Conventional polysomnographic parameters fail to predict unrefreshing sleep in patients suspected of obstructive sleep apnea.

OBJECTIVE

Subjective sleep status does not necessarily correspond to objective sleep parameters. Some subjects complain of unrefreshing sleep (URS) in the morning. The purpose of this study was to clarify whether there is a relationship between total sleep time (TST) misperception and URS.

METHODS

We asked subjects undergoing polysomnography (PSG) for the diagnosis of sleep-related breathing disorders about their subjective TST (sTST) and whether they experienced URS in the morning immediately after PSG. We then analyzed the objective TST (oTST) measured by PSG and examined the relationship between TST misperception and URS.

RESULTS

We conducted an analysis of 150 subjects undergoing PSG. A TST misperception index (MI; TST-MI) was computed using the following formula: MI = [oTST-sTST]/oTST. Multivariate analysis demonstrated that the presence of URS was an independent determinant of TST-MI after adjusting for the apnea hypopnea index (AHI), oTST or sleep efficiency (SE), and some other factors. Furthermore, patients with a high TST-MI tended to have a lower mean AHI and arousal index than those with a low TST-MI; however, the proportion of patients with URS was significantly higher.

CONCLUSION

TST underestimation was significantly associated with URS, independently of oTST and SE. Furthermore, the greater the degree of TST underestimation, the greater the degree of URS.