Antero-cervical thermophysiological characterization of obstructive sleep apnea patients

Obstructive sleep apnea syndrome (OSAS) is characterized by upper airway inflammation. The aim of this study was to characterize thermal profile of the antero-cervical region in OSAS patients through medical thermal imaging and to compare the respective subjects with non-OSAS individuals.

Image capture followed the Glamorgan Protocol. A dynamic thermographic examination of the anterior cervical region (at baseline and after a cold stimulus) was conducted in 26 patients diagnosed with overnight polysomnography (PSG). PSG results stratified the subjects into OSAS and non-OSAS groups and their thermograms were compared.

Eleven non-OSAS and 15 OSAS subjects were evaluated. Antero-cervical right side (RS) temperature was higher in OSAS group at baseline (p = 0.014). Right side index (RSI) temperature-the difference between RS and submental region, considered as control-was lower in OSAS subjects at baseline (p = 0.020) and 10 min after the cold stimuli was applied (p = 0.008), indicating higher absolute temperatures in this group. Left side index (LSI) was also lower at 10 min in OSAS group (p = 0.021). Statistical correlation was found between apnea-hypopnea index and RS at baseline (r = 0.424, p = 0.031) and at 10 min (r = 0.403, p = 0.041) and RSI at baseline (r = - 0.458, p = 0.019) and 10 min after cold provocation was applied (r = - 0.435, p = 0.025).

OSAS patients have shown higher antero-cervical temperatures compared with non-OSAS counterparts and temperature was associated with severity of the condition. Medical thermography may be a suitable tool in the setting of OSAS suspicion.