Sleep becomes more difficult as people age. Until now, it’s been unclear why older individuals experience insomnia and sleep disruption.
Now, a new study finds that the loss of neurons in a particular region of the brain may be partially to blame. The finding could one day lead to specific treatments to treat sleep problems in older people.
In an article in Brain, researchers at the University of Toronto in Canada report that inhibitory neurons are significantly diminished in Alzheimer’s patients and some elderly people.
Researchers analyzed data from a community-based study involving about 1,000 subjects. Investigators followed the participants as healthy 65 years olds from 1997 when the study began until their deaths, when their brains were donated for research.
Every two years, the subjects wore a small water-proof wristwatch device 24 hours a day for seven to 10 days that monitored all their movements.
Toronto neurologist Andrew Lim says the absence of movement for five minutes or longer indicated the subjects were sleeping.
The authors studied the brains of 45 deceased participants. They counted the number of neurons in the brain area associated with regulating sleep patterns, and correlated that with data from the monitoring device.
Among participants who did not have Alzheimer’s disease - those with the highest number of neurons slept the longest during periods of non-movement. Those with fewer brain cells had more fragmented sleep.
However, the greatest sleep impairment was found among Alzheimer’s patients, whose brains had the fewest number of neurons.