Contribution of brain or biological reserve and cognitive or neural reserve to outcome after TBI: A meta-analysis (prior to 2015)

Long-term cognitive and affective consequences of mild traumatic brain injury: comparison with older adults

OBJECTIVE

Memory and affective processing were compared in young adults with a remote mild traumatic brain injury (mTBI), to healthy younger and older adults. We evaluated memory performance when encoding was done under multi-tasking (divided attention) conditions, likely to exacerbate cognitive and psychological symptoms in mTBI.

METHODS

Participants studied pairs of unrelated words under either full or divided attention conditions. Memory for single words (item memory) and for pairs of words (associative memory) was then assessed in sequential independent recognition tests, under full attention.

RESULTS

Associative memory was poorer than item memory, and worse when encoding was done under divided than full attention. The decline in recognition accuracy from full to divided attention conditions on the associative memory test was significantly greater in mTBI compared to young adults and was similar in magnitude to that observed in older adults under full attention. Self-reported mental and total fatigue increased significantly as performance on the memory tests, following the divided attention condition, decreased, but only in the mTBI group.

CONCLUSIONS

Results show lingering memory deficits, and suggest that cognitive tasks may be experienced as psychologically more demanding in those with a mTBI, even months or years after injury.

Mild Traumatic Brain Injury in the Maturing Brain: An Investigation of Symptoms and Cognitive Performance in Soldiers Returning From Afghanistan and Iraq

OBJECTIVE

The majority of traumatic brain injuries (TBIs) are classified as mild and occur in young individuals. The course of recovery varies but can result in chronic or troubling outcomes. The impact of age on TBI outcomes in young adults before complete brain maturation is not well studied.

METHODS

In this study, we compared the effects of mild TBI on cognitive performance and self-reported TBI symptoms and posttraumatic stress disorder (PTSD) in 903 soldiers in 3 different age groups: 24 years or younger, 25 to 27 years, and 28 to 40 years. The soldiers had returned from war zones in Iraq and were screened for TBI within a few days of return. Cognitive performance was measured with the Automated Neuropsychological Assessment Metrics of Military TBI Version 4 (ANAM4). Symptoms associated with mild TBI were self-reported on the Neurobehavioral Symptom Inventory, and the PTSD Checklist-Civilian Version (PCL-C).

RESULTS

Soldiers with TBI in every age group had significantly higher prevalence of most symptoms than those with no TBI. Soldiers with TBI also reported more chronic pain sites, regardless of age. Soldiers aged 28 to 40 years with TBI had the lowest cognitive performance scores (ANAM) across several subtests, both unadjusted and adjusted. The Global Deficit Score was significantly higher for soldiers aged 28 to 40 years and 25 to 27 years with TBI than for soldiers younger than 24 years with no TBI. After adjusting for PTSD symptoms, education, and number of lifetime TBIs, the overall test battery mean for soldiers aged 28 to 40 years with TBI was significantly lower than for soldiers younger than 24 years with no TBI.

CONCLUSION

Soldiers with mild TBI in the younger age group show more symptoms associated to frontal lobe function while soldiers in the older group suffer more cognitive impairment. This may warrant further study as it may indicate a propensity to later cognitive decline among soldiers who were older at the time of injury.

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

BACKGROUND

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

AIMS

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

METHOD

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

RESULTS

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

CONCLUSIONS

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

Traumatic Brain Injury Characteristics Are Not Related to Neurocognitive Decline in Older Adults: A Nationwide Longitudinal Cohort Study

OBJECTIVE

Evaluate whether traumatic brain injury (TBI) characteristics, age of injury, or recency of injury predicts the course of neurocognitive decline and/or increases conversion rates to mild cognitive impairment (MCI) or dementia.

METHODS

Data were obtained from the National Alzheimer's Coordinating Center for participants 50-85 years old with 3-5 visits from 2015 to 2022, with or without TBI history (TBI+ = 508; TBI- = 2,382). Groups were stratified by self-reported TBI history (i.e., single TBI without loss of consciousness [LOC], single TBI with LOC, multiple TBI without LOC, and multiple TBI with LOC), age of most recent TBI, and recency of TBI. Mixed linear models compared neuropsychological composite trajectories (executive functioning/attention/speed, language, memory, and global), co-varying for age, gender, education, apolipoprotein E4 status, race/ethnicity, and baseline diagnosis (normal aging n = 1,720, MCI n = 749, or dementia n = 417). Logistic binary regression examined MCI/dementia conversion rates.

RESULTS

There was a slightly higher frequency of MCI/dementia in those with multiple TBIs (50% to 60% with and without LOC, compared to 39% with no TBI) at baseline, but longitudinal trajectories were similar. TBI history, age of injury, or recency of injury did not impact neurocognitive trajectories or conversion rates to MCI/dementia (all p's > .01).

CONCLUSIONS

TBI history, regardless of injury characteristics, age of injury, or recency of injury, did not worsen neurocognitive decline or MCI/dementia conversion. Additional longitudinal research in more diverse cohorts with a wider range of TBI severity is needed to evaluate the specific factors and possible mechanisms in which TBI may increase dementia risk.

Reserve-building as a buffer for depression among individuals living with disability: a longitudinal study of current activities related to brain health

Aims

This study examined whether reserve-building activities are associated with attenuated reported depression among people who were disabled from work due to a medical condition as compared to employed, retired, and unemployed participants.

Methods

This secondary analysis included 771 individuals who provided data at three time points: baseline (late Spring 2020), follow-up 1 (Spring 2021), and follow-up 2 (Fall 2021). The DeltaQuest Reserve-Building Measure assessed current activities related to brain health. An analysis of variance and Pearson correlation coefficients assessed group differences in reserve-building activity scores. Classification and regression tree (CART) modeling investigated factors associated with higher and lower reported depression by employment group. The random effects (RE) models tested two buffering hypotheses: (1) comparing all groups to the employed group and (2) examining within-group effects.

Results

Engaging in outdoor activities, exercise, and religious/spiritual activities was associated with reduced depression over time in the overall sample. While disabled participants endorsed lower levels of being Active in the World, Outdoor activities, and Exercise and higher levels of Inner Life and Passive Media Consumption than the other employment groups, more reserve-building activities distinguished depression levels in the disabled group's CART models compared to the others. Among the disabled, unemployed, and retired participants, engaging in any reserve-building activities was also associated with lower depression scores, which was distinct from the employed participants. In the RE models that used the employed group as the reference category, only the disabled group's level of depression was buffered by engaging in creative activities. In the within-group RE models, the disabled group's engagement in Religious/Spiritual, Outdoors, and Games was associated with substantially reduced within-group depression, which was different from the other employment groups. In contrast, reserve-building activities were not implicated at all as buffers for employed participants.

Conclusion

This study revealed a beneficial effect of reserve-building activities on buffering depression over time during the COVID-19 pandemic, particularly for disabled people. It documented that even if such individuals engaged in lesser amounts of such activities as compared to other employment groups, the buffering effect was substantial. Given the low-cost and accessible nature of reserve-building activities, it would be worthwhile to encourage such activities for disabled individuals.

Measures of cognitive reserve: An umbrella review

Objective: Recently, there has been a growing interest in operationalizing and measuring cognitive reserve (CR) for clinical and research purposes. This umbrella review aims to summarize the existing systematic and meta-analytic reviews about measures of CR. Method: A literature search was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) and the guidelines of Aromataris et al. (2015) to identify the systematic reviews and meta-analysis involving the assessment of CR. The methodological quality of the papers included in this umbrella review was assessed with A Measurement Tool to Assess Systematic Reviews 2 (AMSTAR-2) and Specialist Unit for Review Evidence (SURE). Results: Thirty-one reviews were identified, sixteen of which were systematic reviews, and fifteen were meta-analyses. Most of the reviews had a critically low quality, according to AMSTAR-2. The reviews included between two and 135 studies. Most of the papers focused on older adults, mainly those with dementia. CR was measured using one to six proxies, but most considered each proxy separately. The most assessed proxies of CR were education on its own, combined with occupation and/or engagement in activities or combined with parental education, bilingualism, and engagement in activities when four CR proxies were studied. Most of the studies included in higher quality reviews focused on three proxies, with education and engagement in activities being the most evaluated using CR questionnaires. Conclusion: Despite the growing interest in measuring CR, its operationalization did not improve since the last umbrella review in this field.

Selecting patients for early interdisciplinary rehabilitation during neurointensive care after moderate to severe traumatic brain injury

BACKGROUND

Early interdisciplinary rehabilitation (EIR) in neurointensive care is a limited resource reserved for patients with moderate to severe traumatic brain injury (TBI) believed to profit from treatment. We evaluated how key parameters related to injury severity and patient characteristics were predictive of receiving EIR, and whether these parameters changed over time.

METHODS

Among 1003 adult patients with moderate to severe TBI admitted over 72 h to neurointensive care unit during four time periods between 2005 and 2020, EIR was given to 578 and standard care to 425 patients. Ten selection criteria thought to best represent injury severity and patient benefit were evaluated (Glasgow Coma Scale, Head Abbreviated Injury Scale, New-Injury-Severity-Scale, intracranial pressure monitoring, neurosurgery, age, employment, Charlson Comorbidity Index, severe psychiatric disease, and chronic substance abuse).

RESULTS

In multivariate regression analysis, patients who were employed (adjOR 1.99 [95% CI 1.41, 2.80]), had no/mild comorbidity (adjOR 3.15 [95% CI 1.72, 5.79]), needed neurosurgery, had increasing injury severity and were admitted by increasing time period were more likely to receive EIR, whereas receiving EIR was less likely with increasing age (adjOR 0.97 [95% CI 0.96, 0.98]) and chronic substance abuse. Overall predictive ability of the model was 71%. Median age and comorbidity increased while employment decreased from 2005 to 2020, indicating patient selection became less restrictive with time.

CONCLUSION

Injury severity and need for neurosurgery remain important predictors for receiving EIR, but the importance of age, employment, and comorbidity have changed over time. Moderate prediction accuracy using current clinical criteria suggest unrecognized factors are important for patient selection.

Identification of Demographic and Clinical Prognostic Factors in Traumatic Intraventricular Hemorrhage

BACKGROUND

The presence of traumatic intraventricular hemorrhage (tIVH) following traumatic brain injury (TBI) is associated with worse neurological outcome. The mechanisms by which patients with tIVH have worse outcome are not fully understood and research is ongoing, but foundational studies that explore prognostic factors within tIVH populations are also lacking. This study aimed to further identify and characterize demographic and clinical variables within a subset of patients with TBI and tIVH that may be implicated in tIVH outcome.

METHODS

In this observational study, we reviewed a large prospective TBI database to determine variables present on admission that predicted neurological outcome 6 months after injury. A review of 7,129 patients revealed 211 patients with tIVH on admission and 6-month outcome data. Hypothesized risk factors were tested in univariate analyses with significant variables (p < 0.05) included in logistic and linear regression models. Following the addition of either the Rotterdam computed tomography or Glasgow Coma Scale (GCS) score, we employed a backward selection process to determine significant variables in each multivariate model.

RESULTS

Our study found that that hypotension (odds ratio [OR] = 0.35, 95% confidence interval [CI] = 0.13-0.94, p = 0.04) and the hemoglobin level (OR = 1.33, 95% CI = 1.09-1.63, p = 0.006) were significant predictors in the Rotterdam model, whereas only the hemoglobin level (OR = 1.29, 95% CI = 1.06-1.56, p = 0.01) was a significant predictor in the GCS model.

CONCLUSIONS

This study represents one of the largest investigations into prognostic factors for patients with tIVH and demonstrates that admission hemoglobin level and hypotension are associated with outcomes in this patient population. These findings add value to established prognostic scales, could inform future predictive modeling studies, and may provide potential direction in early medical management of patients with tIVH.

Cognitive reserve index and long-term disability in patients with severe traumatic brain injury discharged from the intensive rehabilitation unit

Objectives

The "cognitive reserve" (CR) theory posits that higher premorbid cognitive activities can mitigate the effects of brain damage. This study aimed to investigate the association between CR and long-term functional autonomy in patients surviving a severe traumatic brain injury (sTBI).

Setting

Data were collected from the database of inpatients with severe acquired brain injury in a rehabilitation unit admitted from August 2012 to May 2020.

Participants

Patients that had incurred an sTBI, aged 18+ years, completing the phone Glasgow Outcome Scale-Expanded at follow-up (pGOS-E) in absence of previous brain trauma or neurological disease, or cognitive disorders were included. Patients with severe brain injury from non-traumatic etiologies were not included in the study.

Design

In this longitudinal study, all patients underwent a multidimensional assessment including the cognitive reserve index questionnaire (CRIq), the coma recovery scale-revised, the level of cognitive functioning, the Disability Rating Scale (DRS), and the Galveston Orientation and Amnesia Test at admission. At discharge, functional scales were administered again together with the Glasgow Outcome Scale. The pGOS-E was assessed at follow-up.

Main measures

pGOS-E.

Results

A total of 106 patients/caregivers underwent the pGOS-E after 5.8 [3.6] years from the event. Among them, 46 (43.4%) died after discharge, and 60 patients [men: 48 (80%); median age: 54 years; median time post-onset: 37 days; median education level: 10 years; median CRIq total score: 91] were included in the analysis exploring the association between pGOS-E and demographic data, cognitive reserve surrogates, and clinical variables at admission and discharge from the rehabilitation unit. A younger age (B = -0.035, p = 0.004) and a lower DRS category at discharge (B = -0.392, p = 0.029) were significantly related to a higher long-term functional autonomy in the multivariate analysis.

Conclusion

Long-term functional autonomy was not influenced by CR as assessed through the educational level and the CRIq.

Relationships between predisposing, precipitating, and perpetuating factors and executive functioning following mild traumatic brain injury

INTRODUCTION

The aim of this study was to determine the sociodemographic and MTBI-related variables associated with executive functioning (EF).

METHODS

Based on the theoretical model of Hou and colleagues, data on predisposing (age, education, premorbid IQ), precipitating (post-traumatic amnesia, loss of consciousness, presence of frontal lesions, post-accident time to evaluation) and perpetuating (anxious and depressive affects and post-concussive symptoms) factors were retrospectively collected from the medical records of 172 patients with MTBI. EF data based on the 3 processes included in Miyake's prediction model (2000) (updating, cognitive flexibility and inhibition) were collected using respectively the Digit span task of the Weschler - 4^th edition, the Trails A and B as well as the initiation time on the Tower of London- Drexel University.

RESULTS

Updating was significantly associated with education, premorbid IQ, age, anxiety, and depressive affect. Inhibition was associated with education and age. No variable was associated with cognitive flexibility.

CONCLUSIONS

Following a MTBI, clinicians should consider that level of education and pre-morbid IQ may "predispose" patients to higher EF performances. They should also measure level of anxiety and depressive affect knowing that these may "perpetuate" some EF impairments (specifically the updating process).

Comparing Imaging Biomarkers of Cerebral Edema after TBI in Young Adult Male and Female Rats

Traumatic brain injury (TBI) is one of the leading causes of death and disability worldwide. Cerebral edema following TBI is known to play a critical role in injury severity and prognosis. In the current study we used multimodal magnetic resonance imaging (MRI) to assess cerebral edema 24 hours after unilateral contusive TBI in male and female rats. We then directly quantified brain water content in the same subjectsex vivo.We found that both males and females had similarly elevated T₂ values after TBI compared with sham controls. Apparent diffusion coefficient (ADC) was more variable than T₂ and did not show significant injury effects in males or females. Brain water was elevated in male TBI rats compared with sham controls, but there was no difference between female TBI and sham groups. Notably, MRI biomarkers of edema were more closely correlated with brain water in male rats; female rats did not show any relationship between brain water and T₂ or ADC. These observations raise questions about the interpretation of radiological findings traditionally interpreted as edema in female TBI patients. A better understanding of sex differences and similarities in the pathophysiology of post-traumatic edema is needed to help improve patient management and the development of effective treatment strategies for men and women.

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.

Social Support Buffers Against Cognitive Decline in Single Mild Traumatic Brain Injury With Loss of Consciousness: Results From the Canadian Longitudinal Study on Aging

OBJECTIVES

We investigated rates of cognitive decline at 3-year follow-up from initial examination in people reporting mild traumatic brain injury (mTBI) with loss of consciousness (LOC) more than a year prior to initial examination. We examined the role of social support as predictor of preserved cognitive function in this sample.

METHOD

Analyses were conducted on 440 participants who had self-reported LOC of <1 min, 350 with LOC of 1-20 min, and 10,712 healthy controls, taken from the Canadian Longitudinal Study on Aging (CLSA), a nationwide study on health and aging.

RESULTS

People who reported at baseline that they had experienced mTBI with LOC of 1-20 min more than a year prior were 60% more likely to have experienced global cognitive decline than controls at three-year follow-up. Cognitive decline was most apparent on measures of executive functioning. Logistic regression identified increased social support as predictors of relatively preserved cognitive function.

DISCUSSION

mTBI with longer time spent unconscious (i.e., LOC 1-20 min) is associated with greater cognitive decline years after the head injury. Perceived social support, particularly emotional support, may help buffer against this cognitive decline.

Duration of post-traumatic amnesia is uniquely associated with memory functioning in chronic moderate-to-severe traumatic brain injury

BACKGROUND

Disrupted memory circuitry may contribute to post-traumatic amnesia (PTA) after traumatic brain injury (TBI). It is unclear whether duration of PTA (doPTA) uniquely impacts memory functioning in the chronic post-injury stage.

OBJECTIVE

To examine the relationship between doPTA and memory functioning, independent of other cognitive abilities, in chronic moderate-to-severe TBI.

METHODS

Participants were 82 individuals (median chronicity = 10.5 years) with available doPTA estimates and neuropsychological data. Composite memory, processing speed (PS), and executive functioning (EF) performance scores, as well as data on subjective memory (SM) beliefs, were extracted. DoPTA-memory associations were evaluated via linear modeling of doPTA with memory performance and clinical memory status (impaired/unimpaired), controlling for PS, EF and demographic covariates. Interrelationships between doPTA, objective memory functioning, and SM were assessed.

RESULTS

DoPTA was significantly related to memory performance, even after covariate adjustment. Impairment in memory, but not PS or EF, was associated with a history of longer doPTA. SM was associated with memory performance, but unrelated to doPTA.

CONCLUSIONS

Findings suggest a specific association between doPTA-an acute injury phenomenon-and chronic memory deficits after TBI. Prospective studies are needed to understand how underlying mechanisms of PTA shape distinct outcome trajectories, particularly functional abilities related to memory processing.

Evaluation of neurotrophic factors and education level as predictors of cognitive decline in alcohol use disorder

Cognitive reserve (CR) is the capability of an individual to cope with a brain pathology through compensatory mechanisms developed through cognitive stimulation by mental and physical activity. Recently, it has been suggested that CR has a protective role against the initiation of substance use, substance consumption patterns and cognitive decline and can improve responses to treatment. However, CR has never been linked to cognitive function and neurotrophic factors in the context of alcohol consumption. The present cross-sectional study aims to evaluate the association between CR (evaluated by educational level), cognitive impairment (assessed using a frontal and memory loss assessment battery) and circulating levels of brain-derived neurotrophic factor (BDNF) and neurotrophin-3 (NT-3) in patients with alcohol use disorder (AUD). Our results indicated that lower educational levels were accompanied by earlier onset of alcohol consumption and earlier development of alcohol dependence, as well as impaired frontal cognitive function. They also suggest that CR, NT-3 and BDNF may act as compensatory mechanisms for cognitive decline in the early stages of AUD, but not in later phases. These parameters allow the identification of patients with AUD who are at risk of cognitive deterioration and the implementation of personalized interventions to preserve cognitive function.

Cognitive Reserve in Individuals Aging With Traumatic Brain Injury: Independent and Interactive Effects on Cognitive Functioning

OBJECTIVE

To examine the influence of 2 temporal factors-age and injury chronicity-on the relationship between cognitive reserve (CR) and cognitive functioning in older adults with chronic traumatic brain injury (TBI).

SETTING

Outpatient research laboratory.

PARTICIPANTS

Adults, 50 years or older, with a 1- to 45-year history of moderate or severe TBI (N = 108).

DESIGN

Cross-sectional observational study.

MAIN MEASURES

CR was estimated using demographically corrected performance on a word-reading test (an approximation of premorbid IQ). Injury chronicity was operationalized as number of years since the date of injury. Composite cognitive scores were computed from performances on neuropsychological tests of processing speed, executive functioning, and memory.

RESULTS

CR was positively and significantly related to all cognitive performances independent of age, injury chronicity, and injury severity. Greater injury chronicity significantly attenuated the effect of CR on processing speed such that individuals more distal from their injury date evidenced a weaker positive relationship between CR and performance.

CONCLUSION

Temporal factors may modify associations between CR and cognition. Findings suggest that the protective effects of CR are temporally delimited, potentially contending with declines in brain reserve. The prognostic value of traditional outcome determinants should be considered in the context of injury chronicity.

The Association Between Brain Reserve, Cognitive Reserve, and Neuropsychological and Functional Outcomes in Males With Chronic Moderate-to-Severe Traumatic Brain Injury

Purpose Moderate-to-severe traumatic brain injury (TBI) leads to significant neural and cognitive impairment, affecting functional outcome. This study investigated the chronic effects of moderate-to-severe TBI on brain reserve (BR), cognitive reserve (CR), and neuropsychological and functional outcome. Method The group with TBI consisted of 41 male participants with a primary diagnosis of moderate-to-severe closed head injury (time since injury [TSI], M = 6.12 years, range: 1-23, SD = 5.99, Mdn = 4). TBI survivors were compared to 24 neurotypical male participants, matched on age and education. Magnetic resonance imaging T1 anatomical images were used to calculate gray and white matter and cerebrospinal fluid volume. BR was calculated using the ventricle-to-brain ratio. CR was assessed using two hold measures: the Peabody Picture Vocabulary Test and the Pseudowords task. Functional outcome was measured using the Glasgow Outcome Scale-Extended. Results Neuropsychological performance of TBI survivors was significantly lower than their neurotypical controls, as measured by theoretically driven composites of verbal and visual memory, executive functions, attention, and CR. They presented greater ventricle-to-brain ratio volume, compared to noninjured controls, with higher scores indicating lower BR levels. Both BR and TSI were significantly associated with CR. Also, a median-split analysis revealed a TSI effect on CR. Significant associations were evident between the Glasgow Outcome Scale-Extended and the BR and CR measures. Conclusions Lingering neuropsychological deficits in chronic TBI support the role of BR and CR in functional outcome. Furthermore, TSI interferes with CR supporting the notion that TBI sets off a chronic neurodegenerative and progressive course that interferes with semantic knowledge. Supplemental Material https://doi.org/10.23641/asha.14049923.

Challenges of Prevention for a Sustainable Personalized Medicine

The development and implementation of the approaches of personalized medicine for disease prevention are still at infancy, although preventive activities in healthcare represent a key pillar to guarantee health system sustainability. There is an increasing interest in finding informative markers that indicate the disease risk before the manifestation of the disease (primary prevention) or for early disease detection (secondary prevention). Recently, the systematic collection and study of clinical phenotypes and biomarkers consented to the advance of Rehabilomics in tertiary prevention. It consents to identify relevant molecular and physiological factors that can be linked to plasticity, treatment response, and natural recovery. Implementation of these approaches would open avenues to identify people at high risk and enable new preventive lifestyle interventions or early treatments targeted to their individual genomic profile, personalizing prevention and rehabilitation. The integration of personalized medicine into prevention may benefit citizens, patients, healthcare professionals, healthcare authorities, and industry, and ultimately will seek to contribute to better health and quality of life for Europe’s citizens.

Persistent implicit motor learning alterations following a mild traumatic brain injury sustained during late adulthood

Introduction: The neurocognitive outcomes of sustaining a mild traumatic brain injury (mTBI) during late adulthood are vastly understudied. In young, asymptomatic adults, mTBI-related synaptic plasticity alterations have been associated with persistent implicit motor sequence learning impairments outlasting the usual cognitive recovery period. The current study examined whether uncomplicated mTBI sustained during late adulthood could exert persistent deleterious consequences on implicit motor sequence learning.Method: Thirty participants (aged 50-70 years) who experienced an uncomplicated mTBI within 3 to 24 months of testing, and 40 age-, sex- and education-equivalent healthy controls performed an implicit serial reaction time task (SRT task). The SRT task consisted of 10 blocks of a repeating sequence embedded among 4 random blocks. Participants also completed a battery of standardized neuropsychological tests of attention, memory and executive functioning.Results: While both mTBI participants and controls showed significant implicit motor sequence learning effects, the mTBI group achieved a lower level of competence at performing the SRT task as evidenced by smaller gains in reaction times across the 10 training blocks of the repeating sequence. The time elapsed since the injury was unrelated to implicit motor learning effects. There was no evidence of a persistent effect of mTBI on any neuropsychological domain compared to controls.Conclusions: Findings from this study suggest that a single mTBI sustained during older age may have persistent repercussions on training-dependent motor sequence learning capacity outlasting the recovery of mTBI symptoms and gold-standard neuropsychological tests performance.

The Influence of Family History of Neurodegenerative Disease on Adolescent Concussion Outcomes

Evidence suggests that factors associated with a family history of neurodegenerative disease (fhNDD) may influence outcomes following a concussion. However, the relevance of these findings in adolescent populations has not been fully explored. Therefore, the present study sought to evaluate the relationship between fhNDD and neurological outcomes following an adolescent concussion. Data from a local pediatric concussion clinic were used to compare adolescents with (n = 22) and without (n = 44) an fhNDD. Clinical symptom burden, emotional health, cardio-autonomic function, and cognitive performance were assessed at initial (~2 weeks) and follow-up (~5 weeks) post-injury evaluations. Cardio-autonomic function was assessed at rest and during isometric handgrip contraction (IHGC). Results indicated no significant group differences in emotional health or cognitive performance. Across evaluations, those with an fhNDD exhibited greater somatic symptom severity, alterations in HRV at rest, and early blunted cardio-autonomic reactivity during IHGC compared to those without an fhNDD. These findings suggest that positive fhNDD is negatively associated with clinical symptomology and cardio-autonomic functioning following an adolescent concussion. Further, these findings encourage clinicians to utilize a comprehensive neurological evaluation to monitor concussion recovery. Future studies should look into exploring the role of specific neurodegenerative processes and conditions on concussion outcomes in adolescents.

Early reading comprehension and speed of reading impairments in individuals with uncomplicated and complicated mild traumatic brain injury

PURPOSE

Several studies have investigated cognitive-communication disorders affecting oral expression skills following TBI but very few have dealt with reading comprehension abilities. The current study aims to measure reading comprehension and speed of reading in adults with uncomplicated and complicated mild traumatic brain injury (TBI) and to determine which demographic and TBI-related variables are predictive of their performance.

METHOD

The performances of three groups of participants were compared on the Chapman-Cook Speed of Reading Test (CCSRT). The CCSRT was administered in an acute care setting to 85 hospitalized participants with mild TBI showing traumatic cerebral lesions (complicated mild TBI), to 15 hospitalized participants with uncomplicated mild TBI (no cerebral lesions) and to 68 adults without TBI. Linear regression analyses were performed to determine which variables among sex, age, education, TBI severity (measured by the Glasgow Coma Scale score), speed of processing skills, and site of cerebral lesions significantly predicted CCSRT performances.

RESULTS

The control group showed a lower percentage of errors than both TBI groups. On the total score of the CCSRT, the uncomplicated and complicated TBI groups performed worse than the control group. Moreover, as age and speed of processing skills increased, and education decreased, the odds of having a lower score on the CCSRT increased.

CONCLUSION

These findings suggest that reading abilities are compromised after mild TBI. Furthermore, the CCSRT may be a useful bedside tool for clinicians who work with individuals with mild TBI.

The Impact of Medical Complications in Predicting the Rehabilitation Outcome of Patients With Disorders of Consciousness After Severe Traumatic Brain Injury

In this study, we sought to assess the predictors of outcome in patients with disorders of consciousness (DOC) after severe traumatic brain injury (TBI) during neurorehabilitation stay. In total, 96 patients with DOC (vegetative state, minimally conscious state, or emergence from minimally conscious state) were enrolled (69 males; mean age 43.6 ± 20.8 years) and the improvement of the degree of disability, as assessed by the Disability Rating Scale, was considered the main outcome measure. To define the best predictor, a series of demographical and clinical factors were modeled using a twofold approach: (1) logistic regression to evaluate a possible causal effect among variables; and (2) machine learning algorithms (ML), to define the best predictive model. Univariate analysis demonstrated that disability in DOC patients statistically decreased at the discharge with respect to admission. Genitourinary was the most frequent medical complication (MC) emerging during the neurorehabilitation period. The logistic model revealed that the total amount of MCs is a risk factor for lack of functional improvement. ML discloses that the most important prognostic factors are the respiratory and hepatic complications together with the presence of the upper gastrointestinal comorbidities. Our study provides new evidence on the most adverse short-term factors predicting a functional recovery in DOC patients after severe TBI. The occurrence of medical complications during neurorehabilitation stay should be considered to avoid poor outcomes.

Environmental and Cognitive Enrichment in Childhood as Protective Factors in the Adult and Aging Brain

Some recent studies have highlighted a link between a favorable childhood environment and the strengthening of neuronal resilience against the changes that occur in natural aging neurodegenerative disease. Many works have assessed the factors – both internal and external – that can contribute to delay the phenotype of an ongoing neurodegenerative brain pathology. At the crossroads of genetic, environmental and lifestyle factors, these relationships are unified by the concept of cognitive reserve (CR). This review focuses on the protective effects of maintaining this CR through the cognitive aging process, and emphasizes the most essential time in life for the development and strengthening of this CR. The in-depth study of this research shows that early stimulation with regard to social and sensory interactions, contributes to the proper development of cognitive, affective and psychosocial capacities. Childhood thus appears to be the most active phase in the development of CR, and as such we hypothesize that this constitutes the first essential period of primary prevention of pathological aging and loss of cognitive capacities. If this hypothesis is correct, early stimulation of the environment would therefore be considered as a true primary prevention and a public health issue. The earlier identification of neurodevelopmental disorders, which can affect personal and professional development across the lifespan, could therefore have longer-term impacts and provide better protection against aging.

Acute peripheral inflammation and post-traumatic sleep differ between sexes after experimental diffuse brain injury

Identifying differential responses between sexes following traumatic brain injury (TBI) can elucidate the mechanisms behind disease pathology. Peripheral and central inflammation in the pathophysiology of TBI can increase sleep in male rodents, but this remains untested in females. We hypothesized that diffuse TBI would increase inflammation and sleep in males more so than in females. Diffuse TBI was induced in C57BL/6J mice and serial blood samples were collected (baseline, 1, 5, 7 days post-injury [DPI]) to quantify peripheral immune cell populations and sleep regulatory cytokines. Brains and spleens were harvested at 7DPI to quantify central and peripheral immune cells, respectively. Mixed-effects regression models were used for data analysis. Female TBI mice had 77%-124% higher IL-6 levels than male TBI mice at 1 and 5DPI, whereas IL-1β and TNF-α levels were similar between sexes at all timepoints. Despite baseline sex differences in blood-measured Ly6Chigh monocytes (females had 40% more than males), TBI reduced monocytes by 67% in TBI mice at 1DPI. Male TBI mice had 31%-33% more blood-measured and 31% more spleen-measured Ly6G+ neutrophils than female TBI mice at 1 and 5DPI, and 7DPI, respectively. Compared with sham, TBI increased sleep in both sexes during the first light and dark cycles. Male TBI mice slept 11%-17% more than female TBI mice, depending on the cycle. Thus, sex and TBI interactions may alter the peripheral inflammation profile and sleep patterns, which might explain discrepancies in disease progression based on sex.

Cerebral white matter microstructural changes in isolated maxillofacial trauma and associated neuropsychological outcomes

Isolated traumatic maxillofacial injury without concomitant brain injury may cause delayed post-concussive symptoms. Early identification allows optimal diagnosis, prognostication, and therapeutic intervention. The aim of this prospective observational study was to investigate longitudinal microstructural changes of the white matter (WM) tracts based on diffusion tensor imaging (DTI) indices in patients with isolated maxillofacial injuries, immediately and 6 months post-trauma, and to correlate these DTI indices with neuropsychological changes observed. Twenty-one patients with isolated maxillofacial injuries and 21 age-matched controls were recruited. DTI was performed and indices were calculated for 50 WM tracts. The neuropsychological evaluation was done using the screening module of the Neuropsychological Assessment Battery. Patients were subjected to repeat DTI and neuropsychological evaluation at 6 months post-trauma. Reduced fractional anisotropy (FA) and increased median (MD) and radial diffusivity (RD) in the acute phase were seen in major association, projection, and commissural fibre bundles, indicative of vasogenic oedema. These changes correlated with attention and executive function deficits in the acute phase, as well as improvement in memory and visuospatial function in the chronic phase. Isolated maxillofacial trauma patients develop WM microstructural damage, which may impair cognitive performance acutely and over time. DTI indices can serve as predictive imaging biomarkers for long-term cognitive deficits in isolated maxillofacial injuries.

Cognitive Reserve from the Perspective of Preclinical Alzheimer Disease: 2020 Update

The concept of cognitive reserve (CR) was proposed to account for the discrepancy between levels of brain pathologic process or damage and clinical and cognitive function. We provide a detailed review of prospective longitudinal studies that have investigated the interaction between CR and Alzheimer disease (AD) biomarkers on clinical and cognitive outcomes among individuals with normal cognition at baseline. Current evidence is consistent with the view that higher levels of CR are associated with a delay in the onset of symptoms of mild cognitive impairment and that there may be multiple pathways by which CR exerts its protective effects.

Cognitive Reserve Moderates Cognitive Outcome After Mild Traumatic Brain Injury

OBJECTIVE

To investigate whether cognitive reserve moderates differences in cognitive functioning between patients with mild traumatic brain injury (MTBI) and controls without MTBI and to examine whether patients with postconcussion syndrome have lower cognitive functioning than patients without postconcussion syndrome at 2 weeks and 3 months after injury.

DESIGN

Trondheim MTBI follow-up study is a longitudinal controlled cohort study with cognitive assessments 2 weeks and 3 months after injury.

SETTING

Recruitment at a level 1 trauma center and at a general practitioner-run, outpatient clinic.

PARTICIPANTS

Patients with MTBI (n=160) according to the World Health Organization criteria, trauma controls (n=71), and community controls (n=79) (N=310).

MAIN OUTCOME MEASURES

A cognitive composite score was used as outcome measure. The Vocabulary subtest was used as a proxy of cognitive reserve. Postconcussion syndrome diagnosis was assessed at 3 months with the British Columbia Postconcussion Symptom Inventory.

RESULTS

Linear mixed models demonstrated that the effect of vocabulary scores on the cognitive composite scores was larger in patients with MTBI than in community controls at 2 weeks and at 3 months after injury (P=.001). Thus, group differences in the cognitive composite score varied as a function of vocabulary scores, with the biggest differences seen among participants with lower vocabulary scores. There were no significant differences in the cognitive composite score between patients with (n=29) and without (n=131) postconcussion syndrome at 2 weeks or 3 months after injury.

CONCLUSION

Cognitive reserve, but not postconcussion syndrome, was associated with cognitive outcome after MTBI. This supports the cognitive reserve hypothesis in the MTBI context and suggests that persons with low cognitive reserve are more vulnerable to reduced cognitive functioning if they sustain an MTBI.

Structural neuroimaging in mild traumatic brain injury: A chronic effects of neurotrauma consortium study

OBJECTIVES

The chronic effects of neurotrauma consortium (CENC) observational study is a multisite investigation designed to examine the long-term longitudinal effects of mild traumatic brain injury (mTBI). All participants in this initial CENC cohort had a history of deployment in Operation Enduring Freedom (Afghanistan), Operation Iraqi Freedom (Iraq), and/or their follow-on conflicts (Operation Freedom's Sentinel). All participants undergo extensive medical, neuropsychological, and neuroimaging assessments and either meet criteria for any lifetime mTBI or not. These assessments are integrated into six CENC core studies-Biorepository, Biostatistics, Data and Study Management, Neuroimaging, and Neuropathology.

METHODS

The current study outlines the quantitative neuroimaging methods managed by the Neuroimaging Core using FreeSurfer automated software for image quantification.

RESULTS

At this writing, 319 participants from the CENC observational study have completed all baseline assessments including the imaging protocol and tertiary data quality assurance procedures.

CONCLUSIONS/DISCUSSION

The preliminary findings of this initial cohort are reported to describe how the Neuroimaging Core manages neuroimaging quantification for CENC studies.

The Role of Cognitive Reserve in Recovery From Traumatic Brain Injury

OBJECTIVE

To examine whether cognitive reserve (CR) attenuates the initial impact of traumatic brain injury (TBI) on cognitive performance (neural reserve) and results in faster cognitive recovery rates in the first year postinjury (neural compensation), and whether the advantage of CR differs on the basis of the severity of TBI.

SETTING

Inpatient/outpatient clinics at an academic medical center.

PARTICIPANTS

Adults with mild TBI (mTBI; n = 28), complicated mild TBI (cmTBI; n = 24), and moderate to severe TBI (msevTBI; n = 57), and demographically matched controls (n = 66).

DESIGN

Retrospective, longitudinal cohort assessed at 1, 6, and 12 months postinjury.

MAIN MEASURES

Outcomes were 3 cognitive domains: processing speed/executive function, verbal fluency, and memory. Premorbid IQ, estimated with the Wechsler Test of Adult Reading, served as CR proxy.

RESULTS

Higher premorbid IQ was associated with better performance on cognitive domains at 1 month postinjury, and the effect of IQ was similarly beneficial for all groups. Cognitive recovery rate was moderated only by TBI severity; those with more severe TBI had faster recovery in the first year.

CONCLUSION

Results support only the neural reserve theory of CR within a TBI population and indicate that CR is neuroprotective, regardless of the degree of TBI. Higher premorbid CR does not allow for more rapid adaptation and recovery from injury.

The Influence of Cognitive Reserve on Recovery from Traumatic Brain Injury

Objective

we sought to determine the degree to which cognitive reserve, as assessed by the Test of Premorbid Functioning in combination with demographic variables, could act as a buffer against the effect of traumatic brain injury (TBI) on cognitive test performance.

Method

retrospective analysis of a cohort of 121 persons with TBI who completed the Wechsler Adult Intelligence Scale-Fourth Edition (WAIS-IV) within 1-12 months after injury.

Results

regression analyses indicated that cognitive reserve was a statistically significant predictor of all postinjury WAIS-IV factor index scores, after controlling for various premorbid and comorbid confounding variables. Only for Processing Speed did injury severity make an additional statistically significant contribution to the prediction model.

Conclusions

cognitive reserve has a protective effect with regard to the impact of TBI on cognitive test performance but this effect is imperfect and does not completely negate the effect of injury severity.

Effect of Cognitive Reserve on Children With Traumatic Brain Injury

OBJECTIVES

Traumatic brain injury can result in cognitive impairments in children. The objective of this retrospective study was to determine to what extent such outcomes are moderated by cognitive reserve, as indexed by parental education.

METHODS

Sixty 6- to 16-year-old children completed the Wechsler Intelligence Scale for Children-Fifth Edition (WISC-V) within 30-360 days after having sustained a traumatic brain injury (TBI). Their Full-Scale IQ and factor index scores were compared to those of demographically matched controls. In addition, regression analysis was used to investigate in the TBI group the influence of injury severity in addition to parental education on WISC-V factor index scores.

RESULTS

Cognitive reserve moderated the effect of TBI on WISC-V Full Scale IQ, Verbal Comprehension, and Visual Spatial. In the TBI group, it also had a protective effect with regard to performance on the Verbal Comprehension, Visual Spatial, and Fluid Reasoning indices. At the same time, greater injury severity was predictive of lower Visual Spatial and Processing Speed index scores in the TBI group.

CONCLUSIONS

Cognitive reserve as reflected in parental education has a moderating effect with regard to children's performance on the WISC-V after TBI, such that higher cognitive reserve is associated with greater preservation of acquired word knowledge and understanding of visual relationships. Measures that emphasize speed of processing remain affected by severity of TBI, even after accounting for the protective effect associated with cognitive reserve. (JINS, 2019, 25, 355-361).

Cognitive Performance, Aerobic Fitness, Motor Proficiency, and Brain Function Among Children Newly Diagnosed With Craniopharyngioma

OBJECTIVES

Craniopharyngioma survivors experience cognitive deficits that negatively impact quality of life. Aerobic fitness is associated with cognitive benefits in typically developing children and physical exercise promotes recovery following brain injury. Accordingly, we investigated cognitive and neural correlates of aerobic fitness in a sample of craniopharyngioma patients.

METHODS

Patients treated for craniopharyngioma [N=104, 10.0±4.6 years, 48% male] participated in fitness, cognitive and fMRI (n=51) assessments following surgery but before proton radiation therapy.

RESULTS

Patients demonstrated impaired aerobic fitness [peak oxygen uptake (PKVO2)=23.9±7.1, 41% impaired (i.e., 1.5 SD&lt;normative mean)], motor proficiency [Bruininks-Oseretsky (BOT2)=38.6±9.0, 28% impaired], and executive functions (e.g., WISC-IV Working Memory Index (WMI)=96.0±15.3, 11% impaired). PKVO2 correlated with better executive functions (e.g., WISC-IV WMI r=.27, p=.02) and academic performance (WJ-III Calculation r=.24, p=.04). BOT2 correlated with better attention (e.g., CPT-II omissions r=.26, p=.04) and executive functions (e.g., WISC-IV WMI r=.32, p=.01). Areas of robust neural activation during an n-back task included superior parietal lobule, dorsolateral prefrontal cortex, and middle and superior frontal gyri (p&lt;.05, corrected). Higher network activation was associated with better working memory task performance and better BOT2 (p&lt;.001).

CONCLUSIONS

Before adjuvant therapy, children with craniopharyngioma demonstrate significantly reduced aerobic fitness, motor proficiency, and working memory. Better aerobic fitness and motor proficiency are associated with better attention and executive functions, as well as greater activation of a well-established working memory network. These findings may help explain differential risk/resiliency with respect to acute cognitive changes that may portend cognitive late effects. (JINS, 2019, 25, 413-425).

Cognitive Impairment Following Acute Mild Traumatic Brain Injury

Patients with mild traumatic brain injury (mTBI) may present cognitive deficits within the first 24 h after trauma, herein called "acute phase," which in turn may lead to long-term functional impairment and decrease in quality of life. Few studies investigated cognition in mTBI patients during the acute phase. The objectives of this study were to investigate the cognitive profile of patients with mTBI during the acute phase, compared to controls and normative data, and whether loss of consciousness (LOC), previous TBI and level of education influence cognition at this stage. Fifty-three patients with mTBI (aged 19-64 years) and 28 healthy controls participated in the study. All patients were evaluated at bedside within 24 h post-injury. Demographic and clinical data were registered. Cognitive function was assessed with the Mini-mental state examination (MMSE), the Frontal Assessment Battery (FAB), Digit Span (working memory), and the Visual Memory Test/Brief Cognitive Battery (for episodic memory). The clinical sample was composed mainly by men (58.5%). The mean age was 39 years-old and 64.3% of the patients had more than 8 years of education. The most common causes of mTBI were fall from own height (28.3%), aggression (24.5%), and fall from variable heights (24.5%). Compared to controls, mTBI patients exhibited significantly worse performance on MMSE, FAB, naming, incidental memory, immediate memory, learning, and delayed recall. Compared to normative data, 26.4% of patients had reduced global cognition as measured by the MMSE. Episodic memory impairment (13.2%) was more frequent than executive dysfunction (9.4%). No significant differences were found in cognitive performance when comparing patients with or without LOC or those with or without history of previous TBI. Patients with lower educational level had higher rates of cognitive impairment (VMT naming-28.6 vs. 4.2%; VMT immediate memory-32 vs. 4.2%; VMT learning-39.3 vs. 4.2%, all p < 0.05). In sum, we found significant cognitive impairment in the acute phase of mTBI, which was not associated with LOC or history of TBI, but appeared more frequently in patients with lower educational level.

Cognitive Reserve Protects Against Memory Decrements Associated With Neuropathology in Traumatic Brain Injury

OBJECTIVE

To evaluate whether cognitive reserve (CR) moderates the relationship between neuropathology and cognitive outcomes after traumatic brain injury (TBI).

SETTING

Outpatient research organization.

PARTICIPANTS

Patients with complicated mild (n = 8), moderate (n = 9), and severe (n = 44) TBI.

DESIGN

Prospective, cross-sectional study.

MAIN MEASURES

Cognitive reserve was estimated using a test of word reading (Wechsler Test of Adult Reading). Diffusion tensor imaging (functional anisotropy) was used to quantify neuropathology. Neuropsychological test scores were submitted to principal components analyses to create cognitive composites for memory, attention, executive function, and processing speed domains.

RESULTS

At lower levels of neuropathology, people with higher CR exhibited better memory than those with lower CR. This benefit diminished as neuropathology increased and disappeared at the highest levels of neuropathology. Cognitive reserve ceased exerting a protective effect at premorbid intelligence levels below average.

CONCLUSION

Cognitive reserve may differentially protect some cognitive domains against neuropathology relative to others. A clinical cutoff below which CR is no longer protective, together with a possible neuropathology ceiling effect, may be instructive for prognostication and clinical decision-making in cognitive rehabilitation.

Intensive Care in Traumatic Brain Injury Including Multi-Modal Monitoring and Neuroprotection

Moderate to severe traumatic brain injuries (TBI) require treatment in an intensive care unit (ICU) in close collaboration of a multidisciplinary team consisting of different medical specialists such as intensivists, neurosurgeons, neurologists, as well as ICU nurses, physiotherapists, and ergo-/logotherapists. Major goals include all measurements to prevent secondary brain injury due to secondary brain insults and to optimize frame conditions for recovery and early rehabilitation. The distinction between moderate and severe is frequently done based on the Glascow Coma Scale and therefore often is just a snapshot at the early time of assessment. Due to its pathophysiological pathways, an initially as moderate classified TBI may need the same sophisticated surveillance, monitoring, and treatment as a severe form or might even progress to a severe and difficult to treat affection. As traumatic brain injury is rather a syndrome comprising a range of different affections to the brain and as, e.g., age-related comorbidities and treatments additionally may have a great impact, individual and tailored treatment approaches based on monitoring and findings in imaging and respecting pre-injury comorbidities and their therapies are warranted.

Paradoxes in rehabilitation

Paradoxical enhancement and paradoxical recovery of function after brain injury harmonize well with the concept of "ultrabilitation" and its focus on novel forms of flourishing in rehabilitation settings. I consider three sets of paradoxes which may impact on brain injury rehabilitation. Firstly, I consider post-traumatic growth after brain injury and its key determinants. Secondly, I review the role of illusions in rehabilitation and the paradox that some clinical conditions may be improved by invoking perceptual distortions. Thirdly, I consider paradoxical recovery profiles after brain injury, since knowledge of such paradoxical profiles may help inform attempts at rehabilitation of some patients. Finally, I consider how some of these paradoxes relate to components of ultrabilitation, and in addition to the nascent field of positive neuropsychology and the concept of resilience after brain injury.Implications for rehabilitationIllusions can sometimes be harnessed as a therapeutic tool in rehabilitation.There may be spontaneous, positive outcomes of an injury or illness, in the form of "post-traumatic growth", and these should be considered as part of a holistic therapeutic approach in rehabilitation.Some patients make an exceptional recovery from a severe brain insult, and lessons could be learned from such cases, such as disciplined use of compensatory strategies, which could have broader implications for neurorehabilitation.

Defining Cognitive Reserve and Implications for Cognitive Aging

PURPOSE OF REVIEW

The aim of this review is to summarize current conceptual models of cognitive reserve (CR) and related concepts and to discuss evidence for these concepts within the context of aging and Alzheimer's disease.

RECENT FINDINGS

Evidence to date supports the notion that higher levels of CR, as measured by proxy variables reflective of lifetime experiences, are associated with better cognitive performance, and with a reduced risk of incident mild cognitive impairment/dementia. However, the impact of CR on longitudinal cognitive trajectories is unclear and may be influenced by a number of factors. Although there is promising evidence that some proxy measures of CR may influence structural brain measures, more research is needed. The protective effects of CR may provide an important mechanism for preserving cognitive function and cognitive well-being with age, in part because it can be enhanced throughout the lifespan. However, more research on the mechanisms by which CR is protective is needed.

Highlighting the Role of Cognitive and Brain Reserve in the Substance use Disorder Field

BACKGROUND

Cognitive reserve (CR) refers to the ability of an individual to cope with brain pathology remaining free of cognitive symptoms. This protective factor has been related to compensatory and more efficient brain mechanisms involved in resisting brain damage. For its part, Brain reserve (BR) refers to individual differences in the structural properties of the brain which could also make us more resilient to suffer from neurodegenerative and mental diseases.

OBJECTIVE

This review summarizes how this construct, mainly mediated by educational level, occupational attainment, physical and mental activity, as well as successful social relationships, has gained scientific attention in the last years with regard to diseases, such as neurodegenerative diseases, stroke or traumatic brain injury. Nevertheless, although CR has been studied in a large number of disorders, few researches have addressed the role of this concept in drug addiction.

METHODS

We provide a selective overview of recent literature about the role of CR and BR in preventing substance use onset. Likewise, we will also discuss how variables involved in CR (healthy leisure, social support or job-related activities, among others) could be trained and included as complementary activities of substance use disorder treatments.

RESULTS

Evidence about this topic suggests a preventive role of CR and BR on drug use onset and when drug addiction is established, these factors led to less severe addiction-related problems, as well as better treatment outcomes.

CONCLUSION

CR and BR are variables not taken yet into account in drug addiction. However, they could give us a valuable information about people at risk, as well as patient's prognosis.

Psychological Resilience Is Associated With Participation Outcomes Following Mild to Severe Traumatic Brain Injury

Traumatic brain injury (TBI) causes physical and cognitive-behavioral impairments that reduce participation in employment, leisure, and social relationships. Demographic and injury-related factors account for a small proportion of variance in participation post-injury. Personal factors such as resilience may also impact outcomes. This study aimed to examine the association of resilience alongside demographic, injury-related, cognitive, emotional, and family factors with participation following TBI. It was hypothesized that resilience would make an independent contribution to participation outcomes after TBI. Participants included 245 individuals with mild-severe TBI [Mage = 44.41, SDage = 16.09; post traumatic amnesia (PTA) duration M 24.95 days, SD 45.99] who completed the Participation Assessment with Recombined Tools-Objective (PART-O), TBI Quality of Life Resilience scale, Family Assessment Device General Functioning Scale, Rey Auditory Verbal Learning Test, National Adult Reading Test, and Hospital Anxiety and Depression Scale an average 4.63 years post-injury (SD 3.02, R 0.5-13). Multiple regression analyses were used to examine predictors of PART-O scores as the participation measure. Variables in the model accounted for a significant 38% of the variability in participation outcomes, F(13, 211) = 9.93, p < 0.05, R2 = 0.38, adjusted R2 = 0.34. Resilience was a significant predictor of higher participation, along with shorter PTA duration, more years since injury, higher education and IQ, and younger age. Mediation analyses revealed depression mediated the relationship between resilience and participation. As greater resilience may protect against depression and enhance participation this may be a focus of intervention.

Sex-related responses after traumatic brain injury: Considerations for preclinical modeling

Traumatic brain injury (TBI) has historically been viewed as a primarily male problem, since men are more likely to experience a TBI because of more frequent participation in activities that increase risk of head injuries. This male bias is also reflected in preclinical research where mostly male animals have been used in basic and translational science. However, with an aging population in which TBI incidence is increasingly sex-independent due to falls, and increasing female participation in high-risk activities, the attention to potential sex differences in TBI responses and outcomes will become more important. These considerations are especially relevant in designing preclinical animal models of TBI that are more predictive of human responses and outcomes. This review characterizes sex differences following TBI with a special emphasis on the contribution of the female sex hormones, progesterone and estrogen, to these differences. This information is potentially important in developing and customizing TBI treatments.

Rehabilitation Needs of the Elder with Traumatic Brain Injury

The incidence of traumatic brain injury (TBI) in older adults is increasing. As the expected life expectancy increases, there is a heightened need for comprehensive rehabilitation for this population. Elderly patients with TBI benefit from rehabilitation interventions at all stages of injury and can achieve functional gains during acute inpatient rehabilitation. Clinicians should be vigilant of unique characteristics of this population during inpatient rehabilitation, including vulnerability to polypharmacy, posttraumatic hydrocephalus, neuropsychiatric sequelae, sleep disturbances, and sensory deficits. Long-term care should include fall prevention, assessment of cognitive deficits, aerobic activity, community reintegration, and caretaker support. Life expectancy is reduced after TBI.

Postconcussive Symptoms After Single and Repeated Concussions in 10- to 20-Year-Olds: A Cross-Sectional Study

The objective was to characterize cognitive deficits and postconcussive symptoms in a pediatric population with no concussion, a single concussion, and ≥2 concussions, using a cross-sectional design. Cognitive function and postconcussive symptoms were assessed in participants (age 10-20) with no concussion (n = 1118), single concussion (n = 368), and repeated (≥2) concussions (n = 252). Analyses were adjusted for age and gender. Individuals with ≥2 concussions exhibited more total postconcussive symptoms; more loss of consciousness, amnesia and confusion; more headaches; and poorer cognitive function compared to no concussion and single concussion. Postconcussive symptoms may play a modulatory role in cognitive dysfunction after repeated concussions as those with loss of consciousness, amnesia, confusion, or headaches exhibited worse verbal memory, visual memory, visual-motor processing, and poorer impulse control compared to those without these symptoms. This analysis demonstrates that repeated concussions is associated with poorer cognitive function and postconcussive symptoms compared to a single concussion.

Geriatric Traumatic Brain Injury: Epidemiology, Outcomes, Knowledge Gaps, and Future Directions

This review of the literature on traumatic brain injury (TBI) in older adults focuses on incident TBI sustained in older adulthood ("geriatric TBI") rather than on the separate, but related, topic of older adults with a history of earlier-life TBI. We describe the epidemiology of geriatric TBI, the impact of comorbidities and pre-injury function on TBI risk and outcomes, diagnostic testing, management issues, outcomes, and critical directions for future research. The highest incidence of TBI-related emergency department visits, hospitalizations, and deaths occur in older adults. Higher morbidity and mortality rates among older versus younger individuals with TBI may contribute to an assumption of futility about aggressive management of geriatric TBI. However, many older adults with TBI respond well to aggressive management and rehabilitation, suggesting that chronological age and TBI severity alone are inadequate prognostic markers. Yet there are few geriatric-specific TBI guidelines to assist with complex management decisions, and TBI prognostic models do not perform optimally in this population. Major barriers in management of geriatric TBI include under-representation of older adults in TBI research, lack of systematic measurement of pre-injury health that may be a better predictor of outcome and response to treatment than age and TBI severity alone, and lack of geriatric-specific TBI common data elements (CDEs). This review highlights the urgent need to develop more age-inclusive TBI research protocols, geriatric TBI CDEs, geriatric TBI prognostic models, and evidence-based geriatric TBI consensus management guidelines aimed at improving short- and long-term outcomes for the large and growing geriatric TBI population.

Evaluating Cognitive Reserve Through the Prism of Preclinical Alzheimer Disease

The concept of cognitive reserve (CR) was proposed to account for the discrepancy between levels of brain pathologic features or damage and clinical and cognitive function. This article provides a detailed review of prospective longitudinal studies that have investigated the interaction between CR and Alzheimer's disease (AD) biomarkers on clinical and cognitive outcomes among individuals with preclinical AD. Current evidence shows that higher levels of CR are associated with a delay in the onset of symptoms of mild cognitive impairment and that there may be multiple pathways by which CR exerts its protective effects.

APOE gene and neuropsychiatric disorders and endophenotypes: A comprehensive review

The Apolipoprotein E (APOE) gene is one of the main candidates in neuropsychiatric genetics, with hundreds of studies carried out in order to explore the possible role of polymorphisms in the APOE gene in a large number of neurological diseases, psychiatric disorders, and related endophenotypes. In the current article, we provide a comprehensive review of the structural and functional aspects of the APOE gene and its relationship with brain disorders. Evidence from genome-wide association studies and meta-analyses shows that the APOE gene has been significantly associated with several neurodegenerative disorders. Cellular and animal models show growing evidence of the key role of APOE in mechanisms of brain plasticity and behavior. Future analyses of the APOE gene might find a possible role in other neurological diseases and psychiatric disorders and related endophenotypes. © 2016 Wiley Periodicals, Inc.