Embargoed for release 6 p.m. EDT, June 7, 2001
Are you feeling sleepy? Click here - but beware!
U-M study finds many web sites offer potentially misleading sleep problem self-test
ANN ARBOR, Mich. - Finding health information has become one of the top uses of the World Wide Web, but those looking for insights into their sleep problems should beware, a new University of Michigan Health System study shows.
That's because more than 90 sites are offering a simple - but not very accurate - questionnaire that asks about feelings of sleepiness. It may seem like a good tool for sites to provide and for sleepy Web users to try. But the U-M researchers are concerned that the public is getting a misleading and incomplete picture of their sleep problems from it, and not always receiving the information they need to interpret the questionnaire's results.
The new research, which will be presented June 7 at the annual meeting of the Associated Professional Sleep Societies in Chicago, reports that a search of the Web found that 91 sites offered the Epworth Sleepiness Scale, or ESS.
The eight-question ESS, first published in 1991, asks people to rate how likely they would be to fall asleep in different situations, from watching TV to sitting in a meeting. The subjective rating scale for each situation, from 0 for not likely to fall asleep, to 3 for high chance of falling asleep, was designed to assess overall tendency to fall asleep during daily activities.
Sleepiness can reflect many different conditions, including sleep deprivation, depression, obstructive sleep apnea and narcolepsy. Some relatively small studies have shown ESS scores to be higher in those diagnosed with sleep apnea or narcolepsy. But more recent studies, including one performed at U-M, have questioned how well ESS results reflect the sleepiness and sleep disorders that clinicians traditionally evaluate by more objective methods.
The Web sites offering the ESS ranged from academic institutions and professional societies to commercial health information sites, report Alon Avidan, M.D., MPH, a clinical assistant professor of neurology at the U-M Medical School and Ronald Chervin, M.D., an assistant professor of neurology who directs the U-M's Michael S. Aldrich Sleep Disorders Laboratory.
The ESS has grown in clinical use, and indeed is sometimes used by UMHS physicians before and after they evaluate and treat patients who have known symptoms. But UMHS physicians and other specialists around the country who see patients with suspected sleep problems often also perform a Multiple Sleep Latency Test (MSLT) that uses electrodes to measure directly how long it takes someone to fall asleep during several daytime nap periods.
A large study by Chervin and Aldrich published in 1999 found that ESS scores did not correlate well with MSLT results among patients with sleep apnea, nor with other objective measures of the apnea's severity. They concluded that the ESS cannot be used in place of the MSLT to gauge sleepiness. That study, and the growing trend toward self-service health advice on the Web, led Avidan and Chervin to perform the new study.
One quarter of the web sites found in the study offered no interpretations of various ESS scores for users. About 40 percent advised those with higher but still very common scores to consult their physician or another clinician. The authors note that though this advice may help some patients, no studies have been done on the effectiveness of using ESS to screen the general population.
Some sites gave information on what kind of results might be typical of people with narcolepsy or apnea, without mentioning that many other problems, such as poor sleep habits or insufficient time in bed, could also cause the same ESS scores. Some sites graded severity of ESS results - for example, distinguishing between "severe" and "excessive" sleepiness - in a manner that may exaggerate the precision and medical utility of the questionnaire.
No sites noted that depression and insufficient sleep are two of the most common causes of chronic sleepiness, and no sites noted that the meaning and interpretation of ESS scores can be controversial. The omission of other causes of sleepiness, and the lack of contextual information about the ESS's questionable accuracy compared to objective tests, the authors note, may make the online ESS tests deceptive for Web users.
The study was supported by a grant from the National Heart, Lung and Blood Institute of the National Institutes of Health.
The Epworth Sleepiness Scale: How likely are you to doze off or fall asleep in the following situations, in contrast to feeling just tired? This refers to your usual way of life in recent times. Even if you have not done some of these things recently, try to work out how they would have affected you. Choose the most appropriate number for each situation.
(0 = no chance of dozing, 1 = slight chance of dozing, 2 = moderate chance of dozing, 3 = high chance of dozing)
1. Sitting and reading
2. Watching TV
3. Sitting inactive in a public place (e.g., a theater or a meeting)
4. As a passenger in a car for an hour without a break
5. Lying down to rest in the afternoon when circumstances permit
6. Sitting and talking to someone
7. Sitting quietly after a lunch without alcohol
8. In a car, while stopped for a few minutes in traffic
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