Abstract
The diagnostic criteria for obstructive sleep apnea (OSA) in adults, as defined in the International Classification of Sleep Disorders, Third Edition, requires an increased frequency of obstructive respiratory events demonstrated by in-laboratory, attended polysomnography (PSG) or a home sleep apnea test (HSAT). However, there are currently two hypopnea scoring criteria in The AASM Manual for the Scoring of Sleep and Associated Events: Rules, Terminology and Technical Specifications (AASM Scoring Manual). This dichotomy results in differences among laboratory reports, patient treatments and payer policies. Confusion occurs regarding recognizing and scoring "arousal-based respiratory events" during OSA testing. "Arousal-based scoring" recognizes hypopneas associated with electroencephalography-based arousals, with or without significant oxygen desaturation, when calculating an apnea-hypopnea index (AHI), or it includes respiratory effort-related arousals (RERAs), in addition to hypopneas and apneas, when calculating a respiratory disturbance index (RDI). Respiratory events associated with arousals, even without oxygen desaturation, cause significant, and potentially dangerous, sleep apnea symptoms. During PSG, arousal-based respiratory scoring should be performed in the clinical evaluation of patients with suspected OSA, especially in those patients with symptoms of excessive daytime sleepiness, fatigue, insomnia, or other neurocognitive symptoms. Therefore, it is the position of the AASM that the RECOMMENDED AASM Scoring Manual scoring criteria for hypopneas, which includes diminished airflow accompanied by either an arousal or ≥ 3% oxygen desaturation, should be used to calculate the AHI. If the ACCEPTABLE AASM Scoring Manual criteria for scoring hypopneas, which includes only diminished airflow plus ≥ 4% oxygen desaturation (and does not allow for arousal-based scoring alone), must be utilized due to payer policy requirements, then hypopneas as defined by the RECOMMENDED AASM Scoring Manual criteria should also be scored. Alternatively, the AASM Scoring Manual includes an option to report an RDI which also provides an assessment of the sleep-disordered breathing that results in arousal from sleep. Furthermore, given the inability of most HSAT devices to capture arousals, a PSG should be performed in any patient with an increased risk for OSA whose HSAT is negative. If the PSG yields an AHI of 5 or more events/h, or if the RDI is greater than or equal to 5 events/h, then treatment of symptomatic patients is recommended to improve quality of life, limit neurocognitive symptoms, and reduce accident risk.