Could fixing the body clock help people regain consciousness?

April 19, 2017, American Academy of Neurology

For people with severe brain injuries, researchers have found that the rhythm of daily fluctuations in body temperature is related to their level of consciousness, according to a preliminary study published in the April 19, 2017, online issue of Neurology, the medical journal of the American Academy of Neurology.

"Our study suggests that the closer the body temperature patterns of a severely brain injured person are to those of a healthy person's circadian rhythm, the better they scored on tests of recovery from coma, especially when looking at arousal, which is necessary for consciousness," said study author Christine Blume, PhD, of the University of Salzburg in Austria.

Circadian rhythms, which are rhythmic variations in body functions brought about by the body's , are the daily cycles that tell us when to sleep, wake or eat. This biological clock also regulates many of the body's other functions including temperature. It is set by environmental cues, like periods of daylight and dark.

In healthy people, daily variations in body temperature closely follow the , the 24-hour daily sleep pattern controlled by the body's internal clock. Other studies have found that disruptions to the sleep-wake may affect various aspects of health like the immune system and short-term memory. During a normal sleep-wake cycle, the body's core temperature fluctuates and can drop one to two degrees during the early morning hours.

For this study, researchers monitored 18 people with severe brain injuries, those with unresponsive wakefulness syndrome and those in a . Unresponsive wakefulness syndrome, also known as a vegetative state, is when someone has awakened from a coma, is opening his or her eyes and having periods of sleep, but remains unresponsive. A minimally conscious state is when someone shows signs of awareness.

For one week, researchers continually monitored the of participants with external skin sensors. With that temperature data, they were able to determine the length of the circadian rhythm for each person. Length of temperature cycles of participants ranged from 23.5 to 26.3 hours.

Researchers also evaluated the level of consciousness for each person with the Coma Recovery Scale-Revised, measuring things like response to sound and ability to open eyes with or without stimulation. They found that those who scored better on that scale had body temperature patterns that more closely aligned with a healthy 24-hour .

"This is the first time an association has been found between circadian variations in body temperature and arousal in brain-injured patients. Importantly, arousal is essential for consciousness," said Blume. "Circadian variations are something doctors should keep in mind when diagnosing patients. The time of the day when patients are tested could be crucial. Also, doctors may want to consider creating environments for patients that mimic the light patterns of night and day to help achieve a normal sleep-wake cycle. The hope is that this may help bring a person with a severe brain injury closer to consciousness."

The researchers tested bright light stimulation on eight participants for one week and found positive effects in two patients. Blume said that larger studies are needed to test the hypothesis that bright light is indeed beneficial for patients.

One limitation of the study was that magnetic resonance imaging (MRI) data was not available to evaluate the extent of brain damage, especially in the hypothalamus, the portion of the brain where the body clock is located.

Blume suggests that future studies look at the relationship between body rhythms and other rhythms like hormone patterns and rest-activity cycles.

Explore further: ZeitZeiger: Computer tells the time according to your body clock

More information: Christine Blume et al, Significance of circadian rhythms in severely brain-injured patients, Neurology (2017). DOI: 10.1212/WNL.0000000000003942

Related Stories

ZeitZeiger: Computer tells the time according to your body clock

February 27, 2017
A computer method called ZeitZeiger that uses a sample of blood to accurately predict circadian time - the time of day according to a person's body clock - is described in new research published in the open access journal ...

Recovery from brain injury and better sleep go hand in hand

December 21, 2016
After a traumatic brain injury (TBI), people also experience major sleep problems, including changes in their sleep-wake cycle. A new study shows that recovering from these two conditions occurs in parallel. The study is ...

Night shifts may be more disruptive to women than men, brain study suggests

April 19, 2016
We all appreciate the importance of getting enough sleep. Not doing so affects our ability to function effectively, something that becomes painfully apparent during shift-work, especially night shifts. Now research suggests ...

Neurotransmitter serotonin shown to link sleep–wake cycles with the body's natural 24-hour cycle

February 22, 2013
Almost all animals have a hard-wired 'body-clock' that controls biological function in cycles of approximately 24 hours. This is known as the circadian rhythm and, in mammals, it is controlled by signaling in a region of ...

Shift work and sleep problems

December 27, 2016
Dear Mayo Clinic: I started working a night shift six months ago, and I just can't get enough sleep. I'm having a hard time staying asleep during the day. Most days, I get five hours of sleep or less. What can I do to get ...

Recommended for you

Precision neuroengineering enables reproduction of complex brain-like functions in vitro

November 14, 2018
One of the most important and surprising traits of the brain is its ability to dynamically reconfigure the connections to process and respond properly to stimuli. Researchers from Tohoku University (Sendai, Japan) and the ...

A 15-minute scan could help diagnose brain damage in newborns

November 14, 2018
A 15-minute scan could help diagnose brain damage in babies up to two years earlier than current methods.

New brain imaging research shows that when we expect something to hurt it does, even if the stimulus isn't so painful

November 14, 2018
Expect a shot to hurt and it probably will, even if the needle poke isn't really so painful. Brace for a second shot and you'll likely flinch again, even though—second time around—you should know better.

New clues to the origin and progression of multiple sclerosis

November 13, 2018
Mapping of a certain group of cells, known as oligodendrocytes, in the central nervous system of a mouse model of multiple sclerosis (MS), shows that they might have a significant role in the development of the disease. The ...

Mutations, CRISPR, and the biology behind movement disorders

November 12, 2018
Scientists at the RIKEN Center for Brain Science (CBS) in Japan have discovered how mutations related to a group of movement disorders produce their effects. Published in Proceedings of the National Academy of Sciences, the ...

In live brain function, researchers are finally seeing red

November 12, 2018
For years, green has been the most reliable hue for live brain imaging, but after using a new high-throughput screening method, researchers at the John B. Pierce Laboratory and the Yale School of Medicine, together with collaborators ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.