Various types of sleep disturbance due to different sorts of low back pain. A literature review: 2. A single insomnia severity measure and multiple insomnia items

Abstract Aim This is the second part of a literature review series and a data analysis study, which seek to find out whether different types of sleep disturbance can be caused by different sorts of back pain. Here in Part 2, we examine how the single item sleep question acts as a severity measure of back pain for statistical purposes. Conversely, there are multiple subdivisions, items, or factors that are distinctive each in their own right, and may each have clinical meaning. Methods The same search of Medline, Embase, PsycINFO, and the OVID journals databases using the keywords ‘low back pain’ and ‘sleep’ used for the initial part of the review process was again the basis for this part of the literature review. Results The manner in which ancient languages and modern English describe aspects of sleep, insomnia, fatigue, and tiredness has evolved over time was felt to be worth examination. Then the single and multiple item views of insomnia studied in questionnaire-based research were inspected. This was in part done with the help of the few regression, principal component, and factor analyses available in the literature. Back pain seems to have a profound effect on causing insomnia and depressed mood generally. Furthermore, the worse the peak and average pain are, the greater the difficulty getting off to sleep and the more often the awakenings during the night. However, different factors seem to influence the delayed sleep onset and the difficulty maintaining sleep in unexpected ways. Also the experimental sleep disturbance studies and the objective assessments of sleep quantity and quality sometime add an extra twist to the story. Some of the more appropriate aspects of sleep disturbance relating to back pain were identified. Discussion These inspections helped steer the insomnia questionnaire focus away from the psychometric complexion of most material in the current literature towards a more physically based focus suited to inspection of the mechanisms of back pain which cause sleep disturbance.