Table 4.
Associations between Philips Actigraph sleep features and the Pittsburgh Sleep Quality Index global and component scores.
| Metric | PSQIa sleep duration | PSQI sleep disturbances | ||
|
|
Coefficient | P value | Coefficient | P value |
| Total activity count | 0.03 | .80 | 0.24 | .10 |
| Average activity count | −0.14 | .22 | 0.27 | .08 |
| Maximum activity count | 0 | .99 | 0.17 | .23 |
| Duration (minutes) | 0.36b | <.001 | −0.02 | .88 |
| Time spent awake (minutes) | 0.11 | .30 | 0.21 | .10 |
| Percentage of time spent awake | −0.1 | .40 | 0.25 | .09 |
| Number of wake bouts | 0.26 | .01 | 0.09 | .45 |
| Average number of wake bouts | −0.18 | .08 | 0.22 | .11 |
| Time spent sleeping | 0.36 | .001 | −0.07 | .58 |
| Percentage of time spent sleeping | 0.1 | .40 | −0.25 | .09 |
| Sleep onset latency (minutes) | 0.05 | .56 | −0.02 | .87 |
| Time spent resting after waking up (minutes) | −0.09 | .39 | ncc | nc |
| Time of valid rest (minutes) | 0.34 | <.001 | −0.01 | .92 |
| Sleep efficiency | 0.21 | .09 | −0.23 | .11 |
| Sleep start time (hours:minutes) | −0.01 | .93 | −0.26 | .01 |
| Rest start time (hours:minutes) | −0.03 | .78 | −0.25 | .01 |
| Sleep fragmentation | 0 | .99 | 0.17 | .18 |
aPSQI: Pittsburgh Sleep Quality Index.
bItalic values indicate significant correlation (P<.05).
cnc: the model did not converge.