title: Cognitive activity and the cognitive morbidity of Alzheimer disease.
abstract: OBJECTIVE
  To test the hypothesis that frequent cognitive activity predicts slower cognitive decline before dementia onset in Alzheimer disease (AD) and faster decline thereafter.
  
  
  METHODS
  As part of a longitudinal cohort study, older residents of a geographically defined population were assessed at 3-year intervals with brief cognitive performance tests from which a composite measure of global cognition was derived. After each wave of testing, a subset was sampled for clinical evaluation. The present analyses are based on 1,157 participants. They were free of dementia at study enrollment at which time they rated frequency of participation in common cognitively stimulating activities from which a previously validated summary measure was derived. They were sampled for clinical evaluation a mean of 5.6 years after enrollment and subsequently followed a mean of 5.7 years with brief cognitive performance testing at 3-year intervals.
  
  
  RESULTS
  On clinical evaluation, 614 people had no cognitive impairment, 395 had mild cognitive impairment, and 148 had AD. During follow-up, the annual rate of global cognitive decline in persons without cognitive impairment was reduced by 52% (estimate = 0.029, SE = 0.010, p = 0.003) for each additional point on the cognitive activity scale. In the mild cognitive impairment group, cognitive decline rate was unrelated to cognitive activity (estimate = -0.019, SE = 0.018, p = 0.300). In AD, the mean rate of decline per year increased by 42% (estimate = 0.075, SE = 0.021, p < 0.001) for each point on the cognitive activity scale.
  
  
  CONCLUSIONS
  Mentally stimulating activity in old age appears to compress the cognitive morbidity associated with AD by slowing cognitive decline before dementia onset and hastening it thereafter.
authors.affiliation: Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL 60612, USA. rwilson@rush.edu.
authors.forename: R S
authors.initials: RS
authors.lastname: Wilson
authors.forename: L L
authors.initials: LL
authors.lastname: Barnes
authors.forename: N T
authors.initials: NT
authors.lastname: Aggarwal
authors.forename: P A
authors.initials: PA
authors.lastname: Boyle
authors.forename: L E
authors.initials: LE
authors.lastname: Hebert
authors.forename: C F
authors.initials: CF
authors.lastname: Mendes de Leon
authors.forename: D A
authors.initials: DA
authors.lastname: Evans
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000453:epidemiology / Q000523:psychology*; D003071:Cognition / Q000502:physiology*; D003072:Cognition Disorders / Q000453:epidemiology / Q000523:psychology*; D003627:Data Interpretation, Statistical; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D009483:Neuropsychological Tests; D012959:Socioeconomic Factors
references.citation: Neurology. 2002 Dec 24;59(12):1910-4
references.pmid: 12499482
references.citation: J Gerontol B Psychol Sci Soc Sci. 1999 May;54(3):P155-60
references.pmid: 10363036
references.citation: J Alzheimers Dis. 2003 Oct;5(5):349-55
references.pmid: 14646025
references.citation: Neurology. 2005 Mar 8;64(5):834-41
references.pmid: 15753419
references.citation: Neurology. 2003 Sep 23;61(6):812-6
references.pmid: 14504326
references.citation: Arch Neurol. 2000 Dec;57(12):1718-23
references.pmid: 11115237
references.citation: J Urban Health. 2004 Mar;81(1):64-78
references.pmid: 15047786
references.citation: Psychol Aging. 2008 Dec;23(4):765-77
references.pmid: 19140648
references.citation: Int J Neurosci. 1991 Apr;57(3-4):167-78
references.pmid: 1938160
references.citation: Proc Natl Acad Sci U S A. 2000 Apr 11;97(8):4398-403
references.pmid: 10716738
references.citation: Ann Epidemiol. 2005 Feb;15(2):129-36
references.pmid: 15652718
references.citation: Neurology. 2001 Dec 26;57(12):2236-42
references.pmid: 11756603
references.citation: Proc Natl Acad Sci U S A. 2008 May 13;105(19):6829-33
references.pmid: 18443283
references.citation: Am J Epidemiol. 2002 Jun 15;155(12):1081-7
references.pmid: 12048221
references.citation: Arch Gen Psychiatry. 2007 Jul;64(7):802-8
references.pmid: 17606814
references.citation: Biometrics. 1982 Dec;38(4):963-74
references.pmid: 7168798
references.citation: JAMA. 2002 Jun 26;287(24):3230-7
references.pmid: 12076219
references.citation: Neurology. 2009 Feb 3;72(5):460-5
references.pmid: 19188578
references.citation: Neurology. 2007 Nov 13;69(20):1911-20
references.pmid: 17596582
references.citation: J Neurosci. 2006 Jun 7;26(23):6314-7
references.pmid: 16763039
references.citation: Neuropsychol Dev Cogn B Aging Neuropsychol Cogn. 2009;16(1):56-79
references.pmid: 18686051
references.citation: Neurology. 2002 Jul 23;59(2):198-205
references.pmid: 12136057
references.citation: JAMA. 2002 Feb 13;287(6):742-8
references.pmid: 11851541
references.citation: Arch Neurol. 2009 Jun;66(6):767-72
references.pmid: 19506138
references.citation: Neurology. 1984 Jul;34(7):939-44
references.pmid: 6610841
references.citation: Arch Neurol. 2006 May;63(5):665-72
references.pmid: 16682536
references.citation: Neurology. 2010 Mar 23;74(12):951-5
references.pmid: 20308679
references.citation: Neurology. 2006 Mar 28;66(6):821-7
references.pmid: 16467493
references.citation: Psychol Aging. 1999 Jun;14(2):245-63
references.pmid: 10403712
references.citation: Psychol Aging. 2002 Jun;17(2):179-93
references.pmid: 12061405
references.citation: N Engl J Med. 2003 Jun 19;348(25):2508-16
references.pmid: 12815136
references.citation: Arch Neurol. 2007 Dec;64(12):1749-54
references.pmid: 18071038
references.citation: J Gerontol B Psychol Sci Soc Sci. 2003 Sep;58(5):P249-55
references.pmid: 14507930
references.citation: Arch Neurol. 2006 Jan;63(1):38-46
references.pmid: 16401735
references.citation: Neurology. 2006 Mar 28;66(6):911-3
references.pmid: 16291928
references.citation: Psychol Sci Public Interest. 2008 Oct;9(1):1-65
references.pmid: 26162004