title: Exploring the validity of mild cognitive impairment (MCI) subtypes: multiple-domain amnestic MCI is the only identifiable subtype at longitudinal follow-up.
abstract: BACKGROUND
  Epidemiological research exploring risk factors for Alzheimer's dementia resulted in the identification of the mild cognitive impairment (MCI) profile. Subsequently, distinct subtypes of MCI have been proposed; however, the validity of these as diagnostic entities remains uncertain.
  
  
  METHODS
  The aim of the present study was to examine the longitudinal neuropsychological profiles of MCI subtypes. A total of 118 adults aged 60-90 years were classified at screening as amnestic (a-MCI), nonamnestic (na-MCI), and multiple-domain amnestic (a-MCI+) and were assessed at two time points across 20 months on a comprehensive neuropsychological assessment battery.
  
  
  RESULTS
  The a-MCI+ group displayed the poorest performance of all groups in terms of episodic memory, working memory, attention, and executive functioning.
  
  
  CONCLUSIONS
  These findings suggest that the a-MCI+ subtype is the only variant that is recognizable via neuropsychological testing. In contrast, the differentiation between single-domain subtypes and healthy controls is difficult and may not be achievable through current neuropsychological assessment practices.
authors.affiliation: a School of Psychology , University of Tasmania , Launceston , TAS , Australia.
authors.forename: Shannon Zofia
authors.initials: SZ
authors.lastname: Klekociuk
authors.forename: Mathew James
authors.initials: MJ
authors.lastname: Summers
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001288:Attention / Q000502:physiology; D060825:Cognitive Dysfunction / Q000145:classification* / Q000175:diagnosis*; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008569:Memory Disorders / Q000209:etiology; D061212:Memory, Episodic; D011939:Mental Recall / Q000502:physiology; D008875:Middle Aged; D015999:Multivariate Analysis; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D013997:Time Factors; D014706:Verbal Learning / Q000502:physiology