Table 4.
*Correlation is significant at the 0.01 level (two-tailed).
ISI-K: Korean version of the Insomnia Severity Index, KESS: Korean version of the Epworth Sleepiness Scale, PSG: polysomnography, PSQI-K: Korean version of the Pittsburg Sleep Quality Index, SE: sleep efficiency, SOL: sleep onset latency, WASO: wake after sleep onset.