title: Association between sleep-disordered breathing, sleep-wake pattern, and cognitive impairment among patients with chronic heart failure.
abstract: OBJECTIVE
  Chronic heart failure (CHF) and sleep-disordered breathing (SDB) are often co-existing problems among the elderly. Apnoeic events may cause cognitive impairment. The aim of the study was to compare sleep and wake patterns, insomnia, daytime sleepiness, and cognitive function in community-dwelling CHF patients, with and without SDB, and to investigate the association between sleep-related factors and cognitive dysfunction.
  
  
  RESULTS
  In this cross-sectional observational study, SDB was measured with an ApneaLink device and defined as an apnoea-hypopnoea index (AHI) ≥15/h of sleep. Sleep and wake patterns were measured with actigraphy for 1 week. Insomnia was measured with the Minimal Insomnia Symptom Scale, daytime sleepiness with the Epworth Sleepiness Scale, and cognitive function with a neuropsychological test battery. A total of 137 patients (68% male, median age 72 years, 58% NYHA functional class II) were consecutively included. Forty-four per cent had SDB (AHI ≥15). The SDB group had significantly higher saturation time below 90%, more difficulties maintaining sleep, and lower levels of daytime sleepiness compared with the non-SDB group. Cognitive function and sleep and wake patterns did not differ between the SDB and the non-SDB group. Insomnia was associated with decreased global cognition.
  
  
  CONCLUSIONS
  The prevalence of cognitive dysfunction was low in this population with predominantly mild to moderate CHF. This might have influenced the lack of associations between cognitive function and SDB. Insomnia was the only sleep-related factor significantly influencing cognition.
authors: Department of Medical and Health Sciences, Division of Nursing Science, Linköping University, Linköping, Sweden. carina.hjelm@liu.se
authors: Carina
authors: C
authors: Hjelm
authors: Anna
authors: A
authors: Strömberg
authors: Kristofer
authors: K
authors: Arestedt
authors: Anders
authors: A
authors: Broström
mesh_terms: D056044:Actigraphy; D000368:Aged; D000369:Aged, 80 and over; D002908:Chronic Disease; D003071:Cognition / Q000502:physiology; D003072:Cognition Disorders / Q000453:epidemiology / Q000209:etiology*; D003430:Cross-Sectional Studies; D005260:Female; D006333:Heart Failure / Q000150:complications* / Q000503:physiopathology; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D012044:Regression Analysis; D012891:Sleep Apnea Syndromes / Q000150:complications* / Q000503:physiopathology; D020178:Sleep Disorders, Circadian Rhythm / Q000453:epidemiology / Q000209:etiology* / Q000503:physiopathology; D007319:Sleep Initiation and Maintenance Disorders / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology