The course and prognostic factors of cognitive outcomes after traumatic brain injury: A systematic review and meta-analysis

A PROGRESS-driven approach to cognitive outcomes after traumatic brain injury: A study protocol for advancing equity, diversity, and inclusion through knowledge synthesis and mobilization

Evidence syntheses for advancing equitable traumatic brain injury (TBI) research, policy, and practice presents formidable challenges. Research and clinical frameworks are currently not specific to equity, diversity, and inclusion considerations, despite evidence that persons with TBI live in societies in which power imbalances and systems of social dominance may privilege some people and marginalize others. The present protocol outlines a strategy for a research program, supported by the Canadian Institutes of Health Research, that explores the integration of PROGRESS-Plus parameters in research with the goal of advancing open-science databases and tools to improve our understanding of equity in cognitive and brain health outcomes in TBI. PROGRESS-Plus is a framework outlining social, economic, and cultural parameters that may influence health opportunities and outcomes (e.g., place of residence, race, occupation, gender, etc.). A multistep research program is proposed to support three objectives: (1) organizing existing data on TBI-induced changes in cognition and brain health into a template to facilitate future research, including research using machine learning techniques; (2) updating published evidence with a more rigorous approach to the consideration of PROGRESS-Plus parameters; and (3) mobilizing knowledge on the current state of evidence that is relevant, equitable, and accessible. This program facilitates partnerships with knowledge users across clinical, research, academic, and community sectors to address the three research objectives through a unifying workflow of exchange, synthesis, and knowledge mobilization. We anticipate that this global collaboration between topic experts and community leaders in equity in brain health will add significant value to the field of TBI by promoting equity-transformative advancements in knowledge synthesis, policy, and practice.

A literature review of outcome and treatment options after acquired brain injury: Suggestions for adult offenders using knowledge from the general population

BACKGROUND

Acquired brain injury (ABI) is a major health problem, often with negative effects on behaviour and mental health as well as cognition. Prevalence of ABI is exceptionally high among offenders and increases their re-offending risk. Information on risk factors for ABI and its outcomes among offenders that could guide effective treatment for them is, nevertheless, scarce and dispersed. However, there is a more substantial literature about the general population that could inform work with brain-injured offenders, especially when selecting for samples or subgroups with similar relevant characteristics, such as lower socio-economic status (SES), pre-injury lower tested intelligence score (<85) and pre-injury mental health problems.

AIMS

To explore brain injury data from non-offender samples of otherwise similar socio-economic and mental health and ability characteristics to offenders then, first, to describe their untreated outcomes and, secondly, outcomes after frequently used interventions in these circumstances, noting factors associated with their effectiveness.

METHOD

Three databases were systematically searched for the years 2010-2022; first, using terms for brain injury or damage and cognitive (dys)function, mental health or quality of life. Second, in a separate search, we used these terms and terms for interventions and rehabilitation. In the second review, studies were selected for clear, distinguishable data on age, sex, SES and lifestyle factors to facilitate inferences for offenders. A narrative analytical approach was adopted for both reviews.

RESULTS

Samples with characteristics that are typical in offender groups, including lower SES, lower pre-injury intelligence quotient (<85), prior cognitive impairments and prior mental health problems, had poorer cognitive and behavioural outcomes following ABI than those without such additional problems, together with lower treatment adherence. With respect to treatment, adequate motivation and self-awareness were associated with better cognitive and behavioural outcomes than when these were low or absent, regardless of the outcome measured.

CONCLUSIONS

More complex pre-injury mental health problems and social disadvantages typical of offenders are associated with poorer post-brain injury recovery. This paper adds to practical knowledge by bringing together work that follows specific outcome trajectories. Overall, succesful ABI-interventions in the general population that aim at pre-injury difficulties comparable to those seen among offenders, show that personalising injury-specific treatments and taking account of these difficulties, maximised positive outcomes.

Cognition and post-concussive symptom status after pediatric mild traumatic brain injury

Cognitive impairment and post-concussive symptoms (PCS) represent hallmark sequelae of pediatric mild traumatic brain injury (pmTBI). Few studies have directly compared cognition as a function of PCS status longitudinally. Cognitive outcomes were therefore compared for asymptomatic pmTBI, symptomatic pmTBI, and healthy controls (HC) during sub-acute (SA; 1-11 days) and early chronic (EC; approximately 4 months) post-injury phases. We predicted worse cognitive performance for both pmTBI groups relative to HC at the SA visit. At the EC visit, we predicted continued impairment from the symptomatic group, but no difference between asymptomatic pmTBI and HCs. A battery of clinical (semi-structured interviews and self-report questionnaires) and neuropsychological measures were administered to 203 pmTBI and 139 HC participants, with greater than 80% retention at the EC visit. A standardized change method classified pmTBI into binary categories of asymptomatic or symptomatic based on PCS scores. Symptomatic pmTBI performed significantly worse than HCs on processing speed, attention, and verbal memory at SA visit, whereas lower performance was only present for verbal memory for asymptomatic pmTBI. Lower performance in verbal memory persisted for both pmTBI groups at the EC visit. Surprisingly, a minority (16%) of pmTBI switched from asymptomatic to symptomatic status at the EC visit. Current findings suggest that PCS and cognition are more closely coupled during the first week of injury but become decoupled several months post-injury. Evidence of lower performance in verbal memory for both asymptomatic and symptomatic pmTBI suggests that cognitive recovery may be a process separate from the resolution of subjective symptomology.

The association between symptom burden and processing speed and executive functioning at 4 and 12 weeks following pediatric concussion

OBJECTIVES

Symptoms and cognition are both utilized as indicators of recovery following pediatric concussion, yet their interrelationship is not well understood. This study aimed to investigate: 1) the association of post-concussion symptom burden and cognitive outcomes (processing speed and executive functioning [EF]) at 4 and 12 weeks after pediatric concussion, and 2) the moderating effect of sex on this association.

METHODS

This prospective, multicenter cohort study included participants aged 5.00-17.99 years with acute concussion presenting to four Emergency Departments of the Pediatric Emergency Research Canada network. Five processing speed and EF tasks and the Post-Concussion Symptom Inventory (PCSI; symptom burden, defined as the difference between post-injury and retrospective [pre-injury] scores) were administered at 4 and 12 weeks post-concussion. Generalized least squares models were conducted with task performances as dependent variables and PCSI and PCSI*sex interaction as the main predictors, with important pre-injury demographic and injury characteristics as covariates.

RESULTS

311 children (65.0% males; median age = 11.92 [IQR = 9.14-14.21 years]) were included in the analysis. After adjusting for covariates, higher symptom burden was associated with lower Backward Digit Span (χ2 = 9.85, p = .043) and Verbal Fluency scores (χ2 = 10.48, p = .033) across time points; these associations were not moderated by sex, ps ≥ .20. Symptom burden was not associated with performance on the Coding, Continuous Performance Test, and Color-Word Interference scores, ps ≥ .17.

CONCLUSIONS

Higher symptom burden is associated with lower working memory and cognitive flexibility following pediatric concussion, yet these associations were not moderated by sex. Findings may inform concussion management by emphasizing the importance of multifaceted assessments of EF.

Delayed tranexamic acid after traumatic brain injury impedes learning and memory: Early tranexamic acid is favorable but not in sham animals

BACKGROUND

Early but not late tranexamic acid (TXA) after TBI preserves blood-brain-barrier integrity, but it is unclear if and how dose timing affects cognitive recovery beyond hours postinjury. We hypothesized that early (1 hour post-TBI) but not late (24 hours post-TBI) TXA administration improves cognitive recovery for 14 days.

METHODS

CD1 male mice (n = 25) were randomized to severe TBI (injury [I], by controlled cortical impact) or sham craniotomy (S) followed by intravenous saline at 1 hour (placebo [P1]) or 30 mg/kg TXA at 1 hour (TXA1) or 24 hours (TXA24). Daily body weights, Garcia Neurological Test scores, brain/lung water content, and Morris water maze exercises quantifying swimming traffic in the platform quadrant (zone [Z] 1) and platform area (Z5) were recorded for up to 14 days.

RESULTS

Among injured groups, I-TXA1 demonstrated fastest weight gain for 14 days and only I-TXA1 showed rapid (day 1) normalization of Garcia Neurological Test ( p = 0.01 vs. I-P1, I-TXA24). In cumulative spatial trials, compared with I-TXA1, I-TXA24 hindered learning (distance to Z5 and % time in Z1, p < 0.05). Compared with I-TXA1, I-TXA24 showed poorer memory with less Z5 time (0.51 vs. 0.16 seconds, p < 0.01) and Z5 crossing frequency. Unexpectedly, TXA in uninjured animals (S-TXA1) displayed faster weight gain but inferior learning and memory.

CONCLUSION

Early TXA appears beneficial for cognitive and behavioral outcomes following TBI, although administration 24 hours postinjury consistently impairs cognitive recovery. Tranexamic acid in sham animals may lead to adverse effects on cognition.

Prognosis and enhancement of recovery in disorders of consciousness

Disorders of consciousness after severe brain injury encompass conditions of coma, vegetative state/unresponsive wakefulness syndrome, and minimally conscious state. DoC clinical presentation pose perplexing challenges to medical professionals, researchers, and families alike. The outcome is uncertain in the first weeks to months after a brain injury, with families and medical providers often making important decisions that require certainty. Prognostication for individuals with these conditions has been the subject of intense scientific investigation that continues to strive for valid prognostic indicators and algorithms for predicting recovery of consciousness. This manuscript aims to provide an overview of the current clinical landscape surrounding prognosis and optimizing recovery in DoC and the current and future research that could improve prognostic accuracy after severe brain injury. Improved understanding of these factors will aid healthcare professionals in providing optimal care, fostering hope, and advocating for ethical practices in the management of individuals with DoC.

Profiles of Cognitive Functioning at 6 Months After Traumatic Brain Injury Among Patients in Level I Trauma Centers: A TRACK-TBI Study

Importance

Cognitive dysfunction is common after traumatic brain injury (TBI), with a well-established dose-response relationship between TBI severity and likelihood or magnitude of persistent cognitive impairment. However, patterns of cognitive dysfunction in the long-term (eg, 6-month) recovery period are less well known.

Objective

To characterize the prevalence of cognitive dysfunction within and across cognitive domains (processing speed, memory, and executive functioning) 6 months after injury in patients with TBI seen at level I trauma centers.

Design, Setting, and Participants

This prospective longitudinal cohort study used data from Transforming Research and Clinical Knowledge in TBI (TRACK-TBI) and included patients aged 17 years or older presenting at 18 US level I trauma center emergency departments or inpatient units within 24 hours of head injury, control individuals with orthopedic injury recruited from the same centers, and uninjured friend and family controls. Participants were enrolled between March 2, 2014, and July 27, 2018. Data were analyzed from March 5, 2020, through October 3, 2023.

Exposures

Traumatic brain injury (Glasgow Coma Scale score of 3-15) or orthopedic injury.

Main Outcomes and Measures

Performance on standard neuropsychological tests, including premorbid cognitive ability (National Institutes of Health Toolbox Picture Vocabulary Test), verbal memory (Rey Auditory Verbal Learning Test), processing speed (Wechsler Adult Intelligence Scale [4th edition] Processing Speed Index), and executive functioning (Trail Making Test).

Results

The sample included 1057 persons with TBI (mean [SD] age, 39.3 [16.4] years; 705 [67%] male) and 327 controls without TBI (mean [SD] age, 38.4 [15.1] years; 222 [68%] male). Most persons with TBI demonstrated performance within 1.5 SDs or better of the control group (49.3% [95% CI, 39.5%-59.2%] to 67.5% [95% CI, 63.7%-71.2%] showed no evidence of impairment). Similarly, 64.4% (95% CI, 54.5%-73.4%) to 78.8% (95% CI, 75.4%-81.9%) of participants demonstrated no evidence of cognitive decline (defined as performance within 1.5 SDs of estimated premorbid ability). For individuals with evidence of either cognitive impairment or decline, diverse profiles of impairment across memory, speed, and executive functioning domains were observed (ie, the prevalence was >0 in each of the 7 combinations of impairment across these 3 cognitive domains for most TBI subgroups).

Conclusions and Relevance

In this cohort study of patients seen at level I trauma centers 6 months after TBI, many patients with TBI demonstrated no cognitive impairment. Impairment was more prevalent in persons with more severe TBI and manifested in variable ways across individuals. The findings may guide future research and treatment recommendations.

Associations Between Traumatic Brain Injury and Cognitive Decline Among Older Male Veterans: A Twin Study

BACKGROUND AND OBJECTIVES

Traumatic brain injuries (TBIs) are associated with increased risk of dementia, but whether lifetime TBI influences cognitive trajectories in later life is less clear. Cognitive interventions after TBI may improve cognitive trajectories and delay dementia. Because twins share many genes and environmental factors, we capitalize on the twin study design to examine the association between lifetime TBI and cognitive decline.

METHODS

Participants were members of the National Academy of Sciences-National Research Council's Twin Registry of male veterans of World War II with self or proxy-reported history of TBI and with up to 4 observations over 12 years of the modified Telephone Interview for Cognitive Status (TICS-m). We used linear random-effects mixed models to analyze the association between TBI and TICS-m in the full sample and among co-twins discordant for TBI. Additional TBI predictor variables included number of TBIs, severity (loss of consciousness [LOC]), and age of first TBI (age <25 vs 25+ years [older age TBI]). Models were adjusted for age (centered at 70 years), age-squared, education, wave, twin pair, lifestyle behaviors, and medical conditions.

RESULTS

Of 8,662 participants, 25% reported TBI. History of any TBI (β = -0.56, 95% CI -0.73 to -0.39), TBI with LOC (β = -0.51, 95% CI -0.71 to -0.31), and older age TBI (β = -0.66, 95% CI -0.90 to -0.42) were associated with lower TICS-m scores at 70 years. TBI with LOC (β = -0.03, 95% CI -0.05 to -0.001), more than one TBI (β = -0.05, 95% CI -0.09 to -0.002,), and older age TBI (β = -0.06, 95% CI -0.09 to -0.03) were associated with faster cognitive decline. Among monozygotic pairs discordant for TBI (589 pairs), history of any TBI (β = -0.55, 95% CI -0.91 to -0.19) and older age TBI (β = -0.74, 95% CI -1.22 to -0.26) were associated with lower TICS-m scores at 70 years. Those with more than one TBI (β = -0.13, 95% CI -0.23 to -0.03) and older age TBI (β = -0.07, 95% CI -0.13 to -0.002) showed greater cognitive decline compared with their co-twin without TBI.

DISCUSSION

These findings support an association of the effect of TBI on cognitive score and the rapidity of cognitive decline in later life. The results in monozygotic pairs, who share all genes and many exposures, particularly in early life, provide additional evidence of a causal relationship between TBI and poorer late-life cognitive outcomes.

How Subjective and Objective Factors in Research and Practice May Perpetuate Health Disparities Among Patients With Traumatic Brain Injury

ABSTRACT

Research shows disparities exist in traumatic brain injury (TBI)-related outcomes and are associated with objective and subjective factors. Objective factors (e.g., age, sex, race/ethnicity, health insurance status, and socioeconomic status) are defined as variables that are frequently measured, not easily modifiable, and not easily influenced by individual perceptions, opinions, or experiences. Conversely, subjective factors (e.g., personal health literacy, cultural competence, patient/family-clinician communication, implicit bias, and trust) are defined as variables that may be less frequently measured, more easily modifiable, and more easily influenced by individual perceptions, opinions, or experiences. The purpose of this analysis and perspective is to provide recommendations for further examination of subjective factors within TBI research and practice, with the overarching goal of reducing TBI-related disparities. Establishing reliable and valid measures of subjective factors is recommended to allow for further examination of the influence of both objective factors and subjective factors in the TBI population. Providers and researchers must also engage in education and training to recognize their biases and how bias influences decision making. The influence of subjective factors in practice and research must also be considered to ensure that knowledge needed to advance health equity is generated and disparities in outcomes for patients with TBI are reduced.

Olfactory training effects in children after mild traumatic brain injury

OBJECTIVE

Mild traumatic brain injury (mTBI) might impair the sense of smell and cognitive functioning. Repeated, systematic exposure to odors, i.e., olfactory training (OT) has been proposed for treatment of olfactory dysfunctions, including post-traumatic smell loss. Additionally, OT has been shown to mitigate cognitive deterioration in older population and enhance selected cognitive functions in adults. We aimed to investigate olfactory and cognitive effects of OT in the pediatric population after mTBI, likely to exhibit cognitive and olfactory deficits.

METHODS

Our study comprised 159 children after mTBI and healthy controls aged 6-16 years (M = 9.68 ± 2.78 years, 107 males), who performed 6-months-long OT with a set of 4 either high- or low-concentrated odors. Before and after OT we assessed olfactory functions, fluid intelligence, and executive functions.

RESULTS

OT with low-concentrated odors increased olfactory sensitivity in children after mTBI. Regardless of health status, children who underwent OT with low-concentrated odors had higher fluid intelligence scores at post-training measurement, whereas scores of children performing OT with high-concentrated odors did not change.

CONCLUSION

Our study suggests that OT with low-concentrated odors might accelerate rehabilitation of olfactory sensitivity in children after mTBI and support cognitive functions in the area of fluid intelligence regardless of head trauma.

Neuropsychological Function in Traumatic Brain Injury and the Influence of Chronic Pain

Cognitive dysfunction, pain, and psychological morbidity all present unique challenges to those living with traumatic brain injury (TBI). In this study we examined (a) the impact of pain across domains of attention, memory, and executive function, and (b) the relationships between pain and depression, anxiety, and post-traumatic stress disorder (PTSD) in persons with chronic TBI. Our sample included 86 participants with a TBI and chronic pain (n = 26), patients with TBI and no chronic pain (n = 23), and a pain-free control group without TBI (n = 37). Participants visited the laboratory and completed a comprehensive battery of neuropsychological tests as part of a structured interview. Multivariate analysis of covariance using education as a covariate, failed to detect a significant group difference for neuropsychological composite scores of attention, memory, and executive function (p = .165). A follow-up analysis using multiple one-way analysis of variance (ANOVA) was conducted for individual measures of executive function. Post-hoc testing indicated that those in both TBI groups preformed significantly worse on measures of semantic fluency when compared to controls (p < 0.001, ηρ2 = .16). Additionally, multiple ANOVAs indicated that those with TBI and pain scored significantly worse across all psychological assessments (p < .001). We also found significant associations between measures of pain and most psychological symptoms. A follow-up stepwise linear regression among those in the TBI pain group indicated that post concussive complaints, pain severity, and neuropathic pain symptoms differentially contributed to symptoms of depression, anxiety, and PTSD. These findings suggest deficits in verbal fluency among those living with chronic TBI, with results also reinforcing the multidimensional nature of pain and its psychological significance in this population.

Prognostic factors in traumatic brain injuries in emergency department

Background

Traumatic brain injury (TBI) is a leading cause of morbidity and mortality in young adults. The Extended Glasgow Outcome Score (GOSE) has been introduced to assess the global outcome after brain injuries. Therefore, we aimed to evaluate the prognostic factors associated with GOSE.

Materials and Methods

This was a multicenter cross-sectional study conducted on 144 patients with TBI admitted at trauma emergency centers. The patients' information, including demographic characteristics, duration of hospital stay, mechanical ventilation and on-admission laboratory measurements, and on-admission vital signs, were evaluated. The patients' TBI-related symptoms and brain computed tomography (CT) scan findings were recorded.

Results

GOSE assessments showed an increasing trend by the comparison of on-discharge (7.47 ± 1.30), within a month (7.51 ± 1.30) and within 3 months (7.58 ± 1.21) evaluations (P < 0.001). On-discharge GOSE was positively correlated with Glasgow Coma Scale (GCS)(r = 0.729, P < 0.001), motor GCS (r = 0.812, P < 0.001), Hb (r = 0.165, P = 0.048), and pH (r = 0.165, P = 0.048) and inversely with age (r = -0.261, P = 0.002), hospitalization period (r = -0.678, P < 0.001), pulse rate (r = -0.256, P = 0.002), white blood cell (WBC) (r = -0.222, P = 0.008), and triglyceride (r = -0.218, P = 0.009). In multiple linear regression analysis, the associations were significant only for GCS (B = 0.102, 95% confidence interval [CI]: 0-0.202; P = 0.05), hospitalization stay duration (B = -0.004, 95% CI: -0.005--0.003, P = 0.001), and WBC (B = 0.00001, 95% CI: 0.00000014-0.000025; P = 0.024). Among imaging signs and trauma-related symptoms in univariate analysis, intracranial hemorrhage (ICH), interventricular hemorrhage (IVH) (P = 0.006), subarachnoid hemorrhage (SAH) (P = 0.06; marginally at P < 0.1), subdural hemorrhage (SDH) (P = 0.032), and epidural hemorrhage (EDH) (P = 0.037) was significantly associated with GOSE at discharge in multivariable analysis.

Conclusion

According to the current study findings, GCS, hospitalization stay duration, WBC and among imaging signs and trauma-related symptoms ICH, IVH, SAH, SDH, and EDH are independent significant predictors of GOSE at discharge in TBI patients.

Effects and neuroprotective mechanisms of vagus nerve stimulation on cognitive impairment with traumatic brain injury in animal studies: A systematic review and meta-analysis

Introduction

Cognitive impairment is the main clinical feature after traumatic brain injury (TBI) and is usually characterized by attention deficits, memory loss, and decreased executive function. Vagus nerve stimulation (VNS) has been reported to show potential improvement in the cognition level after traumatic brain injury in clinical and preclinical studies. However, this topic has not yet been systematically reviewed in published literature. In this study, we present a systematic review and meta-analysis of the effects of VNS on cognitive function in animal models of TBI and their underlying mechanisms.

Methods

We performed a literature search on PubMed, PsycINFO, Web of Science, Embase, Scopus, and Cochrane Library from inception to December 2021 to identify studies describing the effects of VNS on animal models of TBI.

Results

Overall, nine studies were identified in animal models (36 mice, 268 rats, and 27 rabbits). An analysis of these studies showed that VNS can improve the performance of TBI animals in behavioral tests (beam walk test: SMD: 4.95; 95% confidence interval [CI]: 3.66, 6.23; p < 0.00001) and locomotor placing tests (SMD: -2.39; 95% CI: -4.07, -0.71; p = 0.005), whereas it reduced brain edema (SMD: -1.58; 95% CI: -2.85, -0.31; p = 0. 01) and decrease TNF-α (SMD: -3.49; 95% CI: -5.78, -1.2; p = 0.003) and IL-1β (SMD: -2.84; 95% CI: -3.96, -1.71; p < 0.00001) expression level in the brain tissue. However, the checklist for SYRCLE showed a moderate risk of bias (quality score between 30% and 60%), mainly because of the lack of sample size calculation, random assignment, and blinded assessment.

Conclusion

The present review showed that VNS can effectively promote cognitive impairment and neuropathology in animal models of TBI. We hope that the results of this systematic review can be applied to improve the methodological quality of animal experiments on TBI, which will provide more important and conclusive evidence on the clinical value of VNS. To further confirm these results, there is a need for high-quality TBI animal studies with sufficient sample size and a more comprehensive outcome evaluation.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021290797, identifier: CRD42021290797.

Objective Cognitive Outcomes and Subjective Emotional Sequelae in Litigating Adults with a Traumatic Brain Injury: The Impact of Performance and Symptom Validity Measures

OBJECTIVE

This study examined the relative contribution of performance and symptom validity in litigating adults with traumatic brain injury (TBI), as a function of TBI severity, and examined the relationship between self-reported emotional symptoms and cognitive tests scores while controlling for validity test performance.

METHOD

Participants underwent neuropsychological assessment between January 2012 and June 2021 in the context of compensation-seeking claims related to a TBI. All participants completed a cognitive test battery, the Personality Assessment Inventory (including symptom validity tests; SVTs), and multiple performance validity tests (PVTs). Data analyses included independent t-tests, one-way ANOVAs, correlation analyses, and hierarchical multiple regression.

RESULTS

A total of 370 participants were included. Atypical PVT and SVT performance were associated with poorer cognitive test performance and higher emotional symptom report, irrespective of TBI severity. PVTs and SVTs had an additive effect on cognitive test performance for uncomplicated mTBI, but less so for more severe TBI. The relationship between emotional symptoms and cognitive test performance diminished substantially when validity test performance was controlled, and validity test performance had a substantially larger impact than emotional symptoms on cognitive test performance.

CONCLUSION

Validity test performance has a significant impact on the neuropsychological profiles of people with TBI, irrespective of TBI severity, and plays a significant role in the relationship between emotional symptoms and cognitive test performance. Adequate validity testing should be incorporated into every neuropsychological assessment, and associations between emotional symptoms and cognitive outcomes that do not consider validity testing should be interpreted with extreme caution.

Gender Influences Virtual Reality-Based Recovery of Cognitive Functions in Patients with Traumatic Brain Injury: A Secondary Analysis of a Randomized Clinical Trial

The rehabilitation of cognitive deficits in individuals with traumatic brain injury is essential for promoting patients’ recovery and autonomy. Virtual reality (VR) training is a powerful tool for reaching this target, although the effectiveness of this intervention could be interfered with by several factors. In this study, we evaluated if demographical and clinical variables could be related to the recovery of cognitive function in TBI patients after a well-validated VR training. One hundred patients with TBI were enrolled in this study and equally randomized into the Traditional Cognitive Rehabilitation Group (TCRG: n = 50) or Virtual Reality Training Group (VRTG: n = 50). The VRTG underwent a VRT with BTs-N, whereas the TCRG received standard cognitive treatment. All the patients were evaluated by a complete neuropsychological battery before (T0) and after the end of the training (T1). We found that the VR-related improvement in mood, as well as cognitive flexibility, and selective attention were influenced by gender. Indeed, females who underwent VR training were those showing better cognitive recovery. This study highlights the importance of evaluating gender effects in planning cognitive rehabilitation programs. The inclusion of different repetitions and modalities of VR training should be considered for TBI male patients.

Long-term outcome after severe traumatic brain injury: a systematic literature review

BACKGROUND

Expectation of long-term outcome is an important factor in treatment decision-making after severe traumatic brain injury (sTBI). Conclusive long-term outcome data substantiating these decisions is nowadays lacking. This systematic review aimed to provide an overview of the scientific literature on long-term outcome after sTBI.

METHODS

A systematic search was conducted using PubMed from 2008 to 2020. Studies were included when reporting long-term outcome ≥ 2 years after sTBI (GCS 3-8 or AIS head score ≥ 4), using standardized outcome measures. Study quality and risk of bias were assessed using the QUIPS tool.

RESULTS

Twenty observational studies were included. Studies showed substantial variation in study objectives and study methodology. GOS-E (n = 12) and GOS (n = 8) were the most frequently used outcome measures. Mortality was reported in 46% of patients (range 18-75%). Unfavourable outcome rates ranged from 29 to 100% and full recovery was seen in 21-27% of patients. Most surviving patients reported SF-36 scores lower than the general population.

CONCLUSION

Literature on long-term outcome after sTBI was limited and heterogeneous. Mortality and unfavourable outcome rates were high and persisting sequelae on multiple domains common. Nonetheless, a considerable proportion of survivors achieved favourable outcome. Future studies should incorporate standardized multidimensional and temporal long-term outcome measures to strengthen the evidence-base for acute and subacute decision-making.

HIGHLIGHTS

1. Expectation of long-term outcome is an important factor in treatment decision-making for patients with severe traumatic brain injury (sTBI). 2. Favourable outcome and full recovery after sTBI are possible, but mortality and unfavourable outcome rates are high. 3. sTBI survivors are likely to suffer from a wide range of long-term consequences, underscoring the need for long-term and multi-modality outcome assessment in future studies. 4. The quality of the scientific literature on long-term outcome after sTBI can and should be improved to advance treatment decision-making.

Mixture Model Framework for Traumatic Brain Injury Prognosis Using Heterogeneous Clinical and Outcome Data

Prognoses of Traumatic Brain Injury (TBI) outcomes are neither easily nor accurately determined from clinical indicators. This is due in part to the heterogeneity of damage inflicted to the brain, ultimately resulting in diverse and complex outcomes. Using a data-driven approach on many distinct data elements may be necessary to describe this large set of outcomes and thereby robustly depict the nuanced differences among TBI patients' recovery. In this work, we develop a method for modeling large heterogeneous data types relevant to TBI. Our approach is geared toward the probabilistic representation of mixed continuous and discrete variables with missing values. The model is trained on a dataset encompassing a variety of data types, including demographics, blood-based biomarkers, and imaging findings. In addition, it includes a set of clinical outcome assessments at 3, 6, and 12 months post-injury. The model is used to stratify patients into distinct groups in an unsupervised learning setting. We use the model to infer outcomes using input data, and show that the collection of input data reduces uncertainty of outcomes over a baseline approach. In addition, we quantify the performance of a likelihood scoring technique that can be used to self-evaluate the extrapolation risk of prognosis on unseen patients.

Neural alterations in working memory of mild-moderate TBI: An fMRI study in Malaysia

Working memory (WM) encompasses crucial cognitive processes or abilities to retain and manipulate temporary information for immediate execution of complex cognitive tasks in daily functioning such as reasoning and decision-making. The WM of individuals sustaining traumatic brain injury (TBI) was commonly compromised, especially in the domain of WM. The current study investigated the brain responses of WM in a group of participants with mild-moderate TBI compared to their healthy counterparts employing functional magnetic resonance imaging. All consented participants (healthy: n = 26 and TBI: n = 15) performed two variations of the n-back WM task with four load conditions (0-, 1-, 2-, and 3-back). The respective within-group effects showed a right hemisphere-dominance activation and slower reaction in performance for the TBI group. Random-effects analysis revealed activation difference between the two groups in the right occipital lobe in the guided n-back with cues, and in the bilateral occipital lobe, superior parietal region, and cingulate cortices in the n-back without cues. The left middle frontal gyrus was implicated in the load-dependent processing of WM in both groups. Further group analysis identified that the notable activation changes in the frontal gyri and anterior cingulate cortex are according to low and high loads. Though relatively smaller in scale, this study was eminent as it clarified the neural alterations in WM in the mild-moderate TBI group compared to healthy controls. It confirmed the robustness of the phenomenon in TBI with the reproducibility of the results in a heterogeneous non-Western sample.

The Relationship Between Cognitive Functioning and Symptoms of Depression, Anxiety, and Post-Traumatic Stress Disorder in Adults with a Traumatic Brain Injury: a Meta-Analysis

A thorough understanding of the relationship between cognitive test performance and symptoms of depression, anxiety, or post-traumatic stress disorder (PTSD) in people with traumatic brain injury (TBI) is important given the high prevalence of these emotional symptoms following injury. It is also important to understand whether these relationships are affected by TBI severity, and the validity of test performance and symptom report. This meta-analysis was conducted to investigate whether these symptoms are associated with cognitive test performance alterations in adults with a TBI. This meta-analysis was prospectively registered on the PROSPERO International Prospective Register of Systematic Reviews website (registration number: CRD42018089194). The electronic databases Medline, PsycINFO, and CINAHL were searched for journal articles published up until May 2020. In total, 61 studies were included, which enabled calculation of pooled effect sizes for the cognitive domains of immediate memory (verbal and visual), recent memory (verbal and visual), attention, executive function, processing speed, and language. Depression had a small, negative relationship with most cognitive domains. These relationships remained, for the most part, when samples with mild TBI (mTBI)-only were analysed separately, but not for samples with more severe TBI (sTBI)-only. A similar pattern of results was found in the anxiety analysis. PTSD had a small, negative relationship with verbal memory, in samples with mTBI-only. No data were available for the PTSD analysis with sTBI samples. Moderator analyses indicated that the relationships between emotional symptoms and cognitive test performance may be impacted to some degree by exclusion of participants with atypical performance on performance validity tests (PVTs) or symptom validity tests (SVTs), however there were small study numbers and changes in effect size were not statistically significant. These findings are useful in synthesising what is currently known about the relationship between cognitive test performance and emotional symptoms in adults with TBI, demonstrating significant, albeit small, relationships between emotional symptoms and cognitive test performance in multiple domains, in non-military samples. Some of these relationships appeared to be mildly impacted by controlling for performance validity or symptom validity, however this was based on the relatively few studies using validity tests. More research including PVTs and SVTs whilst examining the relationship between emotional symptoms and cognitive outcomes is needed.

Systematic Review of Sex and Gender Effects in Traumatic Brain Injury: Equity in Clinical and Functional Outcomes

Background: Although traumatic brain injury (TBI) is a leading cause of death and disability in male and female patients worldwide, little is known about the effect of sex and gender on TBI outcomes.

Objectives: This systematic review summarizes the evidence on the effect of sex and gender on core TBI outcomes.

Methods: All English-language studies from six literature databases that addressed core outcomes in adults with TBI and included sex or gender, TBI severity, and age in their analyses were considered eligible. Two reviewers extracted data, and two reviewers assessed study quality using tools recommended by the National Institutes of Health. The results were sorted according to time post-injury, injury severity, gender equity ranking of the study's country of origin, and outcomes studied. The results from the included studies were grouped based on the approach taken in reporting their respective findings.

Results and Limitations: Of 172 articles assessed, 58 studies were selected, comprising 1, 265, 955 participants with TBI (67% male across all studies) of all injury severities. All studies were conducted in countries with a very high or high human development index, while the Gender Inequality Index (GII) varied. While the heterogeneity across studies limited any meaningful conclusions with respect to the role of sex and gender, we did observe that as gender equality ranking improved, differences between male and female participants in outcomes would diminish. Inclusion of social equity parameters in the studies was limited.

Conclusions and Implications: The non-uniform findings observed bring forth the need to develop and use a comprehensive and consistent methodology in the study of sex and gender post-TBI, incorporating social equity parameters to uncover the potential social underpinnings of gender effects on health and functional outcomes.

Systematic Review Registration: CRD42018098697.

Does cognitive decline occur decades after moderate to severe traumatic brain injury? A prospective controlled study

This prospective controlled study examined long-term trajectories of neuropsychological performance in individuals with traumatic brain injury (TBI) compared to healthy controls, and the impact of IQ, age at injury, time since injury, and injury severity on change over time. Fifty-three individuals with moderate to severe TBI (60.37% male; M = 59.77 yrs, SD = 14.03), and 26 controls (46.15% male; M = 63.96 yrs, SD = 14.42) were studied prospectively (M = 12.72 yrs between assessments). Participants completed measures of premorbid IQ (Weschler Test of Adult Reading), processing speed (Digit Symbol Coding Test), working memory (Digit Span Backwards), memory (Rey Auditory Verbal Learning Test) and executive function (Trail Making Test Part B; Hayling Errors), at a mean of 10.62 yrs (Initial) and 23.91 yrs (Follow-Up) post injury. Individuals with TBI did not show a significantly greater decline in neuropsychological performance over time compared with demographically similar controls. There was no association between change over time with IQ, time since injury or injury severity. Being older at injury had a greater adverse impact on executive function at follow-up. In this small sample, a single moderate to severe TBI was not associated with ongoing cognitive decline up to three decades post injury. Changes in cognitive function were similar between the groups and likely reflect healthy aging.

Toward a global and reproducible science for brain imaging in neurotrauma: the ENIGMA adult moderate/severe traumatic brain injury working group

The global burden of mortality and morbidity caused by traumatic brain injury (TBI) is significant, and the heterogeneity of TBI patients and the relatively small sample sizes of most current neuroimaging studies is a major challenge for scientific advances and clinical translation. The ENIGMA (Enhancing NeuroImaging Genetics through Meta-Analysis) Adult moderate/severe TBI (AMS-TBI) working group aims to be a driving force for new discoveries in AMS-TBI by providing researchers world-wide with an effective framework and platform for large-scale cross-border collaboration and data sharing. Based on the principles of transparency, rigor, reproducibility and collaboration, we will facilitate the development and dissemination of multiscale and big data analysis pipelines for harmonized analyses in AMS-TBI using structural and functional neuroimaging in combination with non-imaging biomarkers, genetics, as well as clinical and behavioral measures. Ultimately, we will offer investigators an unprecedented opportunity to test important hypotheses about recovery and morbidity in AMS-TBI by taking advantage of our robust methods for large-scale neuroimaging data analysis. In this consensus statement we outline the working group's short-term, intermediate, and long-term goals.

Cognitive differences between adults with traumatic brain injury and specific learning disorder

Background: Impaired working memory, attention, and processing speed are common in individuals with traumatic brain injury (TBI) and specific learning disorder (SLD). Yet, there is a paucity of research that has examined cognitive differences between these groups.Objective: The current study examined potential group differences between individuals with TBI and SLD on performance-based tests of working memory, attention, and processing speed. Subsequently, the study examined whether just processing speed tests could discriminate persons with TBI versus SLD.Method: The authors analyzed archival data to assess differences between 39 adult participants with moderate-severe TBI versus 57 adult participants with SLD on the Trail Making Test Part A, Trail Making Test Part B, Digit Span test, and Symbol Search test.Results: 95% confidence intervals revealed that participants with TBI performed significantly worse on the Trail Making Test Part A and Symbol Search test. Logistic regression analysis procedures revealed that Trail Making Test Part A was the most sensitive discriminator.Conclusion: Diagnosis of moderate-severe TBI compared to SLD can be determined by poor performance on measures of visual scanning and processing speed. These findings may be used for diagnostic interpretation and treatment planning by clinicians.

Use of Medical Cannabis to Treat Traumatic Brain Injury

There is not a single pharmacological agent with demonstrated therapeutic efficacy for traumatic brain injury (TBI). With recent legalization efforts and the growing popularity of medical cannabis, patients with TBI will inevitably consider medical cannabis as a treatment option. Pre-clinical TBI research suggests that cannabinoids have neuroprotective and psychotherapeutic properties. In contrast, recreational cannabis use has consistently shown to have detrimental effects. Our review identified a paucity of high-quality studies examining the beneficial and adverse effects of medical cannabis on TBI, with only a single phase III randomized control trial. However, observational studies demonstrate that TBI patients are using medical and recreational cannabis to treat their symptoms, highlighting inconsistencies between public policy, perception of potential efficacy, and the dearth of empirical evidence. We conclude that randomized controlled trials and prospective studies with appropriate control groups are necessary to fully understand the efficacy and potential adverse effects of medical cannabis for TBI.

Trajectory of 10-Year Neurocognitive Functioning After Moderate-Severe Traumatic Brain Injury: Early Associations and Clinical Application

OBJECTIVE

This study aimed to explore the 10-year trajectories of neurocognitive domains after moderate-severe traumatic brain injury (TBI), to identify factors related to long-term neurocognitive functioning, and to investigate whether performance remained stable or changed over time.

METHOD

Seventy-nine patients with moderate-severe TBI between the ages of 16 and 55 years were assessed at 3 months, 1, 5, and 10 years postinjury using neuropsychological tests and functional outcomes. Three hierarchical linear models were used to investigate the relationships of domain-specific neurocognitive trajectories (Memory, Executive function, and Reasoning) with injury severity, demographics, functional outcome at 3 months (Glasgow Outcome Scale-Extended) and emotional distress at 1 year (Symptom Checklist 90-Revised).

RESULTS

Education, injury severity measures, functional outcome, and emotional distress were significantly associated with both Memory and Executive function. Education and emotional distress were related to Reasoning. The interaction effects between time and these predictors in predicting neurocognitive trajectories were nonsignificant. Among patients with data at 1 and 10 year follow-ups (n = 47), 94-96% exhibited stable scores on Executive function and Reasoning tasks, and 83% demonstrated stable scores on Memory tasks. Significant memory decline was presented in 11% of patients.

CONCLUSIONS

The findings highlight the differential contribution of variables in their relationships with long-term neurocognitive functioning after moderate-severe TBI. Injury severity was important for Memory outcomes, whereas emotional distress influenced all neurocognitive domains. Reasoning (intellectual) abilities were relatively robust after TBI. While the majority of patients appeared to be cognitively stable beyond the first year, a small subset demonstrated a significant memory decline over time.

The Impact of a Comorbid Spinal Cord Injury on Cognitive Outcomes of Male and Female Patients with Traumatic Brain Injury

INTRODUCTION

Evidence of the effect of comorbid spinal cord injury (SCI) on cognitive outcomes in persons undergoing rehabilitation following newly diagnosed traumatic brain injury (TBI) is limited. We conducted a population-based study to investigate this effect.

OBJECTIVE

To compare cognitive outcomes in patients with TBI with and without a comorbid SCI.

SETTING/PARTICIPANTS

Adult patients diagnosed with TBI were identified and followed for 1 year through provincial health administrative data; those who entered inpatient rehabilitation were studied.

DESIGN

A retrospective matched cohort study using the National Rehabilitation Reporting System data of all acute care and freestanding rehabilitation hospitals in Ontario, Canada.

MAIN MEASURES

The exposure was a comorbid SCI in patients with diagnosed TBI. Exposed patients were matched to unexposed (TBI-only) on sex, age, injury severity, and income, in a ratio of one to two. Gain differences in the cognitive subscale of the Functional Independence Measure were compared between exposed and unexposed patients using multivariable mixed linear model, controlling for comorbidity propensity score, gains in motor function, and rehabilitation care indicators.

RESULTS

Over the first year post injury, 12 750 (0.84%) of all TBI patients entered inpatient rehabilitation, of whom 1359 (10.66%) had a comorbid SCI. A total of 1195 exposed patients (65.4% male, mean age 50.9 ± 20.6 for male and 61.8 ± 21.8 for female patients) were matched to 2390 unexposed patients. Controlling for confounding, exposed patients had lower cognitive gain (beta -0.43; 95% CI -0.72, -0.15), for both male (beta -0.39; 95% CI -0.75, -0.03) and female (beta -0.51; 95% CI -0.97, -0.05) patients. The adverse effects of comorbid SCI were driven largely by lower gains in problem solving and comprehension.

CONCLUSIONS

Adult patients with TBI and comorbid SCI showed a lower cognitive domain response to inpatient rehabilitation than patients with TBI alone. Identifying patients at risk for worse cognitive outcomes may facilitate the development of targeted strategies that improve cognitive outcomes.

Quantitative readability analysis of websites providing information on traumatic brain injury and epilepsy: A need for clear communication

OBJECTIVE

The use of the Internet for health-related questions is increasing, but it is not clear whether individuals can understand the information available online. Most health organizations recommend that health educational materials (HEMs) be written below the sixth grade reading level. This study was designed to evaluate the readability level of available online HEMs pertaining to traumatic brain injury (TBI), epilepsy, and posttraumatic epilepsy (PTE).

METHODS

This cross-sectional readability assessment included HEMs from TBI and epilepsy stakeholder organizations and those obtained from four Internet searches. The search strategy was designed to replicate a nonmedical individual's keyword searches. Each HEM was assessed with an online automated readability tool using three indices (Flesch Reading Ease Score, Flesch-Kincaid Grade Level, and Simple Measure of Gobbledygook). Findings were compared as a function of organization type (journalistic news or health organization), targeted medical condition (TBI, epilepsy, or PTE), or content topic (patient health education, clinical research education, or both).

RESULTS

Readability analysis of 405 identified HEMs revealed scores above the sixth grade reading level recommendation. Only 6.2% of individual HEMs met the sixth grade recommendation. Journalistic news organizations' HEMs had similar readability levels to health organizations' HEMs. PTE-related HEMs required the highest readability level, >11th grade (P < .001). There were significant differences in the readability scores (P < .01 for all indices) among HEMs with information on health education, research education, or both topics. The highest required readability level (>12 grade level) was for HEMs that included both health and research education.

SIGNIFICANCE

The majority of TBI-, epilepsy-, and PTE-related online HEMs do not meet the sixth grade reading recommendation. Improving the readability of HEMs may advance health literacy around TBI, epilepsy, and PTE, leading to more effective participant recruitment/retention strategies for future antiepileptogenesis trials in persons with TBI and perhaps better patient-centered outcomes.

Interventions and cognitive functioning in adults with traumatic spinal cord injuries: a systematic review and meta-analysis

AIM

This research synthesized scientific evidence on the impact of interventions for adults with traumatic spinal cord injury on cognition, to understand if current intervention approaches are appropriate in light of the risk of post-injury cognitive impairments.

METHOD

Medline, Central, Embase, Scopus, PsycINFO and PubMed were searched for intervention in persons with SCI assessing cognition pre- and post-intervention. Study quality was completed using the National Institutes of Health quality assessment tools. Results were grouped by type of intervention. The meta-analysis involved calculation of pooled effect sizes for interventions utilizing the same cognitive measure.

RESULTS

Eleven studies of moderate quality discussed drug therapy, transcutaneous tibial nerve stimulation, diet modification and dietary supplements, and inpatient rehabilitation. Some aspects of cognition were negatively affected by drugs while diet modification and supplement use, and transcutaneous tibial nerve stimulation showed no evidence of a difference in cognitive scores when compared with no intervention. Inpatient rehabilitation revealed a small but beneficial effect, when results of seven studies were pooled.

CONCLUSION

Evidence on the effects of interventions on cognitive functioning in patients with traumatic spinal cord injury is sparse and inconclusive, so work in this area is timely. It is valuable to know not only which interventions are effective for improving cognition, but also how other commonly used interventions, intended to treat other injury sequela, can affect cognition. PROSPERO: CRD42018087238.Implications for rehabilitationHistorically, rehabilitation of patients with traumatic spinal cord injury has targeted physical impairments, with little attention to cognition; this research aimed to understand if current interventions are appropriate in light of the risk of patients' cognitive impairments. Evidence on the effects of drug therapy, diet and dietary supplements interventions on cognitive functioning in traumatic spinal cord injury is sparse and inconclusive.Combining multiple inpatient rehabilitation interventions shows a positive but heterogeneous effect on the cognitive functioning; interventions applied earlier show greater gains.A major challenge for clinicians is to select an outcome measure sensitive to change over time, and to relate the results to patients' change in cognitive abilities with intervention applicationResearch to understand the functional effect of spinal cord injury on the widely distributed networks of the central and autonomic nervous systems subserving cognition, is timely.

Measuring Change Over Time: A Systematic Review of Evaluative Measures of Cognitive Functioning in Traumatic Brain Injury

Objectives: The purpose of evaluative instruments is to measure the magnitude of change in a construct of interest over time. The measurement properties of these instruments, as they relate to the instrument's ability to fulfill its purpose, determine the degree of certainty with which the results yielded can be viewed. This work systematically reviews all instruments that have been used to evaluate cognitive functioning in persons with traumatic brain injury (TBI), and critically assesses their evaluative measurement properties: construct validity, test-retest reliability, and responsiveness. Data Sources: MEDLINE, Central, EMBASE, Scopus, PsycINFO were searched from inception to December 2016 to identify longitudinal studies focused on cognitive evaluation of persons with TBI, from which instruments used for measuring cognitive functioning were abstracted. MEDLINE, instrument manuals, and citations of articles identified in the primary search were then screened for studies on measurement properties of instruments utilized at least twice within the longitudinal studies. Study Selection: All English-language, peer-reviewed studies of longitudinal design that measured cognition in adults with a TBI diagnosis over any period of time, identified in the primary search, were used to identify instruments. A secondary search was carried out to identify all studies that assessed the evaluative measurement properties of the instruments abstracted in the primary search. Data Extraction: Data on psychometric properties, cognitive domains covered and clinical utility were extracted for all instruments. Results: In total, 38 longitudinal studies from the primary search, utilizing 15 instruments, met inclusion and quality criteria. Following review of studies identified in the secondary search, it was determined that none of the instruments utilized had been assessed for all the relevant measurement properties in the TBI population. The most frequently assessed property was construct validity. Conclusions: There is insufficient evidence for the validity and reliability of instruments measuring cognitive functioning, longitudinally, in persons with TBI. Several instruments with well-defined construct validity in TBI samples warrant further assessment for test-retest reliability and responsiveness. Registration Number: www.crd.york.ac.uk/PROSPERO/, identifier CRD42017055309.

Sex-specific incident dementia in patients with central nervous system trauma

Introduction

Despite evidence that central nervous system (CNS) trauma, including traumatic brain injury and spinal cord injury, can cause sustained neurocognitive impairment, it remains unclear whether trauma-related variables are associated with incident dementia independently of other known risk factors.

Methods

All adults without dementia entering the health-care system with diagnoses of CNS trauma were examined for occurrence of dementia. All trauma-related variables were examined as predictors in sex-specific Cox regression models, controlling for other known risk factors.

Results

Over a median follow-up of 52 months, 32,834 of 712,708 patients (4.6%) developed dementia. Traumatic brain injury severity and spinal cord injury interacted with age to influence dementia onset; women were at a greater risk of developing dementia earlier than men, all other factors being equal.

Discussion

Risk stratification of patients with CNS trauma by sex is vital in identifying those most likely to develop dementia and in understanding the course and modifying factors.