Sleep and daytime function in people with spinal cord injury

Abstract

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).

Methods: This cross-sectional cohort study took place in a Veterans Administration (VA) medical center in the Midwestern US. 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 function (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 worse ISI and worse PHQ-9, some WHOQOL-BREF subscales, and SCIM as well as between worse PSQI and worse FFS, PHQ-9, and some WHOQOL-BREF subscales (p's<.05).

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.

Clinical trial registration: Registry: ClinicalTrials.gov; Name: Treatment of Sleep-disordered Breathing in Patients With SCI; URL: https://www.clinicaltrials.gov/study/NCT02830074; Identifier: NCT02830074.

Keywords: daytime functioning; depression; insomnia; sleep-disordered breathing; spinal cord injury.