Table 1.
Demographic and clinical characteristics of the participants.
| Variable | Insomnia (n = 33) Mean (SD) |
Control (n = 31) Mean (SD) |
t | p value |
|---|---|---|---|---|
| Age (years) | 39.18 (9.42) | 35.06 (8.55) | 1.83 | 0.072 |
| Male/female | 14/19 | 15/16 | χ2 = 0.23 | 0.632 |
| Years of education | 16.82 (2.93) | 16.61 (2.16) | 0.32 | 0.752 |
| PSQI | 11.45 (3.26) | 2.32 (1.25) | 14.61 | <0.001*** |
| SOL of sleep diary (min)1 | 54.28 (55.28) | 19.41 (22.09) | 3.27 | 0.002** |
| TST of sleep diary (min)1 | 347.66 (103.93) | 451.90 (50.44) | −4.90 | <0.001*** |
| SOL of PSG (min) | 14.79 (23.65) | 6.73 (5.76) | 1.85 | 0.070 |
| TST of PSG (min) | 400.23 (63.69) | 447.34 (40.15) | −3.51 | <0.001*** |
| Misperception index1 | −0.14 (0.19) | 0.01 (0.09) | −4.07 | <0.001*** |
| TIB (min) | 462.73 (64.68) | 481.53 (31.64) | −1.44 | 0.154 |
| SE (%) | 86.84 (8.89) | 92.85 (5.24) | −3.27 | 0.002** |
| WASO (min) | 42.21 (37.80) | 24.74 (21.11) | 2.30 | 0.026* |
| N1 (min) | 36.52 (14.14) | 36.94 (11.58) | −0.13 | 0.897 |
| N2 (min) | 212.79 (44.57) | 238.94 (27.60) | −2.80 | 0.007** |
| N3 (min) | 69.50 (29.13) | 71.68 (27.90) | −0.31 | 0.761 |
| REM (min) | 81.42 (21.48) | 99.79 (21.39) | −3.43 | 0.001** |
| Arousal index (/h) | 6.29 (3.12) | 4.88 (1.87) | 2.17 | 0.033* |
| AHI (/h) | 1.33 (1.24) | 0.91 (0.87) | 1.59 | 0.118 |
| PLMI (/h) | 3.02 (4.47) | 2.65 (3.66) | 0.36 | 0.717 |
| SDS | 40.76 (8.30) | 30.32 (4.74) | 6.12 | <0.001*** |
| SAS | 38.33 (6.87) | 28.39 (4.81) | 6.67 | <0.001*** |
Notes: Mean (SD) values of variables are reported, along with t-statistics and p values. Significant main effects are in bold. *p < 0.05, **p < 0.01, ***p < 0.001. Misperception index: (Sleep diary TST – PSG TST)/PSG TST.
Abbreviations: PSQI, Pittsburgh Sleep Quality Index; TST, total sleep time; TIB, time in bed; SOL, sleep onset latency; SE, sleep efficiency (PSG TST/TIB); WASO, wakefulness after sleep onset; REM, rapid eye movement; AHI, apnea–hypopnea index; PLMI, periodic limb movement index; SDS, Self-Rating Depression Scale; SAS, Self-Rating Anxiety Scale.
The number of participants used to calculate these terms was 32 for the insomnia group and 29 for the control group because the sleep diaries of 3 participants from the night of the PSG recording were lost.