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Factors associated with maintenance of wakefulness test mean sleep latency in patients with mild to moderate obstructive sleep apnoea and normal subjects
Author(s) -
Banks Siobhan,
Barnes Maree,
Tarquinio Natalie,
Pierce Robert J.,
Lack Leon C.,
Doug McEvoy R.
Publication year - 2004
Publication title -
journal of sleep research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.297
H-Index - 117
eISSN - 1365-2869
pISSN - 0962-1105
DOI - 10.1111/j.1365-2869.2003.00383.x
Subject(s) - multiple sleep latency test , polysomnography , epworth sleepiness scale , stepwise regression , vigilance (psychology) , psychology , analysis of variance , mood , wakefulness , obstructive sleep apnea , audiology , regression analysis , medicine , insomnia , sleep debt , physical therapy , sleep disorder , cardiology , apnea , psychiatry , excessive daytime sleepiness , electroencephalography , statistics , mathematics , neuroscience
Summary This study investigated the possible factors related to the Maintenance of Wakefulness Test (MWT) mean sleep latency. A second analysis explored the characteristics of subjects who had discrepant Epworth Sleepiness Scale (ESS) and MWT scores. A total of 151 subjects (110 mild to moderate obstructive sleep apnoea (OSA) patients and 41 control subjects) were recruited for the study. The subjects completed an overnight Polysomnography (PSG), MWT, cognitive, performance and vigilance tasks and answered self‐report questionnaires on mood and sleepiness. A forward stepwise multiple regression was performed on MWT mean sleep latency. The predictor variables age ( r = 0.28), subjective sleep history for 1 week prior to MWT (sleep diary; r = 0.19) and number of >4% SaO 2 Dips during the PSG ( r = −0.21) best explained the MWT results, but only accounted for 12.8% of the variance in the test. It was found that 33% of subjects had discrepant ESS and MWT scores. A new variable was created to analyse these subjects (MWT/ESS discrepancy score; MED). A forward stepwise multiple regression analysis found that depression, performance errors and sleep disordered breathing explained 13.4% of the variance in MED scores. The MWT is a complex behavioural test whose scores do not seem to have a very robust relationship with potential predictors and co‐correlates. Further comprehensive study is needed if the test is to be used in a diagnostically meaningful way.