Are All-Night Sleep Studies Indicated for Evaluating Insomnia?

By Dr. Gregg D. Jacobs

In a recent report in the journal Sleep (26, 2003:754-756), the American Academy of Sleep Medicine issued a report on the use of all-night sleep studies in the clinical evaluation of insomnia. This article summarizes the Academy's report.

All-night sleep studies (polysomnography, or PSG) are a standard tool in sleep medicine for evaluating sleep disorders. PSG can objectively verify difficulty falling or staying asleep, shortened sleep duration, and co-existing sleep disorders that may underlie insomnia such as sleep apnea or periodic limb movements. PSG can also be used to determine whether an insomniac suffers from sleep state misperception, in which the individual reports that he "did not slept a wink last night" despite the fact the PSG indicates a sleep duration of five hours that night. PSG is also used standardly to assess treatment outcome in clinical research studies in which the efficacy of pharmacological or behavioral therapies is being tested.

Some clinicians and sleep centers standardly use PSG to evaluate insomnia, which can be useful in detecting underlying sleep disorders but which can also involve several drawbacks. First, sleep is often different in the sleep lab than the home environment due to the novelty or stress of the sleep lab. Second, insomnia often shows significant night-to-night variability that cannot be measured by PSG in one or two nights. Third, the cost of a single night of PSG is very high. Fourth, some patients complain of insomnia despite no objective evidence for insomnia.

As a result of these potential drawbacks, the American Academy of Sleep Medicine does not recommended PSG for the routine evaluation of insomnia. However, the Academy does endorse the use of PSG for evaluating insomnia in the following situations: 1. when a sleep-related breathing disorder or periodic limb movement disorder is suspected; 2. the diagnosis of insomnia is still uncertain after a careful clinical evaluation involving a medical, psychiatric, and sleep history has been obtained first; 3. pharmacological or behavioral treatment for insomnia is unsuccessful; 4. violent or injurious behaviors occur during sleep. The Academy does not recommend that PSG be routinely used to evaluate insomnia associated with psychiatric disorders such as depression. The Academy also concluded that PSG is not useful in establishing the diagnosis of insomnia associated with fibromyalgia or chronic fatigue syndrome.