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

Ageing with Traumatic Brain Injury: Long-Term Cognition and Wellbeing

Whether and how traumatic brain injury (TBI) impacts ageing in the decades post-injury remains a matter of debate, partly due to a lack of controlled studies. This study examined the long-term impact of TBI on cognition and wellbeing in middle-aged and older adults and explored the relationship between age, cognition, and wellbeing, compared with a non-TBI control group. Cross-sectional data from 143 participants aged ≥40 with moderate-severe TBI (6-33 years post-injury; mean age 59.64) were compared with 71 non-TBI controls (mean age 62.10) group matched on age, gender, and premorbid IQ. Individuals with significant confounding comorbidities were excluded. A battery of neuropsychological tests and wellbeing measures (emotional distress, sleep, health-related quality of life [HRQoL]) was administered. Older age and TBI were each independently associated with poorer cognition across multiple domains (p < 0.05). The relationship between verbal learning and memory impairment post-TBI differed between age groups: individuals with TBI in their 40s-60s performed significantly worse than same-aged controls on verbal story acquisition (B = 0.09, p = 0.040, 95% confidence interval [CI] [0.004, 0.17]) and recall (B = 0.12, p = 0.009, 95% CI [0.03, 0.21]), and verbal wordlist recall (B = 0.11, p = 0.007, 95% CI [0.03, 0.19]). In comparison, no significant group differences in verbal memory emerged for ages 70-90. The TBI group reported greater emotional distress (B = 3.55, p < 0.001, 95% CI [1.73, 5.37]), poorer sleep quality (B = 1.07, p = 0.016, 95% CI [0.20, 1.94]), and poorer physical HRQoL (B = -4.26, p = 0.003, 95% CI [-7.08, -1.43]) than controls at all ages. Poorer physical HRQoL was related to poorer cognition post-TBI (p < 0.05). Our results challenge the notion that TBI exacerbates ageing. Moderate-severe TBI resulted in significant long-term impairments in cognition and wellbeing, with verbal learning and memory more impaired during middle-adulthood but not older adulthood compared to controls. TBI was not associated with changes to wellbeing with ageing. Intervention for verbal memory deficits in middle-aged adults with TBI is important, along with wider long-term supports for cognition, wellbeing, and activity participation in all individuals with TBI.

Blood-Based Protein Biomarkers in the Chronic Phase of Traumatic Brain Injury: A Systematic Review

There has been limited exploration of blood-based biomarkers in the chronic period following traumatic brain injury (TBI). Our objective was to conduct a systematic review of studies examining blood-based protein biomarkers with at least one sample collected 12 months post-TBI in adults (≥16 years). Database searches were conducted in Embase, MEDLINE, and Science Citation Index-Expanded on July 24, 2023. Risk of bias was assessed using modified Joanna Briggs Institute critical appraisal tools. Only 30 of 12,523 articles met inclusion criteria, with samples drawn from 12 months to 48 years. Higher quality evidence (low risk of bias; large samples) identified promising inflammatory biomarkers at 12 months post-injury in both moderate-severe TBI (GFAP) and mild TBI (eotaxin-1, IFN-y, IL-8, IL-9, IL-17A, MCP-1, MIP-1β, FGF-basic, and TNF-α). Studies with low risk of bias but smaller samples also suggest NSE, MME, and CRP may be informative, alongside protein variants for α-syn (10H, D5), amyloid-β (A4, C6T), TDP-43 (AD-TDP 1;2;3;9;11), and tau (D11C). Findings for NfL were inconclusive. Longitudinal data were mostly available for acute samples followed until 12 months post-injury, with limited evaluation of changes beyond 12 months. Associations of some blood-based biomarkers with cognitive, sleep, and functional outcomes were reported. The overall strength of the evidence in this review was limited by the risk of bias and small sample sizes. Replication is required within prospective longitudinal studies that move beyond 12 months post-injury. Novel efforts should be guided by promising neurodegenerative-disease markers and use panels to model polypathology.

Plasma biomarkers in chronic single moderate-severe traumatic brain injury

Blood biomarkers are an emerging diagnostic and prognostic tool that reflect a range of neuropathological processes following traumatic brain injury (TBI). Their effectiveness in identifying long-term neuropathological processes after TBI is unclear. Studying biomarkers in the chronic phase is vital because elevated levels in TBI might result from distinct neuropathological mechanisms during acute and chronic phases. Here, we examine plasma biomarkers in the chronic period following TBI and their association with amyloid and tau PET, white matter microarchitecture, brain age and cognition. We recruited participants ≥40 years of age who had suffered a single moderate-severe TBI ≥10 years previously between January 2018 and March 2021. We measured plasma biomarkers using single molecule array technology [ubiquitin C-terminal hydrolase L1 (UCH-L1), neurofilament light (NfL), tau, glial fibrillary acidic protein (GFAP) and phosphorylated tau (P-tau181)]; PET tracers to measure amyloid-β (18F-NAV4694) and tau neurofibrillary tangles (18F-MK6240); MRI to assess white matter microstructure and brain age; and the Rey Auditory Verbal Learning Test to measure verbal-episodic memory. A total of 90 post-TBI participants (73% male; mean = 58.2 years) were recruited on average 22 years (range = 10-33 years) post-injury, and 32 non-TBI control participants (66% male; mean = 57.9 years) were recruited. Plasma UCH-L1 levels were 67% higher {exp(b) = 1.67, P = 0.018, adjusted P = 0.044, 95% confidence interval (CI) [10% to 155%], area under the curve = 0.616} and P-tau181 were 27% higher {exp(b) = 1.24, P = 0.011, adjusted P = 0.044, 95% CI [5% to 46%], area under the curve = 0.632} in TBI participants compared with controls. Amyloid and tau PET were not elevated in TBI participants. Higher concentrations of plasma P-tau181, UCH-L1, GFAP and NfL were significantly associated with worse white matter microstructure but not brain age in TBI participants. For TBI participants, poorer verbal-episodic memory was associated with higher concentration of P-tau181 {short delay: b = -2.17, SE = 1.06, P = 0.043, 95% CI [-4.28, -0.07]; long delay: bP-tau = -2.56, SE = 1.08, P = 0.020, 95% CI [-4.71, -0.41]}, tau {immediate memory: bTau = -6.22, SE = 2.47, P = 0.014, 95% CI [-11.14, -1.30]} and UCH-L1 {immediate memory: bUCH-L1 = -2.14, SE = 1.07, P = 0.048, 95% CI [-4.26, -0.01]}, but was not associated with functional outcome. Elevated plasma markers related to neuronal damage and accumulation of phosphorylated tau suggest the presence of ongoing neuropathology in the chronic phase following a single moderate-severe TBI. Plasma biomarkers were associated with measures of microstructural brain disruption on MRI and disordered cognition, further highlighting their utility as potential objective tools to monitor evolving neuropathology post-TBI.

The impact of age on outcome 2 years after traumatic brain injury: Case control study

BACKGROUND

Age is associated with outcome after traumatic brain injury (TBI). However, there are mixed findings across outcome domains and most studies lack controls.

OBJECTIVES

This cross-sectional study examined the association between age group (15-24 years, 25-34 years, 35-44 years, 45-54 years, 55-64 years, and 65 years or more) and outcomes 2 years after TBI in independence in daily activities, driving, public transportation use, employment, leisure activities, social integration, relationships and emotional functioning, relative to healthy controls. It was hypothesized that older individuals with TBI would have significantly poorer outcomes than controls in all domains except anxiety and depression, for which it was expected they would show better outcomes. Global functional outcome (measured using the Glasgow Outcome Scale-Extended) was also examined, and we hypothesized that older adults would have poorer outcomes than younger adults.

METHODS

Participants were 1897 individuals with TBI (mean, SD age 36.7, 17.7 years) who completed measures 2 years post-injury and 110 healthy controls (age 38.3, 17.5 years).

RESULTS

Compared to controls, individuals with TBI were less independent in most activities of daily living, participated less in leisure activities and employment, and were more socially isolated, anxious and depressed (p < 0.001). Those who were older in age were disproportionately less likely to be independent in light domestic activities, shopping and driving; and participated less in occupational activities relative to controls. Functional outcome was significantly higher in the youngest age group than in all older age groups (p < 0.001), but the younger groups were more likely to report being socially isolated (p < 0.001), depressed (p = 0.005) and anxious (p = 0.02), and less likely to be married or in a relationship (p < 0.001).

CONCLUSION

A greater focus is needed on addressing psychosocial issues in younger individuals with TBI, whereas those who are older may require more intensive therapy to maximise independence in activities of daily living and return to employment.

Factors Contributing to Life-Change Adaptation in Family Caregivers of Community-Dwelling Individuals with Acquired Brain Injury

Acquired brain injury (ABI) is a public health issue that affects family caregivers, because individuals with ABI often require semi-permanent care and community support in daily living. Identifying the characteristics of family caregivers and individuals with ABI and examining life-change adaptation may provide valuable insights. The current study sought to explore the factors contributing to life-change adaptation in family caregivers of community-dwelling individuals with ABI. As a secondary analysis, a cross-sectional study was conducted using data obtained in a previous study of 1622 family caregivers in Japan. We hypothesized that life-change adaptation in family caregivers of individuals with ABI would also be related to family caregivers' characteristics and the characteristics of individuals with ABI. In total, 312 valid responses were analyzed using Poisson regression analysis. The results revealed that life-change adaptation in family caregivers of individuals with ABI was related to sex (prevalence ratio [PR]: 0.65, confidence interval [CI]: -0.819;-0.041) and mental health (PR: 2.04, CI: 0.354; 1.070) as family caregivers' characteristics, and topographical disorientation (PR: 1.51, CI: 0.017; 0.805) and loss of control over behavior (PR: 1.61, CI: 0.116; 0.830) as the characteristics of individuals with ABI, after adjusting for the effects of the caregiver's age, sex, and the duration of the caregiver's role. The current study expands existing knowledge and provides a deeper understanding to enhance the development of specific policies for improving caregiving services and supporting families.

Long-term Multidomain Patterns of Change After Traumatic Brain Injury: A TRACK-TBI LONG Study

BACKGROUND AND OBJECTIVES

Traumatic brain injury (TBI) may be a chronic condition carrying risk of future sequelae; few prospective studies examine long-term postinjury outcomes. We examined the prevalence of functional, cognitive, and psychiatric change outcomes from 1 to 7 years postinjury.

METHODS

Transforming Research and Clinical Knowledge in TBI LONG (TRACK-TBI LONG) participants were prospectively enrolled within 24 hours of injury and followed up to 1 year postinjury; a subset participated in long-term follow-up from 2 to 7 years postinjury. Reliable change thresholds for the Brief Test of Adult Cognition by Telephone General Composite (cognition) and Brief Symptom Inventory (BSI)-18 (psychiatric) were derived from orthopedic trauma controls (OTCs). Multiple assessments were completed (postinjury baseline assessment and 2 or 3 visits 2-7 years postinjury) within a sample subset. Change was assessed for functional outcome (Glasgow Outcome Scale-Extended [GOSE]) and self-report/informant report of decline. Prevalence ratios for outcomes classified as stable, improved, and declined were reported individually and collectively. The Fisher exact test and log-binomial regression models examined factors associated with decline and improvement.

RESULTS

Of the sample (N = 1,264; mild TBI [mTBI], Glasgow Coma Scale [GCS] 13-15, n = 917; moderate-to-severe TBI [msTBI], GCS 3-12, n = 193; or OTC n = 154), "stable" was the most prevalent outcome. Functional outcome showed the highest rates of decline, regardless of TBI severity (mild = 29%; moderate/severe = 23%). When measures were collectively considered, rates of decline included mTBI (21%), msTBI (26%), and OTC (15%). Age and preinjury employment status were associated with functional decline (per 10 years; relative risk [RR] 1.16, 95% CI 1.07-1.25, p < 0.001; higher in retired/disabled/not working vs full-time/part-time; RR 1.81, 95% CI 1.33-2.45, respectively) in the mTBI group. Improvement in functional recovery 2-7 years postinjury was associated with higher BSI scores (per 5 points; RR 1.11, 95% CI 1.04-1.18, p = 0.002) and GOSE score of 5-7 (GOSE = 8 as reference; RR 2.64, 95% CI 1.75-3.97, p < 0.001). Higher BSI scores and identifying as Black (RR 2.28, 95% CI 1.59-3.25, p < 0.001) were associated with a greater likelihood of improved psychiatric symptoms in mTBI (RR 1.21, 95% CI 1.14-1.29, p < 0.001). A greater likelihood of cognitive improvement was observed among those with higher educational attainment in msTBI (per 4 years; RR 2.61, 95% CI 1.43-4.79, p = 0.002).

DISCUSSION

Function across domains at 1-year postinjury, a common recovery benchmark, undergoes change across the subsequent 6 years. Results support consideration of TBI as a chronic evolving condition and suggest continued monitoring, rehabilitation, and support is required to optimize long-term independence and quality of life.

Brain age estimation reveals older adults' accelerated senescence after traumatic brain injury

Adults aged 60 and over are most vulnerable to mild traumatic brain injury (mTBI). Nevertheless, the extent to which chronological age (CA) at injury affects TBI-related brain aging is unknown. This study applies Gaussian process regression to T1-weighted magnetic resonance images (MRIs) acquired within [Formula: see text]7 days and again [Formula: see text]6 months after a single mTBI sustained by 133 participants aged 20-83 (CA [Formula: see text] = 42.6 ± 17 years; 51 females). Brain BAs are estimated, modeled, and compared as a function of sex and CA at injury using a statistical model selection procedure. On average, the brains of older adults age by 15.3 ± 6.9 years after mTBI, whereas those of younger adults age only by 1.8 ± 5.6 years, a significant difference (Welch's t32 =  - 9.17, p ≃ 9.47 × 10-11). For an adult aged [Formula: see text]30 to [Formula: see text]60, the expected amount of TBI-related brain aging is [Formula: see text]3 years greater than in an individual younger by a decade. For an individual over [Formula: see text]60, the respective amount is [Formula: see text]7 years. Despite no significant sex differences in brain aging (Welch's t108 = 0.78, p > 0.78), the statistical test is underpowered. BAs estimated at acute baseline versus chronic follow-up do not differ significantly (t264 = 0.41, p > 0.66, power = 80%), suggesting negligible TBI-related brain aging during the chronic stage of TBI despite accelerated aging during the acute stage. Our results indicate that a single mTBI sustained after age [Formula: see text]60 involves approximately [Formula: see text]10 years of premature and lasting brain aging, which is MRI detectable as early as [Formula: see text]7 days post-injury.