Table 1.

Definitions of key terms commonly encountered in sleep medicine research.

Terms	Definitions	Source
Insomnia disorder	Diagnostic criteriaa A. A predominant complaint of dissatisfaction with sleep quantity or quality, associated with one (or more) of the following symptoms:  1. Difficulty initiating sleep  2. Difficulty maintaining sleep, characterized by frequent awakenings or problems returning to sleep after awakenings  3. Early morning awakening with inability to return to sleep B. The sleep disturbance causes clinically significant distress or impairment in social, occupational, educational, academic, behavioral, or other important areas of functioning C. The sleep difficulty occurs at least 3 nights per week D. The sleep difficulty is present for at least 3 mo E. The sleep difficulty occurs despite adequate opportunity for sleep. F. The insomnia is not better explained by and does not occur exclusively during another sleep-wake disorder (eg, narcolepsy, a breathing-related sleep disorder, a circadian rhythm sleep-wake disorder, a parasomnia) G. The insomnia is not attributable to the physiological effects of a substance (eg, a drug of abuse and/or a medication) H. Coexisting mental disorders and medical conditions do not adequately explain the predominant complaint of insomnia	DSM-V 1
ISI	7-item self-report measure assessing the severity of insomnia symptoms (ie, sleep onset latency, wake time after sleep onset, early morning awakening, sleep satisfaction, etc) using 5-point Likert scale	Smith et al2
BDI-II	21-item self-report measure assessing severity of depressive symptoms using multiple choice format	Beck et al3
MFI	20-item self-report measure assessing fatigue including the following dimensions: General Fatigue, Physical Fatigue, Mental Fatigue, Reduced Motivation, and Reduced Activity	Smets et al4
EORTC QLQ-C30	Self-report questionnaire designed for use with a wide range of cancer patient populations and intended to be supplemented by tumor-specific modules. It incorporates 9 multi-item scales: 5 functional scales (Physical, Role, Cognitive, Emotional, and Social functioning), 3 symptom scales (Fatigue, Pain, and Nausea/Vomiting), and a Global Health Status/QOL scale. Six single-item scales are also included (Dyspnea, Insomnia, Appetite Loss, Constipation, Diarrhea, and Financial Difficulties)	Scott et al5
POMS	65-item self-report questionnaire that measures the transient, fluctuating feelings, and enduring affect states. It includes the following scales: Tension or Anxiety, Anger or Hostility, Vigor or Activity, Fatigue or Inertia, Depression or Dejection, Confusion or Bewilderment. It uses a 5-point scale ranging from “not at all” to “extremely”	McNair et al6
STAI	Self-report questionnaire with 20 items measuring trait anxiety and 20 items measuring state anxiety each using a 4-point Likert scale	Spielberger et al7
CES-D	20-item self-report questionnaire assessing level of depression with a 4-point Likert scale for each item	Radloff et al8
FACT-Breast	44-item self-report questionnaire including the FACT-General scale (includes subscales measuring Physical Well-Being, Emotional Well-Being, Social Well-Being, Functional Well-Being, and Relationship with Doctor) and the disease-specific breast cancer subscale (9 items specific to quality of life in breast cancer)	Brady et al9
DBAS	16-item self-report scale with each item including a statement reflecting a dysfunctional belief about sleep with a scale ranging from 0 “strongly disagree” to 10 “strongly agree”	Morin et al10
MDASI	Self-report questionnaire to assess the severity of symptoms experienced by patients with cancer and the interference of daily living caused by these symptoms. It includes 13 core symptoms, can be adapted to different cancer types with specific modules, and uses a 0- to 10-point scale	Cleeland et al11
PSQI	19-item self-report measure assessing sleep continuity and graded severity and frequency of sleep disturbances and behaviors using some free entry and 4-point Likert scale items	Smith et al2
FSI	14-item self-report measure assessing the severity, frequency, and daily pattern of fatigue as well as its perceived interference with quality of life. Severity is measured on a scale ranging from 0 “not at all fatigued” to 10 “as fatigued as I could be” that assess most, least, and average fatigue in the past week as well as current fatigue. Frequency is measured as the number of days in the past week (0-7) that respondents felt fatigued as well as the extent of each day on average they felt fatigued ranging from 0 “none of the day” to 10 “the entire day.” Perceived interference is measured on separate scale ranging from 0 “no interference” to 10 “extreme interference.” The final item provides qualitative information about possible diurnal variation in the daily experience of fatigue	Hann et al12
SF-36	36-item assessment that measures 8 health concepts: (1) limitations in physical activities because of health problems, (2) limitations in social activities because of physical or emotional problems, (3) limitations in usual role activities because of physical health problems, (4) bodily pain, (5) general mental health (psychological distress and well-being), (6) limitations in usual role activities because of emotional problems, (7) vitality (energy and fatigue), and (8) general health perceptions	Ware et al13

Abbreviations: BDI-II, Beck Depression Inventory-II; CES-D, Center for Epidemiological Studies Depression Scale; DBAS, Dysfunctional Beliefs about Sleep; DSM-V, Diagnostic and Statistical Manual of Mental Disorders (Fifth Edition); EORTC QLQ-C30, European Organization for Research and Treatment of Cancer Quality of Life Questionnaire; FACT-Breast, Functional Assessment of Cancer Therapy-Breast; FSI, Fatigue Severity Inventory; ISI, Insomnia Severity Index; MDASI, MD Anderson Symptom Inventory; MFI, Multidimensional Fatigue Inventory; POMS, Profile of Mood States; PSQI, Pittsburgh Sleep Quality Index; QOL, quality of life; SF-36, Medical Outcomes Study Short Form Health Survey.; STAI, State-Trait Anxiety Inventory

^aAbbreviated.