Every year I see many patients that tell me that they get only a few hours of sleep each night. In fact, I have had several swear they barely sleep at all. In most cases, they honestly believe this to be true. Interestingly, if we bring them into our sleep lab, many of these individuals will insist that they slept only a few hours when their electroencephalogram (EEG) indicates that they actually slept much longer.
This is a type of insomnia called Paradoxical Insomnia, also referred to as Sleep State Misperception. Previously, we thought it to be rare and probably present in no more than five percent of insomnia sufferers. We now know this to be incorrect. Furthermore, in several recent studies, the incidence is closer to 50% when defined as misperceiving sleep as wake time by at least one hour or more per night.
As a result, we are now coming to realize there are two basic types of insomniacs–those who sleep greater than six hours but perceive they sleep less, and those who actually sleep less than six hours and accurately estimate their sleep time.
Why is it important to differentiate the two? The group that in reality sleeps less than six hours is much more likely to develop hypertension, diabetes, and suffer earlier death than the group that misperceives their sleep time. These findings are potentially revolutionary when it comes to our understanding of the diagnosis and treatment of insomnia. Consequently, we need objective data in order to differentiate these two types since effective treatment approaches are different.
What I find fascinating is that those with misperception are more likely to respond to CBT (Cognitive Behavioral Therapy). While those who actually sleep less than six hours, the short sleeper type, are more likely to require pharmacological therapies. We believe this to be because the short sleepers have an underlying level of physiological hyperarousal. They have elevated levels of stress hormones such as cortisol and adrenaline, while the misperception group seems to demonstrate more of a psychological basis for their insomnia.
The good news is that in sleep medicine we now have accurate tools for differentiating these two types. We have a device called an actigraph that is worn like a wristwatch on the subject’s arm. It correlates movement with wakefulness and its absence with sleep. Even more astonishing is a new form of technology called the Sleep Profiler. It records the subject’s brain waves during the night at home, accurately differentiating sleep from wake and also the distinctive stages of sleep. In fact, I have used this form of technology in my own practice with great success.
Due to our new understanding of insomnia and these technological advances, we can offer our patients evidenced-based therapies. As with many other things in medicine, we are learning that in the treatment of insomnia, one size does not fit all.
