Correlation of the Epworth Sleepiness Scale with respiratory sleep parameters in patients with sleep-related breathing disorders and upper airway pathology

The aim of the study was to test whether a correlation between the Epworth Sleepiness Scale (ESS) and respiratory sleep parameters recorded by polysomnography (PSG) in patients with sleep-related breathing disorders and upper airway pathology exists. The PSG records of 130 patients (average age 52.6 +/- 10.7 years) with upper airway pathology suspected of having obstructive sleep apnea (OSA) have been retrospectively evaluated. Upper airway pathology included deviation of the nasal septum, inferior nasal turbinate hypertrophy, soft palate webbing, elongated uvula, tonsillar hypertrophy, macroglossia, hypertrophy of the tongue base, unfavorable palate position relative to the tongue base. To test for a possible correlation in this patient population between ESS score and arithmetic values of AHI, SPO2, ODI and Arousal Index, the Spearman's correlation coefficient was calculated. No correlation between ESS and AHI, minimal SpO(2) and ODI was proven and only a weak positive correlation between Arousal Index and ESS was found in this particular patient population. We concluded that in patients with upper airway pathology, it is not possible to predict solely on the basis of the ESS score the existence of OSA or of other disturbances in Arousal Index, minimal SpO(2) and ODI. Nevertheless, historical data evaluated by questionnaires, such as the ESS provide for additional information combined with the clinical findings to select patients who are candidates for further detailed sleep studies.