Subjective estimates of sleep differ from polysomnographic measurements in obstructive sleep apnea patients.

ABSTRACT

It is well established that, as a group, insomnia patients overestimate sleep onset latency (SOL) and underestimate total sleep time (TST) when compared to objective polysomnographic (PSG) findings. Whether a similar phenomenon occurs with other sleep disorders is not fully established. We compared the PSG sleep of 84 patients with suspected sleep apnea (SA) to their subjective experience of sleep reported on a sleep diary the morning after PSG testing. Both patients with SA (SA+) and those without (SA-) tended to overestimate SOL, but the SA+ group (n = 50) made larger overestimations (p < 0.02). The SA+ and SA- groups also differed in their accuracy at estimating TST, with SA+ patients underestimating TST (p < 0.05). These findings support the premise that marked discrepancies between subjective and PSG-determined sleep may not be limited to insomnia, but present in other sleep disorders as well, and should be appreciated by practitioners when obtaining sleep histories.