Brain activity during sleep could predict recovery of patients with brain injury

76 per cent of the patients with sleep spindles and cognitive motor dissociation showed evidence of consciousness by the time they were discharged from hospital, find researchers

Sleep spindles or brain activity occurring during the non-dreaming stage of sleep could help predict recovery of consciousness and independent functioning in those who suffered a brain injury, a new study has suggested.

Researchers from Columbia University and the NewYork-Presbyterian healthcare system, US, said the studies have shown that unresponsive patients with a recent brain injury can possess a degree of consciousness hidden from families and doctors.

For the study, published in the journal Nature Medicine, the researchers looked through electroencephalograms or EEG recordings of brain activity in 226 comatose patients taken over a night.

 “The electrical activity during sleep looks relatively chaotic and then occasionally in some patients, these (bursts of) very organised, fast frequencies appear,” said lead researcher Jan Claassen, an associate professor of neurology at Columbia University.

These bursts of brain activity, called sleep spindles, often preceded the detection of cognitive motor dissociation—in which a patient appears unresponsive but shows evidence of brain activity—the return of consciousness and long-term recovery, the researchers said.

The patients with sleep spindles and cognitive motor dissociation were more likely to recover consciousness and functional independence, the team said.

“Spindles happen normally during sleep and (the patients are) showing some level of organisation in the brain, suggesting circuits between the thalamus and cortex -- (brain regions) needed for consciousness are intact,” Claassen said.

In the study, sleep spindles were seen in “approximately every third behaviorally unresponsive patient after acute brain injury, frequently precede detection of CMD and are a promising complementary predictor for recovery of consciousness and functional independence”.

The researchers said that 76 per cent of the patients with sleep spindles and cognitive motor dissociation showed evidence of consciousness by the time they were discharged from the hospital.

A year later, 41 per cent of these patients had recovered neurological function, with either minor deficits or a moderate disability, and were able to care for themselves during the day, the team said.

They acknowledged the findings do not prove that inducing sleep spindles would translate to better outcomes, but raise the possibility that improving a patient’s sleep may promote recovery.

Further, 19 of 139 patients in the study who did not show sleep spindles or signs of cognitive motor dissociation did recover consciousness, suggesting that other information will likely be needed to make more accurate predictions, the team said.

https://www.tribuneindia.com/news/health/brain-activity-during-sleep-could-predict-recovery-of-patients-with-brain-injury/