Sleep Med Psychophysiol.  2011 Dec;18(2):63-66.

Diagnostic and Clinical Differences in Obstructive Sleep Apnea Syndrome and Upper Airway Resistance Syndrome

• Choi Y

Abstract

It has been controversial whether upper airway resistance syndrome (UARS) is a distinct syndrome or not since it was reported in 1993. The International Classification of Sleep Disorders classified UARS under obstructive sleep apnea syndrome (OSAS) in 2005. UARS can be diagnosed when the apnea-hypopnea index (AHI) is fewer than 5 events per hour, the simultaneously calculated respiratory disturbance index (RDI) is more than 5 events per hour due to abnormal non-apneic non-hypopneic respiratory events accompanying respiratory effort related arousals (RERAs), and oxygen saturation is greater than 92% at termination of an abnormal breathing event. Although esophageal pressure measurement remains the gold standard for detecting subtle breathing abnormality other than hypopnea and apnea, nasal pressure transducer has been most commonly used. RERAs include phase A2 of cyclical alternating patterns (CAPs) associated with EEG changes. Symptoms of OSAS can overlap with UARS, but chronic insomnia tends to be more common in UARS than in OSAS and clinical symptoms similar with functional somatic syndrome are also more common in UARS. In this journal, diagnostic and clinical differences between UARS and OSAS are reviewed.

Keyword

Obstructive sleep apnea syndrome; Upper airway resistance syndrome; Respiratory effort related arousals; Cyclic alternating pattern

MeSH Terms

Airway Resistance
Apnea
Arousal
Electroencephalography
Oxygen
Respiration
Sleep Apnea, Obstructive
Sleep Wake Disorders
Sleep Initiation and Maintenance Disorders
Transducers, Pressure
Oxygen