The efficacy of donepezil hydrochloride on memory functioning in three adolescents with severe traumatic brain injury

Use of donepezil for neurocognitive recovery after brain injury in adult and pediatric populations: a scoping review

There are few pharmacologic options for the treatment of cognitive deficits associated with traumatic brain injury in pediatric patients. Acetylcholinesterase inhibitors such as donepezil have been evaluated in adult patients after traumatic brain injury, but relatively less is known about the effect in pediatric populations. The goal of this review is to identify knowledge gaps in the efficacy and safety of acetylcholinesterase inhibitors as a potential adjuvant treatment for neurocognitive decline in pediatric patients with traumatic brain injury. Investigators queried PubMed to identify literature published from database inception through June 2023 describing the use of donepezil in young adult traumatic brain injury and pediatric patients with predefined conditions. Based on preselected search criteria, 340 unique papers were selected for title and abstract screening. Thirty-two records were reviewed in full after eliminating preclinical studies and papers outside the scope of the project. In adult traumatic brain injury, we review results from 14 papers detailing 227 subjects where evidence suggests donepezil is well tolerated and shows both objective and patient-reported efficacy for reducing cognitive impairment. In children, 3 papers report on 5 children recovering from traumatic brain injury, showing limited efficacy. An additional 15 pediatric studies conducted in populations at risk for cognitive dysfunction provide a broader look at safety and efficacy in 210 patients in the pediatric age group. Given its promise for efficacy in adults with traumatic brain injury and tolerability in pediatric patients, we believe further study of donepezil for children and adolescents with traumatic brain injury is warranted.

Acetylcholinesterase inhibitors to enhance recovery from traumatic brain injury: a comprehensive review and case series

OBJECTIVE

Acetylcholinesterase inhibitors (AChEIs) are used off-label, in both adult and pediatric patients, to help further neuro-recovery after traumatic brain injury (TBI). Evidence is limited and piecemeal. This review describes how TBI affects the cholinergic system and consolidates evidence supporting or refuting the use of AChEIs following TBI.

METHODS

NCBI MEDLINE search included all articles published through March 2021 on AChEI use in acute and post-acute adult TBI rehabilitation (treatment began <90 days or ≥90 days since injury, respectively), and in pediatric TBI rehabilitation. Further, we checked ClinicalTrials.gov for ongoing trials using AChEIs for TBI rehabilitation in the United States.

RESULTS

27 original articles from NCBI Medline, published through March 2021, were included. The use of AChEIs following TBI in acute and post-acute rehabilitation settings, in both adult and pediatric patients, along with medication side effects, is discussed.

CONCLUSIONS

Most studies showed benefits with only moderate effect sizes because of small sample sizes. Reported side effects are minimal and stop soon after AChEIs is discontinued. Conclusions are limited by paucity of research; but fortunately, a large randomized controlled trial is ongoing, and more are needed to truly determine the efficacy of AChEIs in helping with recovery from TBI.

Chronic traumatic encephalopathy and the nucleus basalis of Meynert

Due to the growing number of chronic traumatic encephalopathy (CTE) cases in the military and contact sports, defining the cellular and molecular substrate of this disorder is crucial. Most classic neuropathological investigations describe cortical tau and, to a lesser extent, amyloid lesions, which may underlie the clinical sequela associated with CTE. The application of modern molecular biologic technology to postmortem human brain tissue has made it possible to evaluate the genetic signature of specific neuronal phenotypes at different stages of CTE pathology. Most recently, molecular pathobiology has been used in the field of CTE, with an emphasis on the cholinergic neurons located within the nucleus basalis of Meynert, which develop tau pathology and are associated with cognitive dysfunction similar to that found in Alzheimer's disease (AD). Quantitative findings derived from single-cell transcript investigations provide clues to our understanding of the selective vulnerability of neurons containing AD-like tau pathology at different stages of CTE. Since human tissue-based studies provide a gold standard for the field of CTE, continued molecular pathological studies are needed to reveal novel drug targets for the treatment of this disorder.

Psychopharmacology of traumatic brain injury

The pathophysiology of traumatic brain injury (TBI) can be highly variable, involving functional and/or structural damage to multiple neuroanatomical networks and neurotransmitter systems. This wide-ranging potential for physiologic injury is reflected in the diversity of neurobehavioral and neurocognitive symptoms following TBI. Here, we aim to provide a succinct, clinically relevant, up-to-date review on psychopharmacology for the most common sequelae of TBI in the postacute to chronic period. Specifically, treatment for neurobehavioral symptoms (depression, mania, anxiety, agitation/irritability, psychosis, pseudobulbar affect, and apathy) and neurocognitive symptoms (processing speed, attention, memory, executive dysfunction) will be discussed. Treatment recommendations will reflect general clinical practice patterns and the research literature.

The effect of donepezil on the cognitive ability early in the course of recovery from traumatic brain injury

OBJECTIVE

To investigate the effect of donepezil on cognitive ability in patients who have sustained a traumatic brain injury (TBI). We hypothesized that donepezil, an acetylcholinesterase inhibitor, would enhance cognitive recovery beyond that of usual care in an acute rehabilitation facility.

METHODS

This retrospective, longitudinal analysis included 55 patients who were non-randomly prescribed donepezil during acute care and compared them to 74 patients who received usual rehabilitation treatment. All 129 patients completed neuropsychological assessment at two time points. Donepezil was increased from 5 to 10 mg 7-10 days after initiation and maintained until follow-up cognitive assessment.

MAIN OUTCOMES

Primary cognitive abilities of interest included processing speed, attention and memory. Cognitive and functional abilities were assessed by a standard neuropsychological battery for TBI.

RESULTS

Propensity scores were used to adjust for differences between groups. Mixed effect model analysis showed no significant differences between treatment and control groups on all neuropsychological subtests over time.

CONCLUSIONS

Acute administration of donepezil did not significantly improve measures of cognitive or functional ability beyond that of treatment as usual in patients with moderate-to-severe TBI.

Pediatric Traumatic Brain Injury and Autism: Elucidating Shared Mechanisms

Pediatric traumatic brain injury (TBI) and autism spectrum disorder (ASD) are two serious conditions that affect youth. Recent data, both preclinical and clinical, show that pediatric TBI and ASD share not only similar symptoms but also some of the same biologic mechanisms that cause these symptoms. Prominent symptoms for both disorders include gastrointestinal problems, learning difficulties, seizures, and sensory processing disruption. In this review, we highlight some of these shared mechanisms in order to discuss potential treatment options that might be applied for each condition. We discuss potential therapeutic and pharmacologic options as well as potential novel drug targets. Furthermore, we highlight advances in understanding of brain circuitry that is being propelled by improved imaging modalities. Going forward, advanced imaging will help in diagnosis and treatment planning strategies for pediatric patients. Lessons from each field can be applied to design better and more rigorous trials that can be used to improve guidelines for pediatric patients suffering from TBI or ASD.

Neuroprosthetics in amputee and brain injury rehabilitation

The goals of rehabilitation medicine programs are to promote health, restore functional impairments and improve quality of life. The field of neuroprosthetics has evolved over the last decade given an improved understanding of neuroscience and the incorporation of advanced biotechnology and neuroengineering in the rehabilitation setting to develop adaptable applications to help facilitate recovery for individuals with amputations and brain injury. These applications may include a simple cognitive prosthetics aid for impaired memory in brain-injured individuals to myoelectric prosthetics arms with artificial proprioceptive feedback for those with upper extremity amputations. The integration of neuroprosthetics into the existing framework of current rehabilitation approaches not only improves quality-of-care and outcomes but help broadens current rehabilitation treatment paradigms. Although, we are in the infancy of the understanding the true benefit of neuroprosthetics and its clinical applications in the rehabilitation setting there is tremendous amount of promise for future research and development of tools to help facilitate recovery and improve quality of life in individuals with disabilities.

Progression of tau pathology within cholinergic nucleus basalis neurons in chronic traumatic encephalopathy: A chronic effects of neurotrauma consortium study

OBJECTIVE

To test the hypothesis that the nucleus basalis of Meynert (nbM), a cholinergic basal forebrain (CBF) cortical projection system, develops neurofibrillary tangles (NFTs) during the progressive pathological stages of chronic traumatic encephalopathy (CTE) in the brain of athletes.

METHOD

To characterize NFT pathology, tau-antibodies marking early, intermediate and late stages of NFT development in CBF tissue obtained at autopsy from eighteen former athletes and veterans with a history of repetitive mild traumatic brain injury (TBI) were used.

RESULTS

Analysis revealed that cholinergic nbM neurons develop intracellular tau-immunoreactive changes progressively across the pathological stages of CTE. In particular, there was an increase in pre-tangle (phosphorylated pS422) and oligomeric (TOC1 and TNT1) forms of tau in stage IV compared to stage II CTE cases. The nbM neurons also displayed pathologic TDP-43 inclusions and diffuse extracellular and vascular amyloid-β (Aβ) deposits in CTE. A higher percentage of pS422/p75NTR, pS422 and TNT1 labelled neurons were significantly correlated with age at symptom onset, interval between symptom onset and death and age at death.

CONCLUSION

The development of NFTs within the cholinergic nbM neurons could contribute to an axonal disconnection in CTE. Further studies are needed to determine the mechanism driving NFT formation in the nbM neurons and its relation to chronic cognitive dysfunction in CTE.

Alterations in Cholinergic Pathways and Therapeutic Strategies Targeting Cholinergic System after Traumatic Brain Injury

Traumatic brain injury (TBI) results in varying degrees of disability in a significant number of persons annually. The mechanisms of cognitive dysfunction after TBI have been explored in both animal models and human clinical studies for decades. Dopaminergic, serotonergic, and noradrenergic dysfunction has been described in many previous reports. In addition, cholinergic dysfunction has also been a familiar topic among TBI researchers for many years. Although pharmacological agents that modulate cholinergic neurotransmission have been used with varying degrees of success in previous studies, improving their function and maximizing cognitive recovery is an ongoing process. In this article, we review the previous findings on the biological mechanism of cholinergic dysfunction after TBI. In addition, we describe studies that use both older agents and newly developed agents as candidates for targeting cholinergic neurotransmission in future studies.

Pharmacotherapy of traumatic brain injury: state of the science and the road forward: report of the Department of Defense Neurotrauma Pharmacology Workgroup

Despite substantial investments by government, philanthropic, and commercial sources over the past several decades, traumatic brain injury (TBI) remains an unmet medical need and a major source of disability and mortality in both developed and developing societies. The U.S. Department of Defense neurotrauma research portfolio contains more than 500 research projects funded at more than $700 million and is aimed at developing interventions that mitigate the effects of trauma to the nervous system and lead to improved quality of life outcomes. A key area of this portfolio focuses on the need for effective pharmacological approaches for treating patients with TBI and its associated symptoms. The Neurotrauma Pharmacology Workgroup was established by the U.S. Army Medical Research and Materiel Command (USAMRMC) with the overarching goal of providing a strategic research plan for developing pharmacological treatments that improve clinical outcomes after TBI. To inform this plan, the Workgroup (a) assessed the current state of the science and ongoing research and (b) identified research gaps to inform future development of research priorities for the neurotrauma research portfolio. The Workgroup identified the six most critical research priority areas in the field of pharmacological treatment for persons with TBI. The priority areas represent parallel efforts needed to advance clinical care; each requires independent effort and sufficient investment. These priority areas will help the USAMRMC and other funding agencies strategically guide their research portfolios to ensure the development of effective pharmacological approaches for treating patients with TBI.

Neurorestorative effect of urinary bladder matrix-mediated neural stem cell transplantation following traumatic brain injury in rats

Traumatic brain injury (TBI) is a leading cause of cell death and disability among young adults and lacks a successful therapeutic strategy. The multiphasic injuries of TBI severely limit the success of conventional pharmacological approaches. Recent successes with transplantation of stem cells in bioactive scaffolds in other injury paradigms provide new hope for the treatment of TBI. In this study, we transplanted neural stem cells (0.5x10(5) cells/µl) cultured in a bioactive scaffold derived from porcine urinary bladder matrix (UBM; 4 injection sites, 2.5µl each) into the rat brain following controlled cortical impact (CCI, velocity, 4.0 m/sec; duration, 0.5 sec; depth, 3.2mm). We evaluated the effectiveness of this strategy to combat the loss of motor, memory and cognitive faculties. Before transplantation, compatibility experiments showed that UBM was able to support extended proliferation and differentiation of neural stem cells. Together with its reported anti-inflammatory properties and rapid degradation characteristics in vivo, UBM emerged to be an ideal scaffold. The transplants reduced neuron/tissue loss and white matter injury, and also significantly ameliorated motor, memory, and cognitive impairments. Furthermore, exposure to UBM alone was sufficient to decrease the loss of sensorimotor skills from TBI (examined 3-28 days post-CCI). However, only UBMs that contained proliferating neural stem cells helped attenuate memory and cognitive impairments (examined 26-28 days post-CCI). In summary, these results demonstrate the therapeutic efficacy of stem cells in bioactive scaffolds against TBI and show promise for translation into future clinical use.

Effects of video modelling on emerging speech in an adult with traumatic brain injury: preliminary findings

PRIMARY OBJECTIVE

Research has shown that traumatic brain injury (TBI) can affect a person's ability to perform previously learned skills. Dysexecutive syndrome and inattention, for example, alongside a number of other cognitive and behavioural impairments such as memory loss and lack of motivation, significantly affect day-to-day functioning following TBI. This study examined the efficacy of video modelling in emerging speech in an adult male with TBI caused by an assault.

RESEARCH DESIGN

In an effort to identify functional relations between this novice intervention and the target behaviour, experimental control was achieved by using within-system research methodology, overcoming difficulties of forming groups for such an highly non-homogeneous population.

METHODS AND PROCEDURES

Across a number of conditions, the participant watched a videotape in which another adult modelled a selection of 19 spoken words. When this modelled behaviour was performed in vivo, then generalization across 76 other words in the absence of a videotape took place.

MAIN OUTCOMES AND RESULTS

It was revealed that video modelling can promote the performance of previously learned behaviours related to speech, but more significantly it can facilitate the generalization of this verbal behaviour across untrained words.

CONCLUSIONS

Video modelling could well be added within the rehabilitation programmes for this population.

Single-case experimental designs: a systematic review of published research and current standards

This article systematically reviews the research design and methodological characteristics of single-case experimental design (SCED) research published in peer-reviewed journals between 2000 and 2010. SCEDs provide researchers with a flexible and viable alternative to group designs with large sample sizes. However, methodological challenges have precluded widespread implementation and acceptance of the SCED as a viable complementary methodology to the predominant group design. This article includes a description of the research design, measurement, and analysis domains distinctive to the SCED; a discussion of the results within the framework of contemporary standards and guidelines in the field; and a presentation of updated benchmarks for key characteristics (e.g., baseline sampling, method of analysis), and overall, it provides researchers and reviewers with a resource for conducting and evaluating SCED research. The results of the systematic review of 409 studies suggest that recently published SCED research is largely in accordance with contemporary criteria for experimental quality. Analytic method emerged as an area of discord. Comparison of the findings of this review with historical estimates of the use of statistical analysis indicates an upward trend, but visual analysis remains the most common analytic method and also garners the most support among those entities providing SCED standards. Although consensus exists along key dimensions of single-case research design, and researchers appear to be practicing within these parameters, there remains a need for further evaluation of assessment and sampling techniques and data analytic methods.

Evidence-based approaches to the management of cognitive and behavioral impairments following pediatric brain injury

Much is now known about the short- and long-term sequelae of pediatric acquired brain injury, with impairments found in general intellectual ability and in more specific domains, including attention, memory, executive functioning (e.g., planning and organization) and educational achievement (e.g., spelling and arithmetic). More recently, researchers have investigated behavioral, adaptive, social and mental health outcomes, and similarly, difficulties have been reported in these domains. While the availability of evidence-based treatments is currently limited, the need for the management of such sequelae has led to an emergence of research with a focus on the development and evaluation of management strategies and intervention programs in order to provide such treatment options.

Cholinomimetic agents and neurocognitive impairment following head injury: a systematic review

PRIMARY OBJECTIVE

There has been increasing interest in the role of cholinomimetic agents in the long-term management of cognitive impairment following traumatic brain injury. This paper aims to assess the evidence accumulated thus far.

METHODS

Studies are identified by searching MEDLINE, EMBASE and PsychINFO, contacting experts and pharmaceutical companies and hand searching bibliographies. All study designs are included.

MAIN OUTCOME AND RESULTS

This study identified 25 papers that studied cholinesterase inhibitors, physostigmine and choline in mild-to-severe traumatic brain injury. The outcome with cholinesterase inhibitors and choline is suggestive but not conclusive while physostigmine appears of little benefit. A lack of rigorous studies and a plethora of outcome measures preclude drawing definitive conclusions. Further randomized controlled trials are urgently required.