Pittsburgh Sleep Quality Index

Posted on August 1, 2009 in Latest News

The Pittsburgh Sleep Quality Index (PSQI) is an effective instrument used to measure the quality and patterns of sleep in older adults. This is a self-rated questionnaire which assesses sleep quality and disturbances over a 1-month time interval. It differentiates “poor” from “good” sleep by measuring seven components: subjective sleep quality, sleep latency, sleep duration, habitual sleep efficiency, sleep disturbances, use of sleeping medication, and daytime dysfunction.

Description:
There are 19 self-rated questions and 5 questions rated by a bed partner or roommate in PSQI. Among 19 questions there are 15 multiple-choice questions and 4 write-in questions. Multiple choice questions inquire about frequency of sleep disturbances and subjective sleep quality and write-in questions inquire about typical bedtime, wake-up time, sleep latency, and sleep duration. The 5 bed partner questions are multiple-choice ratings of sleep disturbance.

All items are brief and easy for most adolescents and adults to understand. The items have also been adapted so that they can be administered by a clinician or research assistant. The PSQI can be used for both initial assessment and ongoing comparative measurements with older adults across all health care settings.

Ratings:
The client self-rates each of these seven areas of sleep. Scoring of answers is based on a 0 (no difficulty) to 3 (severe difficulty) scale. The component scores are summed to produce a global score (range of 0–21). A PSQI global score >5 is considered to be suggestive of significant sleep disturbance. Cut off scores are not available for component scales.

Clinical Studies:
The sum of scores for these seven components yields one global score. Clinical and clinometric properties of the PSQI were assessed over an 18-month period with “good” sleepers (healthy subjects, n = 52) and “poor” sleepers (depressed patients, n = 54; sleep-disorder patients, n = 62). Acceptable measures of internal homogeneity, consistency (test-retest reliability), and validity were obtained. A global PSQI score greater than 5 yielded a diagnostic sensitivity of 89.6% and specificity of 86.5% (kappa = 0.75, p less than 0.001) in distinguishing good and poor sleepers. Numerous other studies using the PSQI have supported high validity and reliability.

Limitations of PSQI:
The PSQI is a subjective measure of sleep. Self-reporting by clients can empower the client, but can reflect inaccurate information if the client has difficulty understanding what is written, or can not see or physically write out responses. Moreover, the scale is presented in English. The scale can be adapted to enable clients to respond verbally to items on the scale by having the nurse read the statements to the client.

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