Validation of the Insomnia Severity Index as an outcome measure for insomnia research

Background Although insomnia is a prevalent complaint with significant morbidity, it often remains unrecognized and untreated. Brief and valid instruments are needed both for screening and outcome assessment. This study examined psychometric indices of the Insomnia Severity Index (ISI) to detect cases of insomnia in a population-based sample and to evaluate treatment response in a clinical sample. Methods Participants were 959 individuals selected from the community for an epidemiological study of insomnia (Community sample) and 183 individuals evaluated for insomnia treatment and 62 controls without insomnia (Clinical sample). They completed the ISI and several measures of sleep quality, fatigue, psychological symptoms, and quality of life; those in the Clinical sample also completed sleep diaries, polysomnography, and interviews to validate their insomnia/good sleep status and assess treatment response. In addition to standard psychometric indices of reliability and validity, item response theory analyses were computed to examine ISI item response patterns. Receiver operating curves were used to derive optimal cutoff scores for case identification and to quantify the minimally important changes in relation to global improvement ratings obtained by an independent assessor. Results ISI internal consistency was excellent for both samples (Cronbach α of 0.90 and 0.91). Item response analyses revealed adequate discriminatory capacity for 5 of the 7 items. Convergent validity was supported by significant correlations between total ISI score and measures of fatigue, quality of life, anxiety, and depression. A cutoff score of 10 was optimal (86.1% sensitivity and 87.7% specificity) for detecting insomnia cases in the community sample. In the clinical sample, a change score of -8.4 points (95% CI: -7.1, -9.4) was associated with moderate improvement as rated by an independent assessor after treatment. Conclusion These findings provide further evidence that the ISI is a reliable and valid instrument to detect cases of insomnia in the population and is sensitive to treatment response in clinical patients.

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The Insomnia Severity Index: psychometric indicators to detect insomnia cases and evaluate treatment response.

Background Since falling is associated with serious morbidity among elderly people, we investigated whether the risk of falling could be reduced by modifying known risk factors. Methods We studied 301 men and women living in the community who were at least 70 years of age and who had at least one of the following risk factors for falling: postural hypotension; use of sedatives; use of at least four prescription medications; and impairment in arm or leg strength or range of motion, balance, ability to move safely from bed to chair or to the bathtub or toilet (transfer skills), or gait. These subjects were given either a combination of adjustment in their medications, behavioral instructions, and exercise programs aimed at modifying their risk factors (intervention group, 153 subjects) or usual health care plus social visits (control group, 148 subjects). Results During one year of follow-up, 35 percent of the intervention group fell, as compared with 47 percent of the control group (P = 0.04). The adjusted...

https://www.nejm.org/doi/pdf/10.1056/NEJM199409293311301

A multifactorial intervention to reduce the risk of falling among elderly people living in the community.

https://en.smrc-sa.com/wp-content/uploads/2014/12/Sleep-Patterns-and-Predictors-of-College-Students.pdf

Sleep Patterns and Predictors of Disturbed Sleep in a Large Population of College Students

A cognitive model of insomnia.

A treatment of chronic insomnia is described that is based on the recognition that excessive time spent in bed is one of the important factors that perpetuates insomnia. Thirty-five patients, with a mean age of 46 years and a mean history of insomnia of 15.4 years, were treated initially by marked restriction of time available for sleep, followed by an extension of time in bed contingent upon improved sleep efficiency. At the end of the 8-week treatment program, patients reported an increase in total sleep time (p less than 0.05) as well as improvement in sleep latency, total wake time, sleep efficiency, and subjective assessment of their insomnia (all p less than 0.0001). Improvement remained significant for all sleep parameters at a mean of 36 weeks after treatment in 23 subjects participating in a follow-up assessment. Although compliance with the restricted schedule is difficult for some patients, sleep restriction therapy is an effective treatment for common forms of chronic insomnia.

/pdf/treatment-of-chronic-insomnia-by-restriction-of-time-in-bed-57ei4marvv.pdf

Treatment of Chronic Insomnia by Restriction of Time in Bed

We describe a new syndrome called "delayed sleep phase insomnia." Thirty of 450 patients seen for a primary insomniac complaint had the following characteristics: (1) chronic inability to fall asleep at a desired clock time; (2) when not on a strict schedule, the patients have a normal sleep pattern and after a sleep of normal length awaken spontaneously and feel refreshed; and (3) a long history of unsuccessful attempts to treat the problem. These patients were younger than the general insomniac population and as a group did not have a specific psychiatric disorder. Six patients' histories are described in detail, including the successful nonpharmacological chronotherapy regimen (resetting the patients' biological clock by progressive phase delay). Delayed sleep phase insomnia is proposed to be a disorder of the circadian sleep-wake rhythm in which the "advance" portion of the phase response curve is small.

Delayed Sleep Phase Syndrome: A Chronobiological Disorder With Sleep-Onset Insomnia

Delayed sleep phase syndrome in adolescents

A portable temperature data logger was used for prolonged rectal temperature monitoring in an ambulatory subject with a longer than 24 hr (hypernychthemeral) sleep-wake cycle. The mean period of the sleep-wake and circadian temperature cycles was 24.8 hr. However, the period of the sleep-wake cycle fluctuated considerably, being less than 24.8 hr when he slept during the socially desirable sleep hours and more than 24.8 hr when he slept during the day. In the first instance, the daily temperature fall occurred later than, and in the second earlier than, sleep onset. During the times of desynchronization of the two cycles, he complained of insomnia, fatigue, and reduced performance. We postulate that his hypernychthemeral cycles were the result of either a primary defect in the mechanism of entrainment or "weakened" social zeitgebers due to a personality disorder. These concepts are supported by a sleep-wake pattern resembling that of relative coordination. We therefore raise the possibility that 24 hr was beyond the range of entrainment of the subject's circadian temperature cycle during the study.

Long-Term Ambulatory Temperature Monitoring in a Subject with a Hypernychthemeral Sleep-Wake Cycle Disturbance

Theoretical and technical problems in using Nocturnal Penile Tumescence (NPT) measurements for the differential diagnosis of impotence are discussed and possible solutions are offered: 1) The basic assumption that NPT measurements can distinguish psychogenic from organic impotence has never been demonstrated in patients shown to be psychogenically and organically impotent independent of the NPT measurements themselves. Studies attempting to do this are necessary to determine definitively the limits of the clinical applicability of this important diagnostic tool. 2) Evidence is presented showing that though a direct observation of one of the patient's fullest erections is required for an adequate NPT evaluation, this is not always done. The danger of misdiagnosis if this step is omitted is illustrated with a case report. 3) Disagreements in the literature about NPT criteria for diagnosing psychogenic impotence are discussed and criteria are suggested that are based on demonstrating the intactness of the physiological mechanisms required for erection rather than on values recorded in normal subjects.

Arthur J. Spielman

Papers

Treatment of Chronic Insomnia by Restriction of Time in Bed

Delayed Sleep Phase Syndrome: A Chronobiological Disorder With Sleep-Onset Insomnia

Delayed sleep phase syndrome in adolescents

Long-Term Ambulatory Temperature Monitoring in a Subject with a Hypernychthemeral Sleep-Wake Cycle Disturbance

Theoretical and technical problems in the measurement of nocturnal penile tumescence for the differential diagnosis of impotence.