Correlation between Bispectral Index and Sleep Stage of Patients with Obstructive Sleep Apnea-Hypopnea Syndrome

Objective: The aim of this study was to evaluate the correlation between bispectral indexes (BIS) and sleep staging in patients with moderate to severe obstructive sleep apnea-hypopnea syndrome (OSAHS) under natural sleep conditions. Materials and Methods: Twelve patients who had been clinically diagnosed with OSAHS were monitored by polysomnography (PSG) and bispectral index (BIS) that were simultaneously recorded to determine the BIS at different sleep stages and analyze the patterns.