The Pittsburgh Sleep Quality Index (PSQI) is a questionnaire designed to determine the quality of sleep experienced by a person. The PSQI seeks to measure the sleep quality of a patient over the course of the last month. Originally designed by professors at the Pittsburgh School of Medicine to measure the sleep quality among psychiatric patients, since its introduction in 1989, the PSQI has been applied in many different contexts to many different populations, with a high degree of success.
In its initial test over an 18-month period, the test showed almost a 90 % sensitivity and specificity in distinguishing between good and bad sleepers. Month-to-month repeatability of results was high. Later clinical trials have also established that the test also had a high level of stability over two years.
The PSQI questionnaire includes questions directed at many different parameters over one month. First, it asks about the time a person goes to sleep, how long it takes to fall asleep, time of waking, and the amount of actual sleep per night. It asks questions about disruptions to sleep, including difficulty falling asleep, night waking, breathing difficulties, and bad dreams. The questionnaire also asks the respondent to get information from any cosleeper(s) about nighttime behaviors such as snoring and restless leg syndrome.
Although the PSQI cannot diagnose sleep apnea, it can be a useful tool for helping clarify a suspicion of the condition. It also can be very useful as a source document for starting your sleep diary, since it identifies many key parameters related to the quality of your sleep.
If you suspect you may have sleep apnea, please contact the Snoring and Sleep Apnea Treatment Center, serving patients in the Chicago area, northern Illinois and southern Wisconsin, for a free sleep apnea consultation.