Reinforcement feedback impairs locomotor adaptation and retention.

Introduction: Locomotor adaptation is a motor learning process used to alter spatiotemporal elements of walking that are driven by prediction errors, a discrepancy between the expected and actual outcomes of our actions. Sensory and reward prediction errors are two different types of prediction errors that can facilitate locomotor adaptation. Reward and punishment feedback generate reward prediction errors but have demonstrated mixed effects on upper extremity motor learning, with punishment enhancing adaptation, and reward supporting motor memory. However, an in-depth behavioral analysis of these distinct forms of feedback is sparse in locomotor tasks. Methods: For this study, three groups of healthy young adults were divided into distinct feedback groups [Supervised, Reward, Punishment] and performed a novel locomotor adaptation task where each participant adapted their knee flexion to 30 degrees greater than baseline, guided by visual supervised or reinforcement feedback (Adaptation). Participants were then asked to recall the new walking pattern without feedback (Retention) and after a washout period with feedback restored (Savings). Results: We found that all groups learned the adaptation task with external feedback. However, contrary to our initial hypothesis, enhancing sensory feedback with a visual representation of the knee angle (Supervised) accelerated the rate of learning and short-term retention in comparison to monetary reinforcement feedback. Reward and Punishment displayed similar rates of adaptation, short-term retention, and savings, suggesting both types of reinforcement feedback work similarly in locomotor adaptation. Moreover, all feedback enhanced the aftereffect of locomotor task indicating changes to implicit learning. Discussion: These results demonstrate the multi-faceted nature of reinforcement feedback on locomotor adaptation and demonstrate the possible different neural substrates that underly reward and sensory prediction errors during different motor tasks.

Development of a specific and potent IGF2BP1 inhibitor: A promising therapeutic agent for IGF2BP1-expressing cancers.

IGF2BP1 is a protein that controls the stability, localization, and translation of various mRNA targets. Poor clinical outcomes in numerous cancer types have been associated with its overexpression. As it has been demonstrated to impede tumor growth and metastasis in animal models, inhibiting IGF2BP1 function is a promising strategy for combating cancer. A lead chemical, 7773, which specifically decreased IGF2BP1 RNA binding and cellular activities, was previously identified in a high-throughput screen for effective IGF2BP1 inhibitors. Additional optimization of 7773 described in this manuscript led to the discovery of six compounds that performed equally well or better than 7773. In cell lines with high levels of endogenous IGF2BP1, one of 7773 derivatives, AVJ16, was found to be most efficient at preventing cell migration. Further, AVJ16 was found to be IGF2BP1-specific because it had no effect on cell lines that expressed little or no IGF2BP1 protein. The direct binding of AVJ16 to IGF2BP1 was validated by binding tests, with a 12-fold increase in binding efficiency over the lead compound. AVJ16 was shown to bind to a hydrophobic region at the protein's KH34 di-domain interface between the KH3 and KH4 domains. Overall, the findings imply that AVJ16 is a potent and specific inhibitor of IGF2BP1 activity.

Prediction of the Post-Pubertal Mandibular Length and Y Axis of Growth by Using Various Machine Learning Techniques: A Retrospective Longitudinal Study.

The aim was to predict the post-pubertal mandibular length and Y axis of growth in males by using various machine learning (ML) techniques. Cephalometric data obtained from 163 males with Class I Angle malocclusion, were used to train various ML algorithms. Analysis of variances (ANOVA) was used to compare the differences between predicted and actual measurements among methods and between time points. All the algorithms revealed an accuracy range from 95.80% to 97.64% while predicting post-pubertal mandibular length. When predicting the Y axis of growth, accuracies ranged from 96.60% to 98.34%. There was no significant interaction between methods and time points used for predicting the mandibular length (p = 0.235) and Y axis of growth (p = 0.549). All tested ML algorithms accurately predicted the post-pubertal mandibular length and Y axis of growth. The best predictors for the mandibular length were mandibular and maxillary lengths, and lower face height, while they were Y axis of growth, lower face height, and mandibular plane angle for the post-pubertal Y axis of growth. No significant difference was found among the accuracies of the techniques, except the least squares method had a significantly larger error than all others in predicting the Y axis of growth.

Organizational-Professional Conflict in the Collegiate and Secondary School Practice Settings: A Sequential, Mixed-Methods Study.

CONTEXT: Athletic trainers (ATs) are employed in various settings, which may use 1 of 3 organizational infrastructure models: (1) the sport/athletic model, (2) the medical model, and (3) the academic model. These different settings and organizational infrastructure models may result in varying levels of organizational-professional conflict (OPC). However, how OPC may differ across infrastructure models and practice settings is not known. OBJECTIVE: To examine the prevalence of OPC among ATs in various organizational infrastructures and explore ATs' perceptions of OPC, including its precipitating and mitigating factors. DESIGN: Sequential explanatory mixed-methods study with equal emphasis on quantitative and qualitative components. SETTING: Collegiate and secondary school institutions. PATIENTS OR OTHER PARTICIPANTS: Five hundred ninety-four ATs from collegiate and secondary schools. DATA COLLECTION AND ANALYSIS: We conducted a national cross-sectional survey using a validated scale to assess OPC. We then followed the quantitative survey with individual interviews. Trustworthiness was established with multiple-analyst triangulation and peer debriefing. RESULTS: Athletic trainers experienced low to moderate degrees of OPC with no differences across practice settings or infrastructure models. Poor communication, others' unfamiliarity with the AT's scope of practice, and lack of medical knowledge were precipitating factors for OPC. Organizational relationships founded on trust and respect for one another; administrative support in that ATs were listened to, decisions were endorsed, and appropriate resources provided; and autonomy given to the AT were key components to preventing OPC. CONCLUSIONS: Most ATs experienced primarily low to moderate OPC. However, OPC continues to permeate professional practice to some extent in collegiate and secondary school settings, regardless of the infrastructure model used. The findings of this study highlight the role of administrative support that allows for autonomous AT practice as well as effective communication that is direct, open, and professional to decrease OPC.

Impact of Blockchain-Digital Twin Technology on Precision Health, Pharmaceutical Industry, and Life Sciences: Conference Proceedings, Conv2X 2023.

The convergence of Digital Twin technologies with precision health, the pharmaceutical industry, and life sciences has garnered substantial recent attention. As we advance toward personalized medicine and precision health, the fusion of Digital Twin and blockchain technologies is poised to enhance healthcare outcomes fundamentally. This conference discussion highlighted pivotal drivers accelerating the adoption of Digital Twin-enabled blockchain solutions, encompassing the shift to a decentralized World Wide Web (Web 3.0), the establishment of a global interconnected health ecosystem, and the distinct advantages offered by converging frontier technologies in optimizing healthcare, pharmaceutical industry, and life sciences. Yet, the effective deployment of blockchain-powered Digital Twins in precision health necessitates robust cyber safety measures, proactive ethical frameworks, data validation, provenance assurance, streamlined supply chain management, and heightened interoperability. These proceedings underscored blockchain-powered Digital Twins' pivotal role in reshaping health data management, security, sharing, ownership, and monetization and in revolutionizing pharmaceutical supply chain management and novel drugs and therapeutics development within the precision health domain.

Are negative views of the self, world and future, mediators of the relationship between subjective social status and depressive symptoms?

BACKGROUND: Elevated depressive symptoms are associated with impairments, reduced quality of life, and societal economic burden. A well-established stress-vulnerability model explaining depressive symptoms is Beck's cognitive theory (Beck, 1976). An independent line of research demonstrated that a person's perception of their status in comparison with others' (subjective social status, SSS) is a stressor associated with depressive symptoms. AIMS: Theory-driven research investigating the interplay of different factors associated with depressive symptoms opens the door to improve the lives of the affected individuals and to reduce the overall societal burden. This study's aim was to examine if SSS can be integrated as a stressor into Beck's theory, looking specifically at whether it impacts depressive symptoms through the individual components (self, world and future) of the cognitive triad. METHOD: In this cross-sectional study, 243 community college students (58.6% female; mean age 23.95 years) in the southern United States completed self-reports measuring SSS, negative views of the self, world and future, and depressive symptoms. RESULTS: SSS is negatively associated with each view of the cognitive triad. SSS and views of the self and world are negatively associated with depressive symptoms. Mediation analyses displayed a significant direct effect between SSS and depressive symptoms, as well as two indirect effects via negative view of self and world. CONCLUSIONS: While further research is needed, therapists might benefit from our findings when tailoring their treatment to a client by considering their SSS and which negative view is particularly detrimental for this specific client.

The importance of promoting physical activity and exercise training as adjuvant therapy for people with multiple sclerosis

Abstract Aim: This review aimed to provide evidence and highlight the importance of including physical activity (PA) and/or exercise training (ET) as part of the comprehensive multiple sclerosis (MS) care. Methods: Using the current literature on the subject, we provide a brief overview of MS incorporating its definition, common symptoms, prevalence, and potential disease consequences. We further succinctly describe MS as the first line of treatment, as well as the role of PA and ET in the disease. We end the commentary highlighting important recommendations from an international initiative to improve MS-related physical activity research that we believe will help not only improve the area of study but also best practices within this population. Results: There is compelling evidence for the beneficial effects of PA and/or ET on MS-related symptoms and consequently health and quality of life. There is preliminary evidence suggesting the potential for a disease-modifying effect. Conclusion: Fomenting this discussion is timely due to the increased prevalence of MS in different regions of the globe, and people with MS report low levels of PA participation and high amounts of sedentary time. The consequences of inactivity in this population can be drastic. The current body of evidence supports the notion that PA and ET are safe health behaviors that should be adopted as an adjuvant treatment option within the comprehensive and complex MS care due to its benefits on a variety of disease-related symptoms and its potential for improving health and quality of life in this population.

Running away or running to? Do prey make decisions solely based on the landscape of fear or do they also include stimuli from a landscape of safety?

Predator-prey interactions are a key part of ecosystem function, and non-consumptive effects fall under the landscape of fear theory. Under the landscape of fear, the antipredator responses of prey are based on the spatial and temporal distribution of predatory cues in the environment. However, the aversive stimuli (fear) are not the only stimuli prey can utilize when making behavioral decisions. Prey might also be using attractive stimuli that represent safety to guide decision making. Using a novel, orthogonal design, we were able to spatially separate aversive and attractive stimuli to determine whether prey are utilizing safety cues to navigate their environment. Crayfish Faxonius rusticus were placed in the center of a behavioral arena. Aversive stimuli of either predatory bass Micropterus salmoides cues or conspecific alarm cues increased along the x-axis of the behavioral arena. Safety cues (shelters) increased along the y-axis by decreasing the number of shelter openings in this direction. Crayfish were allowed two phases to explore the arena: one without the fearful stimuli and one with the stimuli. Linear mixed models were conducted to determine whether movement behaviors and habitat utilization were affected by the phase of the trial and the type of aversive stimuli. Crayfish responded more strongly to alarm cues than to fear cues, with only alarm cues significantly impacting habitat utilization. When responding to alarm cues, crayfish used safety cues as well as fear cues to relocate themselves within the arena. Based on these results, we argue that crayfish utilize a landscape of safety in conjunction with a landscape of fear when navigating their environment.

Injury frequency and severity in crayfish communities as indicators of physical habitat quality and water quality within agricultural headwater streams.

Crayfishes (Decapoda) are common inhabitants of agricultural headwater streams in the Midwestern USA that have been impacted by physical habitat degradation and contamination by agricultural pollutants. The frequency and severity of injuries within crayfish communities are indicators of crayfish aggression, which is influenced by physical, chemical, and biotic factors. Previous studies have not evaluated the relationships of the frequency and severity of crayfish injuries with physical habitat quality, water quality, and biotic factors within agricultural headwater streams. Understanding these relationships will assist with determining if crayfish injury variables can serve as an indicator of physical habitat quality or water quality in these small degraded streams. We sampled crayfishes, documented the frequency and type of injuries, and measured instream habitat and water chemistry in 2014 and 2015 within 12 agricultural headwater streams in Indiana, Michigan, and Ohio. We documented five native crayfish species from 1641 adult captures. The most abundant species were Faxonius rusticus, Faxonius immunis, and Faxonius propinquus. Linear mixed effect model analyses indicated that four crayfish injury response variables were positively correlated (p < 0.05) with crayfish density, physical habitat quality, and water velocity diversity and that crayfish injury response variables were more strongly correlated with crayfish density than physical habitat quality or water quality. Our results indicate that response variables describing the severity and frequency of crayfish injuries can be effective indicators of physical habitat quality in agricultural headwater streams.

Age-related differences to neck muscle activation latency as a potential risk factor to fall-related traumatic brain injuries.

This investigation examined age-related differences in neck muscle activation latency in response to anterior and posterior postural perturbations to understand the potential implications in fall-related traumatic brain injuries. 57 adults were recruited and categorized into 3 groups based on age: Young (18-30 years old), Young-Old (60-74 years) and Old-Old (75-89 years) group. Study participants underwent six anterior and posterior postural perturbations while bilateral sternocleidomastoid, upper trapezius, and splenius capitis electromyography was collected. Muscle activation latency time was calculated with established procedures. During anterior translations, a significant group effect for muscle activation latency of the right SCM (F(2,43) = 8.786, p < 0.001), right (F(2,34) = 4.838, p = 0.014) and left (F(2,34) = 5.015, p = 0.012) upper trapezius, and right (F(2,45) = 3.195, p = 0.050) and left (F(2,45) = 3.819, p = 0.029) splenius capitis was observed. During posterior translations, a significant group effect for muscle activation latency was observed in the right (F(2,34) = 6.419, p = 0.004) and left (F(2,41) = 5.275, p = 0.009) SCM, and the right (F(2,34) = 4.925, p = 0.013) and left (F(2,32) = 4.055, p = 0.027) upper trapezius. Both older groups displayed longer muscle activation latencies than the young group. The age-related differences in neck muscle activation latency may be placing older adults at a greater risk of fall-related traumatic brain injuries.

Age-related differences to neck range of motion and muscle strength: potential risk factors to fall-related traumatic brain injuries.

BACKGROUND: Fall-related traumatic brain injuries (TBIs) are a serious health concern for adults over the age of 75 years, yet there is limited knowledge on possible modifiable risk factors. The neck is responsible for supporting the head during falls and age-related differences to the neck muscular could provide modifiable risk factors. However, there is limited empirical data pertaining to age-related differences in neck range of motion (ROM) and muscle strength in adults over the age of 75 years. AIMS: To understand the age-related differences in neck muscle ROM and strength, we quantified neck active and passive ROM and isometric strength in four directions in young (18-30 years), young-old (60-74 years) and old-old (75-89 years) groups. METHODS: 57 participants were divided into groups based on age. Participants underwent testing of neck active and passive ROM and neck isometric strength in flexion, extension, and lateral flexion. RESULTS: One-way ANOVAs revealed a significant effect of group on active and passive ROM in flexion, extension, and right and left lateral flexion (p < 0.001). Moreover, one-way ANOVAs revealed a significant group difference in only left lateral flexion strength (p < 0.030), yet there were large effect sizes observed between the young and old-old groups. DISCUSSION: These findings suggest there are some age-related differences to the neck ROM and strength, which may be placing older adults at a greater risk for fall-related TBIs. CONCLUSION: Future research should investigate the association between neck ROM and strength and head impact during falls in older adults.

Motor Learning in People with Multiple Sclerosis: A Systematic Review and Meta-analysis.

OBJECTIVE: To systematically review and quantitatively synthesize the existing evidence of motor learning in persons with multiple sclerosis (PwMS). DATA SOURCES: PubMed, Cumulative Index to Nursing and Allied Health Literature, and Web of Science were searched using the following terms: multiple sclerosis, task learning, motor learning, skill learning, performance learning. STUDY SELECTION: Studies had to include PwMS with a main outcome being motor learning, be published in peer-reviewed journals, and be written in English. The search yielded 68 results, and the inclusion criteria were met by 17 studies. DATA EXTRACTION: Basic descriptors of each study, study protocol, and motor learning measures were extracted. The Grading of Recommendations Assessment, Development, and Evaluation approach revealed the quality of evidence was low with a high risk of bias. Meta-analysis was conducted to determine the difference in implicit and explicit learning in PwMS and controls without multiple sclerosis. DATA SYNTHESIS: Studies scored on average 15.9 of 18 for quality assessment. PwMS were able to learn functional mobility and upper limb manipulation motor skills as indicated by short-term acquisition, transfer, and retention. Implicit learning conditions from the meta-analysis showed that PwMS were able to learn at a similar rate to controls without multiple sclerosis (P<.001), yet explicit learning conditions did not display a significant rate of learning (P=.133). CONCLUSIONS: While this review indicated that PwMS are capable of motor learning, several knowledge gaps still exist. Future research should focus on using higher-quality evidence to understand motor learning in PwMS and translate the findings to rehabilitation and activities of daily living.

RNA-binding protein IGF2BP1 maintains leukemia stem cell properties by regulating HOXB4, MYB, and ALDH1A1.

Insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) is an oncofetal protein expressed in various cancers including leukemia. In this study, we assessed the role of IGF2BP1 in orchestrating leukemia stem cell properties. Tumor-initiating potential, sensitivity to chemotherapeutic agents, and expression of cancer stem cell markers were assessed in a panel of myeloid, B-, and T-cell leukemia cell lines using gain- and loss-of-function systems, cross-linking immunoprecipitation (CLIP), and photoactivatable ribonucleoside-enhanced cross-linking and immunoprecipitation (PAR-CLIP) techniques. Here, we report that genetic or chemical inhibition of IGF2BP1 decreases leukemia cells' tumorigenicity, promotes myeloid differentiation, increases leukemia cell death, and sensitizes leukemia cells to chemotherapeutic drugs. IGF2BP1 affects proliferation and tumorigenic potential of leukemia cells through critical regulators of self-renewal HOXB4 and MYB and through regulation of expression of the aldehyde dehydrogenase, ALDH1A1. Our data indicate that IGF2BP1 maintains leukemia stem cell properties by regulating multiple pathways of stemness through transcriptional and metabolic factors.

A novel hiPSC-derived system for hematoendothelial and myeloid blood toxicity screens identifies compounds promoting and inhibiting endothelial-to-hematopoietic transition.

The exposure to toxic environmental and pharmaceutical substances can pose a long-term risk to human's health. In this study, we sought to investigate the potential of our recently developed method for induction of myeloid hematoendothelial and blood cells by overexpression of two transcription factors, GATA2 and ETV2, in human induced pluripotent stem cells (hiPSCs) for toxicity screening. For the primary screen in a high-throughput format, we selected twenty-two chemicals with various degrees of cytotoxicity available from the NIEHS National Toxicology Program (Tox21). The compounds were applied during the endothelial-to-hematopoietic transition and to differentiated myeloid progenitors growing in suspension. The system was capable of identifying compounds with both inhibitory and favorable effects on hematopoietic network, changes in expression of hematopoietic markers, and mitochondrial and cytotoxicity. The findings were confirmed and further investigated by secondary screens, colony forming cell assay, and gene expression profiling. The hematoendothelial toxicity of 5-fluorouracil, berberine chloride, and benzo(a)pyrene is characterized by the inhibition of cell division and a shift of hematopoietic programming to non-hemogenic endothelial and mesenchymal fates. This study demonstrates the feasibility of transcription factor (TF)-based differentiation systems to monitor endothelial and hematotoxicity and serves as an informative platform for screening myelosuppressive or stimulatory drugs and mechanistic studies of their action.

Balance and Gait Alterations Observed More Than 2 Weeks After Concussion: A Systematic Review and Meta-Analysis.

OBJECTIVE: The aim of the study was to systematically review and quantitatively synthesize the existing evidence of balance and gait alterations lasting more than 2 wks after concussion in adults. DESIGN: A systematic review was conducted through PubMed, CINAHL, SPORTDiscus, and Web of Science. Investigations must include adult participants with at least one concussion, were measured for 14 days after injury, and reported balance or gait measures. Balance error scoring system scores, center of pressure sway area and displacement, and gait velocity were extracted for the meta-analysis. RESULTS: Twenty-two studies were included. Balance alterations were observed for 2 wks after concussion when participants were tested with eyes closed, for longer durations of time, and with nonlinear regulatory statistics. The meta-analysis of center of pressure sway area with no visual feedback indicated that concussed individuals had greater sway area (P < 0.001). Various gait alterations were also observed, which may indicate that concussed individuals adopt a conservative gait strategy. The meta-analysis revealed that concussed participants walked 0.12 m/sec (P < 0.001) and 0.06 m/sec (P = 0.023) slower in single and dual-task conditions, respectively. CONCLUSIONS: Subtle balance and gait alterations were observed after 2 wks after a concussion. Understanding these alterations may allow clinicians to improve concussion diagnosis and prevent subsequent injury.

Age-Related Differences in Head Impact during Experimentally Induced Sideways Falls.

PURPOSE: To examine head impact incidence and head acceleration during experimentally induced falls as a function of age. METHODS: 15 young adults (21.2±2.7) and 10 older adults (61.9±4.3 years) underwent 6 experimentally induced sideways falls. Participants fell sideways onto a 20cm crash pad. The number of head impacts was tabulated from video recordings and head acceleration was calculated from motion capture data. A total of 147 falls were analyzed. RESULTS: The young group underwent 88 falls, in which 11.4% resulted in head impact. The older group underwent 59 falls, in which 34.5% resulted in head impact. A proportion analysis revealed older adults had a significantly greater proportion of head impacts than young adults (X 2(1) = 11.445, p = 0.001). A two-way ANOVA only revealed a main effect of head impact on acceleration (F(1,142) = 54.342, p<0.001). CONCLUSION: The older adults experienced a greater proportion of head impacts during sideways falls. Head impact resulted in greater head acceleration compared to no head impact. Collectively, this data highlights the possibility that age-related neuromuscular changes to head control may result in elevated risk of fall-related TBIs. Future research examining mechanisms underlying increases in fall-related head impact is warranted.

The Role of Neck Musculature in Traumatic Brain Injuries in Older Adults: Implications From Sports Medicine.

Traumatic brain injuries (TBIs) are common and serious injuries to older adults. The majority of TBIs in older adults are sustained when the head impacts the ground or other surface during a fall. While several non-modifiable risk factors have been identified for fall-related TBIs in older adults, there still remains a dearth of knowledge surrounding modifiable risk factors. Thus, this significant knowledge gap warrants an investigation into research across disciplines. The sports medicine literature has examined several modifiable risk factors to prevent a mild form of TBI known as concussion. While this research has identified several risk factors, one particular risk factor may have potential implications to fall-related TBIs in older adults. The sports medicine literature has shown that decreased neck strength and slower neck muscle activation are significant predictors for sports-related concussion. Similarly, older adults experience age-related declines to neck muscle strength and muscle activation. Consequently, these age-related declines to the neck musculature may result in the inability of older adults to control their head during a fall, which results in greater impact forces being transmitted to the brain and increases the risk of TBI. This perspective article assesses the sports medicine literature related to the implications of neck strength and muscle activation in sports-related concussion, discusses age-related declines to neck strength and muscle activation, and highlights the potential impact of the neck musculature on fall-related TBIs in older adults.

Use of a Short Version of the Activities-specific Balance Confidence Scale in Multiple Sclerosis.

BACKGROUND: Multiple sclerosis (MS) is a neurologic disease that results in balance and mobility impairments that are associated with elevated fall risk. One common patient-reported outcome measure of balance is the 16-item Activities-specific Balance Confidence (ABC) scale. The ABC scale is valid and reliable in assessing balance confidence in people with MS. However, a shorter, six-question version of the ABC scale, the ABC-6 scale, has been proposed to save time in a clinical setting. Thus, we assessed the convergent validity and internal consistency reliability of the ABC-6 scale in people with MS. METHODS: A total of 221 participants were included in this secondary analysis to compare the ABC-6 scale with the ABC scale. Convergent validity and internal consistency reliability were applied to participants based on fall history and physiological fall risk. RESULTS: Statistical analysis indicated a main effect of group of the ABC and ABC-6 scales (P < .001). Both scales showed good to very good internal consistency (Cronbach α range, 0.832-0.975) and good reliability (intraclass correlation coefficient score range, 0.888-0.941). Furthermore, both versions had moderate convergent validity. Sensitivity ranged from 30% to 97%, and specificity ranged from 64% to 100% across groups tested. CONCLUSIONS: The ABC and ABC-6 scales demonstrated good internal consistency reliability and moderate convergent validity in predicting balance confidence in people with MS. However, poor sensitivity of both versions in distinguishing between MS groups at risk for falls may call into question the usefulness of this self-report measure.

The attentional cost of movement in multiple sclerosis.

Individuals living with multiple sclerosis frequently have impairments in mobility. These impairments are more pronounced when they engage in a cognitively demanding mobility tasks (i.e., walking and talking, obstacle clearance, etc). Based in part on the attentional capacity model of movement, these impairments are suggested to result from greater attentional demands. Yet, this model has not been directly tested in neurological populations. The objective of the study was to determine whether individuals with multiple sclerosis have greater attentional cost of movement across a range of tasks. This study tested probe reaction times of 20 individuals with multiple sclerosis and 26 healthy controls in five different movement tasks. The tasks were specifically chosen to challenge the perceptual-motor system based on variations in static and dynamic balance requirements. Participants were asked to verbally respond as quickly as possible to randomly presented audio probes during motor performance. Task order was randomized, and average probe reaction time was calculated for each task. The results showed tasks requiring dynamic stability had greater probe reaction times in both healthy controls and individuals with multiple sclerosis. Furthermore, individuals with multiple sclerosis had longer probe reaction times across all tasks compared to healthy controls. Yet, there was no relationship between probe reaction times and performance during a complex walking scenario. The results indicate the attentional capacity model may be inadequate to explain cognitive-motor interaction in people with multiple sclerosis. Future studies should address the theoretical framework of cognitive-motor interaction, which may influence the design of interventions aimed at improving performance in individuals with MS.

Gait and Balance Impairments in Breast Cancer Survivors: A Systematic Review and Meta-analysis of Observational Studies.

OBJECTIVE: To systematically review and quantitatively synthesize gait and balance impairments in breast cancer survivors compared with age-matched controls or normative values for adults who never had breast cancer. DATA SOURCES: PubMed, Cumulative Index of Nursing and Allied Health, and Web of Science was searched using terms associated with breast cancer, mobility, and adult until November 2018. STUDY SELECTION: Studies were included if they were randomized control trials, cross-sectional, prospective, pre-post, or case-control by design, included adult breast cancer survivors, reported gait and/or balance metrics as primary or secondary outcomes, were peer-reviewed publications, and were written in English. The search yielded 2117 results with 29 studies meeting the inclusion criteria. DATA EXTRACTION: Two reviewers assessed study quality by the National Institutes of Health Quality Assessment Tool for Observational Cohort and Cross-Sectional Studies to determine the strength of evidence for each study that met the inclusion criteria. Basic descriptors of each study, study protocol, and balance and gait measures were extracted. Meta-analysis was performed for the single leg stance, functional reach, center of pressure velocity, gait speed, and timed up and go. DATA SYNTHESIS: For quality assessment, 3 studies were rated good, 16 fair, and 10 poor. The meta-analysis indicated that there were no significant differences in single leg stance between breast cancer survivors and those who never had breast cancer (P=.33). Pooled values of the functional reach task (22.16cm; 95% CI, 8.98-35.33) and center of pressure velocity (1.2cm/s; 95% CI, 0.87-1.55) suggest balance impairment in breast cancer survivors when compared with normative values. Breast cancer survivors also performed worse than those who never had breast cancer in challenging balance conditions that reduced sensory information or altered base of support. Pooled gait speed at a usual speed (0.91m/s; 95% CI, 0.2-1.6), fast speed across a short distance (1.2m/s; 95% CI, 0.31-2.1), and fast gait speed across a long distance (1.65m/s; 95% CI, 1.64-1.66) suggest gait impairments when compared with normative values. CONCLUSIONS: Breast cancer survivors may demonstrate gait and balance impairments compared with normative values. Clinicians should consider assessing changes in balance and gait in breast cancer survivors to improve functional independence and prevent fall-related injuries.