Computer-assisted sleep classification according to the standard of the American Academy of Sleep Medicine: validation study of the AASM version of the Somnolyzer 24 × 7.
BACKGROUND
In 2007, the AASM Manual for the Scoring of Sleep and Associated Events was published by the American Academy of Sleep Medicine (AASM). Concerning the visual classification of sleep stages, these new rules are intended to replace the rules by Rechtschaffen and Kales (R&K).


METHODS
We adapted the automatic R&K sleep scoring system Somnolyzer 24 × 7 to comply with the AASM rules and subsequently performed a validation study based on 72 polysomnographies from the Siesta database (56 healthy subjects, 16 patients, 38 females, 34 males, aged 21-86 years). Scorings according to the AASM rules were performed manually by experienced sleep scorers and semi-automatically by the AASM version of the Somnolyzer. Manual scorings and Somnolyzer reviews were performed independently by at least 2 out of 8 experts from 4 sleep centers.


RESULTS
In the quality control process, sleep experts corrected 4.8 and 3.7% of the automatically assigned epochs, resulting in a reliability between 2 Somnolyzer-assisted scorings of 99% (Cohen's kappa: 0.99). In contrast, the reliability between the 2 manual scorings was 82% (kappa: 0.76). The agreement between the 2 Somnolyzer-assisted and the 2 visual scorings was between 81% (kappa: 0.75) and 82% (kappa: 0.76).


CONCLUSIONS
The AASM version of the Somnolyzer revealed an agreement between semi-automated and human expert scoring comparable to that published for the R&K version with a validity comparable to that of human experts, but with a reliability close to 1, thereby reducing interrater variability as well as scoring time to a minimum.
Anderer
Peter
P
Department of Psychiatry and Psychotherapy, Medical University of Vienna, Währinger Gürtel 18–20, Vienna, Austria. peter.anderer@meduniwien.ac.at
Moreau
Arnaud
A
Woertz
Michael
M
Ross
Marco
M
Gruber
Georg
G
Parapatics
Silvia
S
Loretz
Erna
E
Heller
Esther
E
Schmidt
Andrea
A
Boeck
Marion
M
Moser
Doris
D
Kloesch
Gerhard
G
Saletu
Bernd
B
Saletu-Zyhlarz
Gerda M
GM
Danker-Hopfe
Heidi
H
Zeitlhofer
Josef
J
Dorffner
Georg
G
D000047:Academies and Institutes; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017286:Polysomnography / Q000145:classification* / Q000379:methods*; D012016:Reference Values; D012894:Sleep Stages; D012984:Software