SALZBURG, Austria, Oct. 1 -- Sleep as well as memory may be enhanced
by training specific brain rhythms, researchers here found.
- Explain to interested patients that this study found that a method
of training specific brain activity may help improve sleep and memory.
A technique for training sensorimotor rhythm activity through
instrumental conditioning significantly increased the amplitude of brain
rhythms in 10 sessions (P=0.014), Manuel Schabus, Ph.D., of the University of Salzburg, and colleagues reported in the Oct. 1 issue of Sleep.
The increased sensorimotor rhythm activity translated into better sleep spindle numbers and sleep onset latency.
"Instrumental sensorimotor rhythm conditioning might thus be
considered a promising nonpharmacological treatment for primary insomnia
and other disorders," the researchers said.
In addition, the improved activity was associated with better
retrieval scores on a memory test taken both before and after sleep.
The results of the study "support our general rationale that an
increase in relaxation and a decrease in muscle tension might lead to
less movement during sleep and thereby augment the restorative and
learning enhancing benefits of sleep," Dr. Schabus and colleagues said.
Previous studies in cats have shown that sensorimotor rhythms --
which have a distinctive oscillatory pattern of 12 to 15 Hz on EEG
recordings -- can be conditioned through a reward system, the
So they evaluated whether training these rhythms for increased activity could influence sleep or memory in humans.
They randomized 27 healthy adults (13 male; mean age 23.63) to
undergo instrumental conditioning of sensorimotor rhythm. There were 16
in the experimental group and 11 in a control group given a similar
training regimen for random rhythm.
Each participant had 10 conditioning sessions on 10 consecutive days
during which sensorimotor rhythm was monitored. In addition, they
completed a declarative word-pair association task before and after a
The experimental group was trained to enhance the amplitude of their
sensorimotor-frequency range by using relaxation and other techniques
while monitoring their brain activity on a computer screen displaying
EEG recordings. When they succeeded in increasing the amplitude of the
specific frequency range, they were rewarded with a pleasing picture.
The control group was trained to enhance the amplitude of a different frequency range at each session in a similar manner.
The experimental group significantly increased their sensorimotor
rhythm amplitude from the early training sessions through the end of
training (P=0.014), successfully demonstrating a "shaping of one's own brain activity," according to the researchers.
The increased activity led to significant improvements in sleep spindle number (P=0.004) and sleep onset latency (P=0.006),
"indicating that specific neural mechanisms trained during wakefulness
can be translated into sleep," the researchers said.
On the memory task, only the experimental group had significant improvement in retrieval scores measured before the nap (P=0.011) and after the nap (P=0.018).
There were no similar changes in the control group.
"Possibly heightened attention or relaxation levels (during learning
and/or retrieval) after 10 instrumental sensorimotor rhythm conditioning
sessions … account for the observed improvement in word-pair recall,"
the researchers said.
They said that the results indicate that this technique may be used
as an alternative treatment for primary insomnia, but added that future
studies must look at whether it can be applied in these patients and
evaluate how stable the changes are in the long term.
In addition, they said, "future studies should continue to focus on
the effects of instrumental sensorimotor rhythm conditioning on various
cognitive tasks and also address the potential clinical significance of
this kind of training."
|The study was supported by the Forschungsstipendium Salzburg and the
Stiftungs-und Foerderungsgesellschaft der Universitaet Salzburg.
The authors made no disclosures.