Ce Skilbeck

Issues of loss to follow-up in a population study of traumatic brain injury (TBI) followed to 3 years post-trauma

Primary objective: To examine loss to follow-up (LTFU) using a population with traumatic brain injury (TBI) to include a range of severity and to follow participants to 3 years post-injury. Also investigated were cause of TBI and employment status. Research design: The research included 947 adults from a TBI population study. Data were obtained on severity, cause of TBI and employment status and participants were followed up at 1, 3, 6, 12, 24 and 36 months after injury. Chi-squared analyses were used to examine rates of loss to follow-up. Main outcome and results: Overall LTFU increased from 22% at 1 month post-injury to 81% at 3-year follow-up. Most participants (52%) were employed at the time of their TBI, with 39% of TBIs being motor vehicle related. Lower LTFU at 2 and 3 years post-TBI was significantly associated with severe TBI. Within the mTBI sub-group significantly higher LTFU at 1 and 6 months after injury and at 2 and 3 years post-injury was associated with TBI from assault. Those sustaining mTBI from a fall or sport-related injury showed significantly lower LTFU at the 6-month, 12-month and 2-year follow-up points. The highest LTFU was noted for unemployed participants, with retired participants showing the lowest rate.

Pre-injury estimates of subjective quality of life following traumatic brain injury

Primary objective: To compare the pre-injury subjective quality of life (SQOL) estimates of a representative sample of adults with TBI, using the Quality of Life Inventory (QOLI) with the measures generic US-based norms and identify a factor structure for the instrument within the local TBI population. Research design: A population-based, cross-sectional design conducted with data collected by the Neurotrauma Register of Tasmania (2003–2005). Methods and procedures: As soon as possible following their emergence from post-traumatic amnesia, 470 participants provided pre-injury estimates of their SQOL using the QOLI. The distribution of this sample was compared with the measures normative distribution. The sample was separated evenly into two groups (n = 235) for separate exploratory and confirmatory factor analyses. Main outcomes and results: Small differences were found between the pre-injury estimates and the QOLIs US-based normative distribution. Corrections were provided to clinical classification ranges for this population. Three factors were identified and confirmed for the QOLI in separate TBI samples. Conclusion: The results of this study support the use of the QOLI in measuring SQOL in TBI rehabilitation and outcomes research.

Exploring the effect of the apolipoprotein E (APOE) gene on executive function, working memory, and processing speed during the early recovery period following traumatic brain injury

ABSTRACT Introduction: There is evidence that the e4 allele of the apolipoprotein E (APOE) gene is detrimental to cognitive function, but results from traumatic brain injury (TBI) populations are mixed. A possible explanation is that APOEe2 carriers have routinely been incorporated into APOEe4 and non-e4 groups, despite APOEe2 being proposed to have an ameliorative effect. Our primary aim was to investigate the influence of APOEe4 on cognitive impairment during early recovery following TBI, excluding the potential confound of APOEe2 possession. A secondary objective was to explore whether APOEe4 displays more pronounced effects in moderate to severe TBI and to consider the potential postinjury protective influence of the APOEe2 allele. Method: Participants who recently sustained a TBI (posttraumatic amnesia > 5 minutes) were assessed on measures of information processing speed, executive function, and working memory upon remission of posttraumatic amnesia. APOE genotype was determined by buccal saliva DNA extraction (APOEe4 n = 37, APOEe3 n = 92, APOEe2 n = 13). Results: Stepwise multiple regressions were performed to compare APOEe4 carriers to APOEe3 homozygotes, with injury severity, age, and estimated premorbid IQ included in the first step. This model was found to significantly predict performance on all tasks, accounting for 17.3–24.3% of the variance. When APOEe4 status was added for the second step, there were no significant changes on any tasks (additional variance <1%). The effect of APOEe4 in moderate to severe TBI and the effect of APOEe2 were explored by analysis of covariance (ANCOVA), with no significant effects revealed. Conclusions: It is unlikely that APOE genotype influences cognitive function in the initial recovery period following TBI, regardless of injury severity. However, a more nuanced and long-term exploration of the effect of APOE genotype in the TBI population is warranted.

Impaired National Adult Reading Test (NART) performance in traumatic brain injury

Some research suggests the National Adult Reading Test (NART) may be impaired by traumatic brain injury (TBI). To investigate this, a prospective, longitudinal study included 214 Australian TBI participants given the NART within 1 month post-injury, and at 6 and 12 months. TBI severity, age, education, sex, and mood (HADS) were examined, and significant improvement in NART- estimated full-scale IQ (FSIQ) was noted over time (p < .001). A three-way interaction of time, severity, and age showed younger and middle-aged mild TBI sub-groups improved significantly between 1 and 6 months post-injury, and the older sub-group between 6 and 12 months. In severe TBI, significant NART-estimated FSIQ improvement was noted only for the middle-aged and only between 6 and 12 months post-TBI. NART administration soon after TBI underestimated premorbid IQ, with a complex relationship between time post-injury, severity, and age. Participants with a longer education had higher NART FSIQs, although those with less education gained more IQ points between initial and 6 months assessments suggesting higher initial NART impairment. Regression equations predicted NART FSIQ at 6 (R = 0.813) and 12 months post-trauma (R = 0.792–0.845), their effectiveness being confirmed via cross-validation. No significant relationships were noted between NART-estimated FSIQ and mood variables, or evidence of significant gains in estimated FSIQ between 12 and 24 months post-injury.

Growth Mixture Modeling of Depression Symptoms Following Traumatic Brain Injury

Growth Mixture Modeling (GMM) was used to investigate the longitudinal trajectory of groups (classes) of depression symptoms, and how these groups were predicted by the covariates of age, sex, severity, and length of hospitalization following Traumatic Brain Injury (TBI) in a group of 1074 individuals (696 males, and 378 females) from the Royal Hobart Hospital, who sustained a TBI. The study began in late December 2003 and recruitment continued until early 2007. Ages ranged from 14 to 90 years, with a mean of 35.96 years (SD = 16.61). The study also examined the associations between the groups and causes of TBI. Symptoms of depression were assessed using the Hospital Anxiety and Depression Scale within 3 weeks of injury, and at 1, 3, 6, 12, and 24 months post-injury. The results revealed three groups: low, high, and delayed depression. In the low group depression scores remained below the clinical cut-off at all assessment points during the 24-months post-TBI, and in the high group, depression scores were above the clinical cut-off at all assessment points. The delayed group showed an increase in depression symptoms to 12 months after injury, followed by a return to initial assessment level during the following 12 months. Covariates were found to be differentially associated with the three groups. For example, relative to the low group, the high depression group was associated with more severe TBI, being female, and a shorter period of hospitalization. The delayed group also had a shorter period of hospitalization, were younger, and sustained less severe TBI. Our findings show considerable fluctuation of depression over time, and that a non-clinical level of depression at any one point in time does not necessarily mean that the person will continue to have non-clinical levels in the future. As we used GMM, we were able to show new findings and also bring clarity to contradictory past findings on depression and TBI. Consequently, we recommend the use of this approach in future studies in this area.

Is APOE ε4 associated with poorer cognitive outcome following traumatic brain injury? A meta-analysis.

OBJECTIVE Cognitive impairment is a common sequelae of traumatic brain injury (TBI); however, predicting who will experience poorer outcomes remains challenging. A potential risk factor that has gained attention is the APOE gene, with the ε4 allele hypothesized to have a detrimental effect on post-TBI cognitive outcome. The aim of this meta-analysis was to evaluate the effect of APOE ε4 both in terms of general cognitive function and within specific domains known to be prone to impairment following TBI (executive function, working memory, verbal memory and visual memory). METHOD A literature search was undertaken in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA), resulting in the inclusion of 10 studies (ε4-carriers n = 143, noncarriers n = 510). Neuropsychological tasks were identified, and Cohens d was calculated and pooled. Meta-analyses were conducted on general cognitive functioning and for the specific cognitive domains of interest. RESULTS No significant differences were found between APOE ε4-carriers or noncarriers, either in general cognitive function or in the cognitive domains of executive function, working memory, verbal memory, or visual memory. CONCLUSIONS This meta-analysis indicates that APOE ε4 does not have a detrimental effect on cognitive performance following TBI. We propose that the relationship between APOE and cognitive function following TBI is complex, and a more-nuanced exploration of APOE genotypes is needed. (PsycINFO Database Record

Risk factors for executive function difficulties in preschool and early school-age preterm children

To investigate the relationship between executive functioning and social and perinatal risk factors in four‐ to five‐year‐old preterm children.

The figure copy and recall test of the Adult Memory and Information Processing Battery: inter-rater reliability.

OBJECTIVE Examined inter-rater reliability of the scoring of the Figure Copy and Recall subtest of the Adult Memory and Information Processing Battery (AMIPB; Coughlan & Hollows, 1985). METHOD Figure Copy and Recall tests of 56 individuals referred for neuropsychological assessment were independently scored by three experienced neuropsychologists and the scores correlated. Detailed analysis of reasons for scoring discrepancies was carried out. RESULTS Raters scores were highly correlated in relation to both forms of the tests. The major source of discrepancy was errors in accuracy. CONCLUSIONS Results indicate that the AMIPB manual instructions are sufficiently detailed to obtain good inter-rater reliability when the raters are experienced clinicians. Further research using trainees or assistant psychologists is suggested.

Service utilisation in a public post-acute rehabilitation unit following traumatic brain injury

Traumatic brain injury (TBI) causes disability in a proportion of survivors across the spectrum of injury severity. Previous research suggests physical changes are the primary focus of rehabilitation, although cognitive, emotional and behavioural difficulties cause greater concern in the long-term. There is little information about services accessed by those with mild injuries, who often have no physical disabilities. This study investigated factors determining service utilisation in a population-based sample which included 52% mild injuries (PTA ≤ 24 hours). Chi-squares and t-tests were used to examine the impact of demographic, clinical, psychological and physical variables on referral of 175 TBI patients to clinical disciplines in a public, community-based rehabilitation facility in Hobart, Tasmania. Increased service intensity (total disciplines referred to), was associated with greater injury severity (p = .006) and previous TBI (p = .041). Less traditional rehabilitation services (nursing, psychology) received more referrals than traditional disciplines (physiotherapy, occupational therapy, social work). Referral to physiotherapy and occupational therapy was associated with greater injury severity, functional dependence, hospitalisation and older age. Referral to nursing, psychology and social work was associated with more post-concussion symptoms, younger age, anxiety, depression and assault-related injury. The large number of referrals to psychology strengthens the case for including it as a core rehabilitation discipline.