Sleep and Daytime Function in People with Spinal Cord Injury.

Study Design: Cross-sectional cohort study. Objectives: To determine the role of sleep-disordered breathing (SDB), insomnia symptoms and sleep quality in the daytime function and quality of life of veterans with spinal cord injury (SCI). Setting: A Veterans Administration (VA) medical center in the Midwestern US. Methods: Thirty-eight male veterans with SCI (22 cervical, 16 thoracic; mean [SD] age = 62.9[9.5] years) completed baseline assessments within a larger clinical trial. Measures assessed sleep apnea severity (apnea-hypopnea index, AHI), insomnia symptoms (Insomnia Severity Index, ISI), self-reported sleep quality (Pittsburg Sleep Quality Index, PSQI), daytime sleepiness (Epworth Sleepiness Scale, ESS), fatigue (Flinders Fatigue Scale, FFS), depression (Patient Health Questionnaire-9 item, PHQ-9 excluding sleep item), functioning (Spinal Cord Independence Measure, SCIM), and quality of life (World Health Organization Quality of Life, WHOQOL-BREF). Bivariate correlations (alpha p<.05) were used to assess relationships between sleep (AHI, ISI, PSQI, ESS) and functon(FFS, PHQ-9, SCIM, WHOQOL-BREF). Results: Mean AHI was 29.9(26.6), mean ISI was 9.38(6.2), mean PSQI was 9.0(4.6), and mean ESS was 7.0(5.2). There were no significant relationships between AHI and function measures. Significant relationships emerged between ISI and PHQ-9, some WHOQOL-BREF subscales, and SCIM as well as between PSQI and FFS, PHQ-9, and some WHOQOL-BREF subscales. Conclusions: Among Veterans with SCI, insomnia symptom severity and poor sleep quality were associated with worse functioning, whereas SDB severity was not. Insomnia and poor sleep quality represent modifiable contributors to poor daytime function. Research evaluating the impact of evidence-based insomnia treatments among individuals living with SCI is warranted.