title: The influence of polysomnography on the Multiple Sleep Latency Test and other measures of daytime sleepiness.
abstract: BACKGROUND
  According to its guidelines, the Multiple Sleep Latency Test (MSLT) should be performed following an all-night polysomnography (PSG). However, the sleep quality and consequently the MSLT results may be affected by PSG and by the fact that a subject sleeps under unfamiliar conditions. The aim of this study was to examine whether PSG performed in a sleep laboratory has any influence on the MSLT and other measures of daytime sleepiness.
  
  
  METHODS
  Twenty healthy subjects with a mean age of 35.9+/-10.1 years underwent two MSLT examinations, and the 2 examination days were at least 4 weeks apart. In addition, on each occasion a monotonous vigilance task (VT) was performed and the subjects were asked to fill out the Epworth Sleepiness (ESS) and Visual Analogue Scales (VAS). In a cross-over design, a group of 10 subjects underwent a MSLT (MSLT-P) following a PSG and, on a second occasion, a MSLT (MSLT-N) was performed without a prior PSG. Vice versa, a second group of 10 subjects underwent first MSLT-N and then MSLT-P.
  
  
  RESULTS
  None of the MSLT parameters differed significantly between MSLT-P and MSLT-N. The other measures of daytime sleepiness (VT, ESS, VAS) also showed no evidence of significant differences between days with and without a prior PSG.
  
  
  CONCLUSIONS
  The results of MSLT and other measures of daytime sleepiness in healthy subjects are not influenced by the fact whether or not the subjects had a PSG the night prior to MSLT.
authors.affiliation: Sleep Disorders Centre, Department of Psychiatry, University of Regensburg, Universitätsstr. 84, 93053, Regensburg, Germany. awichniak@poczta.onet.pl
authors.forename: Adam
authors.initials: A
authors.lastname: Wichniak
authors.forename: Peter
authors.initials: P
authors.lastname: Geisler
authors.forename: Ferenc
authors.initials: F
authors.lastname: Tracik
authors.forename: Tatjana
authors.initials: T
authors.lastname: Crönlein
authors.forename: Sean P
authors.initials: SP
authors.lastname: Morrissey
authors.forename: Jürgen
authors.initials: J
authors.lastname: Zulley
mesh_terms: D000328:Adult; D001143:Arousal / Q000502:physiology; D018592:Cross-Over Studies; D004569:Electroencephalography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography / Q000009:adverse effects*; D011597:Psychomotor Performance / Q000502:physiology; D012890:Sleep / Q000502:physiology*; D012894:Sleep Stages / Q000502:physiology*