Recovery from brain injury, better sleep go hand in hand

December 22, 2016

Science Daily/American Academy of Neurology (AAN)

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.

"These results suggest that monitoring a person's sleep-wake cycle may be a useful tool for assessing their recovery after TBI," said study author Nadia Gosselin, PhD, of the University of Montréal in Québec, Canada. "We found that when someone sustained a brain injury and had not recovered a certain level of consciousness to keep them awake and aware of their surroundings, they were not able to generate a good sleep-wake cycle. But as they recovered, their quality of sleep improved."

A good sleep-wake cycle was defined as being alert and active during the day and getting uninterrupted sleep at night.

The study involved 30 people, ages 17 to 58, who had been hospitalized for moderate to severe TBI. Most of the patients were in a coma when they were admitted to the hospital and all initially received care in an intensive care unit. The injuries were caused by motor vehicle accidents for 20 people, falls for seven people, recreational or sports injuries for two people and a blow to the head for one person. They were hospitalized for an average of 45 days with monitoring for the study beginning an average of 21 days into a person's stay.

Each person was monitored daily for an average of 11 days for level of consciousness and thinking abilities using the Rancho Los Amigos scale, which ranges from 1 to 8. Each person also wore an activity monitor on their wrist so researchers could measure their sleep.

Researchers found that consciousness and thinking abilities improved hand-in-hand with measures of quality of sleep, showing a linear relationship.

One measure, the daytime activity ratio, shows percentage of activity that occurs during the day. Immediately after the injury, activity occurs throughout the day and night. The study showed that participants reached an acceptable sleep-wake cycle, with a daytime activity ratio of at least 80 percent, at the same point when they emerged from a minimally conscious state.

The participants still had inadequate sleep-wake cycles at a score of 5 on the Rancho Los Amigos scale, where people are confused and give inappropriate responses to stimuli but are able to follow simple commands. Sleep-wake cycles reached adequate levels at the same time that people reached a score of 6 on the Rancho Los Amigos scale, which is when people can give appropriate responses while still depending on outside input for direction. At that level, they can remember relearned tasks, but cannot remember new tasks.

The results were the same when researchers adjusted for the amount of time that had passed since the injury and the amount of medications they had received while they were in the ICU.

"It's possible that there are common underlying brain mechanisms involved in both recovery from TBI and improvement in sleep," said Gosselin. "Still, more study needs to be done and future research may want to examine how hospital lighting and noise also affect quality of sleep for those with TBI."

https://www.sciencedaily.com/releases/2016/12/161222095319.htm

Silent epidemic? Head injury may be linked to lasting sleep problems

April 27, 2016

Science Daily/American Academy of Neurology

People who have had a traumatic brain injury may still have sleep problems a year and a half after being injured, according to a study. In addition, people with TBI may also be unaware of just how much their sleep is disturbed.

Every year in the United States, 1.7 million people experience a TBI and there is evidence that the rate of TBI is rising worldwide.

"This is the longest prospective and most comprehensive study about sleep quality and TBI to date," said study author Lukas Imbach, MD, of the University Hospital Zurich in Zurich, Switzerland. "We found that the majority of those with TBI, no matter how severe, had long-term sleep disturbances, yet didn't know."

For the study, researchers followed 31 people who had experienced a first TBI for 18 months. The injuries ranged from mild to severe. People with TBI were then compared to a control group of 42 healthy people.

Study participants were asked to report their own sleep behavior and daytime sleepiness. They were also monitored for two weeks with a device worn on the wrist that measures body movement. They also spent a night in a sleep video lab, which measures brain activity, eye movements, muscle activity and heart rhythm. They also took a test for excessive daytime sleepiness, which measures how quickly people fall asleep in a quiet environment during the day.

Researchers found that 67 percent of those with TBI suffered from excessive daytime sleepiness compared to just 19 percent of healthy people. In addition, when they were asked how sleepy they were during the day, those with TBI didn't report feeling any sleepier than those without TBI.

"Excessive daytime sleepiness is associated with public safety hazards such as car accidents, so people with TBI and their doctors should be monitoring for this problem," Imbach said. "The study also shows us that people with TBI may not be able to accurately assess their own sleep problems. Since this is how the sleep quality of many people with TBI is assessed, this may be a concern."

People with mild TBI were just as likely to have sleep problems as people with severe TBI, and the researchers did not find any other health problems that could have contributed to the sleep problems.

Researchers found that those with TBI slept longer, an average of eight hours a night, compared with healthy people who slept an average of seven hours a night.

"This study makes a compelling case that sleep-wake disorders after TBI may represent a silent epidemic," said Imbach. "It raises the question as to whether people with TBI should be referred for sleep studies. But further study is needed before any new recommendations are made or any guidelines are changed."

https://www.sciencedaily.com/releases/2016/04/160427221158.htm

Enhancing sleep after brain injury reduces brain damage, cognitive decline in rats

March 23, 2016

Science Daily/Society for Neuroscience

Enhancing sleep after a head injury may help prevent some damage to brain cells, according to a study. Researchers found that enhancing the slow-wave cycle of sleep after head trauma minimized damage to axons -- the thin extensions that nerve cells use to send signals to other cells -- and helped preserve normal brain function.

Traumatic brain injury is a major cause of death and disability worldwide. While brain cells at the site of impact are damaged immediately, many more cells can perish in the hours and days after the trauma as damaged axons succumb to injury. Studies suggest that widespread axonal injury contributes to many of the long-lasting problems with learning, memory, and movement commonly associated with head injuries. Molecular waste products also build up in the brain after head injury. Recent studies indicate the brain clears out this molecular buildup during the slow-wave stage of sleep where brain activity synchronizes into high-amplitude waves.

The researchers led by Daniela Noain and Christian Baumann investigated whether enhancing slow-wave sleep after a head injury could mitigate axonal injury in rats. Twenty-five rats received a blow to the prefrontal cortex, a brain area associated with decision-making and self-control. One-third of the injured rats were sleep-deprived for short periods of time as previous studies indicate, for a brief period of time afterward, sleep deprivation enhances slow-wave sleep. Another group was treated with sodium oxybate, a drug used to induce a slow-wave sleep-like state in narcolepsy patients. A third group received placebo.

One day after injury and continuing for the next five, researchers modulated the animals' sleep. Employing electroencephalography (EEG) recordings during treatment, they confirmed that the animals experienced slow-wave sleep enhancement as a result of treatment. Afterward, the rats took a memory test, and the team examined their brains for axonal damage, focusing on areas involved in learning and memory, including the hippocampus.

They found that rats receiving treatments to enhance slow-wave sleep were better able to recognize familiar objects than the untreated rats. In addition, the researchers found that levels of a biomarker for diffuse axonal injury were reduced nearly 80 percent in animals that had experienced enhanced sleep compared to untreated rats.

While further study is needed, the work suggests slow-wave sleep administered immediately after a brain injury helps block axon damage and preserve normal brain function, Baumann says.

"Despite the high prevalence of traumatic brain injury worldwide, very few effective treatments exist to mitigate the persistent impairment in memory and cognitive function," says Miranda Lim, a neurologist at Oregon Health & Science University who was not involved in the study. "This study provides important evidence that manipulating sleep may be a promising avenue to enhance recovery after TBI."

https://www.sciencedaily.com/releases/2016/03/160323082229.htm