Risk of dementia after TBI - a cause of growing concern

Head Trauma in Refugees and Asylum Seekers: A Systematic Review

BACKGROUND AND OBJECTIVES

Refugees and asylum seekers are at risk of head trauma. They endure blows to the head due to exigent circumstances necessitating resettlement (e.g., torture, war, interpersonal violence) and during their dangerous journeys to refuge. Our objective was to assess the global prevalence of head trauma in refugees and asylum seekers and describe its clinical characteristics in this population.

METHODS

The protocol was registered in the PROSPERO International Prospective Register of Systematic Reviews (CRD42020173534). PubMed/MEDLINE, PsycInfo, Web of Science, Embase, and Google Scholar databases were searched for relevant studies. We included all studies in English that comprised refugees or asylum seekers of any age and examined the prevalence or characteristics of head trauma. We excluded studies that were not peer-reviewed original research. Information was recorded on the prevalence of head trauma, method of ascertaining head trauma, severity, mechanism of injury, other trauma exposures, and comorbidities. Descriptive analyses and narrative syntheses were performed.

RESULTS

A total of 22 studies were included, of which 13 with 6,038 refugees and asylum seekers reported head trauma prevalence. Prevalence estimates ranged from 9% to 78%. Heterogeneity among studies precluded meta-analysis. Most studies were US based (n = 9, 41%), followed by the Middle East (n = 5, 23%). Most refugees or asylum seekers were from the Middle East (n = 9, 41%), with those from Latin America least represented (n = 3, 14%). Studies disproportionately involved younger (pooled mean age = 29 years) adult samples composed of men. Recruitment settings were predominantly hospitals/clinics (n = 14, 64%), followed by refugee camps (n = 3, 14%). The most common mechanism of injury was direct impact through a beating or blow to the head. Studies varied greatly in how head trauma was defined and ascertained; no study used a validated traumatic brain injury (TBI)-specific screening tool. Similarly, TBI severity was not uniformly assessed, although hospital-based samples captured more moderate-to-severe head injuries. Mental health comorbidities were more frequently documented rather than physical health ones. Only 2 studies included a comparison with local populations.

DISCUSSION

Refugees and asylum seekers are vulnerable to head trauma, but studies using systematic approaches to screening are lacking. Increased attention to head trauma in displaced populations will allow for optimizing equitable care for this growing vulnerable population.

A single closed head injury in male adult mice induces chronic, progressive white matter atrophy and increased phospho-tau expressing oligodendrocytes

Traumatic brain injury (TBI) acutely damages the brain; this injury can evolve into chronic neurodegeneration. While much is known about the chronic effects arising from multiple mild TBIs, far less is known about the long-term effects of a single moderate to severe TBI. We found that a single moderate closed head injury to mice induces diffuse axonal injury within 1-day post-injury (DPI). At 14 DPI, injured animals have atrophy of ipsilesional cortex, thalamus, and corpus callosum, with bilateral atrophy of the dorsal fornix. Atrophy of the ipsilesional corpus callosum is accompanied by decreased fractional anisotropy and increased mean and radial diffusivity that remains unchanged between 14 and 180 DPI. Injured animals show an increased density of phospho-tau immunoreactive (pTau+) cells in the ipsilesional cortex and thalamus, and bilaterally in corpus callosum. Between 14 and 180 DPI, atrophy occurs in the ipsilesional ventral fornix, contralesional corpus callosum, and bilateral internal capsule. Diffusion tensor MRI parameters remain unchanged in white matter regions with delayed atrophy. Between 14 and 180 DPI, pTau+ cell density increases bilaterally in corpus callosum, but decreases in cortex and thalamus. The location of pTau+ cells within the ipsilesional corpus callosum changes between 14 and 180 DPI; density of all cells increases including pTau+ or pTau- cells. >90% of the pTau+ cells are in the oligodendrocyte lineage in both gray and white matter. Density of thioflavin-S+ cells in thalamus increases by 180 DPI. These data suggest a single closed head impact produces multiple forms of chronic neurodegeneration. Gray and white matter regions proximal to the impact site undergo early atrophy. More distal white matter regions undergo chronic, progressive white matter atrophy with an increasing density of oligodendrocytes containing pTau. These data suggest a complex chronic neurodegenerative process arising from a single moderate closed head injury.

Dementia and the aging population: cognitive screening within correctional health

PURPOSE

The purpose of this study was to examine the literature surrounding dementia in the aging correctional population and assess the role of cognitive screening related to dementia detection within corrections. The literature regarding the role of dementia within the justice continuum is scant. Furthermore, correctional health researchers have not reached a consensus on the best age to administer cognitive screening in older persons or prioritizes a screening tool for the early detection of dementia.

DESIGN/METHODOLOGY/APPROACH

A key search term list including dementia screening and was developed to review the literature surrounding dementia and the aging correctional population. PubMed, Criminal Justice Abstracts (Ebsco) and the National Criminal Justice Reference Service were used within the academic search. A gray literature search using these same search terms was conducted reviewing criminal justice federal agencies and organizations for additional information on the dementia experience within correctional settings. Snowballing was used to capture relevant theoretical and empirical knowledge.

FINDINGS

Shortages in aging specialized health-care staffing presents a barrier for the clinical interpretation of Montreal Cognitive Assessment (MoCA) results. Correctional officers are also identified as useful candidates within the administration of cognitive screening with proper training. The MoCA may be the optimal cognitive screening tool for dementia, until an original cognitive screening tool is created specific to the correctional population. An age of 55 years or older may serve as the best cutoff score for classifying incarcerated individuals as older persons, and screening should be prioritized for these individuals. Finally, new specialized programs related to dementia within correctional settings are identified.

RESEARCH LIMITATIONS/IMPLICATIONS

A limitation of this research is the conflicting opinions among researchers regarding the use of general cognitive screening tools within the correctional setting.

ORIGINALITY/VALUE

This research can inform correctional organizational policy and practices regarding the screening of older persons suspected of dementia. Most notably, this research proposes that correctional settings should incorporate the MoCA within initial screening of all individuals 55 years of age or older, enriching the job design of correctional officer's job positions to include cognitive testing, and for correctional settings to provide dementia and age-associated training for correctional officers. Finally, this paper informs future research in the development of a cognitive assessment tool specific to the correctional population.

Neuronally-derived tau is increased in experienced breachers and is associated with neurobehavioral symptoms

Military and law enforcement breachers are exposed to many low-level blasts during their training and occupational experiences in which they detonate explosives to force entry into secured structures. There is a concern that exposure to these repetitive blast events in career breachers could result in cumulative neurological effects. This study aimed to determine concentrations of neurofilament light (NF-L), tau, and amyloid-beta 42 (Aβ42) in serum and in neuronal-derived extracellular vesicles (EVs) in an experienced breacher population, and to examine biomarker associations with neurobehavioral symptoms. Thirty-four participants enrolled in the study: 20 experienced breachers and 14 matched military or civilian law enforcement controls. EV tau concentrations were significantly elevated in experienced breachers (0.3301 ± 0.5225) compared to controls (-0.4279 ± 0.7557; F = 10.43, p = 0.003). No statistically significant changes were observed in EV levels of NF-L or Aβ42 or in serum levels of NF-L, tau, or Aβ42 (p's > 0.05). Elevated EV tau concentrations correlated with increased Neurobehavioral Symptom Inventory (NSI) score in experienced breachers (r = 0.596, p = 0.015) and predicted higher NSI score (F(1,14) = 7.702, p = 0.015, R² = 0.355). These findings show that neuronal-derived EV concentrations of tau are significantly elevated and associated with neurobehavioral symptoms in this sample of experienced breachers who have a history of many low-level blast exposures.

Magnetic Resonance Spectroscopy following Mild Traumatic Brain Injury: A Systematic Review and Meta-Analysis on the Potential to Detect Posttraumatic Neurodegeneration

INTRODUCTION

Traumatic brain injury (TBI) is the most relevant external risk factor for dementia and a major global health burden. Mild TBI (mTBI) contributes to up to 90% of all TBIs, and the classification "mild" often misrepresents the patient's burden who suffer from neuropsychiatric long-term sequelae. Magnetic resonance spectroscopy (MRS) allows in vivo detection of compromised brain metabolism although it is not routinely used after TBI.

OBJECTIVE

Thus, we performed a systematic review and meta-analysis to elucidate if MRS has the potential to identify changes in brain metabolism in adult patients after a single mTBI with a negative routine brain scan (CCT and/or MRI scan) compared to aged- and sex-matched healthy controls (HC) during the acute or subacute postinjury phase (≤90 days after mTBI).

METHODS

A comprehensive literature search was conducted from the first edition of electronic databases until January 31, 2020. Group analyses were performed per metabolite using a random-effects model.

RESULTS

Four and 2 out of 5,417 articles met the inclusion criteria for the meta-analysis and systematic review, respectively. For the meta-analysis, 50 mTBI patients and 51 HC with a mean age of 31 and 30 years, respectively, were scanned using N-acetyl-aspartate (NAA), a marker for neuronal integrity. Glutamate (Glu), a marker for disturbed brain metabolism, choline (Cho), a marker for increased cell membrane turnover, and creatine (Cr) were used in 2 out of the 4 included articles. Regions of interests were the frontal lobe, the white matter around 1 cm above the lateral ventricles, or the whole brain. NAA was decreased in patients compared to HC with an effect size (ES) of -0.49 (95% CI -1.08 to 0.09), primarily measured in the frontal lobe. Glu was increased in the white matter in 22 mTBI patients compared to 22 HC (ES 0.79; 95% CI 0.17-1.41). Cho was decreased in 31 mTBI patients compared to 31 HC (ES -0.31; 95% CI -0.81 to 0.19). Cr was contradictory and, therefore, potentially not suitable as a reference marker after mTBI.

CONCLUSIONS

MRS pinpoints changes in posttraumatic brain metabolism that correlate with cognitive dysfunction and, thus, might possibly help to detect mTBI patients at risk for unfavorable outcome or posttraumatic neurodegeneration early.

VISSA-PLS-DA-Based Metabolomics Reveals a Multitargeted Mechanism of Traditional Chinese Medicine for Traumatic Brain Injury

Metabolomics is an emerging tool to uncover the complex pathogenesis of disease, as well as the multitargets of traditional Chinese medicines, with chemometric analysis being a key step. However, conventional algorithms are not suitable for directly analyzing data at all times. The variable iterative space shrinkage approach-partial least squares-discriminant analysis, a novel algorithm for data mining, was first explored to screen metabolic varieties to reveal the multitargets of Xuefu Zhuyu decoction (XFZY) against traumatic brain injury (TBI) by the 7th day. Rat plasma from Sham, Vehicle, and XFZY groups was used for gas chromatography/mass spectrometry-based metabolomics. This method showed an improved discrimination ability (area under the curve = 93.64%). Threonine, trans-4-hydroxyproline, and creatinine were identified as the direct metabolic targets of XFZY against TBI. Five metabolic pathways affected by XFZY in TBI rats, were enriched using Metabolic Pathway Analysis web tool (i.e., phenylalanine, tyrosine, and tryptophan biosynthesis; phenylalanine metabolism; galactose metabolism; alanine, aspartate, and glutamate metabolism; and tryptophan metabolism). In conclusion, metabolomics coupled with variable iterative space shrinkage approach-partial least squares-discriminant analysis model may be a valuable tool for identifying the holistic molecular mechanisms involved in the effects of traditional Chinese medicine, such as XFZY.