Evaluating mental fatigue in patients with obstructive sleep apnea syndrome by the Maastricht Questionnaire

Mental fatigue in patients with obstructive sleep apnea syndrome (OSAS) was investigated and compared with subjects without OSAS. The study series comprised 189 habitual snoring patients and 75 controls. To measure subjective mental fatigue and somnolence, subjects were asked to complete the Maastricht Questionnaire (MQ) and the Epworth Sleepiness Scale (ESS), respectively, and patients also underwent diagnostic polysomnography. According to the apnea and hypopnea index, patients were classified into the following groups: primary snorers, or having mild, moderate, or severe OSAS. The lowest MQ and highest ESS scores were found in those patients with severe OSAS. It is proposed that the lowest MQ score is due to mental fatigue impairing awareness in patients with severe OSAS, probably because of attention loss.