Sleep Spindle Density May Influence Success of CBT for Insomnia

September 25, 2017

By Anne Harding

NEW YORK—People with a higher sleep spindle density may respond better to cognitive behavioral therapy (CBT) for insomnia than those with less of this type of brain activity, new research suggests.

CBT is the first-line treatment for insomnia, but about 40% of patients don’t get better with this approach, Dr. Thien Thanh Dang-Vu of Concordia University in Montreal, Canada, the study’s first author, noted in a telephone interview with Reuters Health.

In the new study, published September 19 in Sleep Medicine, Dr. Dang-Vu and his colleagues looked at whether sleep spindles, bursts of oscillatory activity that occur during stage 2 and stage 3 non-rapid-eye-movement sleep, affected insomniacs’ response to CBT.

Sleep spindles – representing communication between reticular thalamic and thalamocortical neurons and cortical neurons - have been associated with overnight improvements in memory and intellectual ability, Dr. Dang-Vu explained. The spindles may also play a role in blocking auditory stimuli during sleep.

“They seem to be acting as a gating mechanism to protect the sleeping brain,” he added. Also, sleep spindle density appears to be a stable individual trait.

Twenty-four people with chronic insomnia participated in the study, undergoing a series of sleep-quality measurements before and after they completed a six-week, six-module CBT program for insomnia.

The modules focused on psychoeducation about issues pertaining to sleep, including circadian rhythms, stimulus control, sleep restriction, sleep hygiene, cognitive therapy, and relaxation. Each weekly session lasted 90 minutes.

After adjustment for age, sex and education, lower spindle density before CBT was associated with less post-intervention improvement in insomnia, according to Pittsburgh Sleep Quality Index findings during 12 months of follow-up.

Lower spindle density also was associated with less improvement in sleep-diary-reported sleep efficiency, but not with less improvement on the Insomnia Severity Index.

If the findings are confirmed, clinicians could measure a patient’s sleep spindle density to predict whether he or she will respond to CBT. Medications that increase sleep spindle density might help to increase CBT response, Dr. Dang-Vu added, but more study is needed.

“We are currently running trials to confirm the finding in larger samples, and also look at other possible biomarkers of response to insomnia treatment,” he said.


Sleep Med 2017.

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