Development of a Raman-Based Method for the Diagnosis of People with Obstructive Sleep Apnea Syndrome: The Role of Lactic Acid

Obstructive sleep apnea syndrome (OSAS) is a respiratory disorder in middle-aged and elderly populations, marked by breathing interruptions during sleep. Diagnosis faces challenges due to the absence of specific biomarkers and increasing screening demands. This study aims to identify salivary biomarkers for the diagnosis and monitoring of OSAS using a simplified, rapid, and non-invasive method. Saliva from 51 OSAS patients and 34 healthy controls (CTR) was analyzed using Raman spectroscopy, which identified disease-specific biochemical fingerprints. Raman analysis revealed differences between the OSAS and CTR groups. The area under the curve of the lactic acid peak (920 cm^-1) appeared higher in the OSAS group compared to the CTR group, suggesting potential diagnostic relevance. Significant correlations were found between biomolecular and clinical data, and a final linear model indicated that the lactate concentration significantly influenced the canonical variable. The Raman-based approach and the lactic acid peak represent a promising tool for OSAS diagnosis, monitoring, and supporting decisions in pulmonary rehabilitation. However, further investigation with a larger cohort is needed to clarify the observed discrepancies.