Saturday, March 05, 2011
Alpha brain waves and sleep disturbances
I stay in touch with the world in the course of a night as things that go bump in the night make me jump. Ringing phones send me into a hot flash of anxiety and insomnia even if it's just the gentle whir of a cellphone on vibrate! Last night, my husband's cell went off at 3:30 a.m. one floor and half the house away. He snoozed on while I tossed and turned.
No doubt that many--e.g. mothers, doctors, and plumbers--all need a heightened nighttime awareness of the world, but this sleep-searing sensitivity can get out of hand. "Resistance to acoustic disturbance" is a measure of sleep soundness and is known to vary during the course of a night's sleep and also from sleeper to sleeper. Scientists are hot on the trail of why.
Nocturnal observations of 13 sleepers sleeping in a Massachusetts General sleep study lab revealed certain brain wave characteristics that predicted whether or not an individual would rouse to the noise of traffic or phones(1). As we transition from wakefulness to sleep, certain patterns emerge in our brain wave patterns signaling a shutting down of external awareness and a growing hubbub of internal brain activity. Alpha waves that flow from the back of our brain decline in amplitude as we drift into sleep. However, this wakeful wave does not disappear entirely, and, in fact, the more powerful these alpha signals, the more fragile our sleep.
The scientists confirmed that increased alpha activity as seen on EEG prior to the delivery of an external sound increased the likelihood that the subject would rouse unto wakefulness in response to the noise. Thus, alpha activity in the brain not only correlates with mental alertness by day but easily disturbed snoozing by night. The researchers concluded that this information may someday allow for the over-alpha'd amongst us to be variably medicated based on read outs from sleep monitoring devices rather than bluntly sedated for hours by currently available meds.
Sounds kind of "Brave New World"ish to me. And who then will lie awake waiting for teens?
(1) McKinney SM, Dang-Vu TT, Buxton OM, Solet JM, Ellenbogen JM (2011) Covert Waking Brain Activity Reveals Instantaneous Sleep Depth. PLoS ONE 6(3): e17351. doi:10.1371/journal.pone.0017351.