Arousals in sleep-disordered breathing: patterns and implications.
OBJECTIVE
To describe the whole spectrum of electroencephalographic (EEG) transients associated with the termination and recovery of obstructed respiratory events and, thus, widen the recognized spectrum of arousal phenomena from sleep.


METHODS
Retrospective review of diagnostic polysomnograms.


METHODS
American Academy of Sleep Medicine (AASM)-accredited multidisciplinary sleep disorders center.


METHODS
17 patents with obstructive sleep-disordered breathing.


METHODS
None.


RESULTS
Nasal airflow using a nasal-cannula-pressure-transducer system and oral flow by a thermistor were used to score apneas and hypopneas; the latter included flow-limitation events. The EEG patterns that crested or occurred within 2 to 3 seconds of respiratory recovery were recorded, and posthoc categories were created for the purpose of tabulation ranging from an AASM 3-second arousal to a single K-complex with no electromyographic increase. Chi-square statistic was calculated to assess the difference in EEG patterns at event termination between apneas and hypopneas. Score-rescore agreement was tested. Apneas were significantly more likely to be associated with a 3-second arousal than were hypopneas, but all types of EEG change were seen with both types of events. Spindles were rarely seen with arousal-linked K-complexes. The majority of events in rapid eye movement sleep were terminated with visible electromyography tone increase.


CONCLUSIONS
The spectrum of EEG change associated with the termination of respiratory events identified by using a nasal-cannula-pressure-transducer system is wider than that recognized as arousal phenomena by the 1992 AASM criteria. Scoring arousals with the 3-second rule may falsely minimize the apparent impact of abnormal breathing on sleep. The time may be right to update arousal recognition rules.
Thomas
Robert Joseph
RJ
Sleep Unit, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA. rthomas1@caregroup.harvard.edu
D001143:Arousal / Q000502:physiology*; D004569:Electroencephalography; D004576:Electromyography; D006801:Humans; D018482:Muscle, Skeletal / Q000502:physiology; D017286:Polysomnography / Q000379:methods; D012189:Retrospective Studies; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis* / Q000503:physiopathology*; D012894:Sleep Stages / Q000502:physiology