title: Sleepiness, parkinsonian features and sustained attention in mild Alzheimer's disease.
abstract: BACKGROUND
  we previously demonstrated that patients with mild Alzheimer's disease and parkinsonian features (AD + PF) are at a higher risk of having daytime sleepiness than mild AD patients without PF (AD - PF).
  
  
  OBJECTIVE
  to determine whether AD + PF patients demonstrate a known a consequence of daytime sleepiness, reduced performance-based sustained attention, compared with AD - PF patients.
  
  
  METHODS
  a nocturnal polysomnogram and a next-day multiple sleep latency test (MSLT) were performed. Between MSLT nap opportunities, a 10-min psychomotor vigilance test (PVT) was administered and analysed for reciprocal mean response times (IMEAN), number of lapses (LAPSE) and reciprocal mean slowest 10% (ISLOW).
  
  
  RESULTS
  a total of 35 patients met criteria (AD + PF, n = 16; AD - PF, n = 19). Comparatively, the AD + PF group had slower IMEAN results [F((1,28)) = 6.64, P < 0.05] and higher LAPSE rates [F((1,27)) = 7.57, P < 0.05]. ISLOW measures were not different between groups. When accounting for MSLT results, IMEAN and LAPSE results were no longer significantly different between groups during morning tests, but remained significantly different on afternoon tests.
  
  
  CONCLUSIONS
  PFs in mild AD are associated with decreased sustained attention as measured by the PVT. Sleepiness did not fully account for the impairment in sustained attention, suggesting that the presence of PFs has an independent negative association with sustained attention in mild AD.
authors: Sleep Disorders Center, Rush University Medical Center, 1653 W. Congress Parkway 6th Floor, JRB, Chicago, IL 60611, USA. margaret_park@rush.edu
authors: Margaret
authors: M
authors: Park
authors: Megan M
authors: MM
authors: Hood
authors: Raj C
authors: RC
authors: Shah
authors: Louis F
authors: LF
authors: Fogg
authors: James K
authors: JK
authors: Wyatt
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications / Q000453:epidemiology*; D001288:Attention; D015897:Comorbidity; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D020734:Parkinsonian Disorders / Q000453:epidemiology*; D017286:Polysomnography; D011597:Psychomotor Performance; D012307:Risk Factors; D012893:Sleep Wake Disorders / Q000453:epidemiology*