ABSTRACT
INTRODUCTION Epidemiological studies (1,2) have shown that the most prevalent form of insomnia occurs concurrently with other medical, psychiatric, or sleep disorders. For researchers studying the psychophysiological and neurobiological mechanisms underlying insomnia, however, primary insomnia offers the advantages of being uncomplicated by other conditions. While not entirely homogenous, primary insomnia also offers the advantage of providing a group of relatively uncomplicated patients to evaluate treatment efficacy in clinical trials. Nevertheless, the differential diagnosis and evaluation of insomnia in epidemiological and treatment effectiveness studies require similar measurement approaches for insomnia and relevant domains, to thoroughly characterize the populations of interest. While most insomnia measurement scales and methods described here are derived from instruments developed to study primary insomnia, the goal of capturing insomnia as a distinct and addressable measurement problem remains the same, irrespective of the cause of insomnia. In this chapter, we discuss evaluation measures and methods that have been widely used, and that are validated, reliable, and/or recommended by expert consensus on insomnia measurements (3). These methods are amenable to different purposes for the evaluation of insomnia: clinical evaluation, research assessments, and epidemiological studies. As such, we first discuss the requirements and constraints of these three contexts in relation to the evaluation of insomnia. Selected measures of insomnia reviewed here include clinician-administered scales, self-report questionnaires, sleep diaries, and actigraphy. Polysomnography (PSG) has been used widely as a screening method to rule out other sleep disorders that may masquerade as insomnia (e.g., sleep apnea, periodic leg movement disorder), as a quantitative measurement of sleep disturbances, and as an objective outcome measure in treatment efficacy studies. However, PSG is not a clinically recommended measurement method to diagnose insomnia (4). Additionally, PSG does not quantify all features of insomnia, which also include sleep dissatisfaction, daytime impairments, and related symptoms. These latter daytime symptoms may partially explain the modest relationships between subjective and objective sleep measures in patients with sleep disorders (5).
