Subthalamic nucleus local field potential stability in patients with Parkinson's disease.

BACKGROUND: Despite the large body of work on local field potentials (LFPs), a measure of oscillatory activity in patients with Parkinson's disease (PD), the longitudinal evolution of LFPs is less explored. OBJECTIVE: To determine LFP fluctuations collected in clinical settings in patients with PD and STN deep brain stimulation (DBS). METHODS: Twenty-two STN-DBS patients (age: 67.6 ± 8.3 years; 9 females; disease duration: 10.3 ± 4.5 years) completed bilateral LFP recordings over three visits in the OFF-stimulation setting. Peak and band power measures were calculated from each recording. RESULTS: After bilateral LFP recordings, at least one peak was detected in 18 (81.8%), 20 (90.9%), and 22 (100%) patients at visit 1, 2, and 3, respectively. No significant differences were seen in primary peak amplitude (F = 2.91, p = 0.060) over time. Amplitude of the second largest peak (F = 5.49, p = 0.006) and low-beta (F = 6.89, p = 0.002), high-beta (F = 13.23, p < 0.001), and gamma (F = 12.71, p < 0.001) band power demonstrated a significant effect of time. Post hoc comparisons determined low-beta power (Visit 1-Visit 2: t = 3.59, p = 0.002; Visit 1-Visit 3: t = 2.61, p = 0.031), high-beta (Visit 1-Visit 2: t = 4.64, p < 0.001; Visit 1-Visit 3: t = 4.23, p < 0.001) and gamma band power (Visit 1-Visit 2: t = 4.65, p < 0.001; Visit 1-Visit 3: t = 4.00, p < 0.001) were significantly increased from visit 1 recordings to both follow-up visits. CONCLUSION: Our results provide substantial evidence that LFP can reliably be detected across multiple real-world clinical visits in patients with STN-DBS for PD. Moreover, it provides insights on the evolution of these LFPs.

Effect and Relationship of Gait on Subcortical Local Field Potentials in Parkinson's Disease: A Systematic Review.

OBJECTIVES: Developments in deep brain stimulation (DBS) technology have enabled the ability to detect local field potentials (LFPs) in Parkinson disease (PD). Gait dysfunction is one of the most prevalent deficits seen in PD. However, no consensus has been reached on the effect of gait on LFPs and the relationship between LFPs and clinical measures of gait. The objective of this systematic review was to synthesize existing research regarding the relationship between gait dysfunction and LFPs in PD. METHODS: A systematic search of the literature yielded a total of ten articles, including 132 patients with PD, which met the criteria for inclusion. RESULTS: Beta frequency band measures showed low-to-strong correlation to clinical gait measures (r = -0.50 to 0.82). Two studies found decreased beta power during gait; one found increased beta frequency peaks during gait; and one found higher beta power during dual-task gait than during single-task gait. One of the three studies comparing patients with and without freezing found significantly increased beta burst duration and power during gait in freezers compared with nonfreezers. All studies showed moderate-to-high methodologic quality. CONCLUSIONS: This review highlights the need to consider the effect of gait on LFP recordings, particularly when used to guide DBS programming. Although sample sizes were small, it appears LFPs are associated to and modulated by gait in patients with PD. This evidence suggests that LFPs have the potential to be used as a biomarker of gait dysfunction in PD.

Computerized Cognitive Function Does Not Correlate With Choice Reaction Time During a Hopping Task.

CONTEXT: Cognitive performance has been shown to be associated with musculoskeletal injury risk. Cognitive assessments are often administered in controlled environments despite sport settings challenging cognition in uncontrolled, less predictable environments. Cognitive assessments should be representative of sport demands; thus, integrating motor with cognitive assessments may be more clinically relevant. Accordingly, the purpose of this research was to investigate the relationship between tablet-based cognitive tests and choice reaction time during a hopping task. DESIGN: Cross-sectional. METHODS: A total of 20 healthy participants volunteered to participate. Participants completed 3 tablet-based cognitive assessments. Average raw response time and fully corrected scores were used for analysis. In addition, participants completed a choice reaction hopping task to capture neuromuscular-cognitive reaction time. Participants completed a forward hop over a hurdle, landing on a single limb. Light sensors were utilized for the choice reaction component to capture reaction time in seconds, cue them when to hop, and indicate the landing limb. The relationship between the tablet-based cognitive assessments and reaction time during a hopping task was examined with Pearson correlations (α = .05). RESULTS: The choice reaction time from the hop task had a negligible correlation (r = -.20-.07) to the fully corrected tablet-based cognitive tests. The choice reaction time from the hop task had a negligible correlation (r = .02) to the average response time of the Pattern Comparison Processing Speed Test and a low correlation (r = .34-.36) to the Dimensional Change Card Sort Test and Flanker Inhibitory Control and Attention Test. CONCLUSIONS: This study determined that tablet-based cognitive assessments had trivial relationships to choice reaction time during a hopping task. This research has implications as clinicians aim to evaluate and analyze cognitive performance. Although reaction time was a critical component of all the assessments in this study, an individual's performance on a tablet-based assessment does not indicate performance during a functional reaction time assessment.

Patients Surviving Critical COVID-19 have Impairments in Dual-task Performance Related to Post-intensive Care Syndrome.

OBJECTIVE: The purpose was to examine Dual Task (DT) performance in patients surviving severe and critical COVID-19 compared to patients with chronic lung disease (CLD). Secondarily, we aimed to determine the psychometric properties of the Timed Up and Go (TUG) test in patients surviving COVID-19. DESIGN: Prospective, cross-sectional, observational study. SETTING: Academic medical center within United States. PATIENTS: Ninety-two patients including 36 survivors of critical COVID-19 that required mechanical ventilation (critical-COVID), 20 patients recovering from COVID-19 that required supplemental oxygen with hospitalization (severe-COVID), and 36 patients with CLD serving as a control group. MEASUREMENTS AND MAIN RESULTS: Patients completed the TUG, DT-TUG, Short Physical Performance Battery (SPPB), and Six Minute Walk Test (6MWT) 1-month after hospital discharge. A subset of patients returned at 3-months and repeated testing to determine the minimal detectable change (MDC). Critical-COVID group (16.8 ± 7.3) performed the DT-TUG in significantly slower than CLD group (13.9 ± 4.8 s; P = .024) and Severe-COVID group (13.1 ± 5.1 s; P = .025). Within-subject difference between TUG and DT-TUG was also significantly worse in critical-COVID group (-21%) compared to CLD (-10%; P = .012), even despite CLD patients having a higher comorbid burden (P < .003) and older age (P < .001). TUG and DT-TUG demonstrated strong to excellent construct validity to the chair rise test, gait speed, and 6MWT for both COVID-19 groups (r = -0.84to 0.73, P < .05). One- and 3-months after hospital discharge there was a floor effect of 14% (n = 5/36) and 5.2% (n = 1/19), respectively for patients in the critical-COVID group. Ceiling effects were noted in four (11%) critical-COVID, six (30%) severe-COVID patients for the TUG and DT-TUG at 1-month. CONCLUSION: The ability to maintain mobility performance in the presence of a cognitive DT is grossly impaired in patients surviving critical COVID-19. DT performance may subserve the understanding of impairments related to Post-intensive care syndrome (PICS) for survivors of critical illness.

The Relationship Between Measures of Postural Control in Concussion Assessment.

OBJECTIVE: To determine the relationship between postural sway performance during commonly utilized postural control assessments following a concussion, including the modified Balance Error Scoring System (mBESS), concussion balance test (COBALT), and sensory organization test (SOT) in healthy young adults. APPROACH: Twenty participants completed all balance testing. The mBESS conditions included double limb stance, single limb stance, and tandem stance. The COBALT was comprised of yaw plane head shake (HS) and vestibular ocular reflex cancellation conditions performed on firm and foam surfaces. Subjects performed 6 conditions of the SOT (C1-C6), which systematically perturbed sensory inputs. Postural sway performance was measured using a single force plate and quantified as a sway score for the mBESS and COBALT, and an equilibrium score for the SOT. Spearman rank correlations were used to examine the relationship between postural sway performance for each test. MAIN RESULTS: There was a moderate positive correlation between mBESS-tandem stance and the HS on foam COBALT condition (r = .643, P = .002). There was a moderate negative correlation between mBESS-double limb stance and SOT-C6 (r = -.512, P = .021), and between mBESS-single limb stance and SOT-C6 (r = -.523, P = .018). The COBALT and SOT demonstrated numerous moderate to good negative correlations (r = -.448 to -.708, P ≤ .05), including a good negative correlation between HS on foam and SOT-C1 (r = -.725, P = .0003). SIGNIFICANCE: Performance on the mBESS had minimal relationship to performance on the COBALT and SOT, suggesting that the clinical standard may not challenge sensory integration at the same capacity as other tests. All COBALT conditions had fair to good associations to at least 2 SOT conditions, suggesting both assessments are representative of sensory integration. Further investigation of the current clinical approach is warranted as the COBALT may be a clinically feasible test of sensory integration.

Resting state functional connectivity responses post-mild traumatic brain injury: a systematic review.

Mild traumatic brain injuries (mTBI) are associated with functional network connectivity alterations throughout recovery. Yet, little is known about the adaptive or maladaptive nature of post-mTBI connectivity and which networks are predisposed to altered function and adaptation. The objective of this review was to determine functional connectivity changes post-mTBI and to determine the adaptive or maladaptive nature of connectivity through direct comparisons of connectivity and behavioral data. Literature was systematically searched and appraised for methodological quality. A total of 16 articles were included for review. There was conflicting evidence of post-mTBI connectivity responses as decreased connectivity was noted in 4 articles, 6 articles reported increased connectivity, 5 reported a mixture of increased and decreased connectivity, while 1 found no differences in connectivity. Supporting evidence for adaptive post-mTBI increases in connectivity were found, particularly in the frontoparietal, cerebellar, and default mode networks. Although initial results are promising, continued longitudinal research that systematically controls for confounding variables and that standardizes methodologies is warranted to adequately understand the neurophysiological recovery trajectory of mTBI.

Association of subthalamic beta frequency sub-bands to symptom severity in patients with Parkinson's disease: A systematic review.

OBJECTIVE: Local field potentials (LFP), specifically beta (13-30Hz) frequency measures, have been found to be associated with motor dysfunction in people with Parkinson's disease (PwPD). A consensus on beta subband (low- and high-beta) relationships to clinical state or therapy response has yet to be determined. The objective of this review is to synthesize literature reporting the association of low- and high-beta characteristics to clinical ratings of motor symptoms in PwPD. METHODS: A systematic search of existing literature was completed using EMBASE. Articles which collected subthalamic nucleus (STN) LFPs using macroelectrodes in PwPD, analyzed low- (13-20 Hz) and high-beta (21-35 Hz) bands, collected UPDRS-III, and reported correlational strength or predictive capacity of LFPs to UPDRS-III scores. RESULTS: The initial search yielded 234 articles, with 11 articles achieving inclusion. Beta measures included power spectral density, peak characteristics, and burst characteristics. High-beta was a significant predictor of UPDRS-III responses to therapy in 5 (100%) articles. Low-beta was significantly associated with UPDRS-III total score in 3 (60%) articles. Low- and high-beta associations to UPDRS-III subscores were mixed. CONCLUSION: This systematic review reinforces previous reports that beta band oscillatory measures demonstrate a consistent relationship to Parkinsonian motor symptoms and ability to predict motor response to therapy. Specifically, high-beta, demonstrated a consistent ability to predict UPDRS-III responses to common PD therapies, while low-beta measures were associated with general Parkinsonian symptom severity. Continued research is needed to determine which beta subband demonstrates the greatest association to motor symptom subtypes and potentially offers clinical utility toward LFP-guided DBS programming and adaptive DBS.

Comparisons and Intercorrelations of Physical Performance Variables of Operational Preparedness in Special Operations Forces.

INTRODUCTION: Marine Forces Special Operations Command (MARSOC) deploys teams of operators (OP) and enablers (EN) to accomplish special operations missions. OP and EN are required to train and deploy together to accomplish these missions; however, they have different training and selection pipelines. Advanced strength and conditioning training strategies are applied to both OP and EN to enhance physical preparedness; however, it is unclear how the selection pipeline of these two personnel types affects overall physical preparedness and the relationships between performance variables. The purpose of this study is to gain a greater understanding of the relationships of a wide array of physical preparedness variables in OP and EN in an effort to streamline testing and training strategies. MATERIALS AND METHODS: For this study, 155 male (82 OP, 73 EN) MARSOC personnel (age: 29.5 ± 4.9 years, mass: 87.9 ± 11.1 kg, height: 1.79 ± 0.07 m) completed a physical preparedness assessment that included a DEXA assessment of body composition (BF%), 27.4 m sprint (30 yd), countermovement jump (VJ), 5-10-5 pro-agility (Agility), medicine ball toss (UBP), isometric mid-thigh pull (IMTP), and a 30 second (AnC) and 5 minute (AC) non-motorized treadmill run. Independent samples t tests, Mann-Whitney U tests, and Spearman's Rank correlations were used to compare variables between OP and EN. RESULTS: OP demonstrated greater VJ, UBP, IMTP, AnC, and AC (P < 0.05); and significantly lower BF% and agility time (P < 0.05). Measurements of mass, height, body mass index, and 30 yd were not significantly different (P > 0.05). Weak to moderate correlations were seen between anthropometric and performance variables. OP and EN demonstrated similar correlations for most performance and anthropometric variables. CONCLUSIONS: These results suggest that MARSOC OP demonstrate better physical preparedness over EN, while similar trends are observed between performance variables. Tests with moderate to high correlations may be removed from the protocol to account for testing time constraints. Height, weight, and BF% variables are poorly correlated with performance, particularly in OP, questioning their value in physical performance assessments in this population.

The influence of cognitive tasks on sensory organization test performance.

INTRODUCTION: Many static postural tasks requiring vestibular contributions are completed while dual- tasking. OBJECTIVE: We investigated the influence of dual-tasks on sensory integration for postural control and cognitive performance during the sensory organization test and examined the relationship between cognitive function and dual-task cost during the sensory organization test. METHODS: Twenty adults completed single and dual-task versions of the six conditions of the sensory organization test were completed during two visits separated by one week. A subset of 13 participants completed three National Institute of Health (NIH)-toolbox cognitive tests including the Flanker inhibitory control and attention test, dimensional change card sort test and pattern comparison processing speed test. Wilcoxon signed rank tests were used to compare postural sway during single and dual-task sensory organization test. Friedman's test, with pairwise comparison post-hoc tests, was used to compare single task serial subtraction performance to the 6 dual-task sensory organization test conditions. Spearman's correlation coefficients were used to assess the relationship between cognitive performance on NIH-toolbox test and postural and cognitive dual-task cost during the sensory organization test. RESULTS: Performing a cognitive dual-task during the sensory organization test resulted in a significant increase in postural sway during condition 1 (Z=-3.26, p=0.001, ES=0.73), condition 3 (Z=-2.53, p=0.012, ES=0.56), and condition 6 (Z=-2.02, p=0.044, ES=0.45). Subtraction performance significantly decreased in during condition 6 (Z=-2.479, p=0.011, ES=0.55) compared to single-task. The dimensional change card sort test demonstrated moderate correlations with dual-task cost of serial subtraction performance in condition 5 (dimensional change card sort test: r=-0.62, p=0.02) and condition 6 (dimensional change card sort test: r=-0.56, p=0.04). Pattern comparison processing speed test scores were significantly correlated with dual-task cost of postural control during condition 2. CONCLUSION: Performing a cognitive task during the sensory organization test resulted in significantly increased postural sway during three conditions, particularly during visual environment manipulation oppose to vestibular and somatosensory manipulation. Cognitive performance decreased during the most complex sensory organization test condition. Additionally, we found participants with poorer executive function had greater dual-task cost during more complex sensory integration demands.

Neurocognitive function influences dynamic postural stability strategies in healthy collegiate athletes.

OBJECTIVES: Poorer neurocognitive performance may increase lower extremity injury risk due to alterations in biomechanics. However, it is unclear if poorer neurocognitive function may be associated with altered dynamic postural stability. Therefore, the purpose of this study was to investigate the relationship between neurocognitive performance and dynamic postural stability in healthy collegiate athletes. DESIGN: Cross-sectional cohort. METHODS: Forty-five Division-I collegiate athletes (21 males, 24 females; age: 19.69 ±â€¯1.50) completed neurocognitive assessments from the NIH Toolbox® (NIHTB). Three groups were established from the NIHTB composite score: high performers (HP), moderate performers (MP), and low performers (LP). Additionally, participants completed a dynamic hop-to-stabilization task. Accelerometer and gyroscopic data were recorded during landing through an inertial measurement unit (IMU) on the participant's low back. The root mean squared (RMS) of the accelerometer and gyroscope was calculated for the orthogonal planes and the resultant vector. Group differences for demographic variables, NIHTB composite scores, and IMU based measures were analyzed with one-way ANOVAs with Bonferroni post hoc analyses were performed. Cohen's d effect sizes were also calculated. RESULTS: Post hoc tests determined the LP group had higher vertical acceleration RMS values (p = 0.013, d = -0.85) and lower anteroposterior acceleration RMS values (p = 0.005, d = 0.95) compared to the HP group. CONCLUSIONS: Neurocognitive performance may influence dynamic postural stability strategies in athletes. Higher neurocognitive performers may use different approaches to perform difficult postural tasks by adopting strategies associated with lower vertical and higher anteroposterior acceleration compared to lower neurocognitive performers.

Dual task training effects on gait and balance outcomes in multiple sclerosis: A systematic review.

BACKGROUND: People with Multiple Sclerosis (PwMS) exhibit deteriorated balance and gait performance during dual task (DT) conditions. Impaired dual tasking is related to increased fall risk and lower quality of life in PwMS. While dual task interventions have proven effective in various patient populations, evidence is lacking to support the use of DT interventions to improve clinical measures of balance and gait in PwMS. Therefore, the purpose of this systematic review was to synthesize the effectiveness of DT intervention at improving balance and gait in PwMS. METHODS: A systematic search was completed using CINHAL, PubMed and MEDLINE. Methodological quality, level of evidence and recommendations for included studies was assessed by two reviewers. Effect sizes with 95% confidence intervals comparing single and DT outcomes were calculated for all balance and gait variables. RESULTS: Five randomized control trials (RCTs) were included for review. Of the 23 effect sizes calculated, three had 95% confidence intervals which did not pass zero and were therefore interpreted as strong. Due to inconsistent level one evidence of DT interventions being superior to single task balance and gait interventions a grade B recommendation was given. CONCLUSION: There is inconsistent evidence supporting the use of DT interventions to improve clinical balance measures in PwMS. There is supportive evidence for the use of DT interventions to improve both single and DT gait speed. However, there was heterogeneity between interventions and dosage among RCTs. Despite multiple promising findings, DT interventions appear to have minimal impact on clinical balance and gait measures in PwMS.

The Influence of Cognitive Dual Tasks on Concussion Balance Test Performance.

OBJECTIVE: To determine the influence of a cognitive dual task on postural sway and balance errors during the Concussion Balance Test (COBALT). METHODS: Twenty healthy adults (12 females, eight males; aged 21.95 ± 3.77 years; height = 169.95 ± 9.95 cm; weight = 69.58 ± 15.03 kg) partook in this study and completed single- and dual-task versions of a reduced COBALT. RESULTS: Sway velocity decreased during dual-task head rotations on foam condition (p = .021, ES = -0.57). A greater number of movement errors occurred during dual-task head rotations on firm surface (p = .005, ES = 0.71), visual field flow on firm surface (p = .008, ES = 0.68), and head rotations on foam surface (p < .001, ES = 1.61) compared with single-task conditions. Cognitive performance was preserved throughout different sensory conditions of the COBALT (p = .985). DISCUSSION: Cognitive dual tasks influenced postural control and destabilized movements during conditions requiring advanced sensory integration and reweighting demands. Dual-task versions of the COBALT should be explored as a clinical tool to identify residual deficits past the acute stages of concussion recovery.

Feasibility of Contrasting Brain Connectivity Patterns in Cognitive and Motor Cerebral Networks to Clinical Outcomes in Patients Surviving Acute Respiratory Failure: A Pilot Study.

BACKGROUND: There is a paucity of research regarding the feasibility and association of cerebral cortex function to patient outcomes after acute respiratory failure (ARF). PURPOSE: To determine the feasibility of functional connectivity measures and examine the association of functional connectivity to a multifaceted battery of outcomes in survivors of ARF. METHODS: Eight ARF patients (age:58±3.7, ICU days:10.4±8.6) completed functional magnetic resonance imaging (fMRI), cognitive, physical-function, anxiety, depression, and driving simulator tests at one month post-hospital discharge. Pearson's correlations assessed the relationship between functional connectivity within the default mode network (FPN), sensorimotor network (SMN), and frontoparietal network (FPN) to outcomes. RESULTS: Low physical-function (r=0.75, p=0.03) and divided-attention (r=-0.86, p=0.03) during the driving simulator task correlated with low FPN connectivity. Low SMN connectivity demonstrated relationships to slower gait speed (r=0.82, p=0.01) and low short physical performance battery (SPPB) scores (r=0.81, p=0.01). CONCLUSIONS: fMRI is feasible to assess ARF patients' post-ICU limitations, as low post-ARF brain connectivity may be linked to low physical function, providing potential development of therapeutic interventions.

A Proposed Postural Control Theory Synthesizing Optimal Feedback Control Theory, Postural Motor Learning, and Cerebellar Supervision Learning.

Multiple theories regarding motor learning and postural control development aim to explain how the central nervous system (CNS) acquires, adjusts, and learns postural behaviors. However, few theories of postural motor development and learning propose possible neurophysiologic correlates to support their assumptions. Evidence from behavioral and computational models support the cerebellum's role in supervising motor learning through the production of forward internal models, corrected by sensory prediction errors. Optimal Feedback Control Theory (OFCT) states that the CNS learns new behaviors by minimizing the cost of multi-joint movements that attain a task goal. By synthesizing principles of the OFCT, postural sway characteristics, and cerebellar anatomy and its internal models, we propose an integrated learning model in which cerebellar supervision of postural control is governed by movement cost functions.

The effect of cognitive dual-tasks on dynamic postural sway during gait using inertial measurement units.

OBJECTIVE: To investigate the influence of cognitive dual-tasks on dynamic postural sway variability, measured with a single inertial measurement unit, in healthy collegiate athletes during dual-task gait. APPROACH: Thirty-four athletes ambulated down and back a 10-meter course. Root mean square values of postural sway acceleration were calculated for four sway-planes. Single and dual-task trial times were calculated from gait initiation to termination. Single and dual-task root mean square values were compared using Wilcoxon signed rank tests for each sway plane to determine significance. The relative difference between each sway measures and trial times for single and dual-task gait (i.e. dual-task cost was calculated). Spearman's correlation was used to analyze the association between dual-task cost of sway and trial time data. MAIN RESULTS: During dual-task conditions, participants ambulated slower and demonstrated a significant reduction in root mean square sway in all planes of motion. The greatest decreases were in the medial-lateral (Z = -4.83, p < 0.001, ES = -0.83) and superior-inferior planes (Z = -4.93, p < 0.001, ES = -0.85). Increased trial time cost was associated with a decrease in dual-task cost of postural sway (p < 0.05). SIGNIFICANCE: Performing a cognitive task while ambulating decreased postural sway variability in task-relevant planes of motion compared to single-task conditions. Reduced dual-task cost of sway variability during gait was associated with maintained trial times between single and dual-tasks. These data support the use of instrumented dual-task gait assessment to evaluate postural sway variability.

Validation of Physical Performance Tests in Individuals with Advanced Knee Osteoarthritis.

BACKGROUND: Individuals with advanced osteoarthritis (OA) of the knee experience significant impairments in balance and in essential physical functions such as walking and rising from a chair. There is limited evidence on valid outcome measures to capture these impairments. QUESTIONS/PURPOSES: We sought to examine the construct validity of three physical performance measures in patients with advanced knee OA: a gait speed (GS) test, the Short Physical Performance Battery (SPPB), and the Timed Up and Go (TUG) test. METHODS: We designed a cross-sectional clinical measurement study in which patients with advanced knee OA completed two self-reported measures: the Knee Injury and Osteoarthritis Outcome Score-Physical Function Shortform (KOOS-PS) and a four-part numeric pain rating scale (Q-NPRS). They were also administered the GS test, TUG test, and SPPB. Convergent and divergent construct validity were assessed by examining relationships between the GS test, the SPPB, the TUG test, the KOOS-PS, and the Q-NPRS and calculating Pearson correlation coefficients (r). The scores for the GS, TUG test, and SPPB were compared with established normative values for age-matched healthy controls. RESULTS: Forty-four subjects (mean age, 66.9 ± 8.1 years) participated in the study. The GS test showed low concordance with the SPPB component tests and the TUG test. The relationships between the physical performance measures and the self-reported measures were low. The scores for the GS test, TUG test, and SPPB in our sample were significantly worse when compared with age-matched normative values, indicating impairments in physical performance. CONCLUSION: These results advance the understanding of the validity of the GS test, TUG test, and SPPB in demonstrating the impairments in physical performance that patients with advanced knee OA experience in walking, balancing, and rising from a chair. Future research should examine the reproducibility and responsiveness of the GS test, TUG test, and SPPB in patients with advanced knee OA, in order to facilitate the integration of these measures into clinical practice.

The influence of cognitive tasks on sensory organization test performance / A influência das tarefas cognitivas no desempenho do teste de organização sensorial

Abstract Introduction: Many static postural tasks requiring vestibular contributions are completed while dual- tasking. Objective: We investigated the influence of dual-tasks on sensory integration for postural control and cognitive performance during the sensory organization test and examined the relationship between cognitive function and dual-task cost during the sensory organization test. Methods: Twenty adults completed single and dual-task versions of the six conditions of the sensory organization test were completed during two visits separated by one week. A subset of 13 participants completed three National Institute of Health (NIH)-toolbox cognitive tests including the Flanker inhibitory control and attention test, dimensional change card sort test and pattern comparison processing speed test. Wilcoxon signed rank tests were used to compare postural sway during single and dual-task sensory organization test. Friedman's test, with pairwise comparison post-hoc tests, was used to compare single task serial subtraction performance to the 6 dual-task sensory organization test conditions. Spearman's correlation coefficients were used to assess the relationship between cognitive performance on NIH-toolbox test and postural and cognitive dual-task cost during the sensory organization test. Results: Performing a cognitive dual-task during the sensory organization test resulted in a significant increase in postural sway during condition 1 (Z = −3.26, p = 0.001, ES = 0.73), condition 3 (Z = −2.53, p = 0.012, ES = 0.56), and condition 6 (Z = −2.02, p = 0.044, ES = 0.45). Subtraction performance significantly decreased in during condition 6 (Z = −2.479, p = 0.011, ES = 0.55) compared to single-task. The dimensional change card sort test demonstrated moderate correlations with dual-task cost of serial subtraction performance in condition 5 (dimensional change card sort test: r = −0.62, p = 0.02) and condition 6 (dimensional change card sort test: r= −0.56, p = 0.04). Pattern comparison processing speed test scores were significantly correlated with dual-task cost of postural control during condition 2. Conclusion: Performing a cognitive task during the sensory organization test resulted in significantly increased postural sway during three conditions, particularly during visual environment manipulation oppose to vestibular and somatosensory manipulation. Cognitive performance decreased during the most complex sensory organization test condition. Additionally, we found participants with poorer executive function had greater dual-task cost during more complex sensory integration demands.

Resumo Introdução: Muitas tarefas posturais estáticas que requerem contribuições vestibulares são feitas durante a dupla tarefa. Objetivo: Investigamos a influência da dupla tarefa na integração sensorial para o controle postural e desempenho cognitivo durante o teste de organização sensorial e examinamos a relação entre a função cognitiva e o custo da dupla tarefa durante o teste de organização sensorial. Método: Vinte adultos completaram versões da tarefa única e dupla tarefa das seis condições do teste de organização sensorial, que foram concluídas em duas consultas com um intervalo de uma semana. Um subgrupo de 13 participantes completou três testes cognitivos do NIH-toolbox, inclusive o flanker inhibitory control and attention test, dimensional change card sort test e o pattern comparison processing speed test .O teste de postos sinalizados de Wilcoxon foi usado para comparar a oscilação postural durante o teste de organização sensorial de tarefa única e dupla. O teste de Friedman, com testes post hoc de comparação pareada, foi usado para comparar o desempenho da subtração em série de tarefa única para as 6 condições do teste de organização sensorial de dupla tarefa. Os coeficientes de correlação de Spearman foram usados para avaliar a relação entre o desempenho cognitivo no teste NIH-toolbox e o custo da dupla tarefa postural e cognitivo durante o teste de organização sensorial. Resultados: A feitura de uma dupla tarefa cognitiva durante o teste de organização sensorial resultou em um aumento significativo na oscilação postural durante a condição 1 (Z = -3,26, p = 0,001, TE = 0,73), condição 3 (Z = -2,53, p = 0,012, TE = 0,56) e condição 6 (Z = -2,02, p = 0,044, TE = 0,45). O desempenho de subtração diminuiu significativamente durante a condição 6 (Z =-2,479, p = 0,011, TE = 0,55) em comparação com a tarefa única. O dimensional change card sort test demonstrou correlações moderadas com o custo da dupla tarefa de desempenho de subtração em série na condição 5 (dimensional change card sort test: r=-0,62, p = 0,02) e condição 6 (dimensional change card sort test: r = -0,56, p = 0,04). Os escores do pattern comparison processing speed test foram significativamente correlacionados com o custo da dupla tarefa do controle postural durante a condição 2. Conclusão: A feitura de uma tarefa cognitiva durante o teste de organização sensorial resultou em um aumento significativo na oscilação postural em três condições, principalmente durante a manipulação do ambiente visual em oposição à manipulação vestibular e somatossensorial. O desempenho cognitivo diminuiu durante a condição de teste de organização sensorial mais complexa. Além disso, observamos que os participantes com função executiva pior apresentaram maior custo da dupla tarefa durante demandas de integração sensorial mais complexas.

Dry bedding provides cost-effective enrichment for group-housed rhesus macaques (Macaca mulatta).

Dry bedding has been shown to be an effective enrichment strategy for small groups of captive nonhuman primates housed in cages or in small enclosures with concrete flooring. However, dry bedding is used infrequently for large groups because of the perception that its use is time- and resource-intensive. We investigated the cost-effectiveness of this enrichment strategy in large groups (30 to 50 subjects) of rhesus macaques. Macaques were housed under 3 comparison conditions for 4 wk: pine shavings (n = 4), aspen and pine shaving mixture (n = 4), and nonbedded control (n = 4). As measures of resource consumption, husbandry tasks were documented by using time-in-motion methodology, and water usage was determined. In addition, groups underwent behavioral observations to assess the effect of dry bedding. The time required to care for units did not differ between bedded and nonbedded units. However, significantly less water was used for sanitization of bedded compared with nonbedded units. Monkeys housed in bedded units showed more foraging (13.8% ± 1.6% of time in bedded compared with 4.0% ± 0.3% of time in nonbedded units) and less aggression and self-grooming. Dry bedding benefited the macaques, reduced water usage and costs, and did not affect human resources.