Brain injuries and sleep problems are well-known bedfellows.
 Around 30 to 70 per cent of traumatic brain injuries (TBIs) result in sleep disturbance, with insomnia, fatigue, narcolepsy and sleep apnea among a range of complaints.

Pain and depression that often come with TBI can also hinder a good night’s sleep.
 It is indisputable that trauma damages sleep. Far less is known, however, about the role sleep plays in the rehab journey after brain injury.

Thanks to scientists in Canada, this is changing. Their research has unearthed new potential links between sleep and faster
 TBI recovery.

They have found that recovery of consciousness and improvement in sleep disturbances appear to work in parallel.

“If you fix the sleep problems, could you then speed up recovery? That’s what we’re hoping for,” says Catherine Duclos, lead investigator on the ongoing study. We’ve found that consciousness and sleep evolve together; they go hand in hand.

The research is a joint effort by the Center for Advanced Research in Sleep Medicine, at the Hôpital du Sacré-Coeur de Montréal, and l’Université de Montréal in Quebec.

Its latest paper, published by the American medical journal Neurology, shows the results of a study of 30 acute, hospitalised TBI cases.

Most of the patients, aged 17 to 58, were in a coma when they were admitted to the hospital and all initially received care in an intensive care unit.

Injuries were caused by motor vehicle accidents for 20 people, falls for seven, recreational or sports injuries for two and a blow to the head for another.

They were hospitalised 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 their level of consciousness and thinking abilities, using the Rancho Los Amigos scale, which ranges from one to eight.

They also wore an activity monitor enabling researchers to measure their sleep. Researchers found that consciousness and thinking abilities improved as measures
 of quality of sleep did, showing a clear, linear relationship.

One measure, the daytime activity ratio, shows the percentage of activity that occurs during the day.

The study showed that participants reached an acceptable sleep-wake cycle, with a daytime activity ratio of at least 80 per cent, at the same point as when they emerged from a minimally conscious state.

The participants still had inadequate sleep-wake cycles at a score of five 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 as people reached a score of six on the scale, which is the point at which people can give appropriate responses while still depending on outside input for direction.

At that level, they can remember relearned tasks, but not new ones.

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,” wrote the report’s author Nadia Gosselin.

On the next stage of the study, Duclos 
says: “One hypothesis about why sleep disturbances occur after TBI is that the circadian or biological clock is located in 
the brain.
 So we assume that a blow to the head will dysregulate it.

“We’ll be looking for markers of the clock to see if it’s working properly and is the cause of sleep disturbances.

“In the early stages after a TBI there is a lot of inflammation and lots of neuronal deaths, mostly in the frontal part of the brain.

“There is also axonal [nerve fibre] damage throughout the brain.
 Could it be that the regions of the brain that need to connect to initiate sleep might not be able to do so anymore?
 Or could the clock be being influenced?”

Duclos also points to the possible significance of the hospital setting on sleep in the aftermath of TBI.

“We have also been comparing TBI patients to orthopaedic ones to investigate whether it’s really the brain injury causing the disturbances, because we know the hospital setting is not the best for sleep.

“Often hospital patients don’t have regular access to natural light during the day and there’s too much light at night, with lights turned on during sta interventions. These factors can have a significant influence on sleep patterns.

“If patients had more natural light or even light therapy during the day, that might better train their circadian clock.

Also, there’s the potential impact of melatonin, the sleep hormone which is secreted in the evening and at night to help us sleep. It is very sensitive to light. Therefore, when your eyes are exposed to light, its production is suppressed.”

While the intricacies of the relationship between sleep problems and TBI are yet to be fully proven, Duclos is certain that the power of sleep in neuro-rehab is being underutilised.

“It’s a neglected function in neuro-rehab.
I often hear things like ‘patients aren’t here to sleep, they are here to recover’.

“They seem to forget that sleep goes hand
 in hand with recovery and is intimately tied to our immune function and the generation of new cells and affects the entire body, not just the brain.

“I think more could be done to organise rehab sessions around naps – and to promote rest periods throughout the day
so patients are more refreshed when they participate in rehab activities.

“Sleep disturbances are so common in rehab centres.
”But also in the chronic phase, several months or years a er the injury, not much is done to help with sleep problems.

“In a lot of cases, individuals can’t go back to work because they are too tired or require multiple naps through the day. If we understood more about where these disturbances originate, we could target treatment a little better than simply giving sleeping pills.”