White matter disruption is an important determinant of cognitive impairment after brain injury, but conventional neuroimaging underestimates its extent. In contrast, diffusion tensor imaging provides a validated and sensitive way of identifying the impact of axonal injury. The relationship between cognitive impairment after traumatic brain injury and white matter damage is likely to be complex. We applied a flexible technique—tract-based spatial statistics—to explore whether damage to specific white matter tracts is associated with particular patterns of cognitive impairment. The commonly affected domains of memory, executive function and information processing speed were investigated in 28 patients in the post-acute/chronic phase following traumatic brain injury and in 26 age-matched controls. Analysis of fractional anisotropy and diffusivity maps revealed widespread differences in white matter integrity between the groups. Patients showed large areas of reduced fractional anisotropy, as well as increased mean and axial diffusivities, compared with controls, despite the small amounts of cortical and white matter damage visible on standard imaging. A stratified analysis based on the presence or absence of microbleeds (a marker of diffuse axonal injury) revealed diffusion tensor imaging to be more sensitive than gradient-echo imaging to white matter damage. The location of white matter abnormality predicted cognitive function to some extent. The structure of the fornices was correlated with associative learning and memory across both patient and control groups, whilst the structure of frontal lobe connections showed relationships with executive function that differed in the two groups. These results highlight the complexity of the relationships between white matter structure and cognition. Although widespread and, sometimes, chronic abnormalities of white matter are identifiable following traumatic brain injury, the impact of these changes on cognitive function is likely to depend on damage to key pathways that link nodes in the distributed brain networks supporting high-level cognitive functions.

Traumatic brain injury often results in cognitive impairments that limit recovery. The underlying pathophysiology of these impairments is uncertain, which restricts clinical assessment and management. Here, we use magnetic resonance imaging to test the hypotheses that: (i) traumatic brain injury results in abnormalities of functional connectivity within key cognitive networks; (ii) these changes are correlated with cognitive performance; and (iii) functional connectivity within these networks is influenced by underlying changes in structural connectivity produced by diffuse axonal injury. We studied 20 patients in the chronic phase after traumatic brain injury compared with age-matched controls. Network function was investigated in detail using functional magnetic resonance imaging to analyse both regional brain activation, and the interaction of brain regions within a network (functional connectivity). We studied patients during performance of a simple choice-reaction task and at 'rest'. Since functional connectivity reflects underlying structural connectivity, diffusion tensor imaging was used to quantify axonal injury, and test whether structural damage correlated with functional change. The patient group showed typical impairments in information processing and attention, when compared with age-matched controls. Patients were able to perform the task accurately, but showed slow and variable responses. Brain regions activated by the task were similar between the groups, but patients showed greater deactivation within the default mode network, in keeping with an increased cognitive load. A multivariate analysis of 'resting' state functional magnetic resonance imaging was then used to investigate whether changes in network function were present in the absence of explicit task performance. Overall, default mode network functional connectivity was increased in the patient group. Patients with the highest functional connectivity had the least cognitive impairment. In addition, functional connectivity at rest also predicted patterns of brain activation during later performance of the task. As expected, patients showed widespread white matter damage compared with controls. Lower default mode network functional connectivity was seen in those patients with more evidence of diffuse axonal injury within the adjacent corpus callosum. Taken together, our results demonstrate altered patterns of functional connectivity in cognitive networks following injury. The results support a direct relationship between white matter organization within the brain's structural core, functional connectivity within the default mode network and cognitive function following brain injury. They can be explained by two related changes: a compensatory increase in functional connectivity within the default mode network; and a variable degree of structural disconnection that modulates this change in network function.

The consequences of traumatic brain injury (TBI) for health-related quality of life (HRQoL) are poorly investigated, and a TBI-specific instrument has not previously been available. The cross-cultural development of a new measure to assess HRQoL after TBI is described.An international TBI Task Force derived a conceptual model from previous work, constructed an initial item bank of 148 items, and then reduced the item set through two successive multi-centre validation studies. The first study with eight language versions of the QOLIBRI recruited 1528 participants with TBI and the second with six language versions 921 participants. The data from 795 participants from the second study who had complete GCS and GOS data were used to finalise the instrument.The final version of the QOLIBRI consists of 37 items in six scales. Satisfaction is assessed in the areas of "Cognition", "Self", "Daily life and Autonomy", and "Social Relationships" and feeling bothered by "Emotions "and "Physical Problems". The QOLIBRI scales meet standard psychometric criteria (internal consistency,  = .75 to .89, test-retest reliability, r tt = .78 to .85). Test-retest reliability (r tt = 0.68 to 0.87) as well as internal consistency ( = .81 to .91) was also good in a subgroup of participants with lower cognitive performance. Although there is one strong HRQoL factor, a six scale structure explaining additional variance was validated by exploratory and confirmatory factor analyses and with Rasch modelling.The QOLIBRI is a new cross-culturally developed instrument for assessing HRQoL after TBI that fulfils standard psychometric criteria. It is potentially useful for clinicians and researchers conducting clinical trials, assessing the impact of rehabilitation or other interventions, or carrying out epidemiological surveys.

The QOLIBRI (Quality of Life after Brain Injury) is a novel health-related quality-of-life (HRQoL) instrument specifically developed for traumatic brain injury (TBI). It provides a profile of HRQoL in six domains together with an overall score. Scale validity and factors associated with HRQoL were investigated in a multi-center international study. A total of 795 adults with brain injury were studied from 3 months to 15 years post-injury. The majority of participants (58%) had severe injuries as assessed by 24-h worst Glasgow Coma Scale (GCS) score. Systematic relationships were observed between the QOLIBRI and the Glasgow Outcome Scale-Extended (GOSE), Hospital Anxiety and Depression Scale (HADS), and SF-36. Within each scale patients with disability reported having low HRQoL in two to three times as many areas as those who had made a good recovery. The main correlates of the total QOLIBRI score were emotional state (HADS depression and anxiety), functional status (amount of help needed and outcome on the GOSE), and comorbid health conditions. Together these five variables accounted for 58% of the variance in total QOLIBRI scores. The QOLIBRI is the first tool developed to assess disease-specific HRQoL in brain injury, and it contains novel information not given by other currently available assessments.

Objective: Evaluation of multidisciplinary community based outreach rehabilitation after severe traumatic brain injury (TBI). Methods: A randomised controlled trial compared outreach treatment (mean of two sessions a week for 27.3 (SD 19.1) weeks) in community settings such as participants' homes, day centres, or workplaces, with provision of written information detailing alternative resources. Follow up for an average of 24.8 months after initial allocation was by a blinded independent assessor. Participants were aged 16-65, had sustained severe TBI between 3 months and 20 years previously, and had no other neurological conditions. Of 110 initially allocated, 48 outreach and 46 information participants were successfully followed up. Primary outcome measures (Barthel index (BI) and the brain injury community rehabilitation outcome-39 (BICRO-39)) focused on levels of activity and participation. Secondary measures were the functional independence measure and the functional assessment measure (FIM+FAM) and, in a subgroup of 46 participants, the hospital anxiety and depression scale. Analyses were non-parametric. Results: outreach participants were significantly more likely to show gains on the BI and the BICRO-39 total score and self organisation and psychological wellbeing subscales. There were likewise strong trends (p<0.10) for BICRO personal care and mobility, and on the FIM+FAM for personal care and cognitive functions. Differential improvements were not seen for indices of socialising, productive employment, anxiety, or depression. Median changes on individual subscales were small, reflecting the diversity of the clinical population; however, 40% of outreach but only 20% of information participants made a clinically significant improvement of 2+ points on at least one BICRO-39 scale. Time since injury was unrelated to the magnitude of gains. Conclusions: This is the first RCT of multidisciplinary community rehabilitation after severe TBI, and suggests that even years after injury it can yield benefits which outlive the active treatment period.