Longitudinal cognitive changes in traumatic brain injury: a 30-year follow-up study

Additive effects of mild head trauma, blast exposure, and aging within white matter tracts: A novel Diffusion Tensor Imaging analysis approach

Existing diffusion tensor imaging (DTI) studies of neurological injury following high-level blast exposure (hlBE) in military personnel have produced widely variable results. This is potentially due to prior studies often not considering the quantity and/or recency of hlBE, as well as co-morbidity with non-blast head trauma (nbHT). Herein, we compare commonly used DTI metrics: fractional anisotropy and mean, axial, and radial diffusivity, in Veterans with and without history of hlBE and/or nbHT. We use both the traditional method of dividing participants into 2 equally weighted groups and an alternative method wherein each participant is weighted by quantity and recency of hlBE and/or nbHT. While no differences were detected using the traditional method, the alternative method revealed diffuse and extensive changes in all DTI metrics. These effects were quantified within 43 anatomically defined white matter tracts, which identified the forceps minor, middle corpus callosum, acoustic and optic radiations, fornix, uncinate, inferior fronto-occipital and inferior longitudinal fasciculi, and cingulum, as the pathways most affected by hlBE and nbHT. Moreover, additive effects of aging were present in many of the same tracts suggesting that these neuroanatomical effects may compound with age.

Detecting and Predicting Cognitive Decline in Individuals with Traumatic Brain Injury: A Longitudinal Telephone-Based Study

Traumatic brain injuries (TBIs) can lead to long-lasting cognitive impairments, and some survivors experience cognitive decline post-recovery. Early detection of decline is important for care planning, and understanding risk factors for decline can elucidate targets for prevention. While neuropsychological testing is the gold standard approach to characterizing cognitive function, there is a need for brief, scalable tools that are capable of detecting clinically significant changes in post-TBI cognition. This study examines whether a clinically significant change can be detected using the Brief Test of Adult Cognition by Telephone (BTACT) in a sample of individuals with chronic TBI and investigates whether potentially modifiable factors are associated with cognitive decline. Ninety participants aged 40 or older with complicated mild-to-severe TBI participated in two telephone-based study visits ∼1 year apart. Demographic, head trauma exposure, comorbid medical conditions, physical, and psychosocial functioning data were collected via self-report. The BTACT, a brief measure of global cognitive function, was used to assess cognitive performance across six domains. A reliable change index for quantifying clinically significant changes in BTACT performance was calculated. Results revealed cognitive decline in 10-27% of participants across various cognitive domains. More specifically, only depressive symptoms, including depressed affect and anhedonia, were significantly associated with cognitive decline after correcting for multiple comparisons using false discovery rate (FDR). Other factors such as the number of blows to the head, male gender, dyspnea, increased anxiety symptoms, seizures, illicit drug use, and fewer cardiovascular comorbidities should be considered hypothesis generating. Importantly, age was not a significant predictor of cognitive decline, which challenges the assumption that cognitive decline is solely related to the natural aging process. It suggests that there are unique factors associated with TBI that impact cognitive function, and these factors can affect individuals across the lifespan. The BTACT is a brief and sensitive tool for identifying clinically meaningful changes in cognitive function over a relatively brief period (i.e., 1 year) in a sample of individuals in the chronic stages of TBI (i.e., x̄ = 6.7 years post-TBI). Thus, the BTACT may be useful in surveillance efforts aimed at understanding and detecting decline, particularly in situations where in-person cognitive screening is impractical or unfeasible. We also identified potentially modifiable targets for the prevention of post-TBI cognitive decline. These findings can offer insights into treatment goals and preventive strategies for individuals at risk for cognitive decline, as well as help to facilitate early identification efforts.

Executive functioning in early and middle age adult patients operated for epidural hematoma: A comparative study

Epidural Hematoma (EDH) is a common condition of traumatic brain injury. It has a good prognosis if prompt surgical intervention is conducted. There is a dearth of studies on neuropsychological assessment of executive functioning exclusively in post-operative EDH patients. Moreover, age as a variable in determining executive functions in patients post-head injury, has been studied mostly in the older adults. This cross-sectional case-control study assessed Executive Functions (EF) in 62 post-surgery patients with EDH and compared 57 healthy controls (HC) using standardized assessment tools of sustained attention, speed, working memory, fluency, set-shifting, perseveration, planning, and response inhibition. Further, executive functions in two phases of adulthood, viz. Early Adulthood (20-39 years) and Middle Adulthood (40-60 years) were compared in the EDH group (E-EDH and M-EDH) and HC (E-HC and M-HC). A two-way Analysis of Variance (ANOVA) and correlational analysis was conducted. Results showed a trend where the M-EDH group performed significantly poorer on executive function tests (viz a viz., time taken, errors, and correct responses), followed by E-EDH, M-HC, and E-HC. The main effect of age was found significant on Digit Symbol, Color Trail 1, N-Back 2, Animal Naming, and Stroop Effect (p < 0.01 level) while N-Back 1, WCST-PE, and Tower of London (p < 0.05 level). The findings have significant clinical and therapeutic implications. In addition, it gives guidance regarding planning specific neuropsychological tests and rehabilitation targeting specific areas of executive functions decline due to age in EDH post-surgery patients.

Association Between Traumatic Brain Injury and Cognitive Decline Among Middle-to-Older Aged Men in the Vietnam Era Twin Study of Aging

Traumatic brain injury (TBI) is associated with increased risk of dementia. However, whether TBI is associated with greater cognitive decline over time in specific cognitive domains among older adults is not well understood. This prospective cohort study used data from 1476 male Vietnam Era Twin Study of Aging participants (average age at study entry = 57.9 years, range = 51-71 years; 97.6% non-Hispanic; 92.5% White) collected from 2003 to 2019, who had complete information on prior TBI. Participants completed a comprehensive neuropsychological assessment at up to three visits over up to a 12-year follow-up period during which they also self-reported their history of TBI. Multivariable, linear mixed-effects models were used to assess associations between TBI and cognitive performance trajectories. Effect measure modification by apolipoprotein E (APOE) epsilon 4 (ε4) genotype status was assessed in a subset of participants. Thirty-one percent of participants reported a history of TBI; 29.4% were APOE ε4 carriers. There were no statistically significant associations of TBI with decline in episodic memory, executive function, or processing speed among participants overall. In models stratified by APOE ε4 carrier status, TBI was associated with a larger magnitude of decline in executive function for APOE ε4 carriers (β = -0.0181; 95% confidence interval [CI] -0.0335, -0.0027) compared to noncarriers (β = -0.0031; 95% CI -0.0128, 0.0067; P Interaction = 0.03). In sensitivity analyses, TBI earlier in life (before military induction, average age = 20 years) was associated with faster declines in executive function compared to no TBI, irrespective of APOE ε4 status. In this sample of middle-to-older aged men, TBI was associated with faster declines in executive function among APOE ε4 carriers and among those who reported TBI in early life. These findings support the importance of a life course perspective when considering factors that may influence cognitive health in aging.

Cognitive impairment in Chinese traumatic brain injury patients: from challenge to future perspectives

Traumatic Brain Injury (TBI) is a prevalent form of neurological damage that may induce varying degrees of cognitive dysfunction in patients, consequently impacting their quality of life and social functioning. This article provides a mini review of the epidemiology in Chinese TBI patients and etiology of cognitive impairment. It analyzes the risk factors of cognitive impairment, discusses current management strategies for cognitive dysfunction in Chinese TBI patients, and summarizes the strengths and limitations of primary testing tools for TBI-related cognitive functions. Furthermore, the article offers a prospective analysis of future challenges and opportunities. Its objective is to contribute as a reference for the prevention and management of cognitive dysfunction in Chinese TBI patients.

Impaired cortical neuronal homeostasis and cognition after diffuse traumatic brain injury are dependent on microglia and type I interferon responses

Neuropsychiatric complications including depression and cognitive decline develop in the years after traumatic brain injury (TBI), negatively affecting quality of life. Microglial and type 1 interferon (IFN-I) responses are associated with the transition from acute to chronic neuroinflammation after diffuse TBI in mice. Thus, the purpose of this study was to determine if impaired neuronal homeostasis and increased IFN-I responses intersected after TBI to cause cognitive impairment. Here, the RNA profile of neurons and microglia after TBI (single nucleus RNA-sequencing) with or without microglia depletion (CSF1R antagonist) was assessed 7 dpi. There was a TBI-dependent suppression of cortical neuronal homeostasis with reductions in CREB signaling, synaptogenesis, and synaptic migration and increases in RhoGDI and PTEN signaling (Ingenuity Pathway Analysis). Microglial depletion reversed 50% of TBI-induced gene changes in cortical neurons depending on subtype. Moreover, the microglial RNA signature 7 dpi was associated with increased stimulator of interferon genes (STING) activation and IFN-I responses. Therefore, we sought to reduce IFN-I signaling after TBI using STING knockout mice and a STING antagonist, chloroquine (CQ). TBI-associated cognitive deficits in novel object location and recognition (NOL/NOR) tasks at 7 and 30 dpi were STING dependent. In addition, TBI-induced STING expression, microglial morphological restructuring, inflammatory (Tnf, Cd68, Ccl2) and IFN-related (Irf3, Irf7, Ifi27) gene expression in the cortex were attenuated in STINGKO mice. CQ also reversed TBI-induced cognitive deficits and reduced TBI-induced inflammatory (Tnf, Cd68, Ccl2) and IFN (Irf7, Sting) cortical gene expression. Collectively, reducing IFN-I signaling after TBI with STING-dependent interventions attenuated the prolonged microglial activation and cognitive impairment.

Extension domain of amyloid processor protein inhibits amyloidogenic cleavage and balances neural activity in a traumatic brain injury mouse model

BACKGROUND

Mechanisms underlying cognitive dysfunction following traumatic brain injury (TBI) partially due to abnormal amyloid processor protein (APP) cleavage and neural hyperactivity. Binding of the extension domain of APP (ExD17) to the GABAbR1 receptor results in reduced neural activity, which might play a role in the mechanisms of cognitive dysfunction caused by TBI.

METHODS

Stretch-induced injury was utilized to establish a cell injury model in HT22 cells. The TBI model was created by striking the exposed brain tissue with a free-falling weight. Topical or intraperitoneal administration of ExD17 was performed. Cell viability was assessed through a cell counting kit-8 assay, while intracellular Ca2+ was measured using Fluo-4. Western blotting was used to investigate the expression of APP amyloidogenic cleavage proteins, GABAbR1, phospholipase C (PLC), PLCB3, and synaptic proteins. ELISA was performed to analyze the levels of Aβ42. Seizures were assessed using electroencephalography (EEG). Behaviors were evaluated through the novel object recognition test, open field test, elevated plus maze test, and nest-building test.

RESULTS

ExD17 improved cell viability and reduced intracellular calcium in the cell injury model. The treatment also suppressed the increased expression of APP amyloidogenic cleavage proteins and Aβ42 in both cell injury and TBI models. ExD17 treatment reversed the abnormal expression of GABAbR1, GRIA2, p-PLCG1/PLCG1 ratio, and p-PLCB3/PLCB3 ratio. In addition, ExD17 treatment reduced neural activity, seizure events, and their duration in TBI. Intraperitoneal injection of ExD17 improved behavioral outcomes in the TBI mouse model.

CONCLUSIONS

ExD17 treatment results in a reduction of amyloidogenic APP cleavage and neuroexcitotoxicity, ultimately leading to an improvement in the behavioral deficits observed in TBI mice.

Moderate-Severe TBI as a Progressive Disorder: Patterns and Predictors of Cognitive Declines in the Chronic Stages of Injury

BACKGROUND

Moderate-severe traumatic brain injury (TBI) has been associated with progressive cognitive decline in the chronic injury stages in a small number of studies.

OBJECTIVE

This study aimed to (i) replicate our previous findings of decline from 1 to 3+ years post-injury in a larger, non-overlapping sample and (ii) extend these findings by examining the proportion of decliners in 2 earlier time windows, and by investigating novel predictors of decline.

METHODS

N = 48 patients with moderate-severe TBI underwent neuropsychological assessment at 2, 5, 12 months, and 30+ months post-injury. We employed the Reliable Change Index (RCI) to evaluate decline, stability and improvement across time and logistic regression to identify predictors of decline (demographic/cognitive reserve; injury-related).

RESULTS

The proportions of patients showing decline were: 12.5% (2-5 months post-injury), 17% (5-12 months post-injury), and 27% (12-30+ months post-injury). Measures of verbal retrieval were most sensitive to decline. Of the predictors, only left progressive hippocampal volume loss from 5 to 12 months post-injury significantly predicted cognitive decline from 12 to 30+ months post-injury.

CONCLUSIONS

Identical to our previous study, 27% of patients declined from 12 to 30+ months post-injury. Additionally, we found that the further from injury, the greater the proportion of patients declining. Importantly, earlier progressive hippocampal volume loss predicted later cognitive decline. Taken together, the findings highlight the need for ongoing research and treatment that target these deleterious mechanisms affecting patients in the chronic stages of moderate-severe TBI.

Microglia moonlighting after traumatic brain injury: aging and interferons influence chronic microglia reactivity

Most of the individuals who experience traumatic brain injury (TBI) develop neuropsychiatric and cognitive complications that negatively affect recovery and health span. Activation of multiple inflammatory pathways persists after TBI, but it is unclear how inflammation contributes to long-term behavioral and cognitive deficits. One outcome of TBI is microglial priming and subsequent hyper-reactivity to secondary stressors, injuries, or immune challenges that further augment complications. Additionally, microglia priming with aging contributes to exaggerated glial responses to TBI. One prominent inflammatory pathway, interferon (IFN) signaling, is increased after TBI and may contribute to microglial priming and subsequent reactivity. This review discusses the contributions of microglia to inflammatory processes after TBI, as well as the influence of aging and IFNs on microglia reactivity and chronic inflammation after TBI.

Actigraphic and nursing sleep log measures in moderate-to-severe traumatic brain injury: Identifying discrepancies in total sleep time

BACKGROUND

Sleep disturbances are common in patients with traumatic brain injury (TBI). In an inpatient rehabilitation setting, clinicians often use information from sleep logs filled out by trained nurses to identify and treat sleep disturbances. However, there are limited data related to accuracy of sleep logs, and patient-reported sleep diaries are poor predictors of total sleep time, which raises concern about the accuracy of sleep logs filled out by a third party.

OBJECTIVE

To examine the reliability of sleep logs for participants with TBI by comparing total sleep time determined by sleep logs versus actigraphy.

DESIGN

Prospective, cross-sectional study.

SETTING

Free-standing, academic inpatient rehabilitation facility.

PARTICIPANTS

Thirty individuals (n = 30) participated in the study. Inclusion criteria were (1) diagnosis of moderate-to-severe TBI; (2) age ≥ 18 years at the time of TBI; and (3) participating in inpatient rehabilitation with no prior inpatient rehabilitation admissions.

INTERVENTIONS

Actigraph monitoring using ActiGraph GT9X Link devices was initiated within 72 hours of admission and continued for 7 consecutive days. Sleep logs were concurrently filled out by trained nurses.

MAIN OUTCOME MEASURES

Sleep parameter correspondence between actigraphy and sleep logs in moderate-to-severe TBI.

RESULTS

Only 51.4% of participants' sleep logs and actigraph total sleep time measurements were within 1 hour of each other, and only 23.8% were within 30 minutes. On average, sleep logs overestimated actigraphy-determined total sleep time by 60 minutes compared to actigraphic measurement.

CONCLUSIONS

For those with moderate-to-severe TBI undergoing inpatient rehabilitation, sleep logs are poor predictors of sleep time because they overestimate total sleep time compared to actigraphy. Therefore, clinicians should use caution when using sleep log data to make decisions regarding treatment for sleep disturbances in TBI.

Screening for Brain Injury Sustained in the Context of Intimate Partner Violence (IPV): Measure Development and Preliminary Utility of the Brain Injury Screening Questionnaire IPV Module

Abstract Intimate partner violence (IPV) is associated with risk for multi-etiology brain injury (BI), including repetitive head impacts, isolated traumatic brain injuries (TBI), and anoxic/hypoxic injury secondary to nonfatal strangulation (NFS). IPV-related injuries are often unreported, but evidence suggests that survivors are more likely to report when asked directly. There are currently no validated tools for screening of brain injury related to IPV that meet World Health Organization guidelines for this population. Here, we describe measure development methods and preliminary utility of the Brain Injury Screening Questionnaire IPV (BISQ-IPV) module. We culled items from existing IPV and TBI screening tools and sought two rounds of stakeholder feedback regarding content coverage, terminology, and safety of administration. The resulting stakeholder-informed BISQ-IPV module is a seven-item self-report measure that uses contextual cues (e.g., being shoved, shaken, strangled) to query lifetime history of IPV-related head/neck injury. We introduced the BISQ-IPV module into the Late Effects of TBI (LETBI) study to investigate rates of violent and IPV-specific head/neck injury reporting in a TBI sample. Among those who completed the BISQ-IPV module (n = 142), 8% of the sample (and 20% of women) reported IPV-related TBI, and 15% of the sample (34% of women) reported IPV-related head or neck injury events that did not result in loss or alteration of consciousness. No men reported NFS; one woman reported inferred BI secondary to NFS, and 6% of women reported NFS events. Those who endorsed IPV-BI were all women, many were highly educated, and many reported low incomes. We then compared reporting of violent TBIs and head/neck injury events among individuals who completed the core BISQ wherein IPV is not specifically queried (administered from 2015-2018; n = 156) to that of individuals who completed the core BISQ preceded by the BISQ-IPV module (BISQ+IPV, administered from 2019-2021; n = 142). We found that 9% of those who completed the core BISQ reported violent TBI (e.g., abuse, assault), whereas 19% of those who completed the BISQ+IPV immediately preceding the core BISQ reported non-IPV-related violent TBI on the core BISQ. These findings suggest that standard TBI screening tools are inadequate for identifying IPV-BI and structured cueing of IPV-related contexts yields greater reporting of both IPV- and non-IPV-related violent BI. When not queried directly, IPV-BI remains a hidden variable in TBI research studies.

Spatiotemporal profile of atrophy in the first year following moderate-severe traumatic brain injury

Traumatic brain injury (TBI) triggers progressive neurodegeneration resulting in brain atrophy that continues months-to-years following injury. However, a comprehensive characterization of the spatial and temporal evolution of TBI-related brain atrophy remains incomplete. Utilizing a sensitive and unbiased morphometry analysis pipeline optimized for detecting longitudinal changes, we analyzed a sample consisting of 37 individuals with moderate-severe TBI who had primarily high-velocity and high-impact injury mechanisms. They were scanned up to three times during the first year after injury (3 months, 6 months, and 12 months post-injury) and compared with 33 demographically matched controls who were scanned once. Individuals with TBI already showed cortical thinning in frontal and temporal regions and reduced volume in the bilateral thalami at 3 months post-injury. Longitudinally, only a subset of cortical regions in the parietal and occipital lobes showed continued atrophy from 3 to 12 months post-injury. Additionally, cortical white matter volume and nearly all deep gray matter structures exhibited progressive atrophy over this period. Finally, we found that disproportionate atrophy of cortex along sulci relative to gyri, an emerging morphometric marker of chronic TBI, was present as early as 3 month post-injury. In parallel, neurocognitive functioning largely recovered during this period despite this pervasive atrophy. Our findings demonstrate msTBI results in characteristic progressive neurodegeneration patterns that are divergent across regions and scale with the severity of injury. Future clinical research using atrophy during the first year of TBI as a biomarker of neurodegeneration should consider the spatiotemporal profile of atrophy described in this study.

Effects of Neurofeedback on Cognitive Function, Productive Activity, and Quality of Life in Patients With Traumatic Brain Injury: A Randomized Controlled Trial

BACKGROUND

Cognitive impairment is common in patients with traumatic brain injury (TBI). Studies that have examined the effectiveness of neurofeedback (NFB) on cognitive function following TBI have had poor study designs and small sample sizes.

OBJECTIVES

This randomized controlled trial assessed the effects of low-resolution tomography Z-score NFB (LZNFB) and theta/beta NFB on cognitive impairment, return to productive activity, and quality of life in patients with TBI.

METHODS

We randomly assigned 87 patients with TBI with cognitive impairment to LZNFB, theta/beta NFB, or usual care (UC) groups. Patients in both NFB groups received weekly 60-minute treatment for 10 weeks, and those in the control group received UC and telephone interviews for 10 weeks. The primary outcome was cognitive function as measured by performance on cognitive tasks; the secondary outcomes included productive activity and quality of life based on the Community Integration Questionnaire-revised (CIQ-R) and the Quality of Life after Brain Injury (QOLIBRI), respectively, at baseline and immediately after the last intervention.

RESULTS

The LZNFB group exhibited significantly greater improvements in immediate recall, delayed recall, recognition memory, and selective attention compared with the UC group; the theta/beta NFB group exhibited improvements in only immediate memory and selective attention (P < .05). The total CIQ-R scores of the LZNFB group after treatment were significantly improved than those of the UC group were.

CONCLUSION

Consecutive LZNFB achieved therapeutic effects in memory, attention, and productive activity, whereas theta/beta NFB improved memory and attention in patients with TBI.This trial was prospectively registered at ClinicalTrial.gov (registration number: NCT03515317; https://clinicaltrials.gov/ct2/show/NCT03515317).

Longitudinal Patterns of Functional Connectivity in Moderate-to-Severe Traumatic Brain Injury

Longitudinal neuroimaging studies aid our understanding of recovery mechanisms in moderate-to-severe traumatic brain injury (TBI); however, there is a dearth of longitudinal functional connectivity research. Our aim was to characterize longitudinal functional connectivity patterns in two clinically important brain networks, the frontoparietal network (FPN) and the default mode network (DMN), in moderate-to-severe TBI. This inception cohort study of prospectively collected longitudinal data used resting-state functional magnetic resonance imaging (fMRI) to characterize functional connectivity patterns in the FPN and DMN. Forty adults with moderate-to-severe TBI (mean ± standard deviation [SD]; age = 39.53 ± 16.49 years, education = 13.92 ± 3.20 years, lowest Glasgow Coma Scale score = 6.63 ± 3.24, sex = 70% male) were scanned at approximately 0.5, 1-1.5, and 3+ years post-injury. Seventeen healthy, uninjured participants (mean ± SD; age = 38.91 ± 15.57 years, education = 15.11 ± 2.71 years, sex = 29% male) were scanned at baseline and approximately 11 months afterwards. Group independent component analyses and linear mixed-effects modeling with linear splines that contained a knot at 1.5 years post-injury were employed to investigate longitudinal network changes, and associations with covariates, including age, sex, and injury severity. In patients with TBI, functional connectivity in the right FPN increased from approximately 0.5 to 1.5 years post-injury (unstandardized estimate = 0.19, standard error [SE] = 0.07, p = 0.009), contained a slope change in the opposite direction, from positive to negative at 1.5 years post-injury (estimate = -0.21, SE = 0.11, p = 0.009), and marginally declined afterwards (estimate = -0.10, SE = 0.06, p = 0.079). Functional connectivity in the DMN increased from approximately 0.5 to 1.5 years (estimate = 0.15, SE = 0.05, p = 0.006), contained a slope change in the opposite direction, from positive to negative at 1.5 years post-injury (estimate = -0.19, SE = 0.08, p = 0.021), and was estimated to decline from 1.5 to 3+ years (estimate = -0.04, SE = 0.04, p = 0.303). Similarly, the left FPN increased in functional connectivity from approximately 0.5 to 1.5 years post-injury (estimate = 0.15, SE = 0.05, p = 0.002), contained a slope change in the opposite direction, from positive to negative at 1.5 years post-injury (estimate = -0.18, SE = 0.07, p = 0.008), and was estimated to decline thereafter (estimate = -0.04, SE = 0.03, p = 0.254). At approximately 0.5 years post-injury, patients showed hypoconnectivity compared with healthy, uninjured participants at baseline. Covariates were not significantly associated in any of the models. Findings of early improvement but a tapering and possible decline in connectivity thereafter suggest that compensatory effects are time-limited. These later reductions in connectivity mirror growing evidence of behavioral and structural decline in chronic moderate-to-severe TBI. Targeting such declines represents a novel avenue of research and offers potential for improving clinical outcomes.

INCOG 2.0 Guidelines for Cognitive Rehabilitation Following Traumatic Brain Injury, Part II: Attention and Information Processing Speed

INTRODUCTION

Moderate to severe traumatic brain injury (MS-TBI) commonly causes disruption in aspects of attention due to its diffuse nature and injury to frontotemporal and midbrain reticular activating systems. Attentional impairments are a common focus of cognitive rehabilitation, and increased awareness of evidence is needed to facilitate informed clinical practice.

METHODS

An expert panel of clinicians/researchers (known as INCOG) reviewed evidence published from 2014 and developed updated guidelines for the management of attention in adults, as well as a decision-making algorithm, and an audit tool for review of clinical practice.

RESULTS

This update incorporated 27 studies and made 11 recommendations. Two new recommendations regarding transcranial stimulation and an herbal supplement were made. Five were updated from INCOG 2014 and 4 were unchanged. The team recommends screening for and addressing factors contributing to attentional problems, including hearing, vision, fatigue, sleep-wake disturbance, anxiety, depression, pain, substance use, and medication. Metacognitive strategy training focused on everyday activities is recommended for individuals with mild-moderate attentional impairments. Practice on de-contextualized computer-based attentional tasks is not recommended because of lack of evidence of generalization, but direct training on everyday tasks, including dual tasks or dealing with background noise, may lead to gains for performance of those tasks. Potential usefulness of environmental modifications is also discussed. There is insufficient evidence to support mindfulness-based meditation, periodic alerting, or noninvasive brain stimulation for alleviating attentional impairments. Of pharmacological interventions, methylphenidate is recommended to improve information processing speed. Amantadine may facilitate arousal in comatose or vegetative patients but does not enhance performance on attentional measures over the longer term. The antioxidant Chinese herbal supplement MLC901 (NeuroAiD IITM) may enhance selective attention in individuals with mild-moderate TBI.

CONCLUSION

Evidence for interventions to improve attention after TBI is slowly growing. However, more controlled trials are needed, especially evaluating behavioral or nonpharmacological interventions for attention.

Risk factors and consequences of traumatic brain injury in a Swiss male population cohort

OBJECTIVE

To investigate the risk factors for and the consequences (ie, substance use disorders (SUD), depression, personality traits) of traumatic brain injury (TBI) in young Swiss men.

DESIGN

This is a three-wave cohort study. Risk factors were measured at baseline (2010-2012) and at follow-up 1 (FU1; 2012-2014), while the consequences and TBI were measured at follow-up 2 (FU2; 2016-2018).

SETTING

Switzerland.

PARTICIPANTS

All participants at FU2 (Mage=25.43, SD=1.25) of the Cohort Study on Substance Use Risk Factors (N=4881 young Swiss men after listwise deletion).

MEASURES

The outcomes measured were TBI, SUD (ie, alcohol, nicotine, cannabis, other illicit drugs), depression and personality traits (ie, sensation seeking, anxiety-neuroticism, sociability, aggression-hostility) at FU2. The predictors were previous TBI (lifetime TBI but not in the past 12 months at FU2), SUD, personality traits and sociodemographics (highest level of achieved education, age, linguistic region) measured at FU1.

RESULTS

At FU2, 3919 (80.3%) participants reported to never have had TBI, 102 (2.1%) have had TBI in the last 12 months (TBI new cases), and 860 (17.6%) have had TBI during their lifetime but not in the 12 months preceding FU2 (previous TBI). Low educational attainment (OR=3.93, 95% CI 2.10 to 7.36), depression (OR=2.87, 95% CI 1.35 to 6.11), nicotine dependence (OR=1.72, 95% CI 1.09 to 2.71), high sociability (OR=1.18, 95% CI 1.07 to 1.30), high aggression-hostility (OR=1.15, 95% CI 1.06 to 1.26) and high sensation seeking (OR=1.33, 95% CI 1.04 to 1.68) at FU1 were significantly associated with TBI new cases at FU2. Previous TBI was significantly associated with nicotine dependence (OR=1.46, 95% CI 1.16 to 1.83), depression (OR=2.16, 95% CI 1.56 to 2.99) and aggression-hostility (B=0.14, 95% CI >0.00 to 0.28) at FU2.

CONCLUSION

Low educational attainment and depression are the most significant risk factors associated with increased odds of future TBI, while depression, nicotine dependence and high aggression-hostility are the main consequences of previous TBI. TBI should be considered an underlying factor in the treatment of depression, SUD or unfavourable personality profiles.

Hyperbaric oxygen therapy for cognitive impairments in patients with traumatic brain injury: A systematic review

Cognitive deficits are the most common impairments after traumatic brain injury (TBI). It can be linked with poor physical function. Hyperbaric oxygen therapy (HBOT) increases blood flow and oxygen supply to the brain. This review aimed to summarize and evaluate the available literature on the influences of HBOT on cognitive deficits in patients with TBI. PubMed, SCOPUS, PEDro, REHABDATA, MIDLINE, CHINAL, EMBASE, and Web of Science were searched from inception until June 2021. The methodological quality was measured using the physiotherapy evidence database (PEDro) scale. Ten studies met the eligibility criteria. Six studies were randomized controlled trials, and four were pilot studies. The scores on the PEDro scale ranged from two to nine, with a median score of seven. The included studies showed heterogeneity results for the beneficial effects of HBOT on improving cognitive functions in patients with TBI. The evidence for the beneficial effects of HBOT on cognitive functions post-TBI was limited. Further randomized controlled trials with large sample sizes are strongly needed to understand the effects of HBOT on cognitive functions in patients with TBI.

A Levee to the Flood: Pre-injury Neuroinflammation and Immune Stress Influence Traumatic Brain Injury Outcome

Increasing evidence demonstrates that aging influences the brain's response to traumatic brain injury (TBI), setting the stage for neurodegenerative pathology like Alzheimer's disease (AD). This topic is often dominated by discussions of post-injury aging and inflammation, which can diminish the consideration of those same factors before TBI. In fact, pre-TBI aging and inflammation may be just as critical in mediating outcomes. For example, elderly individuals suffer from the highest rates of TBI of all severities. Additionally, pre-injury immune challenges or stressors may alter pathology and outcome independent of age. The inflammatory response to TBI is malleable and influenced by previous, coincident, and subsequent immune insults. Therefore, pre-existing conditions that elicit or include an inflammatory response could substantially influence the brain's ability to respond to traumatic injury and ultimately affect chronic outcome. The purpose of this review is to detail how age-related cellular and molecular changes, as well as genetic risk variants for AD affect the neuroinflammatory response to TBI. First, we will review the sources and pathology of neuroinflammation following TBI. Then, we will highlight the significance of age-related, endogenous sources of inflammation, including changes in cytokine expression, reactive oxygen species processing, and mitochondrial function. Heightened focus is placed on the mitochondria as an integral link between inflammation and various genetic risk factors for AD. Together, this review will compile current clinical and experimental research to highlight how pre-existing inflammatory changes associated with infection and stress, aging, and genetic risk factors can alter response to TBI.

The influence of cognitive reserve in the protection of the cognitive status after an acquired brain injury: A systematic review

BACKGROUND

Cognitive Reserve (CR) hypothesis was introduced to account for the variability in cognitive performance of patients with similar degrees of brain injury or pathology. The individual variability of CR is modulated by the interaction of innate capacities and exposures throughout life, which can act as protectors against neuropathology's clinical effects. Individuals with higher CR appear to have better cognitive performance after a brain injury. The present review aimed to identify and map the scientific evidence available in literature regarding CR's influence in protecting the cognitive status after an Acquired Brain Injury (ABI).

METHOD

A systematic review was performed for published studies until October 2020 in PubMed, Scopus, and CINAHL electronic databases. Studies regarding CR's influence in protecting the cognitive status after an ABI were included in this review. The Newcastle-Ottawa Scale was used to assess risk of bias in the included studies. This systematic review was recorded in the International Prospective Register of Systematic Reviews (PROSPERO) under the number CRD42021236594.

RESULTS

Twenty-one studies published between 2003 and 2020 were selected and analyzed. The literature analysis showed that CR has a positive effect on cognitive status after an ABI. Various proxies were used to estimate CR, including estimated premorbid IQ, education, occupation attainment, socioeconomic status, leisure activities, bilingualism, and social integration. CR proxies constitute a set of variables that may have a significant influence on cognitive status. Higher CR levels were associated with lower cognitive impairment after an ABI.

CONCLUSIONS

Although more research is necessary for a complete understanding of CR's impact on cognition, the synthesis of these studies confirmed that there is evidence on the beneficial impact of CR on cognitive status after an ABI. These findings support CR's cognitive status role following an ABI and may provide additional information for prognosis and rehabilitation plans.

Alzheimer's Disease-Related Dementias Summit 2019: National research priorities for the investigation of traumatic brain injury as a risk factor for Alzheimer's Disease and Related Dementias

TBI is a risk factor for later life dementia. Clinical and preclinical studies have elucidated multiple mechanisms through which TBI may influence or exacerbate multiple pathological processes underlying Alzheimer's Disease and Alzheimer's Disease Related Dementias (AD/ADRD). The National Institutes of Health hosts triennial ADRD Summits to inform a national research agenda, and the 2019 ADRD Summit was the first to highlight 'TBI and AD/ADRD Risk' as an emerging topic in the field. A multidisciplinary committee of TBI researchers with relevant expertise reviewed extant literature, identified research gaps and opportunities, and proposed draft research recommendations at the 2019 ADRD Summit. These research recommendations, further refined after broad stakeholder input at the Summit, cover four overall areas: (1) Encourage crosstalk and interdisciplinary collaboration between TBI and dementia researchers, (2) Establish infrastructure to study TBI as a risk factor for AD/ADRD, (3) Promote basic and clinical research examining the development and progression of TBI AD/ADRD neuropathologies and associated clinical symptoms, and (4) Characterize the clinical phenotype of progressive dementia associated with TBI and develop non-invasive diagnostic approaches. These recommendations recognize a need to strengthen communication and build frameworks to connect the complexity of TBI with rapidly evolving AD/ADRD research. Recommendations acknowledge TBI as a clinically and pathologically heterogeneous disease whose associations with AD/ADRDs remain incompletely understood. The recommendations highlight the scientific advantage of investigating AD/ADRD in the context of a known TBI exposure, the study of which can directly inform on disease mechanisms and treatment targets for AD/ADRDs with shared common pathways.

Functional Outcome Trajectories Following Inpatient Rehabilitation for TBI in the United States: A NIDILRR TBIMS and CDC Interagency Collaboration

OBJECTIVE

To describe trajectories of functioning up to 5 years after traumatic brain injury (TBI) that required inpatient rehabilitation in the United States using individual growth curve models conditioned on factors associated with variability in functioning and independence over time.

DESIGN

Secondary analysis of population-weighted data from a multicenter longitudinal cohort study.

SETTING

Acute inpatient rehabilitation facilities.

PARTICIPANTS

A total of 4624 individuals 16 years and older with a primary diagnosis of TBI.

MAIN OUTCOME MEASURES

Ratings of global disability and supervision needs as reported by participants or proxy during follow-up telephone interviews at 1, 2, and 5 years postinjury.

RESULTS

Many TBI survivors experience functional improvement through 1 and 2 years postinjury, followed by a decline in functioning and decreased independence by 5 years. However, there was considerable heterogeneity in outcomes across individuals. Factors such as older age, non-White race, lower preinjury productivity, public payer source, longer length of inpatient rehabilitation stay, and lower discharge functional status were found to negatively impact trajectories of change over time.

CONCLUSIONS

These findings can inform the content, timing, and target recipients of interventions designed to maximize functional independence after TBI.

Dexmedetomidine Ameliorates Perioperative Neurocognitive Disorders by Suppressing Monocyte-Derived Macrophages in Mice With Preexisting Traumatic Brain Injury

BACKGROUND

Traumatic brain injury (TBI) initiates immune responses involving infiltration of monocyte-derived macrophages (MDMs) in the injured brain tissue. These MDMs play a key role in perioperative neurocognitive disorders (PNDs). We tested the hypothesis that preanesthetic treatment with dexmedetomidine (DEX) could suppress infiltration of MDMs into the hippocampus of TBI model mice, ameliorating PND.

METHODS

We first performed bone marrow transplantation from green fluorescent protein-transgenic mice to C57BL/6 mice to identify MDMs. We used only male mice for homogeneity. Four weeks after transplantation, a controlled cortical impact model of TBI was created using recipient mice. Four weeks after TBI, mice received pretreatment with DEX before general anesthesia (GA). Mice performed the Barnes maze test (8-12 mice/group) 2 weeks after GA and were euthanized for immunohistochemistry (4-5 mice/group) or immunoblotting (7 mice/group) 4 weeks after GA.

RESULTS

In Barnes maze tests, TBI model mice showed longer primary latency (mean difference, 76.5 [95% confidence interval, 41.4-111.6], P < .0001 versus Naïve), primary path length (431.2 [98.5-763.9], P = .001 versus Naïve), and more primary errors (5.7 [0.62-10.7], P = .017 versus Naïve) than Naïve mice on experimental day 3. Expression of MDMs in the hippocampus was significantly increased in TBI mice compared to Naïve mice (2.1 [0.6-3.7], P = .003 versus Naïve). Expression of monocyte chemotactic protein-1 (MCP1)-positive areas in the hippocampus was significantly increased in TBI mice compared to Naïve mice (0.38 [0.09-0.68], P = .007 versus Naïve). Immunoblotting indicated significantly increased expression of interleukin-1β in the hippocampus in TBI mice compared to Naïve mice (1.59 [0.08-3.1], P = .035 versus Naïve). In contrast, TBI mice pretreated with DEX were rescued from these changes and showed no significant difference from Naïve mice. Yohimbine, an α2 receptor antagonist, mitigated the effects of DEX (primary latency: 68.3 [36.5-100.1], P < .0001 versus TBI-DEX; primary path length: 414.9 [120.0-709.9], P = .0002 versus DEX; primary errors: 6.6 [2.1-11.2], P = .0005 versus TBI-DEX; expression of MDMs: 2.9 [1.4-4.4], P = .0001 versus TBI-DEX; expression of MCP1: 0.4 [0.05-0.67], P = .017 versus TBI-DEX; expression of interleukin-1β: 1.8 [0.34-3.35], P = .01 versus TBI-DEX).

CONCLUSIONS

Preanesthetic treatment with DEX suppressed infiltration of MDMs in the hippocampus and ameliorated PND in TBI model mice. Preanesthetic treatment with DEX appears to suppress infiltration of MDMs in the hippocampus and may lead to new treatments for PND in patients with a history of TBI.

Traumatic brain injury fast-forwards Alzheimer's pathology: evidence from amyloid positron emission tomorgraphy imaging

PURPOSE

Traumatic brain injury (TBI) has been proposed as a risk factor for Alzheimer's disease (AD), although the mechanisms underlying the putative association are poorly understood. We investigated elderly individuals with a remote history of TBI, aiming to understand how this may have influenced amyloidosis, neurodegeneration, and clinical expression along the AD continuum.

METHODS

Total of 241 individual datasets including amyloid beta (Aβ) positron emission tomography ([¹⁸F]-AV45), structural MRI, and neuropsychological measures, were obtained from the Alzheimer's Disease Neuroimaging Initiative. The data were stratified into groups with (TBI +) or without (TBI -) history of head injury, and by clinical dementia rating (CDR) scores, into subgroups with normal cognition (CDR = 0) and those with symptomatic cognitive decline (CDR ≥ 0.5). We contrasted the TBI + and TBI - subgroups with respect to the onset age and extent of cognitive decline, cortical thickness changes, and Aβ standard uptake value (SUVr).

RESULTS

Compared to the TBI -/CDR ≥ 0.5 subgroup, the TBI + /CDR ≥ 0.5 subgroup showed a 3-4 year earlier age of cognitive impairment onset (ACIO, p = 0.005). Among those participants on the AD continuum (Aβ + , as defined by a cortical SUVr ≥ 1.23), irrespective of current CDR, a TBI + history was associated with greater Aβ deposition and more pronounced cortical thinning. When matched for severity of cognitive status, the TBI + /CDR ≥ 0.5 group showed greater Aβ burden, but earlier ACIO as compared to the TBI -/CDR ≥ 0.5, suggesting a more indolent clinical AD progression in those with TBI history.

CONCLUSION

Remote TBI history may alter the AD onset trajectory, with approximately 4 years earlier ACIO, greater amyloid deposition, and cortical thinning.

Complex Autoantibody Responses Occur following Moderate to Severe Traumatic Brain Injury

Most of the variation in outcome following severe traumatic brain injury (TBI) remains unexplained by currently recognized prognostic factors. Neuroinflammation may account for some of this difference. We hypothesized that TBI generated variable autoantibody responses between individuals that would contribute to outcome. We developed a custom protein microarray to detect autoantibodies to both CNS and systemic Ags in serum from the acute-phase (the first 7 d), late (6-12 mo), and long-term (6-13 y) intervals after TBI in human patients. We identified two distinct patterns of immune response to TBI. The first was a broad response to the majority of Ags tested, predominantly IgM mediated in the acute phase, then IgG dominant at late and long-term time points. The second was responses to specific Ags, most frequently myelin-associated glycopeptide (MAG), which persisted for several months post-TBI but then subsequently resolved. Exploratory analyses suggested that patients with a greater acute IgM response experienced worse outcomes than predicted from current known risk factors, suggesting a direct or indirect role in worsening outcome. Furthermore, late persistence of anti-MAG IgM autoantibodies correlated with raised serum neurofilament light concentrations at these time points, suggesting an association with ongoing neurodegeneration over the first year postinjury. Our results show that autoantibody production occurs in some individuals following TBI, can persist for many years, and is associated with worse patient outcome. The complexity of responses means that conventional approaches based on measuring responses to single antigenic targets may be misleading.

National Institute of Neurological Disorders and Stroke Consensus Diagnostic Criteria for Traumatic Encephalopathy Syndrome

OBJECTIVE

To develop evidence-informed, expert consensus research diagnostic criteria for traumatic encephalopathy syndrome (TES), the clinical disorder associated with neuropathologically diagnosed chronic traumatic encephalopathy (CTE).

METHODS

A panel of 20 expert clinician-scientists in neurology, neuropsychology, psychiatry, neurosurgery, and physical medicine and rehabilitation, from 11 academic institutions, participated in a modified Delphi procedure to achieve consensus, initiated at the First National Institute of Neurological Disorders and Stroke Consensus Workshop to Define the Diagnostic Criteria for TES, April, 2019. Before consensus, panelists reviewed evidence from all published cases of CTE with neuropathologic confirmation, and they examined the predictive validity data on clinical features in relation to CTE pathology from a large clinicopathologic study (n = 298).

RESULTS

Consensus was achieved in 4 rounds of the Delphi procedure. Diagnosis of TES requires (1) substantial exposure to repetitive head impacts (RHIs) from contact sports, military service, or other causes; (2) core clinical features of cognitive impairment (in episodic memory and/or executive functioning) and/or neurobehavioral dysregulation; (3) a progressive course; and (4) that the clinical features are not fully accounted for by any other neurologic, psychiatric, or medical conditions. For those meeting criteria for TES, functional dependence is graded on 5 levels, ranging from independent to severe dementia. A provisional level of certainty for CTE pathology is determined based on specific RHI exposure thresholds, core clinical features, functional status, and additional supportive features, including delayed onset, motor signs, and psychiatric features.

CONCLUSIONS

New consensus diagnostic criteria for TES were developed with a primary goal of facilitating future CTE research. These criteria will be revised as updated clinical and pathologic information and in vivo biomarkers become available.

Patterns of Functional Change Five to Ten Years after Moderate-Severe Traumatic Brain Injury

This study aims to characterize the patterns of functional change experienced between 5 and 10 years after moderate-severe traumatic brain injury (TBI). The study included TBI Model Systems national database participants (N = 372) at six sites who experienced TBI, received inpatient rehabilitation, and were followed at 5 and 10 years post-TBI. Outcome measures included self- or proxy-reported Functional Independence Measure (FIM^TM) structured interview at 5 and 10 years post-TBI and domain change indices (DCIs) at 10 years to assess subjective change over the previous 5 years. When all seven FIM and subjective DCI subscales were considered together, 69% reported improvement in at least one subscale and 41% reported decline in at least one subscale; 51% reported more domains improved than declined, and 20% reported more domains declined than improved. Age at injury, post-traumatic amnesia duration, FIM, and depression and anxiety at year 5 were associated with FIM change and DCI measures. Although most persons with moderate-severe TBI do not experience widespread change from year 5 to 10 on individual FIM subscales or perceived domain-specific subscales, the vast majority do report change in one or more domains, with more improvement than decline and more change in subjective DCI than in FIM. Clinicians and researchers should be alert to the possibility of both positive and deleterious changes many years after TBI.

Abnormal dorsal attention network activation in memory impairment after traumatic brain injury

Memory impairment is a common, disabling effect of traumatic brain injury. In healthy individuals, successful memory encoding is associated with activation of the dorsal attention network as well as suppression of the default mode network. Here, in traumatic brain injury patients we examined whether: (i) impairments in memory encoding are associated with abnormal brain activation in these networks; (ii) whether changes in this brain activity predict subsequent memory retrieval; and (iii) whether abnormal white matter integrity underpinning functional networks is associated with impaired subsequent memory. Thirty-five patients with moderate-severe traumatic brain injury aged 23-65 years (74% males) in the post-acute/chronic phase after injury and 16 healthy control subjects underwent functional MRI during performance of an abstract image memory encoding task. Diffusion tensor imaging was used to assess structural abnormalities across patient groups compared to 28 age-matched healthy controls. Successful memory encoding across all participants was associated with activation of the dorsal attention network, the ventral visual stream and medial temporal lobes. Decreased activation was seen in the default mode network. Patients with preserved episodic memory demonstrated increased activation in areas of the dorsal attention network. Patients with impaired memory showed increased left anterior prefrontal activity. White matter microstructure underpinning connectivity between core nodes of the encoding networks was significantly reduced in patients with memory impairment. Our results show for the first time that patients with impaired episodic memory show abnormal activation of key nodes within the dorsal attention network and regions regulating default mode network activity during encoding. Successful encoding was associated with an opposite direction of signal change between patients with and without memory impairment, suggesting that memory encoding mechanisms could be fundamentally altered in this population. We demonstrate a clear relationship between functional networks activated during encoding and underlying abnormalities within the structural connectome in patients with memory impairment. We suggest that encoding failures in this group are likely due to failed control of goal-directed attentional resources.

Combined Memory Training: An Approach for Episodic Memory Deficits in Traumatic Brain Injury

Purpose The study aimed to test a combination of semantic memory and traditional episodic memory therapies on episodic memory deficits in adults with traumatic brain injury. Method Twenty-five participants who had been diagnosed with traumatic brain injury and had episodic memory deficits were randomly assigned either to a combined memory treatment group (n = 16) or to a wait-list control group (n = 9). Before and after treatment, they completed standardized neuropsychological testing for episodic memory and related cognitive domains, including the California Verbal Learning Test-Second Edition, the Controlled Oral Word Association Test, the University of Southern California Repeatable Episodic Memory Test, the Wechsler Abbreviated Scale of Intelligence-Second Edition Matrices, the Test of Everyday Attention, the Memory Assessment Clinics Self-Rating Scale, the Expressive Vocabulary Test-Second Edition, and the Story Recall subtest from the Rivermead Behavioural Memory Test. In addition to a traditional episodic memory therapy, the treatment group received a novel semantic memory-focused therapy, which involved participants finding meaningful connections between diverse concepts represented by sets of two or three words. Results The treatment group demonstrated statistically significant improvement in memory for list learning tasks, and there was a significant difference from pretest to posttest between the treatment group and the wait-list control group. Clinical significance was demonstrated for the treatment group using minimally important difference calculations. Conclusion Combined memory therapy resulted in significant improvements in episodic memory, semantic memory, and attention, in comparison to no treatment. Supplemental Material https://doi.org/10.23641/asha.14049968.

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.

Differential neuropathology and functional outcome after equivalent traumatic brain injury in aged versus young adult mice

The CDC estimate that nearly 3 million Americans sustain a traumatic brain injury (TBI) each year. Even when medical comorbidities are accounted for, age is an independent risk factor for poor outcome after TBI. Nonetheless, few studies have examined the pathophysiology of age-linked biologic outcomes in TBI. We hypothesized that aged mice would demonstrate more severe neuropathology and greater functional deficits as compared to young adult mice after equivalent traumatic brain injuries. Young adult (14-week-old) and aged (80-week-old) C57BL/6 male mice underwent an open-head controlled cortical impact to induce TBI or a sham injury. At 30-days post-injury groups underwent behavioral phenotyping, magnetic resonance imaging, and histologic analyses. Contrary to our hypothesis, young adult TBI mice exhibited more severe neuropathology and greater loss of white matter connectivity as compared to aged mice after TBI. These findings correlated to differential functional outcomes in anxiety response, learning, and memory between young adult and aged mice after TBI. Although the mechanisms underlying this age-effect remain unclear, attenuated signs of secondary brain injury in aged TBI mice point towards different inflammatory and repair processes between age groups. These data suggest that age may need to be an a priori consideration in future clinical trial design.

Effects of neurological music therapy on behavioural and emotional recovery after traumatic brain injury: A randomized controlled cross-over trial

Traumatic brain injury (TBI) causes deficits in executive function (EF), as well as problems in behavioural and emotional self-regulation. Neurological music therapy may aid these aspects of recovery. We performed a cross-over randomized controlled trial where 40 persons with moderate-severe TBI received a 3-month neurological music therapy intervention (2 times/week, 60 min/session), either during the first (AB, n = 20) or second (BA, n = 20) half of a 6-month follow-up period. The evidence from this RCT previously demonstrated that music therapy enhanced general EF and set shifting. In the current study, outcome was assessed with self-report and caregiver-report questionnaires performed at baseline, 3-month, 6-month, and 18-month stages. The results showed that the self-reported Behavioural Regulation Index of the Behaviour Rating Inventory of Executive Function (BRIEF-A) improved more in the AB than BA group from baseline to 3-month stage and the effect was maintained in the 6-month follow-up. No changes in mood or quality of life questionnaires were observed. However, a qualitative content analysis of the feedback revealed that many participants experienced the intervention as helpful in terms of emotional well-being and activity. Our results suggest that music therapy has a positive effect on everyday behavioural regulation skills after TBI.

Neuropathophysiological Mechanisms and Treatment Strategies for Post-traumatic Epilepsy

Traumatic brain injury (TBI) is a leading cause of death in young adults and a risk factor for acquired epilepsy. Severe TBI, after a period of time, causes numerous neuropsychiatric and neurodegenerative problems with varying comorbidities; and brain homeostasis may never be restored. As a consequence of disrupted equilibrium, neuropathological changes such as circuit remodeling, reorganization of neural networks, changes in structural and functional plasticity, predisposition to synchronized activity, and post-translational modification of synaptic proteins may begin to dominate the brain. These pathological changes, over the course of time, contribute to conditions like Alzheimer disease, dementia, anxiety disorders, and post-traumatic epilepsy (PTE). PTE is one of the most common, devastating complications of TBI; and of those affected by a severe TBI, more than 50% develop PTE. The etiopathology and mechanisms of PTE are either unknown or poorly understood, which makes treatment challenging. Although anti-epileptic drugs (AEDs) are used as preventive strategies to manage TBI, control acute seizures and prevent development of PTE, their efficacy in PTE remains controversial. In this review, we discuss novel mechanisms and risk factors underlying PTE. We also discuss dysfunctions of neurovascular unit, cell-specific neuroinflammatory mediators and immune response factors that are vital for epileptogenesis after TBI. Finally, we describe current and novel treatments and management strategies for preventing PTE.

Traumatic Brain Injury Causes Chronic Cortical Inflammation and Neuronal Dysfunction Mediated by Microglia

Traumatic brain injury (TBI) can lead to significant neuropsychiatric problems and neurodegenerative pathologies, which develop and persist years after injury. Neuroinflammatory processes evolve over this same period. Therefore, we aimed to determine the contribution of microglia to neuropathology at acute [1 d postinjury (dpi)], subacute (7 dpi), and chronic (30 dpi) time points. Microglia were depleted with PLX5622, a CSF1R antagonist, before midline fluid percussion injury (FPI) in male mice and cortical neuropathology/inflammation was assessed using a neuropathology mRNA panel. Gene expression associated with inflammation and neuropathology were robustly increased acutely after injury (1 dpi) and the majority of this expression was microglia independent. At 7 and 30 dpi, however, microglial depletion reversed TBI-related expression of genes associated with inflammation, interferon signaling, and neuropathology. Myriad suppressed genes at subacute and chronic endpoints were attributed to neurons. To understand the relationship between microglia, neurons, and other glia, single-cell RNA sequencing was completed 7 dpi, a critical time point in the evolution from acute to chronic pathogenesis. Cortical microglia exhibited distinct TBI-associated clustering with increased type-1 interferon and neurodegenerative/damage-related genes. In cortical neurons, genes associated with dopamine signaling, long-term potentiation, calcium signaling, and synaptogenesis were suppressed. Microglial depletion reversed the majority of these neuronal alterations. Furthermore, there was reduced cortical dendritic complexity 7 dpi, reduced neuronal connectively 30 dpi, and cognitive impairment 30 dpi. All of these TBI-associated functional and behavioral impairments were prevented by microglial depletion. Collectively, these studies indicate that microglia promote persistent neuropathology and long-term functional impairments in neuronal homeostasis after TBI.SIGNIFICANCE STATEMENT Millions of traumatic brain injuries (TBIs) occur in the United States alone each year. Survivors face elevated rates of cognitive and psychiatric complications long after the inciting injury. Recent studies of human brain injury link chronic neuroinflammation to adverse neurologic outcomes, suggesting that evolving inflammatory processes may be an opportunity for intervention. Here, we eliminate microglia to compare the effects of diffuse TBI on neurons in the presence and absence of microglia and microglia-mediated inflammation. In the absence of microglia, neurons do not undergo TBI-induced changes in gene transcription or structure. Microglial elimination prevented TBI-induced cognitive changes 30 d postinjury (dpi). Therefore, microglia have a critical role in disrupting neuronal homeostasis after TBI, particularly at subacute and chronic timepoints.

Neurocognitive performance and mental health of retired female football players compared to non-contact sport athletes

Background

Adverse long-term effects of playing football due to repetitive head impact exposure on neurocognition and mental health are controversial. To date, no studies have evaluated such effects in women.

Aims

To (1) compare neurocognitive performance, cognitive symptoms and mental health in retired elite female football players (FB) with retired elite female non-contact sport athletes (CON), and to (2) assess whether findings are related to history of concussion and/or heading exposure in FB.

Methods

Neurocognitive performance, mental health and cognitive symptoms were assessed using computerised tests (CNS-vital signs), paper pen tests (Category fluency, Trail-Making Test, Digit Span, Paced Auditory Serial Addition Test), questionnaires (Hospital Anxiety and Depression Scale, SF-36v2 Health Survey) and a symptom checklist. Heading exposure and concussion history were self-reported in an online survey and in a clinical interview, respectively. Linear regression was used to analyse the effect of football, concussion and heading exposure on outcomes adjusted for confounders.

Results

FB (n=66) performed similar to CON (n=45) on neurocognitive tests, except for significantly lower scores on verbal memory (mean difference (MD)=−7.038, 95% CI −12.98 to –0.08, p=0.038) and verbal fluency tests (MD=−7.534, 95% CI –13.75 to –0.46, p=0.016). Among FB weaker verbal fluency performance was significantly associated with ≥2 concussions (MD=−10.36, 95% CI –18.48 to –2.83, p=0.017), and weaker verbal memory performance with frequent heading (MD=−9.166, 95% CI –17.59 to –0.123, p=0.041). The depression score differed significantly between study populations, and was significantly associated with frequent heading but not with history of concussion in FB.

Conclusion

Further studies should investigate the clinical relevance of our findings and whether the observed associations point to a causal link between repetitive head impacts and verbal memory/fluency or mental health.

Functional Change from Five to Fifteen Years after Traumatic Brain Injury

Few studies have assessed the long-term functional outcomes of traumatic brain injury (TBI) in large, well-characterized samples. Using the Traumatic Brain Injury Model Systems cohort, this study assessed the maintenance of independence between years 5 and 15 post-injury and risk factors for decline. The study sample included 1381 persons with TBI who received inpatient rehabilitation, survived to 15 years post-injury, and were available for data collection at 5 or 10 years and 15 years post-injury. The Functional Independence Measure (FIM) and Disability Rating Scale (DRS) were used to measure functional outcomes. The majority of participants had no changes during the 10-year time frame. For FIM, only 4.4% showed decline in Self-Care, 4.9% declined in Mobility, and 5.9% declined in Cognition. Overall, 10.4% showed decline in one or more FIM subscales. Decline was detected by DRS Level of Function (24% with >1-point change) and Employability (6% with >1-point change). Predictors of decline factors across all measures were age >25 years and, across most measures, having less than or equal to a high school education. Additional predictors of FIM decline included male sex (FIM Mobility and Self-Care) and longer rehabilitation length of stay (FIM Mobility and Cognition). In contrast to studies reporting change in the first 5 years post-TBI inpatient rehabilitation, a majority of those who survive to 15 years do not experience functional decline. Aging and cognitive reserve appear to be more important drivers of loss of function than original severity of the injury. Interventions to identify those at risk for decline may be needed to maintain or enhance functional status as persons age with a TBI.

Traumatic Brain Injury and Risk of Long-Term Brain Changes, Accumulation of Pathological Markers, and Developing Dementia: A Review

Traumatic brain injuries (TBI) have received widespread media attention in recent years as being a risk factor for the development of dementia and chronic traumatic encephalopathy (CTE). This has sparked fears about the potential long-term effects of TBI of any severity on cognitive aging, leading to a public health concern. This article reviews the evidence surrounding TBI as a risk factor for the later development of changes in brain structure and function, and an increased risk of neurodegenerative disorders. A number of studies have shown evidence of long-term brain changes and accumulation of pathological biomarkers (e.g., amyloid and tau proteins) related to a history of moderate-to-severe TBI, and research has also demonstrated that individuals with moderate-to-severe injuries have an increased risk of dementia. While milder injuries have been found to be associated with an increased risk for dementia in some recent studies, reports on long-term brain changes have been mixed and often are complicated by factors related to injury exposure (i.e., number of injuries) and severity/complications, psychiatric conditions, and opioid use disorder. CTE, although often described as a neurodegenerative disorder, remains a neuropathological condition that is poorly understood. Future research is needed to clarify the significance of CTE pathology and determine whether that can explain any clinical symptoms. Overall, it is clear that most individuals who sustain a TBI (particularly milder injuries) do not experience worse outcomes with aging, as the incidence for dementia is found to be less than 7% across the literature.

Factors predicting rehabilitation outcomes after severe acquired brain injury in trauma, stroke and anoxia populations: A cohort study

Severe acquired brain injury has long-term physical and cognitive effects. Identifying patient variables predictive of recovery in different brain injury populations would generate improved prognostic information and help rehabilitation teams set appropriate therapeutic goals. This cohort study of 447 NHS neurorehabilitation inpatients aimed to identify functional and cognitive predictors of recovery following severe acquired brain injury caused by trauma, stroke and anoxia. Motor and cognitive impairment ratings were collected at admission and discharge using the Functional Independence Measure and Functional Assessment Measure (FIM+FAM), and injury-related and demographic data were collated from medical records. Predictors of physical, cognitive and overall recovery were identified via hierarchical regression analyses. Several key findings emerged. Firstly, on-admission motor skills predicted functional and overall outcomes across groups. Secondly, on-admission social interaction skills predicted cognitive discharge outcomes in stroke and trauma, and overall outcomes for stroke, but did not predict anoxia outcomes. Thirdly, age predicted all forms of recovery for stroke only. Further group-specific factors were also identified as predicting motor and cognitive recovery, indicating that factors key to the rehabilitation trajectory may differ between populations. These variables should be considered in rehabilitation goal planning, although further research is required to explore their contributions to recovery.

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.

Neuroimaging and Psychometric Assessment of Mild Cognitive Impairment After Traumatic Brain Injury

Traumatic brain injury (TBI) can be serious partly due to the challenges of assessing and treating its neurocognitive and affective sequelae. The effects of a single TBI may persist for years and can limit patients’ activities due to somatic complaints (headaches, vertigo, sleep disturbances, nausea, light or sound sensitivity), affective sequelae (post-traumatic depressive symptoms, anxiety, irritability, emotional instability) and mild cognitive impairment (MCI, including social cognition disturbances, attention deficits, information processing speed decreases, memory degradation and executive dysfunction). Despite a growing amount of research, study comparison and knowledge synthesis in this field are problematic due to TBI heterogeneity and factors like injury mechanism, age at or time since injury. The relative lack of standardization in neuropsychological assessment strategies for quantifying sequelae adds to these challenges, and the proper administration of neuropsychological testing relative to the relationship between TBI, MCI and neuroimaging has not been reviewed satisfactorily. Social cognition impairments after TBI (e.g., disturbed emotion recognition, theory of mind impairment, altered self-awareness) and their neuroimaging correlates have not been explored thoroughly. This review consolidates recent findings on the cognitive and affective consequences of TBI in relation to neuropsychological testing strategies, to neurobiological and neuroimaging correlates, and to patient age at and assessment time after injury. All cognitive domains recognized by the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) are reviewed, including social cognition, complex attention, learning and memory, executive function, language and perceptual-motor function. Affect and effort are additionally discussed owing to their relationships to cognition and to their potentially confounding effects. Our findings highlight non-negligible cognitive and affective impairments following TBI, their gravity often increasing with injury severity. Future research should study (A) language, executive and perceptual-motor function (whose evolution post-TBI remains under-explored), (B) the effects of age at and time since injury, and (C) cognitive impairment severity as a function of injury severity. Such efforts should aim to develop and standardize batteries for cognitive subdomains—rather than only domains—with high ecological validity. Additionally, they should utilize multivariate techniques like factor analysis and related methods to clarify which cognitive subdomains or components are indeed measured by standardized tests.

Association of traumatic brain injury with dementia and memory decline in older adults in the United States

INTRODUCTION

To examine associations of history of traumatic brain injuries (TBIs) with loss of consciousness (LOC) with dementia incidence and memory decline.

METHODS

We studied 2718 participants from the 1992 enrollment cohort of the Health and Retirement Study (HRS) aged 65 years or older in 2000. History of TBI with LOC was self-reported in 1992. Dementia was assessed using four algorithms established in HRS. Participants were followed from 2000 to 2014 with repeated measures of dementia and memory performance. Cox models and linear mixed-effects models were used.

RESULTS

In 1992, 11.9% of the participants reported a history of TBI with LOC. In fully adjusted models for all four algorithms, participants with a history of TBI with LOC had no statistically significant difference in dementia incidence nor in memory decline, compared to participants without TBI history.

DISCUSSION

Our study did not find evidence of a long-term association between history of TBI with LOC (of unknown frequency and severity) and dementia incidence or memory decline.

Measurement properties of instruments to assess mental function during activity and participation in individuals surviving traumatic brain injury: A systematic review protocol

Background: Most studies assessing mental function in individuals with traumatic brain injury (TBI) assess the impairments through pen and paper tests. However, weak correlation has been found between the results from pen and paper tests and the results from performance-based tests during activity and participation. Objective: To investigate measurement properties of performance-based instruments that are used to assess mental function during activity and participation in individuals with a TBI. Material and methods: PubMed, EMBASE, CINAHL, PsycINFO, and OTseeker will be searched for relevant studies reporting on measurement properties of performance-based instruments to assess mental function in individuals with a TBI. The COnsensus-based Standards for selection of Health Measurement Instruments (COSMIN) checklist will be used to evaluate the methodological quality of the included studies. The Terwee quality criteria will be applied to evaluate the study findings for each measurement property. To summarize all the evidence, a best evidence synthesis will be performed. Results: Results will be presented in text and tables. Conclusions: Conclusion will be drawn up-on the overall evidence Significance: It is expected that the findings of the review will provide evidence to guide clinicians in the selection of instruments to use in occupational therapy practice and research.

A Clinicopathological Report of a 93-Year-Old Former Street Boxer With Coexistence of Chronic Traumatic Encephalopathy, Alzheimer's Disease, Dementia With Lewy Bodies, and Hippocampal Sclerosis With TDP-43 Pathology

Chronic traumatic encephalopathy (CTE) was recently recognized as a new tauopathy in which multifocal perivascular phosphorylated tau aggregates accumulate in neurons, astrocytes, and neurites at the depths of the cortical sulci. Traumatic brain injury (TBI) in early or mid-life is known to be associated with an increased risk of dementia in late life. This case report describes a 93-year-old former street boxer with a premortem diagnosis of severe dementia, who showed pathological evidence of the coexistence of Alzheimer's disease, CTE, dementia with Lewy bodies, and hippocampal sclerosis with TDP-43 pathology. These findings suggest that TBI may trigger a variety of misfolded proteins leading to dementia. Currently, clear clinical diagnostic criteria for CTE have not been established. Therefore, clinicians should be aware that TBI is a risk factor for dementia and that CTE can overlap with other neurodegenerative diseases.

Enduring and Sex-specific Changes in Hippocampal Gene Expression after a Subchronic Immune Challenge

Major illnesses, including heart attack and sepsis, can cause cognitive impairments, depression, and progressive memory decline that persist long after recovery from the original illness. In rodent models of sepsis or subchronic immune challenge, memory deficits also persist for weeks or months, even in the absence of ongoing neuroimmune activation. This raises the question of what mechanisms in the brain mediate such persistent changes in neural function. Here, we used RNA-sequencing as a large-scale, unbiased approach to identify changes in hippocampal gene expression long after a subchronic immune challenge previously established to cause persistent memory impairments in both males and females. We observed enduring dysregulation of gene expression three months after the end of a subchronic immune challenge. Surprisingly, there were striking sex differences in both the magnitude of changes and the specific genes and pathways altered, where males showed persistent changes in both immune- and plasticity-related genes three months after immune challenge, whereas females showed few such changes. In contrast, females showed striking differential gene expression in response to a subsequent immune challenge. Thus, immune activation has enduring and sex-specific consequences for hippocampal gene expression and the transcriptional response to subsequent stimuli. Together with findings of long-lasting memory impairments after immune challenge, these data suggest that illnesses can cause enduring vulnerability to, cognitive decline, affective disorders, and memory impairments via dysregulation of transcriptional processes in the brain.

Measurement properties of performance-based instruments to assess mental function during activity and participation in traumatic brain injury: A systematic review

Background: Performance-based measures that focus primarily on the ability to engage in ADL are routinely used by occupational therapists to assess a client's cognitive abilities.Objective: To perform a systematic review to investigate measurement properties of performance-based instruments to assess mental function during activity and participation in individuals with traumatic brain injury.Material and methods: Pubmed, EMBASE, CINAHL, PsycINFO and OTseeker were searched. The Consensus-based Standards for the selection of health measurement instruments checklist was used to evaluate methodological quality of each included study. The quality criteria adapted by Terwee were applied to extract the results of each measurement property followed by a best evidence synthesis.Results: Twenty-eight articles, including 40 ratings of measurement properties, were included. The combination of the Functional Independence Measure and the Functional Assessment Measure showed moderate evidence of good internal consistency (Cronbach's alpha 0.99), but conflicting evidence of reliability (ICC 0.83) and poor evidence of construct validity. All other instruments showed limited or unknown evidence.Conclusions: This review provides an overview of measurement properties of performance-based instruments and contributes to such methodological considerations before choosing an instrument. Though, the results reveal a lack of high-quality evidence for any of the measurement properties, it is recommended to use tools with the highest possible evidence for positive ratings.Significance: This review contributes with psychometric evidence on instruments to use in occupational therapy practice and research.

Is a structured work task application for the assessment of work performance in a constructed environment, useful for patients with attention deficits?

BACKGROUND

The purpose of our study was to develop a Structured Work Task application for the Assessment of Work Performance for patients with attention deficits.

MATERIAL AND METHODS

We developed a computer-based registration task titled the Attention-demanding Registration Task. It had a structured administrative procedure with additional scoring regarding time and accuracy, also linked to the original scoring of the Assessment of Work Performance. We evaluated the Attention-demanding Registration Task for content validity. Furthermore, we investigated it concerning sensitivity and specificity in patients with attention deficits due to acquired brain injury (n = 65) against a comparison group of healthy people (n = 47).

RESULTS

Our investigation on content validity using the Assessment of Work Characteristics confirmed that the Attention-demanding Registration Task sets high demands on process skills, especially on energy, temporal organization, and adaptation. The Attention-demanding Registration Task showed high sensitivity and specificity in differing between patients with attention deficits and a healthy working group; nine out of ten participants were placed in the correct group.

CONCLUSIONS

To assess work performance, the use of a Structured Work Task application, the Attention-demanding Registration Task, linked with the Assessment of Work Performance, proved to be sensitive to attention deficits.Implications for rehabilitationA Structured Work Task application for the Assessment of Work Performance was developed for use in people with attention deficits and showing a high degree of sensitivity and specificity.Linking performance time and accuracy to the Assessment of Work Performance scoring and providing a guide for linking task performance to the Assessment of Work Performance skills in addition to the usual observations performed, may increase scoring accuracy.Reference data for a comparison group of healthy subjects are provided.The use of the Attention demanding Registration Task, while using the Assessment of Work Performance within clinical practice ensures a more accurate description of process skills in performance.