Effect of positive social comparative feedback on the resting state connectivity of dopaminergic neural pathways: A preliminary investigation.

Positive social comparative feedback is hypothesized to generate a dopamine response in the brain, similar to reward, by enhancing expectancies to support motor skill learning. However, no studies have utilized neuroimaging to examine this hypothesized dopaminergic mechanism. Therefore, the aim of this preliminary study was to investigate the effect of positive social comparative feedback on dopaminergic neural pathways measured by resting state connectivity. Thirty individuals practiced an implicit, motor sequence learning task and were assigned to groups that differed in feedback type. One group received feedback about their actual response time to complete the task (RT ONLY), while the other group received feedback about their response time with positive social comparison (RT + POS). Magnetic resonance imaging was acquired at the beginning and end of repetitive motor practice with feedback to measure practice-dependent changes in resting state brain connectivity. While both groups showed improvements in task performance and increases in performance expectancies, ventral tegmental area and the left nucleus accumbens (mesolimbic dopamine pathway) resting state connectivity increased in the RT + POS group but not in the RT ONLY group. Instead, the RT ONLY group showed increased connectivity between ventral tegmental area and primary motor cortex. Positive social comparative feedback during practice of a motor sequence task may induce a dopaminergic response in the brain along the mesolimbic pathway. However, given that absence of effects on expectancies and motor learning, more robust and individualized approaches may be needed to provide beneficial psychological and behavioral effects.

Effect of behavioural practice targeted at the motor action selection network after stroke.

Motor action selection engages a network of frontal and parietal brain regions. After stroke, individuals activate a similar network, however, activation is higher, especially in the contralesional hemisphere. The current study examined the effect of practice on action selection performance and brain activation after stroke. Sixteen individuals with chronic stroke (Upper Extremity Fugl-Meyer motor score range: 18-61) moved a joystick with the more-impaired hand in two conditions: Select (externally cued choice; move right or left based on an abstract rule) and Execute (simple response; move same direction every trial). On Day 1, reaction time (RT) was longer in Select compared to Execute, which corresponded to increased activation primarily in regions in the contralesional action selection network including dorsal premotor, supplementary motor, anterior cingulate and parietal cortices. After 4 days of practice, behavioural performance improved (decreased RT), and only contralesional parietal cortex significantly increased during Select. Higher brain activation on Day 1 in the bilateral action selection network, dorsolateral prefrontal cortex and contralesional sensory cortex predicted better performance on Day 4. Overall, practice led to improved action selection performance and reduced brain activation. Systematic changes in practice conditions may allow the targeting of specific components of the motor network during rehabilitation after stroke.

Health Promotion and Wellness in Neurologic Physical Therapy: Strategies to Advance Practice.

BACKGROUND AND PURPOSE: Neurologic physical therapy (PT) can assist people with neurologic conditions and injuries to optimize their health and well-being by addressing barriers at the individual, relationship, community, and societal levels. The purpose of this special interest article is to provide consensus-driven strategies to address barriers to implementing health promotion and wellness (HPW)-related neurologic PT practice. SUMMARY OF KEY POINTS: Environmental scan, literature review, and expert input were used to determine barriers and develop strategies. Barriers include lack of time; low knowledge, self-efficacy, and awareness; client complexity; and lack of HPW resources; as well as concerns regarding payment and scope of practice. Four key strategies emerged: (1) develop and disseminate a consensus-based scope of practice for HPW in neurologic PT; (2) increase knowledge of resources related to HPW; (3) promote delivery models for HPW-related neurologic PT; and (4) encourage advocacy, community building and partnership along the continuum of care. RECOMMENDATIONS FOR CLINICAL PRACTICE: Clinicians should practice to their full scope of HPW-related PT practice. This includes optimizing movement, including physical activity and fitness, as well as reinforcing the importance of healthy sleep, nutrition, stress, and smoking cessation. These activities address primary, secondary, and tertiary prevention. Clinicians are encouraged to report their experiences with HPW-focused delivery models and outcomes. Additional research is needed to understand the full impact of HPW on PT practice (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A364).

Measuring Gait Parameters from Structural Vibrations.

Measuring gait parameters (e.g. speed, cadence, step duration) accurately is invaluable for evaluation during treatment of older adults who struggle with disability onset, disease progression, balance, and injurious falls. Traditionally stopwatches or timing gates are used to measure gait speed in clinical settings, and these are limited to measuring gait speed. Other wearable and non-wearable technologies offer the ability to measure additional gait parameters though patients are known to walk differently with the devices and even tend to slow down before engaging with a non-wearable such as a floor mat. Floor vibrations are a promising option to measuring gait parameters while not being intrusive and not requiring line-of-sight to the patient for measurements. This paper presents methodology for extracting gait parameters using vibrations with comparisons to APDM Wearable Technologies Mobility Lab sensors and stopwatch measurements. Performance is examined across 97 participants for self-selected speed forward, full speed forward, and backwards walks at three different testing sites for a total of 1039 walks. Gait speed vibrations measurements demonstrated excellent reliability with APDM Mobility Lab (ICC: 0.98; 99% CI: 0.01±0.01 m/s) and stopwatch (ICC: 0.97; 99% CI: -0.01±0.01 m/s) measurements. Similar excellent results are reported for cadence, gait cycle duration, step duration, and stride length parameters.

Predictors of Daily Steps at 1-Year Poststroke: A Secondary Analysis of a Randomized Controlled Trial.

Background and Purpose: Walking has the potential to improve endurance and community participation after stroke. Obtaining ≥6000 daily steps can decrease subsequent stroke risk. Early identification of those prone to low daily steps could facilitate interventions that lead to increased walking and improved health. The purpose of this study was to (1) determine which factors at 2 months poststroke can predict daily step counts at 1 year and (2) determine what step count at 2 months corresponds to obtaining ≥6000 daily steps at 1-year poststroke. Methods: This was a secondary analysis of data from the Locomotor Experience Applied Post Stroke trial, which enrolled participants with walking speeds <0.80 m/second at 2 months poststroke. Daily steps were assessed at 2 months and 1-year poststroke. Linear regression was used to predict daily step counts at 1 year based on factors including age, sex, race and/or ethnicity, stroke severity, walking speed, endurance, fitness, motor function, balance, and balance confidence. A receiver operating characteristic curve determined which step count corresponded to reaching ≥6000 steps at 1 year. Results: Data from 206 participants, mean age=63 (13) years, 43% female, mean baseline daily step count=2922 (2749) steps, were analyzed. The final model to predict daily steps at 1 year poststroke contained daily steps at 2 months and balance (Berg Balance Scale score); these factors explained 38% of the variability in daily steps at 1 year (P≤0.001). Participants obtaining ≥1632 daily steps at 2 months were 1.86 (95% CI, 1.52­2.27) times more likely to reach ≥6000 daily steps at 1-year poststroke. Conclusions: Daily steps and balance at 2 months poststroke were the strongest predictors of future daily steps. Improving daily physical activity and targeting balance early after stroke may be necessary to increase physical activity at 1-year poststroke.

Targeted Engagement of the Action Selection Network during Task-Oriented Arm Training after Stroke.

Action selection (AS), or selection of an action from a set of alternatives, is an important movement preparation process that engages a frontal-parietal network. The addition of AS demands to arm training after stroke could be used to engage this motor planning process and the neural network that supports it. The purpose of this case series is to describe the feasibility and outcomes associated with task-oriented arm training aimed at engaging the AS behavioral process and the related neural network in three individuals with chronic stroke. Three participants with mild to moderate motor deficits completed 13 to 15 sessions of task-oriented arm training that included AS cues for each movement repetition; cues dictated movement direction, height, or distance. Before and after training, individuals completed an AS brain-behavior probe during functional MRI. AS behavioral performance improved after training (increased accuracy, decreased reaction time) in all participants while brain activation in the AS network (dorsal premotor, parietal, dorsolateral prefrontal cortices) decreased in two participants. Gains in motor function were also found in all three participants, especially on patient-reported measures of perceived difficulty and confidence to complete upper extremity functional tasks. It was feasible to target the AS behavioral process and the related neural network through the addition of AS demands to functional, task-oriented arm training in three individuals with mild to moderate motor dysfunction poststroke.

Instrument-assisted soft tissue mobilization and proprioceptive neuromuscular facilitation techniques improve hamstring flexibility better than static stretching alone: a randomized clinical trial.

Objectives: Tight hamstrings contribute to inefficiency of movement and increased risk for injury. Static stretching is the most common intervention for this problem, but the use of alternatives like instrument-assisted soft tissue mobilization (IASTM) and proprioceptive neuromuscular facilitation (PNF) is increasing among clinicians. This study examined two prospective studies with the common aim of demonstrating the effectiveness of IASTM or PNF over static stretching for improving hamstring tightness. Methods: Nondisabled adults were recruited on a university campus. IASTM study: N = 17 (11 males and 6 females). PNF study: N = 23 (7 males and 16 females). Hip flexion range of motion was measured with a passive straight leg raise (for IASTM) or active straight leg raise (for PNF) before and after stretching. Participants performed a self-static stretch on one leg and received the alternative intervention on the contralateral leg. The two studies were analyzed separately for reliability indices and significant differences between interventions. Results: Hip flexion measures showed good reliability in both studies (intraclass correlation coefficient = 0.97) with a minimal detectable change of <4.26. Both studies showed significant interactions between time and intervention (p < 0.05). Follow-up analyses revealed PNF and IASTM interventions resulted in greater increases in hip flexion range than static stretching. Discussion: These findings demonstrate the effectiveness of PNF and IASTM techniques over static stretching for hamstring flexibility. These interventions provide more efficient alternatives for improving flexibility in the clinic, allowing greater progress in a shorter period of time than an equivalent static stretching program. Level of Evidence: 1b.

Cortical disconnection of the ipsilesional primary motor cortex is associated with gait speed and upper extremity motor impairment in chronic left hemispheric stroke.

Advances in neuroimaging have enabled the mapping of white matter connections across the entire brain, allowing for a more thorough examination of the extent of white matter disconnection after stroke. To assess how cortical disconnection contributes to motor impairments, we examined the relationship between structural brain connectivity and upper and lower extremity motor function in individuals with chronic stroke. Forty-three participants [mean age: 59.7 (±11.2) years; time poststroke: 64.4 (±58.8) months] underwent clinical motor assessments and MRI scanning. Nonparametric correlation analyses were performed to examine the relationship between structural connectivity amid a subsection of the motor network and upper/lower extremity motor function. Standard multiple linear regression analyses were performed to examine the relationship between cortical necrosis and disconnection of three main cortical areas of motor control [primary motor cortex (M1), premotor cortex (PMC), and supplementary motor area (SMA)] and motor function. Anatomical connectivity between ipsilesional M1/SMA and the (1) cerebral peduncle, (2) thalamus, and (3) red nucleus were significantly correlated with upper and lower extremity motor performance (P ≤ 0.003). M1-M1 interhemispheric connectivity was also significantly correlated with gross manual dexterity of the affected upper extremity (P = 0.001). Regression models with M1 lesion load and M1 disconnection (adjusted for time poststroke) explained a significant amount of variance in upper extremity motor performance (R2  = 0.36-0.46) and gait speed (R2  = 0.46), with M1 disconnection an independent predictor of motor performance. Cortical disconnection, especially of ipsilesional M1, could significantly contribute to variability seen in locomotor and upper extremity motor function and recovery in chronic stroke. Hum Brain Mapp 39:120-132, 2018. © 2017 Wiley Periodicals, Inc.

The effect of energy-matched exercise intensity on brain-derived neurotrophic factor and motor learning.

BACKGROUND: Pairing a bout of high-intensity exercise with motor task practice can enhance motor learning beyond task practice alone, which is thought, in part, to be facilitated by an exercise-related increase in brain-derived neurotrophic factor (BDNF). The purpose of the current study was to examine the effect of different exercise intensities on BDNF levels and motor learning while controlling for exercise-related energy expenditure. METHODS: Forty-eight young, healthy participants were assigned to one of three groups: high-intensity exercise [High], low-intensity exercise [Low], or quiet rest [Rest]. The duration of the exercise bouts were individually adjusted so that each participant expended 200 kcals regardless of exercise intensity. BDNF was measured before and after exercise or rest. After exercise or rest, all participants practiced a 3-dimensional motor learning task, which involved reach movements made to sequentially presented targets. Retention was tested after 24-h. BDNF genotype was determined for each participant to explore its effects on BDNF and motor learning. RESULTS: All participants equally improved performance, indicated by a reduction in time to complete the task. However, the kinematic profile used to control the reach movement differed by group. The Rest group travelled the shortest distance between the targets, the High group had higher reach speed (peak velocity), and the Low group had earlier peak velocities. The rise in BDNF post-exercise was not significant, regardless of exercise intensity, and the change in BDNF was not associated with motor learning. The BDNF response to exercise did not differ by genotype. However, performance differed between those with the polymorphism (Met carriers) and those without (Val/Val). Compared to the Val/Val genotype, Met carriers had faster response times throughout task practice, which was supported by higher reach speeds and earlier peak velocities. CONCLUSION: Results indicated that both low and high-intensity exercise can alter the kinematic approach used to complete a reach task, and these changes appear unrelated to a change in BDNF. In addition, the BDNF genotype did not influence BDNF concentration, but it did have an effect on motor performance of a sequential target reach task.

Intrarater and interrater reliability of a hand-held dynamometric technique to quantify palmar thumb abduction strength in individuals with and without carpal tunnel syndrome.

STUDY DESIGN: Clinical measurement. INTRODUCTION: Individuals with carpal tunnel syndrome (CTS) sometimes exhibit weakness of palmar abduction strength (TAS). Reliable assessment of this strength in both subjects with and without CTS with the commonly available Microfet 2 is not known. PURPOSE OF THE STUDY: The purpose of this study was to determine the intrarater and interrater reliabilities of a handheld dynamometric (HHD) method to assess TAS in individuals with and without CTS using the commercially available MicroFET2 and to examine the association between TAS in individuals with CTS and the Carpal Tunnel Symptom Questionnaire (CTSQ) scores. METHODS: In 2 different study phases, individuals with and without CTS were assessed for TAS by 2 different examiners. The CTSQ was administered to the individuals with CTS. RESULTS: Intrarater and interrater reliability coefficients (0.89-0.93 and 0.82-0.90, respectively) were excellent in individuals with and without CTS. Weak negative correlations were found between TAS and overall CTSQ and symptom severity subscale scores, and a moderate negative correlation was found between TAS and functional Status Subscale score. DISCUSSION: This HHD method of reliably assessing TAS better quantifies deficits and progress than traditional manual muscle testing for muscle grades greater than 3/5. CONCLUSION: This method of HHD reliably quantifies TAS but is more reliable with the same than different raters.