Table 6 Convergent validity as assessed by correlations between two questions related to sleep from the General Health Questionnaire (GHQ) and the Pittsburgh Sleep Quality Index (PSQI) for the TMD cases sample (N = 609)
GHQ question | N | PSQI global score(mean) | PSQI global score (SD) | Spearman’s rho (95% CI), and a level of significance |
|---|---|---|---|---|
Have you recently lost much sleep over worry? | 0.43 (0.36 to 0.49)* | |||
Not at all | 296 | 5.4 | 3.4 | |
No more than usual | 239 | 8.1 | 3.8 | |
Rather more than usual | 63 | 9.6 | 4.0 | |
Much more than usual | 11 | 12.5 | 2.7 | |
Have you recently had difficulty in staying asleep? | 0.48 (0.42 to 0.54)* | |||
Not at all | 288 | 5.1 | 2.8 | |
No more than usual | 211 | 7.9 | 3.9 | |
Rather more than usual | 94 | 10.1 | 4.1 | |
Much more than usual | 16 | 11.8 | 2.9 |