THURSDAY, March 3 (HealthDay News) -- New findings about brain rhythms could lead to the development of improved sleep treatments, a new study suggests.
A team at Massachusetts General Hospital found that a brain rhythm regarded as the emblem of wakefulness persists in a hidden form during sleep, where it becomes more intense at certain times -- something that appears to affect people's vulnerability to being awakened by noise or other disturbances.
To test their theory, the researchers used computerized electroencephalography (EEG) rhythms in 13 volunteers who slept -- or at least tried to -- three nights in the MGH Sleep Lab. At many intervals throughout each night, the volunteers were exposed to 10 seconds of typical background noises, such as traffic or a ringing telephone. The sounds were repeated at increasingly louder levels until the EEG showed that sleep had been disrupted.
An analysis of the EEG measurements showed that the intensity of the alpha signal predicted how easily volunteers could be disturbed at the moment the measurement was taken, with a stronger alpha signal linked to more fragile sleep.
"We found that the alpha rhythm is not just a marker of the transition between sleep and wakefulness but carries rich information about sleep stability," study author Scott McKinney, informatics manager at the MGH Sleep LAB, said in a hospital news release.
"This suggests that sleep -- rather than proceeding in discrete stages -- actually moves along a continuum of depth. It also opens the door to real-time tracking of sleep states and creates the potential for sleep-induction systems that interface directly with the brain," he added.
Although the alpha rhythm was discovered nearly 100 years ago, researchers once thought it disappeared when sleep began because they no longer saw it on an EEG. However, a technique called spectral analysis can pick up subtle fluctuations in the alpha rhythm during
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