Objectives: To determine the rates of cognitive impairment 1 year after severe traumatic brain injury (TBI) and to examine the influence of demographic, injury severity, rehabilitation, and subacute functional outcomes on cognitive outcomes 1 year after severe TBI.
Setting: National multicenter cohort study over 2 years.
Participants: Patients (N = 105), aged 16 years or older, with Glasgow Coma Scale score of 3 to 8 and Galveston Orientation and Amnesia Test score of more than 75.
Main Measures: : Neuropsychological tests representing cognitive domains of Executive Functions, Processing Speed, and Memory. Injury severity included Rotterdam computed tomography score, Glasgow Coma Scale score, and posttraumatic amnesia (PTA) duration, together with length of rehabilitation and Glasgow Outcome Scale–Extended score.
Results: In total, 67% of patients with severe TBI had cognitive impairment. Executive Functions, Processing Speed, and Memory were impaired in 41%, 58%, and 57% of patients, respectively. Using multiple regression analysis, Processing Speed was significantly related to PTA duration, Glasgow Outcome Scale–Extended score, and length of inpatient rehabilitation (R2 = 0.30); Memory was significantly related to Glasgow Outcome Scale–Extended score (R2 = 0.15); and Executive Functions to PTA duration (R2 = 0.10). Rotterdam computed tomography and Glasgow Coma Scale scores were not associated with cognitive functioning at 1 year postinjury.
Conclusion: Findings highlight cognitive consequences of severe TBI, with nearly two-thirds of patients showing cognitive impairments in at least 1 of 3 cognitive domains. Regarding injury severity predictors, only PTA duration was related to cognitive functioning.
Department of Research, Sunnaas Rehabilitation Hospital, Nesoddtangen, Norway (Drs Sigurdardottir and Schanke); Institute of Health and Society, Research Centre for Habilitation and Rehabilitation Models and Services (CHARM) (Drs Sigurdardottir and Andelic), Faculty of Medicine (Dr Roe), and Department of Psychology, Faculty of Social Sciences (Dr Schanke), University of Oslo, Oslo, Norway; Division of Surgery and Clinical Neuroscience, Department of Physical Medicine and Rehabilitation (Drs Andelic, Roe, and Holthe), and Department of Neuroradiology (Dr Jerstad), Oslo University Hospital, Oslo, Norway; Department of Physical Medicine and Rehabilitation, Haukeland University Hospital, Bergen, Norway (Dr Wehling); Department of Biological and Medical Psychology, University of Bergen, Bergen, Norway (Dr Wehling); Department of Rehabilitation, University Hospital of North Norway, Tromso, Norway (Drs Anke and Aslaksen); Departments of Clinical Medicine (Dr Anke) and Psychology (Dr Aslaksen), Faculty of Health Sciences, University of Tromso, Tromso, Norway; Department of Physical Medicine and Rehabilitation, St Olavs Hospital, Trondheim, Norway (Dr Skandsen); and Department of Neuroscience, Faculty of Medicine, Norwegian University of Science and Technology (NTNU), Trondheim, Norway (Dr Skandsen).
Corresponding Author: Solrun Sigurdardottir, CPsych, PhD, Department of Research, Sunnaas Rehabilitation Hospital, 1450 Nesoddtangen, Norway (firstname.lastname@example.org).
The authors thank the Trauma Registry at Oslo University Hospital, Ulleval, and Haukeland University Hospitals for providing data regarding injury severity. The authors also thank all the neuropsychologists who were involved in collecting neuropsychological data and all the participants in this national research project.
The authors declare no conflicts of interest.