Excessive Sleepiness Lingers in TBI Patients

18 months later, TBI patients slept an hour more each night than healthy controls

Patients who've suffered a traumatic brain injury (TBI) need more sleep than those who haven't sustained a head impact, researchers found.

In a small study of 31 patients with "acute, first-ever" TBI who were compared with 42 healthy controls, those with TBI needed 8.1 hours of sleep per every 24-hour period 18 months after their injury, compared with 7.1 hours for controls (P<.005), Lukas Imbach, MD, of the University of Zurich, and colleagues reported online in Neurology.

And 67% of TBI patients had excessive daytime sleepiness at that time, compared with 19% of controls, they found.

"I remember a patient. His wife told me, 'Well, you know, my husband sleeps all the time. This started since he had his accident,'" Imbach said, explaining that the study was inspired by the authors' clinical observations. "If I referred directly to the patient, he would say, 'Well, I'm fine. Nothing is wrong with me.'"

As a result, he said he hopes clinicians realize that many patients who've suffered TBIs have persistent sleep problems, but won't necessarily go to a doctor about them.

"You must be suspicious even if a patient directly tells you 'Well, I don't have a problem,'" he said. "You might consider doing other more objective tests to test specifically for that."

Imbach and his team initially screened 140 TBI patients, but they ruled out patients with sleep-wake disorders, prior brain trauma, substance abuse, neurologic or systemic diseases, and psychiatric comorbidities. Eighteen months later, they performed sleep assessments in 31 patients. The 42 controls never had brain trauma and were matched on age, sex, and sleep satiation.

The researchers used structured interviews to screen for changes in sleep habits, fatigue, and other items, and they used wrist sensors for 2 weeks to monitor the amount of sleep needed in a 24-hour period. They also used video-polysomnography from 11 p.m. to 7 a.m. to measure variations in other aspects of sleep.

Total sleep time in nocturnal polysomnography was higher in TBI patients compared with the controls (432 minutes versus 392 minutes, P<.0005).

Researchers did not find comorbidities that could have contributed to this excess sleepiness after TBI. Although intracranial hemorrhage was a risk factor for pleiosomnia, or excessive sleep need, 6 months after TBI, this association was gone by 18 months post injury.

Patients also kept sleep logs in which controls thought they slept slightly more than they did, and TBI patients thought they slept slightly less, showing that TBI patients "vastly underestimated" their sleep-wake problems, Brian Edlow, MD, of Harvard University, and Gert Jan Lammers, MD, of Leiden University Medical Centre in the Netherlands, wrote in their editorial to accompany Imbach's study.

"If approximately 50% of patients with TBI experience sleep–wake disturbances, as prior epidemiologic studies have shown, and if many of these patients do not recognize their own symptoms, should all patients with TBI be referred for sleep studies?" they ask in their editorial, before answering that this would be premature without more research no matter how well designed Imbach's study was.

Edlow and Lammers concluded that Imbach and colleagues' work is the "most comprehensive longitudinal analysis of posttraumatic sleep–wake disturbances to date." Still, they have questions about why this excess need for sleep persists for so long. They hypothesized that it could be the result of adaptive or pathogenic processes, but it's still unclear because Imbach and colleagues enrolled people with a range of TBIs.

It's this aspect of the study that Edward Hall, PhD, of the University of Kentucky, says isn't ideal. Most of the TBI patients in Imbach's study only had mild TBIs, or concussions, which Hall said he wouldn't expect to be associated with the kind of persistent sleepiness found in patients with moderate or severe TBIs. As a result, the results could be skewed. Still, he called it a "nice study."

Imbach said until the mechanisms behind sleepiness in TBI patients are better understood, it may be too soon to try using drugs to lessen sleep needs. His next study will use brain imaging to help better understand these mechanisms.

Reviewed by Henry A. Solomon, MD, FACP, FACC Clinical Associate Professor, Weill Cornell Medical College and Dorothy Caputo, MA, BSN, RN, Nurse Planner

last updated 04.28.2016

Primary Source

Imbach L, et al "Sleep-wake disorders persist 18 months after traumatic brain injury but remain underrecognized" Neurology 2016; DOI: 10.1212/WNL.0000000000002697.

This article was first published on MedPage Today and reprinted with permission from UBM Medica. Free registration is required.

Disclosures:

The authors report no conflict of interest relevant to the study.