Degree of cognitive impairment after 6 months dependent on TBI severity

Key Takeaways:

• The study included 1,057 individuals with TBI or orthopedic injury.
• Participants showed diverse impairment profiles in memory, speed and executive function.

In a cohort of adults with traumatic brain injury, level of impairment for those who exhibited cognitive impairment after 6 months was directly correlated to TBI severity, according to research from JAMA Network Open.

“Traumatic brain injuries are often associated with cognitive dysfunction in a dose-response manner relative to TBI severity,” Andrew M. Bryant, PhD, postdoctoral fellow in the department of neurosurgery at tge Medical College of Wisconsin Milwaukee, and colleagues wrote. “Patients with TBI often display reduced cognitive abilities followed by gradual recovery that is sometimes incomplete in the long term.”

As long-term patterns of cognitive dysfunction in the recovery period from TBI are less well known, Bryant and colleagues aimed to characterize the prevalence of cognitive dysfunction within and across cognitive domains 6 months after injury.

Their prospective longitudinal cohort study analyzed data from Transforming Research and Clinical Knowledge in TBI (TRACK-TBI) to include 1,057 individuals with TBI or orthopedic injury as measured by the Glasgow Coma Scale (mean age 39.3 years; 67% male) who presented at 18 Level 1 trauma center EDs or inpatient units in the United States within 24 hours of head injury and 327 controls without TBI (mean age, 38.4 years; 68% male).

Outcomes for the study were performance on standard neuropsychological tests including premorbid cognitive ability (NIH Toolbox Picture Vocabulary Test), verbal memory (Rey Auditory Verbal Learning Test), processing speed (Wechsler Adult Intelligence Scale 4th edition Processing Speed Index) and executive functioning (Trail Making Test).

According to results, those with TBI demonstrated performance within 1.5 standard deviations or better compared with the control group (49.3% [95% CI, 39.5%-59.2%] to 67.5% [95% CI, 63.7%-71.2%] showed no evidence of impairment).

Similarly, 64.4% (95% CI, 54.5%-73.4%) to 78.8% (95% CI, 75.4%-81.9%) of participants showed no cognitive decline.

Researchers also found that for individuals with evidence of either cognitive impairment or decline, diverse profiles of impairment existed across memory, speed and executive functioning domains (prevalence was >0 in each of the seven combinations of impairment across these three cognitive domains for most TBI subgroups).

“Prevalence data can guide clinical judgments about patients’ cognitive performance and aid in the design of interventions to help persons with TBI compensate for and recover from long-term cognitive dysfunction,” Bryant and colleagues wrote.