Issue Navigator

Volume 14 No. 11
Earn CME
Accepted Papers

Letters to the Editor

Hypopnea Scoring Criteria: Time to Move Toward a Single Standardized Definition

Mukesh Kapoor, MD
Unity Sleep Disorders Center, Rochester Regional Health, Rochester, New York

The recent position statement from the American Academy of Sleep Medicine (AASM) on the scoring of arousal-based respiratory events is noteworthy.1 The apnea-hypopnea index (AHI) has been shown to change significantly when hypopneas are scored based on the “recommended” criteria.2 Hypopneas associated with arousals and/or associated with milder desaturations can have clinically significant effects.3,4 Patients whose studies have been scored using the “acceptable” criteria alone and based on this have been told that they do not have obstructive sleep apnea (OSA) may actually have OSA were their studies to be scored using the “recommended” criteria. Thus, the use of the “acceptable” criteria alone may be falsely reassuring. These patients who may actually have OSA may not receive the correct diagnosis, be deprived of treatment with positive airway pressure (PAP) therapy, and may possibly undergo a Multiple Sleep Latency Test (MSLT) and potentially receive a diagnosis of hypersomnia and started on stimulants when in reality they may have benefitted from PAP therapy alone. This position statement will hopefully encourage sleep providers and sleep centers to re-review the studies of such patients using the “recommended criteria.”

Unfortunately, so far, the Centers for Medicare & Medicaid Services has rejected the use of the “recommended” criteria and only adjudicate treatment coverage based on the “acceptable” criteria. As a prior article pointed out, the scoring of respiratory events seems to have evolved in part to accommodate what health insurances accept.5 Imagine having a “recommended” and “acceptable” definition for hypertension or coronary artery disease. It may be time for the AASM to educate insurers and other stakeholders about the importance of the “recommended” criteria, the potential risks associated with not treating these patients who have OSA based on the “recommended” criteria but who do not meet the “acceptable” criteria, and to use the “recommended” criteria as the single definition for hypopneas. This may be crucial to not only help our patients but to also continue to keep our field relevant.

On a separate note, much progress needs to be made in the scoring of arousals. As some prior studies have shown, the interscorer reliability for scoring arousals can range from low to moderate.68 The current scoring criteria for arousals also excludes subcortical autonomic arousals, which may be precursors to full EEG arousal and which by themselves have been shown to be clinically relevant.9,10 Techniques such as analysis of heart rate, respiratory rate, pulse transit time, peripheral arterial tonometry, pulse wave amplitude, chin electromyography, and limb electromyography may help better characterize arousals when an obvious respiratory event is seen but there is no associated desaturation or clearly discernable change on the electroencephalogram.1115 One recent paper showed that the AHI determined by peripheral arterial tonometry was higher compared to polysomnography, thus possibly indicating that peripheral arterial tonometry may be better at detecting arousal-based respiratory events.16 The use of such techniques may also possibly increase the interscorer reliability for scoring arousals.


The author reports no conflicts of interest.


Kapoor M. Hypopnea scoring criteria: time to move toward a single standardized definition. J Clin Sleep Med. 2018;14(11):1961–1962.



Malhotra RK, Kirsch DB, Kristo DA, et al. Polysomnography for obstructive sleep apnea should include arousal-based scoring: an American Academy of Sleep Medicine Position Statement. J Clin Sleep Med. 2018;14(7):1245–1247. [PubMed Central][PubMed]


Ho V, Crainiceanu CM, Punjabi NM, Redline S, Gottlieb DJ. Calibration model for apnea-hypopnea indices: impact of alternative criteria for hypopneas. Sleep. 2015;38(12):1887–1892. [PubMed Central][PubMed]


Koch H, Schneider LD, Finn LA, et al. Breathing disturbances without hypoxia are associated with objective sleepiness in sleep apnea. Sleep. 2017;40(11)


Stamatakis K, Sanders MH, Caffo B, et al. Fasting glycemia in sleep disordered breathing: lowering the threshold on oxyhemoglobin desaturation. Sleep. 2008;31(7):1018–1024. [PubMed Central][PubMed]


Thomas RJ, Guilleminault C, Ayappa I, Rapoport DM. Scoring respiratory events in sleep medicine: who is the driver--biology or medical insurance? J Clin Sleep Med. 2014;10(11):1245–1247. [PubMed Central][PubMed]


Magalang UJ, Chen NH, Cistulli PA, et al. Agreement in the scoring of respiratory events and sleep among international sleep centers. Sleep. 2013;36(4):591–596. [PubMed Central][PubMed]


Loredo JS, Clausen JL, Ancoli-Israel S, Dimsdale JE. Night-to-night arousal variability and interscorer reliability of arousal measurements. Sleep. 1999;22(7):916–920. [PubMed]


Whitney CW, Gottlieb DJ, Redline S, et al. Reliability of scoring respiratory disturbance indices and sleep staging. Sleep. 1998;21(7):749–757. [PubMed]


Lofaso F, Goldenberg F, d'Ortho MP, Coste A, Harf A. Arterial blood pressure response to transient arousals from NREM sleep in nonapneic snorers with sleep fragmentation. Chest. 1998;113(4):985–991. [PubMed]


Martin SE, Wraith PK, Deary IJ, Douglas NJ. The effect of nonvisible sleep fragmentation on daytime function. Am J Respir Crit Care Med. 1997;155(5):1596–1601. [PubMed]


Katz ES, Lutz J, Black C, Marcus CL. Pulse transit time as a measure of arousal and respiratory effort in children with sleep-disordered breathing. Pediatric Res. 2003;53(4):580–588


Pillar G, Bar A, Shlitner A, Schnall R, Shefy J, Lavie P. Autonomic arousal index: an automated detection based on peripheral arterial tonometry. Sleep. 2002;25(5):543–549. [PubMed]


Delessert A, Espa F, Rossetti A, Lavigne G, Tafti M, Heinzer R. Pulse wave amplitude drops during sleep are reliable surrogate markers of changes in cortical activity. Sleep. 2010;33(12):1687–1692. [PubMed Central][PubMed]


Mograss MA, Ducharme FM, Brouillette RT. Movement/arousals. Description, classification, and relationship to sleep apnea in children. Am J Respir Crit Care Med. 1994;150(6 Pt 1):1690–1696. [PubMed]


Baumert M, Kohler M, Kabir M, Kennedy D, Pamula Y. Cardiorespiratory response to spontaneous cortical arousals during stage 2 and rapid eye movement sleep in healthy children. J Sleep Res. 2010;19(3):415–424. [PubMed]


Sobremonte-King M, Conwell W, Friedman N, et al. Validating the use of peripheral arterial tonometry in detecting obstructive sleep apnea in children 5-12 years old [abstract]. Sleep. 2018;41(abstract suppl.):A294.