Understanding the Mechanisms of Recovery and/or Compensation following Injury

The relationship between levels of physical activity and participation in everyday life in stroke survivors: A systematic review and meta-analysis

BACKGROUND

Stroke survivors demonstrate decreased physical activity (PA) and take time to return to participation in everyday life, but the relationship between the two variables is unknown.

OBJECTIVE

To investigate the correlation and trajectory over time between levels of PA and participation in everyday life in stroke survivors.

METHODS

PubMed, Web of Science, Scopus, SPORTDiscus, Rehabilitation&Sport Medicine Source, and PEDro databases were searched from inception to January 2024. Cross-sectional and prospective studies evaluating both levels of PA and participation in stroke survivors were included. Two reviewers independently conducted the study selection, data extraction, and quality assessment. Meta-analyses of pooled correlation coefficients were calculated when at least two studies reported a correlation coefficient between the same PA and participation outcomes.

RESULTS

Of 4962 studies identified, 49 were included in the systematic review. Studies were rated high (55%%) or fair (45%) quality. A wide range of monitoring methodologies for assessing PA and participation were found in the 23 prospective studies. Seven studies were included in the meta-analyses, showing a positive moderate correlation between PA time and participation in activities of daily living (n = 148; r = 0.52; P < 0.01; I2 = 81%) in participants <6 months post-stroke, and between PA time and the participation in all areas (n = 126; r = 0.44; P < 0.01; I2 = 0%) in participants ≥6 months post-stroke. Overall, while PA showed significant improvements over time, participation only showed a tendency.

CONCLUSION

Despite the heterogeneity, consistent positive associations were found between PA time and participation levels in some areas. Establishing consensus is crucial to reduce heterogeneity and facilitate data pooling.

"Your brain can't wait": perspectives of children and adolescents with acquired brain injury and their parents on physical rehabilitation during the subacute phase

PURPOSE

Physical interventions during subacute rehabilitation have potential to improve functional recovery. This study explored the perspectives of children and adolescents with acquired brain injury (ABI) and their parents with respect to physical rehabilitation during the subacute phase.

METHODS

Thirteen children and adolescents with ABI and their parents were included and interviewed using semi-structured interviews. Interview transcripts were analysed using inductive thematic analysis approach.

RESULTS

Six themes were identified: 1) beliefs of physical rehabilitation, 2) content of physical rehabilitation, 3) tailored care, 4) impact of context, 5) communication and 6) transition. The importance of intensive physical practice was widely supported. The positive can-do mentality was emphasised to create an atmosphere of hope, meaning that every effort would be made to achieve maximum recovery. Intensive involvement of parents is considered essential during subacute rehabilitation including an open and mutual dialogue about the focus of rehabilitation, therapy goals and future participation in their own environment.

CONCLUSIONS

Our findings highlight the need for an intensive rehabilitation approach, tailored to the individual's needs. The perspectives of children and adolescents and their parents in our study contribute to a better understanding of factors that are important for optimal recovery through physical rehabilitation during the subacute phase.

Repetitive Subconcussive Head Impacts in Sports and Their Impact on Brain Anatomy and Function: A Systematic Review

Repetitive subconcussive head impacts occur regularly in sports. However, the exact relationship between their biomechanical properties and their consequences on brain structure and function has not been clarified yet. We therefore reviewed prospective cohort studies that objectively reported the biomechanical characteristics of repetitive subconcussive head impacts and their impact on brain anatomy and function. Only studies with a pre- to post-measurement design were included. Twenty-four studies met the inclusion criteria. Structural white matter alterations, such as reduced fractional anisotropy and an increase in mean diffusivity values, seem to be evident in athletes exposed to repetitive subconcussive head impacts exceeding 10 g. Such changes are observable after only one season of play. Furthermore, a dose-response relationship exists between white matter abnormalities and the total number of subconcussive head impacts. However, functional changes after repetitive subconcussive head impacts remain inconclusive. We therefore conclude that repetitive subconcussive head impacts induce structural changes, but thus far without overt functional changes.

ENIGMA's simple seven: Recommendations to enhance the reproducibility of resting-state fMRI in traumatic brain injury

Resting state functional magnetic resonance imaging (rsfMRI) provides researchers and clinicians with a powerful tool to examine functional connectivity across large-scale brain networks, with ever-increasing applications to the study of neurological disorders, such as traumatic brain injury (TBI). While rsfMRI holds unparalleled promise in systems neurosciences, its acquisition and analytical methodology across research groups is variable, resulting in a literature that is challenging to integrate and interpret. The focus of this narrative review is to address the primary methodological issues including investigator decision points in the application of rsfMRI to study the consequences of TBI. As part of the ENIGMA Brain Injury working group, we have collaborated to identify a minimum set of recommendations that are designed to produce results that are reliable, harmonizable, and reproducible for the TBI imaging research community. Part one of this review provides the results of a literature search of current rsfMRI studies of TBI, highlighting key design considerations and data processing pipelines. Part two outlines seven data acquisition, processing, and analysis recommendations with the goal of maximizing study reliability and between-site comparability, while preserving investigator autonomy. Part three summarizes new directions and opportunities for future rsfMRI studies in TBI patients. The goal is to galvanize the TBI community to gain consensus for a set of rigorous and reproducible methods, and to increase analytical transparency and data sharing to address the reproducibility crisis in the field.

Efficacy of Intervention of Participation and Executive Functions (I-PEX) for Adults Following Traumatic Brain Injury: A Preliminary Pilot Randomized Controlled Trial

BACKGROUND

Participation restrictions following traumatic brain injury are associated with executive function (EF) deficits (EFDs). The subacute recovery phase's specific characteristics (enhanced brain plasticity and impaired self-awareness) and contextual factors (inpatient setting) warrant adjusting cognitive rehabilitation protocols. The Intervention of Participation and Executive Functions (I-PEX) was designed to improve EFDs during subacute inpatient rehabilitation.

OBJECTIVE

To investigate the I-PEX's preliminary efficacy to improve EFDs during the performance of complex daily activities and enhance self-awareness, cognitive self-efficacy, participation, and quality of life postdischarge.

METHODS

A pilot pre-, post-, and follow-up double-blind randomized controlled trial with 25 participants randomly allocated to the I-PEX (n = 13) or treatment-as-usual (n = 12) group. Cognitive assessments were administered pre- and postintervention, and quality of life and participation questionnaires 1-month postdischarge. Data analysis included repeated measures analysis of variance mixed design and independent t-tests, extracting effect sizes.

RESULTS

Significant group-by-time interaction effect with a medium effect size was found for the primary outcome measure; EFs manifested in complex daily activities, indicating a larger improvement for the experimental group. The group effect was not significant. The experimental group's mean delta score (pre-post improvement) was significantly higher (1.75 ± 2.89; t(23) = 2.52, P = .019), with a large effect size (d = 1.012, 95% confidence interval [0.166-1.840]). We found no significant group and interaction effects for EFs, self-awareness, and cognitive self-efficacy or no significant differences in participation or quality of life postdischarge.

CONCLUSIONS

Results provide initial evidence for the I-PEX efficacy in treating EFDs in the subacute phase and could help determine effect size for future studies.

CLINICAL TRIAL REGISTRY NUMBER

ClinicalTrial.gov NCT04292925.

Optimizing an exercise training program in pediatric brain tumour survivors: Does timing postradiotherapy matter?

Background

While exercise training (ET) programs show positive outcomes in cognition, motor function, and physical fitness in pediatric brain tumor (PBT) survivors, little is known about the optimal timing of intervention. The aim of this work was to explore the feasibility and benefits of ET based on its timing after radiotherapy.

Methods

This retrospective analysis (ClinicalTrials.gov, NCT01944761) analyzed data based on the timing of PBT survivors' participation in an ET program relative to their completion of radiotherapy: <2 years (n = 9), 2-5 years (n = 10), and > 5 years (n = 13). We used repeated measures analysis of variance to compare feasibility and efficacy indicators among groups, as well as correlation analysis between ET program timing postradiotherapy and preliminary treatment effects on cognition, motor function and physical fitness outcomes.

Results

Two to five years postradiotherapy was the optimal time period in terms of adherence (88.5%), retention (100%), and satisfaction (more fun, more enjoyable and recommend it more to other children). However, the benefits of ET program on memory recognition (r = -0.379, P = .047) and accuracy (r = -0.430, P = .032) decreased with increased time postradiotherapy. Motor function improved in all groups, with greater improvements in bilateral coordination (P = .043) earlier postradiotherapy, and in running (P = .043) later postradiotherapy. The greatest improvement in pro-rated work rate occurred in the < 2-year group (P = .008).

Conclusion

Participation in an ET program should be offered as part of routine postradiotherapy care in the first 1-2 years and strongly encouraged in the first 5 years.

A Comprehensive Review on the Role of Resting-State Functional Magnetic Resonance Imaging in Predicting Post-Stroke Motor and Sensory Outcomes

Stroke is a major leading cause of chronic disability, often affecting patients' motor and sensory functions. Functional magnetic resonance imaging (fMRI) is the most commonly used method of functional neuroimaging, and it allows for the non-invasive study of brain activity. The time-dependent coactivation of different brain regions at rest is described as resting-state activation. As a non-invasive task-independent functional neuroimaging approach, resting-state fMRI (rs-fMRI) may provide therapeutically useful information on both the focal vascular lesion and the connectivity-based reorganization and subsequent functional recovery in stroke patients. Considering the role of a prompt and accurate prognosis in stroke survivors along with the potential of rs-fMRI in identifying patterns of neuroplasticity in different post-stroke phases, this review provides a comprehensive overview of the latest literature regarding the role of rs-fMRI in stroke prognosis in terms of motor and sensory outcomes. Our comprehensive review suggests that with the advancement of MRI acquisition and data analysis methods, rs-fMRI emerges as a promising tool to study the motor and sensory outcomes in stroke patients and evaluate the effects of different interventions.

Adolescent Sport-Related Concussion and the Associated Neurophysiological Changes: A Systematic Review

BACKGROUND

Sport-related concussion (SRC) has been shown to induce cerebral neurophysiological deficits, quantifiable with electroencephalography (EEG). As the adolescent brain is undergoing rapid neurodevelopment, it is fundamental to understand both the short- and long-term ramifications SRC may have on neuronal functioning. The current systematic review sought to amalgamate the literature regarding both acute/subacute (≤28 days) and chronic (>28 days) effects of SRC in adolescents via EEG and the diagnostic accuracy of this tool.

METHODS

The review was registered within the Prospero database (CRD42021275256). Search strategies were created and input into the PubMed database, where three authors completed all screening. Risk of bias assessments were completed using the Scottish Intercollegiate Guideline Network and Methodological Index for Non-Randomized Studies.

RESULTS

A total of 128 articles were identified; however, only seven satisfied all inclusion criteria. The studies ranged from 2012 to 2021 and included sample sizes of 21 to 81 participants, albeit only ∼14% of the included athletes were females. The studies displayed low-to-high levels of bias due to the small sample sizes and preliminary nature of most investigations. Although heterogeneous methods, tasks, and analytical techniques were used, 86% of the studies found differences compared with control athletes, in both the symptomatic and asymptomatic phases of SRC. One study used raw EEG data as a diagnostic indicator demonstrating promise; however, more research and standardization are a necessity.

CONCLUSIONS

Collectively, the findings highlight the utility of EEG in assessing adolescent SRC; however, future studies should consider important covariates including biological sex, maturation status, and development.

Diffusion basis spectrum imaging detects subclinical traumatic optic neuropathy in a closed-head impact mouse model of traumatic brain injury

Introduction

Traumatic optic neuropathy (TON) is the optic nerve injury secondary to brain trauma leading to visual impairment and vision loss. Current clinical visual function assessments often fail to detect TON due to slow disease progression and clinically silent lesions resulting in potentially delayed or missed treatment in patients with traumatic brain injury (TBI).

Methods

Diffusion basis spectrum imaging (DBSI) is a novel imaging modality that can potentially fill this diagnostic gap. Twenty-two, 16-week-old, male mice were equally divided into a sham or TBI (induced by moderate Closed-Head Impact Model of Engineered Rotational Acceleration device) group. Briefly, mice were anesthetized with isoflurane (5% for 2.5 min followed by 2.5% maintenance during injury induction), had a helmet placed over the head, and were placed in a holder prior to a 2.1-joule impact. Serial visual acuity (VA) assessments, using the Virtual Optometry System, and DBSI scans were performed in both groups of mice. Immunohistochemistry (IHC) and histological analysis of optic nerves was also performed after in vivo MRI.

Results

VA of the TBI mice showed unilateral or bilateral impairment. DBSI of the optic nerves exhibited bilateral involvement. IHC results of the optic nerves revealed axonal loss, myelin injury, axonal injury, and increased cellularity in the optic nerves of the TBI mice. Increased DBSI axon volume, decreased DBSI λ||, and elevated DBSI restricted fraction correlated with decreased SMI-312, decreased SMI-31, and increased DAPI density, respectively, suggesting that DBSI can detect coexisting pathologies in the optic nerves of TBI mice.

Conclusion

DBSI provides an imaging modality capable of detecting subclinical changes of indirect TON in TBI mice.

Effects of constraint induced movement therapy in patients with multiple sclerosis: A systematic review

BACKGROUND

Multiple sclerosis (MS) is a chronic neurodegenerative disorder of the central nervous system (CNS) that commonly affects young and middle-aged adults. Neurodegeneration of the CNS affects its functions such as sensorimotor, autonomic and cognitive functions. Affectation of motor function can result in disability in performance of daily life activities. Thus, effective rehabilitation interventions are needed to help prevent disability in patients with MS. One of these interventions is the constraint induced movement therapy (CIMT). The CIMT is used to improve motor function in patients with stroke and other neurological conditions. Recently, its use in patients with MS is gaining ground. The aim of this study is to carry out a systematic review and meta-analysis to determine from the literature, the effects of CIMT on upper limb function in patients with MS.

METHODS

PubMED, Embase, Web of Science (WoS), PEDro, and CENTRAL were searched until October 2022. Randomized controlled trials in patients with MS who were 18 years and above were included. Data on the characteristics of the study participants such as disease duration, type of MS, the mean scores of the outcomes of interest such as motor function and use of the arm in daily activities, and white matter integrity were extracted. Methodological quality and risks of bias of the included studies were assessed using PEDro scale and Cochrane risks of bias tool. The data was analysed using both narrative and quantitative syntheses. In the quantitative synthesis, random effect model meta-analysis of the mean and standard deviation of the scores on the outcomes of interest and the study sample size (for both the CIMT and the control group) post intervention was carried out. In addition, percentage of variation across the studies due to heterogeneity (I²) was considered significant when it is between 50% and 90% at p < 0.05.

RESULTS

Two studies comprising of 4 published articles with good methodological quality were included in the study. The results showed that, CIMT is safe and improved white matter integrity, motor function, muscle strength, dexterity, real-world arm use and biomechanical parameters post intervention. However, although there was a trend towards better improvement in the CIMT group in all the outcomes, there was no statistically significant difference between groups in motor function (SMD=0.44, 95% CI=-0.20 to 1.07, p = 0.18) and quality of movement (SMD=0.96, -1.15 to 3.07, p = 0.37).

CONCLUSION

CIMT can be used in patients with MS since it is safe as well as effective at improving functional outcomes. However, more studies are required to confirm its safety and effectiveness.

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

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

Nutritional interventions to support acute mTBI recovery

When mild traumatic brain injury (mTBI) occurs following an impact on the head or body, the brain is disrupted leading to a series of metabolic events that may alter the brain's ability to function and repair itself. These changes may place increased nutritional demands on the body. Little is known on whether nutritional interventions are safe for patients to implement post mTBI and whether they may improve recovery outcomes. To address this knowledge gap, we conducted a systematic review to determine what nutritional interventions have been prescribed to humans diagnosed with mTBI during its acute period (<14 days) to support, facilitate, and result in measured recovery outcomes.

Methods

Databases CINAHL, PubMed, SPORTDiscus, Web of Science, and the Cochrane Library were searched from inception until January 6, 2021; 4,848 studies were identified. After removing duplicates and applying the inclusion and exclusion criteria, this systematic review included 11 full papers.

Results

Patients that consumed enough food to meet calorie and macronutrient (protein) needs specific to their injury severity and sex within 96 h post mTBI had a reduced length of stay in hospital. In addition, patients receiving nutrients and non-nutrient support within 24-96 h post mTBI had positive recovery outcomes. These interventions included omega-3 fatty acids (DHA and EPA), vitamin D, mineral magnesium oxide, amino acid derivative N-acetyl cysteine, hyperosmolar sodium lactate, and nootropic cerebrolysin demonstrated positive recovery outcomes, such as symptom resolution, improved cognitive function, and replenished nutrient deficiencies (vitamin D) for patients post mTBI.

Conclusion

Our findings suggest that nutrition plays a positive role during acute mTBI recovery. Following mTBI, patient needs are unique, and this review presents the potential for certain nutritional therapies to support the brain in recovery, specifically omega-3 fatty acids. However, due to the heterogenicity nature of the studies available at present, it is not possible to make definitive recommendations.

Systematic review registration

The systematic review conducted following the PRISMA guidelines protocol was registered (CRD42021226819), on Prospero.

First Metabolomic Signature of Blood-Brain Barrier Opening Induced by Microbubble-Assisted Ultrasound

Microbubble (MB)-assisted ultrasound (US) is a promising physical method to increase non-invasively, transiently, and precisely the permeability of the blood-brain barrier (BBB) to therapeutic molecules. Previous preclinical studies established the innocuity of this procedure using complementary analytical strategies including transcriptomics, histology, brain imaging, and behavioral tests. This cross-sectional study using rats aimed to investigate the metabolic processes following acoustically-mediated BBB opening in vivo using multimodal and multimatrices metabolomics approaches. After intravenous injection of MBs, the right striata were exposed to 1-MHz sinusoidal US waves at 0.6 MPa peak negative pressure with a burst length of 10 ms, for 30 s. Then, the striata, cerebrospinal fluid (CSF), blood serum, and urine were collected during sacrifice in three experimental groups at 3 h, 2 days, and 1 week after BBB opening (BBBO) and were compared to a control group where no US was applied. A well-established analytical workflow using nuclear magnetic resonance spectrometry and non-targeted and targeted high-performance liquid chromatography coupled to mass spectrometry were performed on biological tissues and fluids. In our experimental conditions, a reversible BBBO was observed in the striatum without physical damage or a change in rodent weight and behavior. Cerebral, peri-cerebral, and peripheral metabolomes displayed specific and sequential metabolic kinetics. The blood serum metabolome was more impacted in terms of the number of perturbated metabolisms than in the CSF, the striatum, and the urine. In addition, perturbations of arginine and arginine-related metabolisms were detected in all matrices after BBBO, suggesting activation of vasomotor processes and bioenergetic supply. The exploration of the tryptophan metabolism revealed a transient vascular inflammation and a perturbation of serotoninergic neurotransmission in the striatum. For the first time, we characterized the metabolic signature following the acoustically-mediated BBBO within the striatum and its surrounding biological compartments.

Tau pathology, metal dyshomeostasis and repetitive mild traumatic brain injury: an unexplored link paving the way for neurodegeneration

Repetitive mild traumatic brain injury (r-mTBI), commonly experienced by athletes and military personnel, causes changes in multiple intracellular pathways, one of which involves the tau protein. Tau phosphorylation plays a role in several neurodegenerative conditions including chronic traumatic encephalopathy (CTE), a progressive neurodegenerative disorder linked to repeated head trauma. There is now mounting evidence suggesting that tau phosphorylation may be regulated by metal ions (such as iron, zinc and copper), which themselves are implicated in ageing and neurodegenerative disorders such as Alzheimer's disease (AD). Recent work has also shown that a single TBI can result in age-dependent and region-specific modulation of metal ions. As such, this review explores the link between TBI, CTE, ageing and neurodegeneration with a specific focus on the involvement of (and interaction between) tau pathology and metal dyshomeostasis. The authors highlight that metal dyshomeostasis has yet to be investigated in the context of repeat head trauma or CTE. Given the evidence that metal dyshomeostasis contributes to the onset and/or progression of neurodegeneration, and that CTE itself is a neurodegenerative condition, this brings to light an uncharted link that should be explored. The development of adequate models of r-mTBI and/or CTE will be crucial in deepening our understanding of the pathological mechanisms that drive the clinical manifestations in these conditions and also in the development of effective therapeutics targeted towards slowing progressive neurodegenerative disorders.

Physical rehabilitation interventions in children with acquired brain injury: a scoping review

AIM

To synthesize the evidence about the characteristics (frequency, intensity, time, type) and effects of physical rehabilitation interventions on functional recovery and performance in daily functioning in children and young people with acquired brain injury (ABI), including traumatic brain injuries (TBI) and non-TBI, during the subacute rehabilitation phase.

METHOD

Using scoping review methodology, a systematic literature search was performed using four databases. Articles were screened by title and abstract and data from eligible studies were extracted for synthesis.

RESULTS

Nine of 3009 studies were included. The results demonstrated a variety of intervention characteristics: frequency varied between 1 and 7 days per week; time of intervention varied between 25 minutes and 6 hours a day; intervention types were specified in seven studies; and none of the included studies reported details of intensity of intervention. All studies reported positive results on the International Classification of Functioning, Disability and Health: Children and Youth (ICF-CY) levels of body function and activities after the intervention period, with study designs of included studies being cohort studies without concurrent controls (n=7) or case reports (n=2).

INTERPRETATION

Inconsistency in results hampers generalizability to guide clinical practice. Physical interventions during subacute rehabilitation have potential to improve functional recovery with intervention characteristics as an important factor influencing its effectiveness. Future well-designed studies are indicated to gain knowledge and optimize rehabilitation practice in paediatric ABI and high-quality research including outcomes across all ICF-CY domains is needed.

Patterns of change in cortical morphometry following traumatic brain injury in adults

Progressive cortical volumetric loss following moderate–severe traumatic brain injury (TBI) has been observed; however, regionally specific changes in the structural determinants of cortical volume, namely, cortical thickness (CT) and cortical surface area (CSA), are unknown and may inform the patterns and neural substrates of neurodegeneration and plasticity following injury. We aimed to (a) assess differences in CT and CSA between TBI participants and controls in the early chronic stage post‐injury, (b) describe longitudinal changes in cortical morphometry following TBI, and (c) examine how regional changes in CT and CSA are associated. We acquired magnetic resonance images for 67 participants with TBI at up to 4 time‐points spanning 5 months to 7 years post‐injury, and 18 controls at 2 time‐points. In the early chronic stage, TBI participants displayed thinner cortices than controls, predominantly in frontal regions, but no CSA differences. Throughout the chronic period, TBI participants showed widespread CT reductions in posterior cingulate/precuneus regions and moderate CT increase in frontal regions. Additionally, CSA showed a significant decrease in the orbitofrontal cortex and circumscribed increase in posterior regions. No changes were identified in controls. Relationships between regional cortical changes in the same morphological measure revealed coordinated patterns within participants, whereas correlations between regions with CT and CSA change yielded bi‐directional relationships. This suggests that these measures may be differentially affected by neurodegenerative mechanisms such as transneuronal degeneration following TBI and that degeneration may be localized to the depths of cortical sulci. These findings emphasize the importance of dissecting morphometric contributions to cortical volume change.

Neural coupling between upper and lower limb muscles in Parkinsonian gait

OBJECTIVE

To explore to what extent neuronal coupling between upper and lower limb muscles during gait is preserved or affected in patients with Parkinson's Disease (PD).

METHODS

Electromyography recordings were obtained from the bilateral deltoideus anterior and bilateral rectus femoris and biceps femoris muscles during overground gait in 20 healthy participants (median age 69 years) and 20 PD patients (median age 68.5 years). PD patients were able to walk independently (Hoehn and Yahr scale: Stage 2-3), had an equally distributed symptom laterality (6 left side, 7 both sides and 7 right side) and no cognitive problems or tremor dominant PD. Time-dependent directional intermuscular coherence analysis was employed to compare the neural coupling between upper and lower limb muscles between healthy participants and PD patients in three different directions: zero-lag (i.e. common driver), forward (i.e. shoulders driving the legs) and reverse component (i.e. legs driving the shoulders).

RESULTS

Compared to healthy participants, PD patients exhibited (i) reduced intermuscular zero-lag coherence in the beta/gamma frequency band during end-of-stance and (ii) enhanced forward as well as reverse directed coherence in the alpha and beta/gamma frequency bands around toe-off.

CONCLUSIONS

PD patients had a reduced common cortical drive to upper and lower limb muscles during gait, possibly contributing to disturbed interlimb coordination. Enhanced bidirectional coupling between upper and lower limb muscles on subcortical and transcortical levels in PD patients suggests a mechanism of compensation.

SIGNIFICANCE

These findings provide support for the facilitating effect of arm swing instructions in PD gait.

Characteristics and Outcomes of a Community Upper Limb Rehabilitation Group for Adult Stroke Survivors in Australia: A Pre-Post Cohort Study

This study investigated outcomes of a community-based upper limb rehabilitation group for adult stroke survivors in metropolitan Australia. Pre-post data were extracted from medical records. Participants (n  =  27) were predominantly men (n = 22, 81%); mean age 61 years (SD 17) and median time 109 days post stroke. Participants improved on upper limb outcomes, with statistically significant changes on several of the items on the Motor Assessment Scale (item seven mean improvement 0.93 (95% CI 0.48-2.19), p = .016; item eight mean improvement 1.4 (95% CI 0.38-2.42), p = .016) and grip strength (mean improvement 4.5 kg/9 pounds, 14.73 ounces (95% CI 1.5-7.6), p = .006). These results guide occupational therapists implementing community-based upper limb rehabilitation groups.

Contralesional plasticity following constraint-induced movement therapy benefits outcome: contributions of the intact hemisphere to functional recovery

Stroke is a leading cause of death and disability worldwide. A common, chronic deficit after stroke is upper limb impairment, which can be exacerbated by compensatory use of the nonparetic limb. Resulting in learned nonuse of the paretic limb, compensatory reliance on the nonparetic limb can be discouraged with constraint-induced movement therapy (CIMT). CIMT is a rehabilitative strategy that may promote functional recovery of the paretic limb in both acute and chronic stroke patients through intensive practice of the paretic limb combined with binding, or otherwise preventing activation of, the nonparetic limb during daily living exercises. The neural mechanisms that support CIMT have been described in the lesioned hemisphere, but there is a less thorough understanding of the contralesional changes that support improved functional outcome following CIMT. Using both human and non-human animal studies, the current review explores the role of the contralesional hemisphere in functional recovery of stroke as it relates to CIMT. Current findings point to a need for a better understanding of the functional significance of contralesional changes, which may be determined by lesion size, location, and severity as well stroke chronicity.

Long-term monitoring of chronic demyelination and remyelination in a rat ischemic stroke model using macromolecular proton fraction mapping

Remyelination is a key process enabling post-stroke brain tissue recovery and plasticity. This study aimed to explore the feasibility of demyelination and remyelination monitoring in experimental stroke from the acute to chronic stage using an emerging myelin imaging biomarker, macromolecular proton fraction (MPF). After stroke induction by transient middle cerebral artery occlusion, rats underwent repeated MRI examinations during 85 days after surgery with histological endpoints for the animal subgroups on the 7th, 21st, 56th, and 85th days. MPF maps revealed two sub-regions within the infarct characterized by distinct temporal profiles exhibiting either a persistent decrease by 30%-40% or a transient decrease followed by return to nearly normal values after one month of observation. Myelin histology confirmed that these sub-regions had nearly similar extent of demyelination in the sub-acute phase and then demonstrated either chronic demyelination or remyelination. The remyelination zones also exhibited active axonal regrowth, reconstitution of compact fiber bundles, and proliferation of neuronal and oligodendroglial precursors. The demyelination zones showed more extensive astrogliosis from the 21st day endpoint. Both sub-regions had substantially depleted neuronal population over all endpoints. These results histologically validate MPF mapping as a novel approach for quantitative assessment of myelin damage and repair in ischemic stroke.

Patterns of brain c-Fos expression in response to feeding behavior in acute and chronic inflammatory pain condition

OBJECTIVES

Feeding behavior is known to have potential to alleviate pain. We recently demonstrated that both 24 h fasting and 2 h refeeding (food intake after 24 h fasting) induce analgesia in inflammatory pain conditions via different brain mechanisms. However, brain structures that distinctly involved fasting- and refeeding-induced analgesia is still unknown. Hence, this study is aimed to reveal brain structures mediating fasting- and refeeding-induced analgesia.

METHODS

Mice were given intraplantar (i.pl.) injection of formalin and complete Freund's adjuvant into the left hind paw to induce acute and chronic inflammatory pain, respectively. We examined changes in c-Fos expression with 24 h fasting and 2 h refeeding under acute and chronic inflammatory pain conditions in the contralateral brain.

RESULTS

Under acute pain condition, c-Fos expression changed with fasting in the anterior cingulate cortex (ACC), central amygdala (CeA), lateral hypothalamus (LH) and nucleus accumbens core (NAcC). Refeeding changed c-Fos expression in the CeA, LH and lateral parabrachial nucleus (lPBN). On the other hand, under chronic inflammatory pain condition, c-Fos expression changed with fasting in the lPBN, medial prefrontal cortex (mPFC) and nucleus accumbens shell (NAcS) while refeeding changed c-Fos expression in the anterior insular cortex, lPBN, mPFC and NAcS.

CONCLUSION

The present results show that brain regions that participated in the fasting- and refeeding-induced analgesia were completely different in acute and chronic inflammatory pain conditions. Also, refeeding recruits more brain regions under chronic inflammatory pain conditions compared to the acute inflammatory pain condition. Collectively, our findings provide novel insights into brain regions involved in fasting- and refeeding-induced analgesia, which can be potential neural circuit-based targets for the development of novel therapeutics.

The Influence of Stomach Back-Shu and Front-Mu Points on Insular Functional Connectivity in Functional Dyspepsia Rat Models

Functional Dyspepsia (FD) is a common functional gastrointestinal disease, which can reduce the quality of life in patients. Prior research has indicated that insula is closely related to FD and that acupuncture can regulate the functional connectivity (FC) of FD. Therefore, we hypothesized that acupuncture on FD was effected through the insular pathway. To test our hypothesis, we performed electroacupuncture (EA) on FD rat models and then examined the FC between insula and other brain regions through resting-state functional magnetic resonance imaging (rs-fMRI). Seven-day-old male infant Sprague-Dawley (SD) rats were randomly divided into control group, FD model group, and FD acupuncture group, with twelve rats per group (n = 36). Upon establishing successful models, the FD acupuncture group was subjected to EA intervention using Stomach back-shu (BL-21) and front-mu (RN-12) points for ten consecutive days for durations of 20 minutes each day. After intervention, each group was subject to rs-fMRI. The digital image data obtained were analyzed using FC analysis methods. Subsequently, gastric ligation was performed to measure gastric emptying rates. Before EA intervention, the FD model group exhibited decreased functional connections between the insula and a number of brain regions. After EA intervention, FD acupuncture group exhibited increasing FC between insula and regions when compared to the FD model group, such as the primary somatosensory cortex (S1), hippocampal CA3 (CA3), polymorphic layer of dentate gyrus (PoDG), caudate putamen (CPu), and oral pontine reticular nuclei (PnO) (P < 0.05); decreasing FC was also exhibited between insula and regions such as the bilateral primary and secondary motor cortexes (M1/2), paraventricular hypothalamic nucleus (PVA), and limbic cortex (LC). These findings indicate that the effective treatment of FD using EA may be through regulating the abnormal FC between insula and several brain regions, in particular CA3, PoDG, and PVA.

Sex differences in recovery of motor function in a rhesus monkey model of cortical injury

BACKGROUND

Stroke disproportionately affects men and women, with women over 65 years experiencing increased severity of impairment and higher mortality rates than men. Human studies have explored risk factors that contribute to these differences, but additional research is needed to investigate how sex differences affect functional recovery and hence the severity of impairment. In the present study, we used our rhesus monkey model of cortical injury and fine motor impairment to compare sex differences in the rate and degree of motor recovery following this injury.

METHODS

Aged male and female rhesus monkeys were trained on a task of fine motor function of the hand before undergoing surgery to produce a cortical lesion limited to the hand area representation of the primary motor cortex. Post-operative testing began two weeks after the surgery and continued for 12 weeks. All trials were video recorded and latency to retrieve a reward was quantitatively measured to assess the trajectory of post-operative response latency and grasp pattern compared to pre-operative levels.

RESULTS

Postmortem analysis showed no differences in lesion volume between male and female monkeys. However, female monkeys returned to their pre-operative latency and grasp patterns significantly faster than males.

CONCLUSIONS

These findings demonstrate the need for additional studies to further investigate the role of estrogens and other sex hormones that may differentially affect recovery outcomes in the primate brain.

Consciousness after split-brain surgery: The recent challenge to the classical picture

In a recent series of experiments, Pinto and colleagues found that the split-brain patient D.D.C. was able to respond accurately to stimuli in either visual field, whether using his right hand, his left hand, or verbally. Pinto and colleagues argue that this demonstrates that a split-brain patient remains a unitary agent and thus continues to possess a unified consciousness. This paper provides a critical evaluation of that claim. First, we argue that two conceptions of the unity of consciousness need to be distinguished: an agency-based conception and an experience-based conception. Second, we argue that it is an open question whether the data presented by Pinto and colleagues is best understood in terms of the unity of agency. Whether that interpretation is correct depends not only on the mechanisms that produce split-brain behaviour, but also on what is involved in being a single agent. Third, we argue that even if the behavioral data indicated that D.D.C has a unified consciousness in the agency-based sense of the term, it is difficult to reconcile them with the claim that his consciousness is fully unified in the experience-based sense.

Recommendations for the Design and Implementation of Virtual Reality for Acquired Brain Injury Rehabilitation: Systematic Review

BACKGROUND

Virtual reality (VR) is increasingly being used for the assessment and treatment of impairments arising from acquired brain injuries (ABIs) due to perceived benefits over traditional methods. However, no tailored options exist for the design and implementation of VR for ABI rehabilitation and, more specifically, traumatic brain injury (TBI) rehabilitation. In addition, the evidence base lacks systematic reviews of immersive VR use for TBI rehabilitation. Recommendations for this population are important because of the many complex and diverse impairments that individuals can experience.

OBJECTIVE

This study aims to conduct a two-part systematic review to identify and synthesize existing recommendations for designing and implementing therapeutic VR for ABI rehabilitation, including TBI, and to identify current evidence for using immersive VR for TBI assessment and treatment and to map the degree to which this literature includes recommendations for VR design and implementation.

METHODS

This review was guided by PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses). A comprehensive search of 11 databases and gray literature was conducted in August 2019 and repeated in June 2020. Studies were included if they met relevant search terms, were peer-reviewed, were written in English, and were published between 2009 and 2020. Studies were reviewed to determine the level of evidence and methodological quality. For the first part, qualitative data were synthesized and categorized via meta-synthesis. For the second part, findings were analyzed and synthesized descriptively owing to the heterogeneity of data extracted from the included studies.

RESULTS

In the first part, a total of 14 papers met the inclusion criteria. Recommendations for VR design and implementation were not specific to TBI but rather to stroke or ABI rehabilitation more broadly. The synthesis and analysis of data resulted in three key phases and nine categories of recommendations for designing and implementing VR for ABI rehabilitation. In the second part, 5 studies met the inclusion criteria. A total of 2 studies reported on VR for assessment and three for treatment. Studies were varied in terms of therapeutic targets, VR tasks, and outcome measures. VR was used to assess or treat impairments in cognition, balance, and anxiety, with positive outcomes. However, the levels of evidence, methodological quality, and inclusion of recommendations for VR design and implementation were poor.

CONCLUSIONS

There is limited research on the use of immersive VR for TBI rehabilitation. Few studies have been conducted, and there is limited inclusion of recommendations for therapeutic VR design and implementation. Future research in ABI rehabilitation should consider a stepwise approach to VR development, from early co-design studies with end users to larger controlled trials. A list of recommendations is offered to provide guidance and a more consistent model to advance clinical research in this area.

Progressive Neurodegeneration Across Chronic Stages of Severe Traumatic Brain Injury

OBJECTIVE

To examine the trajectory of structural gray matter changes across 2 chronic periods of recovery in individuals who have sustained severe traumatic brain injury (TBI), adding to the growing literature indicating that neurodegenerative processes occur in the months to years postinjury.

PARTICIPANTS

Patients who experienced posttraumatic amnesia of 1 hour or more, and/or scored 12 or less on the Glasgow Coma Scale at the emergency department or the scene of the accident, and/or had positive brain imaging findings were recruited while receiving inpatient care, resulting in 51 patients with severe TBI.

METHODS

Secondary analyses of gray matter changes across approximately 5 months, 1 year, and 2.5 years postinjury were undertaken, using an automated segmentation protocol with improved accuracy in populations with morphological anomalies. We compared patients and matched controls on regions implicated in poorer long-term clinical outcome (accumbens, amygdala, brainstem, hippocampus, thalamus). To model brain-wide patterns of change, we then conducted an exploratory principal component analysis (PCA) on the linear slopes of all regional volumes across the 3 time points. Finally, we assessed nonlinear trends across earlier (5 months-1 year) versus later (1-2.5 years) time-windows with PCA to compare degeneration rates across time. Chronic degeneration was predicted cortically and subcortically brain-wide, and within specific regions of interest.

RESULTS

(1) From 5 months to 1 year, patients showed significant degeneration in the accumbens, and marginal degeneration in the amygdala, brainstem, thalamus, and the left hippocampus when examined unilaterally, compared with controls. (2) PCA components representing subcortical and temporal regions, and regions from the basal ganglia, significantly differed from controls in the first time-window. (3) Progression occurred at the same rate across both time-windows, suggesting neither escalation nor attenuation of degeneration across time.

CONCLUSION

Localized yet progressive decline emphasizes the necessity of developing interventions to offset degeneration and improve long-term functioning.

Cell-Based Therapies for Traumatic Brain Injury: Therapeutic Treatments and Clinical Trials

Traumatic brain injury (TBI) represents physical damage to the brain tissue that induces transitory or permanent neurological disabilities. TBI contributes to 50% of all trauma deaths, with many enduring long-term consequences and significant medical and rehabilitation costs. There is currently no therapy to reverse the effects associated with TBI. An increasing amount of research has been undertaken regarding the use of different stem cells (SCs) to treat the consequences of brain damage. Neural stem cells (NSCs) (adult and embryonic) and mesenchymal stromal cells (MSCs) have shown efficacy in pre-clinical models of TBI and in their introduction to clinical research. The purpose of this review is to provide an overview of TBI and the state of clinical trials aimed at evaluating the use of stem cell-based therapies in TBI. The primary aim of these studies is to investigate the safety and efficacy of the use of SCs to treat this disease. Although an increasing number of studies are being carried out, few results are currently available. In addition, we present our research regarding the use of cell therapy in TBI. There is still a significant lack of understanding regarding the cell therapy mechanisms for the treatment of TBI. Thus, future studies are needed to evaluate the feasibility of the transplantation of SCs in TBI.

Immersive Virtual Reality to Improve Outcomes in Veterans With Stroke: Protocol for a Single-Arm Pilot Study

BACKGROUND

Over the last decade, virtual reality (VR) has emerged as a cutting-edge technology in stroke rehabilitation. VR is defined as a type of computer-user interface that implements real-time simulation of an activity or environment allowing user interaction via multiple sensory modalities. In a stroke population, VR interventions have been shown to enhance motor, cognitive, and psychological recovery when utilized as a rehabilitation adjunct. VR has also demonstrated noninferiority to usual care therapies for stroke rehabilitation.

OBJECTIVE

The proposed pilot study aims to (1) determine the feasibility and tolerability of using a therapeutic VR platform in an inpatient comprehensive stroke rehabilitation program and (2) estimate the initial clinical efficacy (effect size) associated with the VR platform using apps for pain distraction and upper extremity exercise for poststroke neurologic recovery.

METHODS

This study will be conducted in the Comprehensive Integrated Inpatient Rehabilitation Program at the James A Haley Veterans' Hospital. Qualitative interviews will be conducted with 10 clinical staff members to assess the feasibility of the VR platform from the clinician perspective. A prospective within-subject pretest-posttest pilot design will be used to examine the tolerability of the VR platform and the clinical outcomes (ie, upper extremity neurologic recovery, hand dexterity, pain severity) in 10 veteran inpatients. A VR platform consisting of commercially available pain distraction and upper extremity apps will be available at the participants' bedside for daily use during their inpatient stay (approximately 4-6 weeks). Clinician interviews will be analyzed using qualitative descriptive analysis. Cohen d effect sizes with corresponding 95% CIs will be calculated for upper extremity neurologic recovery, hand dexterity, and pain. The proportion of participants who achieve minimal clinically important difference after using the VR platform will be calculated for each clinical outcome.

RESULTS

This study was selected for funding in August 2020. Institutional review board approval was received in October 2020. The project start date was December 2020. The United States Department has issued a moratorium on in-person research activities secondary to COVID-19. Data collection will commence once this moratorium is lifted.

CONCLUSIONS

Our next step is to conduct a large multi-site clinical trial that will incorporate the lessons learned from this pilot feasibility study to test the efficacy of a VR intervention in inpatient rehabilitation and transition to home environments. When VR is used in patients' rooms, it serves to provide additional therapy and may reduce clinician burden. VR also presents an opportunity similar to home-based practice exercises. VR can be implemented in both clinical settings and people's own homes, where engagement in ongoing self-management approaches is often most challenging. This unique experience offers the potential for seamless transition from inpatient rehabilitation to the home.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/26133.

Toward Improving the Prediction of Functional Ambulation After Spinal Cord Injury Though the Inclusion of Limb Accelerations During Sleep and Personal Factors

OBJECTIVE

To determine if functional measures of ambulation can be accurately classified using clinical measures; demographics; personal, psychosocial, and environmental factors; and limb accelerations (LAs) obtained during sleep among individuals with chronic, motor incomplete spinal cord injury (SCI) in an effort to guide future, longitudinal predictions models.

DESIGN

Cross-sectional, 1-5 days of data collection.

SETTING

Community-based data collection.

PARTICIPANTS

Adults with chronic (>1 year), motor incomplete SCI (N=27).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Ambulatory ability based on the 10-m walk test (10MWT) or 6-minute walk test (6MWT) categorized as nonambulatory, household ambulator (0.01-0.44 m/s, 1-204 m), or community ambulator (>0.44 m/s, >204 m). A random forest model classified ambulatory ability using input features including clinical measures of strength, sensation, and spasticity; demographics; personal, psychosocial, and environmental factors including pain, environmental factors, health, social support, self-efficacy, resilience, and sleep quality; and LAs measured during sleep. Machine learning methods were used explicitly to avoid overfitting and minimize the possibility of biased results.

RESULTS

The combination of LA, clinical, and demographic features resulted in the highest classification accuracies for both functional ambulation outcomes (10MWT=70.4%, 6MWT=81.5%). Adding LAs, personal, psychosocial, and environmental factors, or both increased the accuracy of classification compared with the clinical/demographic features alone. Clinical measures of strength and sensation (especially knee flexion strength), LA measures of movement smoothness, and presence of pain and comorbidities were among the most important features selected for the models.

CONCLUSIONS

The addition of LA and personal, psychosocial, and environmental features increased functional ambulation classification accuracy in a population with incomplete SCI for whom improved prognosis for mobility outcomes is needed. These findings provide support for future longitudinal studies that use LA; personal, psychosocial, and environmental factors; and advanced analyses to improve clinical prediction rules for functional mobility outcomes.

Neural Safeguards against Global Impacts of Memory Modification on Identity: Ethical and Practical Considerations

Zawadzki and Adamczyk question whether removal of painful memories that anchor one’s narrative identity might leave behind a “free-floating” self plagued by feelings of inauthenticity. We argue that this scenario is unlikely, based on evidence that suggests our neural systems – especially those critical to human functioning1 – are naturally protected against minor, localized disruptions due to their synergistic distribution and redundancy2. For the same reason that artificial deep neural networks are increasingly designed to incorporate computational redundancy (especially those with safety-critical applications, such as self-driving cars), our own neural networks contain a degree of “cognitive reserve”3 to help mitigate against total system failure4,5 by drawing upon supplementary neural networks and forming new and more efficient connections (neuroplasticity) to compensate for disruptions.6 Neural representations of identity, a construct which evolutionary psychologists and behavioral ecologists argue is critical for survival at the individual, group and species levels7, are likely to incorporate such redundancy as a safeguard. The distribution of memory components across different brain regions supports the notion of cognitive reserve in the case of narrative identity. This arrangement complicates the capacity of optogenetic interventions to effectively erase complex autobiographical memories. Even if it were possible, we argue that disruptions to one’s identity and values are not necessarily ethically problematic, and must be viewed within the context of a risk-benefit ratio in which autonomously choosing to modify one’s debilitating or pathology-causing memories may confer benefits that outweigh potential challenges of identity reconstruction and (temporary) feelings of inauthenticity.

Secreted Peptides for Diagnostic Trajectory Assessments in Brain Injury Rehabilitation

BACKGROUND

Rehabilitation following traumatic brain injury (TBI) significantly improves outcomes; yet TBI heterogeneity raises the need for molecular evidence of brain recovery processes to better track patient progress, evaluate therapeutic efficacy, and provide prognostication.

OBJECTIVE

Here, we assessed whether the trajectory of TBI-responsive peptides secreted into urine can produce a predictive model of functional recovery during TBI rehabilitation.

METHODS

The multivariate urinary peptidome of 12 individuals with TBI was examined using quantitative peptidomics. Measures were assessed upon admission and discharge from inpatient rehabilitation. A combination of Pavlidis template matching and partial least-squares discriminant analysis was used to build models on Disability Rating Scale (DRS) and Functional Independence Measure (FIM) scores, with participants bifurcated into more or less functional improvement groups.

RESULTS

The produced models exhibited high sensitivity and specificity with the area under the receiver operator curve being 0.99 for DRS- and 0.95 for FIM-based models using the top 20 discriminant peptides. Predictive ability for each model was assessed using robust leave-one-out cross-validation with Q² statistics of 0.64 (P = .00012) and 0.62 (P = .011) for DRS- and FIM-based models, respectively, both with a high predictive accuracy of 0.875. Identified peptides that discriminated improved functional recovery reflected heightened neuroplasticity and synaptic refinement and diminished cell death and neuroinflammation, consistent with postacute TBI pathobiology.

CONCLUSIONS

Produced models of urine-based peptide measures reflective of ongoing recovery pathobiology can inform on rehabilitation progress after TBI, warranting further study to assess refined stratification across a larger population and efficacy in assessing therapeutic interventions.

Rehabilitation Effects of Fatigue-Controlled Treadmill Training After Stroke: A Rat Model Study

Background: Traditional rehabilitation with uniformed intensity would ignore individual tolerance and introduce the second injury to stroke survivors due to overloaded training. However, effective control of the training intensity of different stroke survivors is still lacking. The purpose of the study was to investigate the rehabilitative effects of electromyography (EMG)-based fatigue-controlled treadmill training on rat stroke model. Methods: Sprague-Dawley rats after intracerebral hemorrhage and EMG electrode implantation surgeries were randomly distributed into three groups: the control group (CTRL, n = 11), forced training group (FOR-T, n = 11), and fatigue-controlled training group (FAT-C, n = 11). The rehabilitation interventions were delivered every day from day 2 to day 14 post-stroke. No training was delivered to the CTRL group. The rats in the FOR-T group were forced to run on the treadmill without rest. The fatigue level was monitored in the FAT-C group through the drop rate of EMG mean power frequency, and rest was applied to the rats when the fatigue level exceeded the moderate fatigue threshold. The speed and accumulated running duration were comparable in the FAT-C and the FOR-T groups. Daily evaluation of the motor functions was performed using the modified Neurological Severity Score. Running symmetry was investigated by the symmetry index of EMG bursts collected from both hind limbs during training. The expression level of neurofilament-light in the striatum was measured to evaluate the neuroplasticity. Results: The FAT-C group showed significantly lower modified Neurological Severity Score compared with the FOR-T (P ≤ 0.003) and CTRL (P ≤ 0.003) groups. The FAT-C group showed a significant increase in the symmetry of hind limbs since day 7 (P = 0.000), whereas the FOR-T group did not (P = 0.349). The FAT-C group showed a higher concentration of neurofilament-light compared to the CTRL group (P = 0.005) in the unaffected striatum and the FOR-T group (P = 0.021) in the affected striatum. Conclusion: The treadmill training with moderate fatigue level controlled was more effective in motor restoration than forced training. The fatigue-controlled physical training also demonstrated positive effects in the striatum neuroplasticity. This study indicated that protocol with individual fatigue-controlled training should be considered in both animal and clinical studies for better stroke rehabilitation.

Conditions requiring hospitalisations, more than general anaesthesia itself, are associated with diagnosis of learning disorders in children

BACKGROUND

Anaesthesia is neurotoxic in developing primates. Retrospective clinical studies show a correlation between exposure to anaesthesia during infancy and the occurrence of learning disorders (LD). Prospective studies failed to detect any influence of a single exposure to anaesthesia on neurodevelopment. We hypothesised that some specific populations of children were electively sensitive to anaesthesia-related neurotoxicity.

METHODS

Using a case-control design, we analysed the medical histories of children with LD, compared to those of their normally reading siblings. Interviews were conducted and medical records were reviewed. The numbers of hospitalisations and anaesthesia exposures before the age of five years were determined.

RESULTS

Four hundred fourteen dyslexic children were screened over a one-year period. Two hundred and seventy patients were excluded due to confounding variables (single child, all siblings showing LD or any condition placing the neurological prognosis at risk (N = 107/414 for the latter)) or inability to accurately collect evaluation criteria. In the 144 case-control pairs studied, the mean number of hospitalisations was significantly different (N = 1.097 ± 0 .135/case versus 0.667 ± 0.097/control, p = 0.0052), as was the proportion of hospitalised patients (54.2% versus 38.9%, p = 0.0031). The mean number of anaesthesia exposures per individual was not statistically different (N = 0.958 ± 0.183/case versus 0.569 ± 0.107/control, p =  0.0732), but the proportion of children anaesthetised at least once was (43.8% (cases) versus 33.3% (controls), p =  0.0301).

DISCUSSION

One or more hospitalisation(s) may reflect a health status and/or have an iatrogenic effect disrupting the normal setting up of learning abilities. Anaesthesia may play a role, but a correlation between LD and anaesthesia is of a lower magnitude than between LD and hospitalisation.

Is Aphasia Treatment Beneficial for the Elderly? A Review of Recent Evidence

Purpose

We review recent literature regarding aphasia therapy in the elderly. Relevant articles from the last 5 years were identified to determine whether or not there is evidence to support that various therapeutic approaches can have a positive effect on post-stroke aphasia in the elderly.

Recent findings

There were no studies examining the effects of aphasia therapy specifically in the elderly within the timeframe searched. Therefore, we briefly summarize findings from 50 relevant studies that included large proportions of participants with post-stroke aphasia above the age of 65. A variety of behavioral and neuromodulation therapies are reported.

Summary

We found ample evidence suggesting that a variety of behavioral and neuromodulatory therapeutic approaches can benefit elderly individuals with post-stroke aphasia.

Comparing the effects of anticipatory postural adjustments focused training and balance training on postural preparation, balance confidence and quality of life in elderly with history of a fall

BACKGROUND

Impairment of postural adjustments in elderly is associated with decreased functional mobility, balance confidence and quality of life.

AIMS

We studied the effects of anticipatory postural adjustments focused training on postural preparation, balance confidence and quality of life of the elderly.

METHODS

It was a single-blind randomized controlled trial. The sample included 60 males with history of falling (at least once in the past 6 months). They were matched and randomly assigned into three groups: perturbation, balance, and no training. The electrical activity of the muscles was measured by electromyography. The Activities-specific Balance Confidence (ABC) scale and the SF-36 questionnaire were used to assess balance confidence and quality of life, respectively. Repeated-measures ANOVA was used for data analysis (significant level 0.05).

RESULTS

The type of training had significant interaction effect on muscle latency (F_{(2, 46)} ≥ 71.06, P ≤ 0.001, η² ≥ 0.75). Compared to the other two groups, perturbation training group showed significantly more improvement in ABC scale (F_{(2, 46)} = 14.94, P ≤ 0.000, η² ≥ 0.39). It also significantly showed more improvement than no training group in all areas of SF-36 questionnaire, except for mental health (F_{(2, 46)} ≥ 6.56, P ≤ 0.03, η² ≥ 0.22).

CONCLUSIONS

Our findings support the use of perturbation training, as it reduced the probability of falling (by decreasing muscle latency and increasing posture preparation), improved the balance confidence for daily activities, and improved the quality of life.

Community reintegration following holistic milieu-oriented neurorehabilitation up to 30 years post-discharge

BACKGROUND

The primary goal of neurorehabilitation for individuals with acquired brain injury (ABI) is successful community reintegration, which commonly focuses on home independence, productivity, and social engagement. Previous research has demonstrated that holistic treatment approaches have better long-term outcomes than other treatment approaches. Holistic approaches go beyond the fundamental components of neurorehabilitation and address metacognition and self-awareness, as well as interpersonal and functional skills.

OBJECTIVES

The present study aimed to examine community reintegration of individuals with ABI who completed holistic milieu-oriented neurorehabilitation at the Center for Transitional Neuro-Rehabilitation (CTN), Barrow Neurological Institute (BNI) at up to 30-years post-discharge. We evaluated (a) functional independence, (b) productivity and driving status, and (c) psychosocial profiles of the brain injury survivors.

METHOD

Participants included 107 individuals with ABI with heterogeneous etiologies who attended holistic milieu-oriented neurorehabilitation between 1986 and 2016. These participants completed the Mayo-Portland Adaptability Inventory-4 (MPAI-4) and a long-term outcome questionnaire (LOQ) specifically developed for this study.

RESULTS

The results demonstrate that 89% of participants were productive at up to 30 years post-discharge (73% engaged in competitive work and/or school) after excluding the retired participants. Almost all of the participants who were engaged in work and/or school reported using compensatory strategies on a long-term basis. Furthermore, only 14% out of 102 study participants were driving at the time of program admission; whereas 58% out of 96 were driving at the time of discharge; and impressively, 70% out of 107 participants were driving at the time of follow-up. Regression analyses revealed that older age at the time of injury, shorter duration between injury and treatment, and better functionality indicated by lower MPAI-4 Ability Index scores significantly predicted a return to driving status at the time of study participation. Psychosocial data from the LOQ revealed positive findings with respect to patients' marital status, living situation, income, and quality of social life.

CONCLUSION

The findings from this study suggest that functional gains made during holistic neurorehabilitation have enduring effects and that patients can benefit highly from holistic milieu therapy beyond the early post-acute phases of their recovery. Additionally, they provide evidence that there is potential to return to driving, years after treatment completion.Our holistic milieu treatment approach addressing metacognition, self-awareness, social and coping skills training, and actively transitioning to community settings, is thought to have contributed to the exceptional and long-lasting outcomes in this study.

Motor Learning, Neuroplasticity, and Strength and Skill Training: Moving From Compensation to Retraining in Behavioral Management of Dysphagia

Purpose Learning a motor skill and regaining a motor skill after it is lost are key tenets to the field of speech-language pathology. Motor learning and relearning have many theoretical underpinnings that serve as a foundation for our clinical practice. This review article applies selective motor learning theories and principles to feeding and swallowing across the life span. Conclusion In reviewing these theoretical fundamentals, clinical exemplars surrounding the roles of strength, skill, experience, compensation, and retraining, and their influence on motor learning and plasticity in regard to swallowing/feeding skills throughout the life span are discussed.

Long-term beneficial effects of hematopoietic growth factors on brain repair in the chronic phase of severe traumatic brain injury

Severe traumatic brain injury (TBI) is the major cause of long-term, even life-long disability and cognitive impairments in young adults. The lack of therapeutic approaches to improve recovery in the chronic phase of severe TBI is a big challenge to the medical research field. Using a single severe TBI model in young adult mice, this study examined the restorative efficacy of two hematopoietic growth factors, stem cell factor (SCF) and granulocyte colony-stimulating factor (G-CSF), on brain repair in the chronic phase of TBI. SCF and G-CSF alone or combination (SCF + G-CSF) treatment was administered at 3 months post-TBI. Functional recovery was evaluated by neurobehavioral tests during the period of 21 weeks after treatment. Neuropathology was examined 22 weeks after treatment. We observed that severe TBI caused persistent impairments in spatial learning/memory and somatosensory-motor function, long-term and widespread neuropathology, including dendritic reduction, decrease and overgrowth of axons, over-generated excitatory synapses, and demyelination in the cortex, hippocampus and striatum. SCF, G-CSF, and SCF + G-CSF treatments ameliorated severe TBI-induced widespread neuropathology. SCF + G-CSF treatment showed superior efficacy in improving long-term functional outcome, enhancing neural plasticity, rebalancing neural structure networks disturbed by severe TBI, and promoting remyelination. These novel findings demonstrate the therapeutic potential of SCF and G-CSF in enhancing recovery in the chronic phase of severe TBI .

A method for assessing recovery of fine motor function of the hand in a rhesus monkey model of cortical injury: an adaptation of the Fugl-Meyer Scale and Eshkol-Wachman Movement Notation

Motor dysfunction of the upper extremity can result from stroke, cortical injury and neurological diseases and causes significant disruption of activities of daily living. While some spontaneous recovery in terms of compensatory movements does occur after injury to cortical motor areas, full recovery is rare. The distinction between complete recovery and compensatory recovery is important as the development of compensatory movements in the upper extremity may not translate into full functional use in human patients. However, current animal models of stroke do not distinguish full recovery from compensatory recovery. We have developed a Non-Human Primate Grasp Assessment Scale (GRAS) to quantify the precise recovery of composite movement, individual digit action, and finger-thumb pinch in our rhesus monkey model of cortical injury. To date, we have applied this GRAS scale to assess the recovery of fine motor function of the hand in young control and cell-therapy treated monkeys with cortical injury confined to the hand representation in the dominant primary motor cortex. We have demonstrated that with this scale we can detect and quantify significant impairments in fine motor function of the hand, the development of compensatory function during recovery and finally a return to full fine motor function of the hand in monkeys treated with a cell therapy.

Mesenchymal derived exosomes enhance recovery of motor function in a monkey model of cortical injury

BACKGROUND

Exosomes from mesenchymal stromal cells (MSCs) are endosome-derived vesicles that have been shown to enhance functional recovery in rodent models of stroke.

OBJECTIVE

Building on these findings, we tested exosomes as a treatment in monkeys with cortical injury.

METHODS

After being trained on a task of fine motor function of the hand, monkeys received a cortical injury to the hand representation in primary motor cortex. Twenty-four hours later and again 14 days after injury, monkeys received exosomes or vehicle control. Recovery of motor function was followed for 12 weeks.

RESULTS

Compared to monkeys that received vehicle, exosome treated monkeys returned to pre-operative grasp patterns and latency to retrieve a food reward in the first three-five weeks of recovery.

CONCLUSIONS

These results provide evidence that in monkeys exosomes delivered after cortical injury enhance recovery of motor function.

Principles of Neurorehabilitation After Stroke Based on Motor Learning and Brain Plasticity Mechanisms

What are the principles underlying effective neurorehabilitation? The aim of neurorehabilitation is to exploit interventions based on human and animal studies about learning and adaptation, as well as to show that the activation of experience-dependent neuronal plasticity augments functional recovery after stroke. Instead of teaching compensatory strategies that do not reduce impairment but allow the patient to return home as soon as possible, functional recovery might be more sustainable as it ensures a long-term reduction in impairment and an improvement in quality of life. At the same time, neurorehabilitation permits the scientific community to collect valuable data, which allows inferring about the principles of brain organization. Hence neuroscience sheds light on the mechanisms of learning new functions or relearning lost ones. However, current rehabilitation methods lack the exact operationalization of evidence gained from skill learning literature, leading to an urgent need to bridge motor learning theory and present clinical work in order to identify a set of ingredients and practical applications that could guide future interventions. This work aims to unify the neuroscientific literature relevant to the recovery process and rehabilitation practice in order to provide a synthesis of the principles that constitute an effective neurorehabilitation approach. Previous attempts to achieve this goal either focused on a subset of principles or did not link clinical application to the principles of motor learning and recovery. We identified 15 principles of motor learning based on existing literature: massed practice, spaced practice, dosage, task-specific practice, goal-oriented practice, variable practice, increasing difficulty, multisensory stimulation, rhythmic cueing, explicit feedback/knowledge of results, implicit feedback/knowledge of performance, modulate effector selection, action observation/embodied practice, motor imagery, and social interaction. We comment on trials that successfully implemented these principles and report evidence from experiments with healthy individuals as well as clinical work.

Locomotion and eating behavior changes in Yucatan minipigs after unilateral radio-induced ablation of the caudate nucleus

The functional roles of the Caudate nucleus (Cd) are well known. Selective Cd lesions can be found in neurological disorders. However, little is known about the dynamics of the behavioral changes during progressive Cd ablation. Current stereotactic radiosurgery technologies allow the progressive ablation of a brain region with limited adverse effects in surrounding normal tissues. This could be of high interest for the study of the modified behavioral functions in relation with the degree of impairment of the brain structures. Using hypofractionated stereotactic radiotherapy combined with synchrotron microbeam radiation, we investigated, during one year after irradiation, the effects of unilateral radio-ablation of the right Cd on the behavior of Yucatan minipigs. The right Cd was irradiated to a minimal dose of 35.5 Gy delivered in three fractions. MRI-based morphological brain integrity and behavioral functions, i.e. locomotion, motivation/hedonism were assessed. We detected a progressive radio-necrosis leading to a quasi-total ablation one year after irradiation, with an additional alteration of surrounding areas. Transitory changes in the motivation/hedonism were firstly detected, then on locomotion, suggesting the influence of different compensatory mechanisms depending on the functions related to Cd and possibly some surrounding areas. We concluded that early behavioral changes related to eating functions are relevant markers for the early detection of ongoing lesions occurring in Cd-related neurological disorders.

Data-driven analyses of motor impairments in animal models of neurological disorders

Behavior provides important insights into neuronal processes. For example, analysis of reaching movements can give a reliable indication of the degree of impairment in neurological disorders such as stroke, Parkinson disease, or Huntington disease. The analysis of such movement abnormalities is notoriously difficult and requires a trained evaluator. Here, we show that a deep neural network is able to score behavioral impairments with expert accuracy in rodent models of stroke. The same network was also trained to successfully score movements in a variety of other behavioral tasks. The neural network also uncovered novel movement alterations related to stroke, which had higher predictive power of stroke volume than the movement components defined by human experts. Moreover, when the regression network was trained only on categorical information (control = 0; stroke = 1), it generated predictions with intermediate values between 0 and 1 that matched the human expert scores of stroke severity. The network thus offers a new data-driven approach to automatically derive ratings of motor impairments. Altogether, this network can provide a reliable neurological assessment and can assist the design of behavioral indices to diagnose and monitor neurological disorders.

Computer-Based Cognitive Rehabilitation in Patients with Visuospatial Neglect or Homonymous Hemianopia after Stroke

OBJECTIVES

The purpose of this pilot study was to investigate the feasibility and effects of computer-based cognitive rehabilitation (CBCR) in patients with symptoms of visuospatial neglect or homonymous hemianopia in the subacute phase following stroke.

METHOD

A randomized, controlled, unblinded cross-over design was completed with early versus late CBCR including 7 patients in the early intervention group (EI) and 7 patients in the late intervention group (LI). EI received CBCR training immediately after inclusion (m = 19 days after stroke onset) for 3 weeks and LI waited for 3 weeks after inclusion before receiving CBCR training for 3 weeks (m = 44 days after stroke onset).

RESULTS

CBCR improved visuospatial symptoms after stroke significantly when administered early in the subacute phase after stroke. The same significant effect was not found when CBCR was administered later in the rehabilitation. The difference in the development of the EI and LI groups during the first 3 weeks was not significant, which could be due to a lack of statistical power. CBCR did not impact mental well-being negatively in any of the groups. In the LI group, the anticipation of CBCR seemed to have a positive impact of mental well-being.

CONCLUSION

CBCR is feasible and has a positive effect on symptoms in patients with visuospatial symptoms in the subacute phase after stroke. The study was small and confirmation in larger samples with blinded outcome assessors is needed.

Repetitive verbal behaviors are not always harmful signs: Compensatory plasticity within the language network in aphasia

Repetitive verbal behaviors such as conduite d'approche (CdA) and mitigated echolalia (ME) are well-known phenomena since early descriptions of aphasia. Nevertheless, there is no substantial fresh knowledge on their clinical features, neural correlates and treatment interventions. In the present study we take advantage of three index cases of chronic fluent aphasia showing CdA, ME or both symptoms to dissect their clinical and neural signatures. Using multimodal neuroimaging (structural magnetic resonance imaging and [18]-fluorodeoxyglucose positron emission tomography during resting state), we found that despite of the heterogeneous lesions in terms of etiology (stroke, traumatic brain injury), volume and location, CdA was present when the lesion affected in greater extent the left dorsal language pathway, while ME resulted from preferential damage to the left ventral stream. The coexistence of CdA and ME was associated with involvement of areas overlapping with the structural lesions and metabolic derangements described in the subjects who showed one of these symptoms (CdA or ME). These findings suggest that CdA and ME represent the clinical expression of plastic changes that occur within the spared language network and its interconnected areas in order to compensate for the linguistic functions that previously relied on the activity of the damaged pathway. We discuss the results in the light of this idea and consider alternative undamaged neural networks that may support CdA and ME.

Perilesional and homotopic area activation during proverb comprehension after stroke

INTRODUCTION

The mechanism of functional recovery in right hemisphere (RH) stroke patients when attempting to comprehend a proverb has not been identified. We previously reported that there is bilateral hemisphere involvement during proverb comprehension in the normal population. However, the underlying mechanisms of proverb comprehension following a right middle cerebral artery (MCA) infarction have not yet been fully elucidated.

METHODS

We here compared the brain regions activated by literal sentences and by opaque or transparent proverbs in right MCA infarction patients using functional magnetic resonance imaging (fMRI). Experimental stimuli included 18 opaque proverbs, 18 transparent proverbs, and 18 literal sentences that were presented pseudorandomly in 1 of 3 predesigned sequences.

RESULTS

Fifteen normal adults and 17 right MCA infarction patients participated in this study. The areas of the brain in the stroke patients involved in understanding a proverb compared with a literal sentence included the right middle frontal gyrus (MFG) and frontal pole, right anterior cingulate gyrus/paracingulate gyrus and left inferior frontal gyrus (IFG), middle temporal gyrus (MTG), precuneus, and supramarginal gyrus (SMG). When the proverbs were presented to these stroke patients in the comprehension tests, the left supramarginal, postcentral gyrus, and right paracingulate gyrus were activated for the opaque proverbs compared to the transparent proverbs.

CONCLUSIONS

These findings suggest that the functional recovery of language in stroke patients can be explained by perilesional activation, which is thought to arise from the regulation of the excitatory and inhibitory neurotransmitter system, and by homotopic area activation which has been characterized by decreased transcallosal inhibition and astrocyte involvement.

Increase in Blood Levels of Growth Factors Involved in the Neuroplasticity Process by Using an Extremely Low Frequency Electromagnetic Field in Post-stroke Patients

Background: Neuroplasticity ensures the improvement of functional status in patients after stroke. The aim of this study was to evaluate the effect of extremely low-frequency electromagnetic field therapy (ELF-EMF) on brain plasticity in the rehabilitation of patients after stroke.

Methods: Forty-eight patients were divided into two groups underwent the same rehabilitation program, but in the study group, the patients additionally were exposed to a standard series of 10 ELF-EMF treatments. To determine the level of neuroplasticity, we measured the plasma level of the brain-derived neurotrophic factor (BDNF), the vascular-endothelial growth factor, as well as BDNF mRNA expression. Additionally, we determined the molecule levels for hepatocyte growth factor, stem cell factor, stromal cell-derived factor 1α, nerve growth factor β, and leukemia inhibitory factor, using 5plex cytokine panel in plasma. After 4 weeks, during which patients had undergone neurorehabilitation and neurological examinations, we assessed functional recovery using the Barthel Index, Mini-Mental State Examination (MMSE), Geriatric Depression Scale, National Institutes of Health Stroke Scale (NIHSS), and the modified Rankin Scale (mRS).

Results: We observed that ELF-EMF significantly increased growth factors and cytokine levels involved in neuroplasticity, as well as promoted an enhancement of functional recovery in post-stroke patients. Additionally, we presented evidence that these effects could be related to the increase of gene expression on the mRNA level. Moreover, a change of BDNF plasma level was positively correlated with the Barthel Index, MMSE, and negatively correlated with GDS.

Conclusion: Extremely low-frequency electromagnetic field therapy improves the effectiveness of rehabilitation of post-stroke patients by improving neuroplasticity processes.