For the 33 percent of Americans who suffer from insomnia, a good night’s sleep is no more than a dream. Part of the their problem could be that they overestimate how long it takes them to get to sleep, thus sustaining a self-perpetuating cycle of sleep-related anxiety.
Nicole Yang and Alison Harvey (Oxford University) recruited 40 students with primary insomnia from two Oxford universities. All the participants said that for at least a month they had suffered difficulty sleeping as frequently as three nights per week.
The participants were kitted out with a watch-like gadget – an actigraph – that provided an objective measure of sleep, based on how much they tossed and turned in the night. For three nights they wore the gadget and kept a sleep diary. Afterwards, half of the participants were shown, based on the actigraph’s measurements, how they had overestimated in their diary how long it took them to get to sleep. The procedure was then repeated for a further three nights.
For the second three-night session, the participants who had seen the discrepancy between their own and the actigraph’s measure of how long they took to drift off, now estimated this period more accurately and reported significantly less sleep-related anxiety than did the other participants.
“The findings support the proposal that distorted perception of sleep functions to maintain insomnia by fuelling anxiety and preoccupation with sleep” the authors claimed. And use of an actigraph “provides a non-intrusive, easy to administer method” of correcting these distortions.
Tang, N.K.Y. & Harvey, A.G. (2004). Correcting distorted perception of sleep in insomnia: a novel behavioural experiment? Behaviour Research and Therapy, 42, 27-39.