Functional level after Traumatic Brain Injury

Abstract

Objectives: The objectives of the thesis were to describe the functional level (papers I and II) and self awareness of functional deficits (paper III) after moderate and severe Traumatic Brain Injury (TBI), and to evaluate the predictive impact of pre-injury and injury-related factors on functional level (papers I, II) and awareness of functional deficits (paper III). Material and methods: Papers I-II were cohort studies of 55 TBI patients (moderate = 21, severe = 34) and 65 TBI patients (moderate = 21, severe = 44). Their functional level was assessed by FIM (Functional Independence Measure) at admission and discharge from in-hospital sub-acute rehabilitation (paper I), and by FIM and GOSE (Glasgow Outcome Scale Extended) 12 months after injury (paper II). Possible predictors of FIM at discharge (paper I) and at 12 months (paper II) were analyzed in a regression model. Paper III was a cohort study of 50 TBI patients (moderate = 17, severe = 33) assessed by Patient Competence Rating Scale (PCRS) 12 months after injury. Awareness of functional deficits was investigated by subtracting PCRS relative ratings (PCRS-R) from PCRS patient ratings (PCRS-P). Predictors of PCRS-P ratings and differences between patient and relative ratings were analyzed in a regression model. Results: At discharge from sub-acute rehabilitation, on average 53 (± 24) days post-injury, the FIM motor and cognitive scores had improved in both moderate and severe TBI patients, but 57% of those with moderate TBI and 91% of those with severe TBI still had impaired motor and cognitive function with a FIM score < 126 (paper I). The activity limitations were mild (FIM109-126 = functionally independent) in 95% of moderate TBI patients and in 62% of severe TBI patients. During the period from discharge to 12 months after injury, the FIM motor score improved in severe TBI but not in moderate TBI patients, and the FIM cognitive score did not improve in any of the groups (paper II). At 12 months, 19% of moderate TBI patients and 40% of severe TBI patients still had impaired motor and cognitive function as assessed by FIM. The activity limitations were mild (FIM 109-126) in 95% with moderate and in 74% with severe TBI (paper II). Functional global outcome as assessed by GOSE showed “good recovery” in 52% with moderate TBI versus 33% in severe TBI, “moderate disability” in 33% with moderate TBI versus 31% in severe TBI, and “severe disability” in 14% with moderate TBI versus 36% in severe TBI. Longer stays at the rehabilitation unit, a short PTA period and a high GCS score at admission to rehabilitation were positive predictors of functional level (FIM) at discharge and 12 months follow-up (papers I and II). Self-perceived function 12 months after injury was assessed by PCRS–P and compared to relative-perceived function (PCRS-R) with mean scores of 122/150 (95% CI = 115; 129) and 117/150 (95% CI = 110; 125), p = 0.93. The patients scored themselves slightly higher than their relatives in the domains of Activities of Daily Living (ADL) and cognitive function, but not in the domains of interpersonal and emotional function. The strongest predictor of PCRSP was GCS at admission to rehabilitation (GCS rehab) (B = 3.314, p = 0.008), while others were GCS acute (admission acute hospital) (B = -1.771, p = 0.044), age (B = 0.510, p = 0.002), and PTA duration (B = -0.330, p < 0.001). Predictors of differences in PCRS-P and PCRS-R (overestimation of own function) were GCS acute (B = -3.530, p = 0.001), age (B = 0.304, p = 0.036), and PTA (B = -0.160, p = 0.020). Analyses of predictors in different domains showed that lower GCS rehabilitation predicted overestimation of ADL functioning (B = -0.526, p = 0.037), lower GCS acute was the strongest predictor of overestimation of cognition (B = -0.851, p = 0.001), and of emotional regulation (B = -1.042, p = 0.042) while being married (12 months post-injury) was the strongest negative predictor of overestimation of interpersonal functioning (B = -3.622, p = 0.015). Conclusions: The greatest improvement after moderate and severe TBI was in the sub-acute phase during the stay in a specialised rehabilitation unit. A short PTA period, a high GCS score and FIM score at admission to rehabilitation, and a longer stay in the rehabilitation unit were positive predictors of functional level at discharge and 12 months after injury. Residual disability was reported in 48% of moderate TBI patients measured by GOSE 12 months post injury. A slight lack of awareness of dysfunction in the domains of ADL and cognitive function were reported 12 months after injury. Higher age was a predictor of more severe awareness deficits 12 months after injury. More severe injury (longer PTA) was a predictor of low self-perceived function though negatively associated with degree of awareness deficits 12 months after injury.