Long-term outcome of medically confirmed and self-reported early traumatic brain injury in two nationwide samples

Is dementia more likely following traumatic brain injury? A systematic review

BACKGROUND

The association between traumatic brain injury (TBI) and dementia is controversial, and of growing importance considering the ageing demography of TBI.

OBJECTIVE

To review the scope and quality of the existing literature investigating the relationship between TBI and dementia.

METHODS

We conducted a systematic review following PRISMA guidelines. Studies that compared TBI exposure and dementia risk were included. Studies were formally assessed for quality with a validated quality-assessment tool.

RESULTS

44 studies were included in the final analysis. 75% (n = 33) were cohort studies and data collection was predominantly retrospective (n = 30, 66.7%). 25 studies (56.8%) found a positive relationship between TBI and dementia. Clearly defined and valid measures of assessing TBI history were lacking (case-control studies-88.9%, cohort studies-52.9%). Most studies failed to justify a sample size (case-control studies-77.8%, cohort studies-91.2%), blind assessors to exposure (case-control-66.7%) or blind assessors to exposure status (cohort-3.00%). Studies that identified a relationship between TBI and dementia had a longer median follow-up time (120 months vs 48 months, p = 0.022) and were more likely to use validated TBI definitions (p = 0.01). Studies which clearly defined TBI exposure (p = 0.013) and accounted for TBI severity (p = 0.036) were also more likely to identify an association between TBI and dementia. There was no consensus method by which studies diagnosed dementia and neuropathological confirmation was only available in 15.5% of studies.

CONCLUSIONS

Our review suggests a relationship between TBI and dementia, but we are unable to predict the risk of dementia for an individual following TBI. Our conclusions are limited by heterogeneity in both exposure and outcome reporting and by poor study quality. Future studies should; (a) use validated methods to define TBI, accounting for TBI severity; (b) follow consensus agreement on criteria for dementia diagnosis; and (c) undertake follow-up that is both longitudinal, to determine if there is a progressive neurodegenerative change or static post-traumatic deficit, and of sufficient duration.

Age, Ethnicity, and Socioeconomic Factors Impacting Infant and Toddler Fall-Related Trauma

OBJECTIVE

To characterize trauma-related falls in infants and toddlers aged 0 to 3 years over a 4-year period and develop a risk stratification model of causes of fall injuries.

METHODS

Data on falls of 0 to 3 year olds from 2009 to 2012 were identified from a Jerusalem tertiary hospital trauma registry (N = 422) and the National Trauma Registry of Israel (N = 4,131).

RESULTS

Almost half of falls occurred during the first year of life, and 57% of the children were Jewish. The majority of the children lived in low socioeconomic environments, both in the Jewish (59.2%) and Arab (97.6%) samples. Most (74%) of the falls resulted in head injury. A classification and regression tree analysis indicated that falls from furniture were the leading cause of injury in 0 to 12 month olds (estimated probability of 37.9%), whereas slipping is the leading cause in 13 to 36 month olds (estimated probability of 38.4%). Age and ethnicity emerged as the leading predictors of the nature of a fall; Injury Severity Score and the child's sex were secondary. Compared with the national data, Jerusalem children had a higher incidence of falls from buildings (9.3%; 2.4%), a higher moderate-severe Injury Severity Score (>16), a higher incidence of traumatic brain injury, and a longer hospital length of stay (P < 0.001).

CONCLUSIONS

The leading determinants of fall injuries in children below the age of 3 years are age, ethnicity, and low socioeconomic status. Future outreach community interventions should target these risk groups and be tailored to their defining characteristics.

Neurobehavioral Characteristics of Older Veterans With Remote Traumatic Brain Injury

OBJECTIVE

While traumatic brain injury (TBI) is common across the life span, the detailed neurobehavioral characteristics of older adults with prior TBI remain unclear. Our goal was to compare the clinical profile of older independently living veterans with and without prior TBI.

SETTING

Two veterans' retirement communities.

PARTICIPANTS

Seventy-five participants with TBI and 71 without (mean age = 78 years).

DESIGN

Cross-sectional.

MAIN MEASURES

TBI history was determined by the Ohio State University TBI Questionnaire. We assessed psychiatric and medical history via interviews and chart review and conducted measures assessing functional/lifestyle, psychiatric, and cognitive outcomes. Regression analyses (adjusted for demographics, diabetes, prior depression, substance abuse, and site) were performed to compare between TBI and non-TBI participants.

RESULTS

Compared with veterans without TBI, those with TBI had greater functional impairment (adjusted P = .05), endorsed more current depressive (adjusted P = .04) and posttraumatic stress disorder symptoms (adjusted P = .01), and had higher rates of prior depression and substance abuse (both adjusted Ps < .01). While composite memory and language scores did not differ between groups, participants with TBI performed worse on tests of executive functioning/processing speed (adjusted P = .01).

CONCLUSIONS

Our results suggest that TBI may have adverse long-term neurobehavioral consequences and that TBI-exposed adults may require careful screening and follow-up.

Chronic Histopathological and Behavioral Outcomes of Experimental Traumatic Brain Injury in Adult Male Animals

The purpose of this review is to survey the use of experimental animal models for studying the chronic histopathological and behavioral consequences of traumatic brain injury (TBI). The strategies employed to study the long-term consequences of TBI are described, along with a summary of the evidence available to date from common experimental TBI models: fluid percussion injury; controlled cortical impact; blast TBI; and closed-head injury. For each model, evidence is organized according to outcome. Histopathological outcomes included are gross changes in morphology/histology, ventricular enlargement, gray/white matter shrinkage, axonal injury, cerebrovascular histopathology, inflammation, and neurogenesis. Behavioral outcomes included are overall neurological function, motor function, cognitive function, frontal lobe function, and stress-related outcomes. A brief discussion is provided comparing the most common experimental models of TBI and highlighting the utility of each model in understanding specific aspects of TBI pathology. The majority of experimental TBI studies collect data in the acute postinjury period, but few continue into the chronic period. Available evidence from long-term studies suggests that many of the experimental TBI models can lead to progressive changes in histopathology and behavior. The studies described in this review contribute to our understanding of chronic TBI pathology.