Sleep staging and respiratory events in refractory epilepsy patients: Is there a first night effect?
OBJECTIVE
We performed this analysis of possible first night effects (FNEs) on sleep and respiratory parameters in order to evaluate the need for two serial night polysomnograms (PSGs) to diagnose obstructive sleep apnea (OSA) in epilepsy patients.


METHODS
As part of a pilot multicenter clinical trial investigating the effects of treating sleep apnea in epilepsy, two nights of PSG recording were performed for 40 patients with refractory epilepsy and OSA symptoms. Sleep architecture was examined in detail, along with respiratory parameters including apnea/hypopnea index (AHI) and minimum oxygen saturation. Analysis included two-tailed t-tests, Wilcox sign rank analysis, and Bland Altman measures of agreement.


RESULTS
Total sleep time differed between the two nights (night 1,363.8 min + 59.4 vs. 386.3 min + 68.6, p = 0.05). Rapid eye movement (REM) sleep and percentage of REM sleep were increased during night two (night 1: 12.3% + 5.9 vs. night 2: 15.5% + 6.2, p = 0.007), and the total minutes of slow-wave sleep (SWS) were increased (night 1: 35.6 + 60.7 vs. night 2: 46.4 + 68.1, p = 0.01). No other sleep or respiratory variables differed between the two nights. Given an AHI inclusion criterion of five apneas per hour, the first PSG identified all but one patient with OSA.


CONCLUSIONS
Respiratory parameters showed little variability between the first and second nights. Sleep architecture was mildly different between the first and second PSG night. Performing two consecutive baseline PSGs to diagnose OSA may not be routinely necessary in this population.
Department of Neurology, University of Michigan Medical Center, Ann Arbor, Michigan 48109-0117, USA. lmselwa@umich.edu
Linda M
LM
Selwa
Mary L
ML
Marzec
Ronald D
RD
Chervin
Kevin J
KJ
Weatherwax
Bradley V
BV
Vaughn
Nancy
N
Foldvary-Schaefer
Lily
L
Wang
Yanna
Y
Song
Beth A
BA
Malow
D000328:Adult; D004569:Electroencephalography; D004827:Epilepsy / Q000150:complications*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography; D012119:Respiration; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000209:etiology*; D012894:Sleep Stages / Q000502:physiology*; D014851:Wakefulness; D055815:Young Adult