Researchers analysed the sleeping patterns of 59 people with brain injury staying in a rehabilitation unit in Oxford, and 55 people who didn’t have a brain injury and were at home.

Participants were asked about their quality of sleep over a month and wore a monitor on their wrists that recorded movement, which would suggest sleep disruption.

Those with brain injuries reported having lower quality sleep, and the monitors recorded more disrupted sleep compared to the control group.

People with brain injury who had less disrupted sleep recovered quicker than those who had more disrupted sleep. They scored higher on arm/hand function tests, showed less overall movement impairment in their affected arm and legs and were more mobile.

This is because disrupted sleep can impair learning, says Melanie Fleming, researcher at the Wellcome Centre for Integrative Neuroimaging at the University of Oxford, who led the study, which was published this month in the ‘Neurorehabilitation and neural repair’ journal.

“Our main hypothesis is the idea that if you don’t sleep well, you don’t consolidate what you learnt from your physio session that day, and don’t make improvements day to day as quickly as you might if you consolidate what you learnt better,” Fleming says.

“There’s a lot of research showing that if you learn a sequence of movements then sleep overnight, you learn it better in the morning than if you were to stay awake during the night and try again it in the morning.”

Fleming didn’t directly measure how much patients engaged with rehabilitation, although she did measure how much time people were sedentary and active, but didn’t see any patterns.

“Some studies have looked at staff from rehabilitation units who say they feel people don’t engage as well when they’re reporting having bad sleep, which is easy to see – if you’re exhausted in the morning after a terrible sleep it’s very hard to then go to a physiotherapy session,” Fleming says.

Between 30 and 70 percent of patients experience sleep disturbances after a brain injury and have at least one sleep disorder, research has found.

This can partly be attributed to the noises and other disturbances ongoing throughout the night in hospital environments, but it’s not the sole cause.

Fleming says brain injuries themselves can also impact sleep quality due to damage to parts of the brain that control sleep, as well as low mood, which occurs more often in people with brain injuries, and is associated with difficulty sleeping.

Fleming’s study was observational, which means it couldn’t prove a cause-and-effect relationship between sleep quality and recovery. The most effective way to find this out would be to do an interventional study where researchers try to improve people’s sleep in hospital and see if it effects recovery. Fleming is currently in the process of applying for funding to carry out research of this nature.

“This study can’t say if people are sleeping poorly, but it’s common sense,” she says. “Low mood and poor sleep are really linked. Quality of life is better if you can improve a person’s sleep, and they engage better in rehabilitation.

“The main takeaway from this study is that when people say they’re sleeping badly, they really are – we need to be thinking about this when we think about the rehabilitation environment.”