title: Cognitive impairment in individuals with insomnia: clinical significance and correlates.
abstract: OBJECTIVE
  The aims of this study were to (1) investigate the nature of cognitive impairment in individuals with insomnia, (2) document their clinical significance, (3) examine their correlates, and (4) explore differences among individuals with insomnia with and without cognitive complaints.
  
  
  METHODS
  Participants underwent 3 consecutive nights of polysomnography. On the morning following the third night, they completed a battery of questionnaires and neuropsychological tests.
  
  
  METHODS
  The sample included 25 adults with primary insomnia (mean age: 44.4 ± 11.5 y, 56% women) and 16 controls (mean age: 42.8 ± 12.9 y, 50% women) matched for sex, age, and education.
  
  
  METHODS
  N/A.
  
  
  RESULTS
  Participants completed neuropsychological tests covering attention, memory, working memory, and executive functions, as well as questionnaires assessing the subjective perception of performance, depression, anxiety, fatigue, sleepiness, and hyperarousal. There were significant group differences for the attention and episodic memory domains. Clinically significant deficits were more frequent in the insomnia group. Within the insomnia group, individuals with cognitive complaints exhibited significantly poorer performance on a larger number of neuropsychological variables. All impaired aspects of performance were significantly associated with either subjective or objective sleep continuity, and some were also independently related to sleep microstructure (i.e., relative power for alpha frequencies) or selected psychological variables (i.e., beliefs or arousal).
  
  
  CONCLUSIONS
  These findings suggest clinically significant alterations in attention and episodic memory in individuals with insomnia. Objective deficits were more pronounced and involved more aspects of performance in a subgroup of individuals with cognitive complaints. These deficits appear associated with sleep continuity, and may also be related to sleep microstructure and dysfunctional beliefs.
authors.affiliation: Université Laval, Québec (Québec), Canada.
authors.forename: Emilie
authors.initials: E
authors.lastname: Fortier-Brochu
authors.affiliation: Université Laval, Québec (Québec), Canada.
authors.forename: Charles M
authors.initials: CM
authors.lastname: Morin
mesh_terms: D000328:Adult; D001007:Anxiety; D001143:Arousal; D001288:Attention; D001290:Attitude; D003071:Cognition; D003072:Cognition Disorders / Q000150:complications* / Q000209:etiology / Q000523:psychology*; D003863:Depression; D056344:Executive Function; D005221:Fatigue; D005260:Female; D006801:Humans; D008297:Male; D008568:Memory; D008570:Memory, Short-Term; D008875:Middle Aged; D009483:Neuropsychological Tests; D017286:Polysomnography; D007319:Sleep Initiation and Maintenance Disorders / Q000150:complications* / Q000523:psychology*; D012894:Sleep Stages; D011795:Surveys and Questionnaires
keywords: attention; cognitive performance; insomnia; memory