive symptoms , personality changes (Thenganatt & Louis, 2012), changes in sleep patterns (Benito-León, Louis, & Bermejo-Pareja, 2013;Gerbin, Viner, & Louis, 2012), changes in visual reaction time (Jiménez-Jiménez et al, 2010), and hearing impairment Ondo, Sutton, Dat Vuong, Lai, & Jankovic, 2003).…”

“…The current view of essential tremor (ET), one of the most common adult neurological disorders (Benito-León, 2009;Louis & Ferreira, 2010), is that it may be a family of diseases, unified by the presence of kinetic tremor, and characterized by etiological, clinical and pathological heterogeneity (Benito-León, 2014;Benito-León & Louis, 2006;. Aside from classic motor manifestations, ET is now considered a heterogeneous entity associated with a number of nonmotor manifestations, Sengul, Sengul, Sural, Bakim, & Forta, 2015) including cognitive disorders (Benito-León, Louis, Bermejo-Pareja, & Neurological Disorders in Central Spain Study Group, 2006a; Benito-León, Louis, Bermejo-Pareja, & Neurological Disorders in Central Spain Study Group et al, 2006b;Benito-León, Louis, Mitchell, & Bermejo-Pareja, 2011;Bermejo-Pareja et al, 2007;Cersonsky et al, 2018;Collins et al, 2017), depressive symptoms , personality changes (Thenganatt & Louis, 2012), changes in sleep patterns (Benito-León, Louis, & Bermejo-Pareja, 2013;Gerbin, Viner, & Louis, 2012), changes in visual reaction time (Jiménez-Jiménez et al, 2010), and hearing impairment Ondo, Sutton, Dat Vuong, Lai, & Jankovic, 2003).…”

The Experience of Essential Tremor Caregivers: Burden and Its Correlates

“…Cognitive deficits are not uncommon, affecting 30–60% of patients ( 14 ), but run a wide range of severities from subclinical abnormalities to mild cognitive impairment (MCI) and dementia. Specific cognitive deficits in ET include impairments in executive function, working memory, verbal memory, and language ( 14 , 15 ). Furthermore, individuals with ET also experience increased frailty as they age ( 16 ), and psychosocial factors contribute to the difficulty of dealing with ET.…”