The effect of time on cognitive impairments after non-traumatic subarachnoid haemorrhage and after traumatic brain injury

Objectives: To compare the effect of time on cognitive impairments after Subarachnoid Haemorrhage and Traumatic Brain Injury and explore associations with baseline variables and global function. Methods: Patients with a Glasgow Coma Scale score of 3-13, were assessed at 3, 6 and 12 months post injury by use of BNIS for cognitive impairment, RLAS-R to categorise cognitive and behavioural function, Barthel Index to assess performance of daily living, HADS to screen for depression and anxiety, and EuroQoL-5D, LiSat-11 and Glasgow Outcome Scale Extended to assess global function. Results: BNIS T-scores did not differ significantly between groups and the proportion of patients with cognitive impairments was not significantly different at any time point. Cognition improved significantly between all time points in both groups except from 6 to 12 months after TBI. Generalised estimating equation showed non-significant signs of slower recovery of BNIS T-scores over time after SAH. Acute GCS scores were associated with BNIS T-scores after TBI but not after SAH. At 12 months, similar proportions of patients with SAH and TBI had good outcome. Conclusions: Cognitive improvements after SAH and TBI exhibit similarities and correlate with global function. GCS scores are associated with outcome after TBI but not after SAH.