title: Four-year outcome of mild cognitive impairment: the contribution of executive dysfunction.
abstract: OBJECTIVE
  The contribution of executive cognition (EC) to the prediction of incident dementia remains unclear. This prospective study examined the predictive value of EC for subsequent cognitive decline in persons with mild cognitive impairment (MCI) over a 4-year period.
  
  
  METHODS
  One hundred forty-one persons with MCI (amnestic and nonamnestic, single- and multiple-domain) received a baseline and two biennial follow-up assessments. Eighteen tests, assessing six different aspects of EC, were administered at baseline and at 2-year follow-up, together with screening cognitive and daily functioning measures. Longitudinal logistic regression models and generalized estimating equations (GEE) were used to examine whether EC could predict progression to a Clinical Dementia Rating Scale (CDR; C. P. Hughes, L. Berg, W. L. Danziger, L. A. Coben, & R. L. Martin, 1982, A new clinical scale for the staging of dementia, British Journal of Psychiatry, Vol. 140, pp. 566-572) score of 1 or more over the 4-year period, first at the univariate level and then in the context of demographic and clinical characteristics, daily functioning measures, and other neurocognitive factors.
  
  
  RESULTS
  Over the 4-year period, 56% of MCI patients remained stable, 35% progressed to CDR ≥ 1, and 8% reverted to normal (CDR = 0). Amnestic MCI subtypes were not associated with higher rates of progression to dementia, whereas subtypes with multiple impairments were so associated. Eight out of the 18 EC measures, including all three measures assessing inhibition of prepotent responses, predicted MCI outcome at the univariate level. However, the multivariate GEE model indicated that age, daily functioning, and overall cognitive functioning best predicted progression to dementia.
  
  
  CONCLUSIONS
  Measures of EC (i.e., inhibitory control) are associated with MCI outcome. However, age and global measures of cognitive and functional impairment are better predictors of incident dementia.
authors.affiliation: Departments of Psychiatry and Behavioral Sciences and Neurology, Johns Hopkins University School of Medicine.
authors.forename: Eleni
authors.initials: E
authors.lastname: Aretouli
authors.affiliation: Department of Hygiene and Epidemiology, University of Ioannina School of Medicine.
authors.forename: Konstantinos K
authors.initials: KK
authors.lastname: Tsilidis
authors.affiliation: Departments of Psychiatry and Behavioral Sciences and Neurology, Johns Hopkins University School of Medicine.
authors.forename: Jason
authors.identifier: 0000-0001-7381-6244
authors.initials: J
authors.lastname: Brandt
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000704:Analysis of Variance; D060825:Cognitive Dysfunction / Q000503:physiopathology*; D018450:Disease Progression; D056344:Executive Function / Q000502:physiology*; D005260:Female; D006801:Humans; D016015:Logistic Models; D008137:Longitudinal Studies; D008297:Male; D009483:Neuropsychological Tests; D011237:Predictive Value of Tests; D013997:Time Factors