title: Mild Cognitive Impairment Subtypes in a Cohort of Elderly Essential Tremor Cases.
abstract: 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.
  
  
  
  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+).
  
  
  
  Ninety-one (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; 16.7%), 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=.042).
  
  
  
  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. (JINS, 2017, 23, 390-399).
authors.affiliation: 1Division of Movement Disorders,Department of Neurology,Yale School of Medicine,Yale University,New Haven,Connecticut.
authors.forename: Kathleen
authors.initials: K
authors.lastname: Collins
authors.affiliation: 1Division of Movement Disorders,Department of Neurology,Yale School of Medicine,Yale University,New Haven,Connecticut.
authors.forename: Brittany
authors.initials: B
authors.lastname: Rohl
authors.affiliation: 1Division of Movement Disorders,Department of Neurology,Yale School of Medicine,Yale University,New Haven,Connecticut.
authors.forename: Sarah
authors.initials: S
authors.lastname: Morgan
authors.affiliation: 2Department of Psychiatry,College of Physicians and Surgeons,Columbia University,New York,New York.
authors.forename: Edward D
authors.initials: ED
authors.lastname: Huey
authors.affiliation: 1Division of Movement Disorders,Department of Neurology,Yale School of Medicine,Yale University,New Haven,Connecticut.
authors.forename: Elan D
authors.initials: ED
authors.lastname: Louis
authors.affiliation: 3Department of Neurology,College of Physicians and Surgeons,Columbia University,New York,New York.
authors.forename: Stephanie
authors.initials: S
authors.lastname: Cosentino
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D060825:Cognitive Dysfunction / Q000145:classification / Q000175:diagnosis / Q000209:etiology; D015331:Cohort Studies; D020329:Essential Tremor / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D010555:Personality Inventory; D021641:Recognition, Psychology; D012720:Severity of Illness Index
keywords: Cognition; Dementia; Executive function; Longitudinal; Memory; Movement disorders