Asymmetric running is associated with pain during outdoor running in individuals with Achilles tendinopathy in the return-to-sport phase

OBJECTIVES

To determine the relationships between (1) Achilles tendon pain and loading symmetry, and (2) number of running bouts and symptom severity, during two weeks of outdoor running in individuals with Achilles tendinopathy.

DESIGN

Prospective, observational study.

SETTING

Biomechanics laboratory and outdoors.

PARTICIPANTS

Seventeen runners with Achilles tendinopathy in the return-to-sport phase of rehabilitation.

MAIN OUTCOME MEASURES

Symptom severity was recorded with the Victorian Institute of Sports Assessment-Achilles (VISA-A) questionnaire. Running bouts and Achilles tendon pain during runs were recorded with daily training logs. Ground contact time was collected during runs with wearable sensors. Linear mixed modeling determined if the relationship between Achilles tendon pain and ground contact time symmetry during running was moderated by consecutive run days. Multiple regression determined the relationship between number of running bouts and change in VISA-A scores over two weeks, adjusted for run distance.

RESULTS

Greater ground contact time on the contralateral leg corresponded to increased ipsilateral tendon pain for each consecutive run day (b = -0.028, p < 0.001). Number of running bouts was not associated with 2-week changes in VISA-A scores (p = 0.672).

CONCLUSIONS

Pain during running is associated with injured leg off-loading patterns, and this relationship strengthened with greater number of consecutive run days. Number of running bouts was not related to short-term symptom severity.

Efficacy and safety of using auditory-motor entrainment to improve walking after stroke: a multi-site randomized controlled trial of InTandemTM

Walking slowly after stroke reduces health and quality of life. This multi-site, prospective, interventional, 2-arm randomized controlled trial (NCT04121754) evaluated the safety and efficacy of an autonomous neurorehabilitation system (InTandemTM) designed to use auditory-motor entrainment to improve post-stroke walking. 87 individuals were randomized to 5-week walking interventions with InTandem or Active Control (i.e., walking without InTandem). The primary endpoints were change in walking speed, measured by the 10-meter walk test pre-vs-post each 5-week intervention, and safety, measured as the frequency of adverse events (AEs). Clinical responder rates were also compared. The trial met its primary endpoints. InTandem was associated with a 2x larger increase in speed (Δ: 0.14 ± 0.03 m/s versus Δ: 0.06 ± 0.02 m/s, F(1,49) = 6.58, p = 0.013), 3x more responders (40% versus 13%, χ2(1) ≥ 6.47, p = 0.01), and similar safety (both groups experienced the same number of AEs). The auditory-motor intervention autonomously delivered by InTandem is safe and effective in improving walking in the chronic phase of stroke.

Immediate and Short-Term Effects of In-Shoe Heel-Lift Orthoses on Clinical and Biomechanical Outcomes in Patients With Insertional Achilles Tendinopathy

Background

Physical therapists frequently employ heel lifts as an intervention to reduce Achilles tendon pain and restore function.

Purpose

To determine the short-term effect of heel lifts on clinical and gait outcomes in participants with insertional Achilles tendinopathy (IAT).

Study Design

Case series; Level of evidence, 4.

Methods

Participants with IAT underwent eligibility screening and completed assessments at baseline and 2 weeks later. Primary outcomes included symptom severity (Victoria Institute of Sports Assessment-Achilles [VISA-A]), gait analysis with the 10-m walk-test at 2 speeds (normal and fast), and pain during walking. Pain and gait analysis were assessed under 3 conditions: before fitting 20-mm heel lifts, immediately after heel-lift fitting, and after 2 weeks of wearing heel lifts. Ultrasound images and measurements at the Achilles insertion were obtained from prone and standing positions (with and without heel lifts). Spatiotemporal gait parameters and tibial tilt angles were evaluated at normal speed using inertia measurement units during the 3 study conditions. Differences between the conditions were analyzed using paired t test or analysis of variance.

Results

Overall, 20 participants (12 female, 13 with bilateral IAT; mean age, 51 ± 9.3 years; mean body mass index 31.6 ± 6.8 kg/m2) completed all assessments. Symptom severity (VISA-A) of the more symptomatic side significantly improved at 2 weeks (60 ± 20.6) compared with baseline (52.2 ± 20.4; P < .01). Pain during gait (Numeric Pain Rating Scale) was significantly reduced immediately after heel-lift fitting (0.7 ± 2.0) when compared with baseline (2.2 ± 2.7, P = .043). Spatiotemporal gait parameters and tibial tilt angle before and after using heel lifts at normal walking speed were not significantly different; however, gait speed, stride length, and tibial tilt angle on both sides increased significantly immediately after using heel lifts and were maintained after 2 weeks of wear.

Conclusion

Using heel lifts not only improved symptom severity after 2 weeks but also immediately reduced pain during gait and had a positive impact on gait pattern and speed.

Sex influences blood pressure but not blood pressure variability in response to dietary sodium and potassium in salt-resistant adults

Dietary sodium and potassium have been shown to affect blood pressure (BP) but their influence on BP variability (BPV) is less studied as is the influence of sex. The aim of this study was to compare 24 h BP and short-term BPV in response to varying dietary levels of sodium and potassium in healthy non-obese normotensive salt-resistant adults. We hypothesized that high sodium would increase short-term BP and BPV while the addition of high potassium would counteract this increase. Furthermore, we hypothesized that women would experience greater increases in BPV under high sodium conditions compared to men while potassium would attenuate this response. Thirty-seven participants (17 M/20 W; 27 ± 5 years old; BMI 24.3 ± 3 kg/m2) completed seven days each of the following randomized diets: moderate potassium/low sodium (MK/LS), moderate potassium/high sodium (MK/HS) and high potassium/high sodium (HK/HS). BP and short-term BPV were assessed using 24 h ambulatory BP monitoring starting on day 6. BPV was calculated using the average real variability (ARV) index. Twenty-four hour, daytime, and nighttime systolic BP (SBP) were lower in women compared to men regardless of diet. However, 24 h and daytime SBP were lowered in women on the HK/HS diet compared to the MK/HS diet. There were no significant effects of diet or sex for 24 h, daytime or nighttime SBP ARV. However, men exhibited a higher 24 hDBP ARV than women regardless of diet. In conclusion, a high potassium diet lowered BP under high sodium conditions in women alone while men exhibited higher short-term BPV that was not influenced by diet.

A Clinical Measure of Trunk Neuromuscular Function Predicts Falling in Older Adults With Chronic Low Back Pain

BACKGROUND AND PURPOSE

Older adults with low back pain (LBP) are at risk for falling, but condition-specific mechanisms are unknown. Trunk neuromuscular function is critical for maintaining balance during mobility tasks and is often impaired in older adults with LBP. The purpose of this study was to assess whether aberrant lumbopelvic movements (or aberrant movements), a clinical index of trunk neuromuscular function, were associated with increased fall risk among older adults with chronic LBP over a 12-month follow-up period.

METHODS

This study analyzed data from a prospective cohort study of 250 community-dwelling older adults with chronic LBP. Participants were screened for 4 aberrant movements during 3 trials of forward flexion from a standing position: instability catch, painful arc, altered lumbopelvic rhythm, and Gower's sign. Aberrant movements were totaled to yield a summary score (ie, 0-4). Prospective falls were monitored via monthly fall calendars for 12 months. A generalized linear model with Poisson distribution and log link function was used to evaluate the association between aberrant movements and prospective fall risk. Age, sex, body mass index, LBP intensity, dynamic balance performance, prior falls, anxiolytic medication usage, and hip osteoarthritis characteristics were included as covariates in the model.

RESULTS

Baseline aberrant movements were independently associated with greater fall risk (risk ratio = 1.249, 95% CI = 1.047-1.491, P = .014); each 1-unit increase in aberrant movement score imparted a 24.9% increase in the risk of falling.

CONCLUSIONS

Aberrant movements increased the risk of falling among older adults with chronic LBP over a 1-year span.

Trajectories of Physical Function and Disability Over 12 Months in Older Adults With Chronic Low Back Pain

BACKGROUND AND PURPOSE

Understanding prognosis is critical for clinical care and health policy initiatives. The purpose of this study was to determine whether distinct prognostic trajectories of physical function and disability exist in a cohort of 245 community-dwelling older adults with chronic low back pain (LBP), and to characterize the demographic, health, and pain-related profiles of each trajectory subgroup.

METHODS

All participants underwent standard clinic examinations at baseline, 3 months, 6 months, and 12 months. At each time point, the Late Life Function & Disability Instrument (LLFDI) was used to measure general physical function (LLFDI Function) and disability (LLFDI Disability-Limitation); the Quebec LBP Disability Questionnaire was used to measure disability due to pain. Growth mixture modeling (GMM) was performed on each outcome to identify distinct trajectory classes/subgroups; baseline demographic (eg, age and sex), health (eg, comorbidities, depressive symptoms, and physical activity level), and pain-related (eg, LBP intensity, pain-related fear, and pain catastrophizing) characteristic profiles were compared across subgroups.

RESULTS

GMM statistics revealed an optimal number of 3 to 4 trajectory subgroups, depending on the outcome examined. Subgroups differed across demographic, health, and pain-related characteristics; the classes with the most favorable prognoses had consistent profile patterns: fewer depressive symptoms, fewer comorbidities, higher physical activity levels, lower LBP intensities, less pain-related fear, and less pain catastrophizing.

CONCLUSION

Our findings indicate that several distinct trajectory subgroups exist that would have been masked by observing mean cohort change alone. Furthermore, subgroup characteristic profiles may help clinicians identify likely prognostic trajectories for their patients. Future research should focus on identifying modifiable risk factors that best predict group membership, and tailoring interventions to mitigate the risk of poor prognosis.

Increasing Activity After Stroke: A Randomized Controlled Trial of High-Intensity Walking and Step Activity Intervention

BACKGROUND

Physical inactivity in people with chronic stroke profoundly affects daily function and increases recurrent stroke risk and mortality, making physical activity improvements an important target of intervention. We compared the effects of a high-intensity walking intervention (FAST), a step activity monitoring behavioral intervention (SAM), or a combined intervention (FAST+SAM) on physical activity (ie, steps/day). We hypothesized the combined intervention would yield the greatest increase in steps/day.

METHODS

This assessor-blinded multisite randomized controlled trial was conducted at 4 university/hospital-based laboratories. Participants were 21 to 85 years old, walking without physical assistance following a single, unilateral noncerebellar stroke of ≥6 months duration, and randomly assigned to FAST, SAM, or FAST+SAM for 12 weeks (2-3 sessions/week). FAST training consisted of walking-related activities at 70% to 80% heart rate reserve, while SAM received daily feedback and goal setting of walking activity (steps/day). Assessors and study statistician were masked to group assignment. The a priori-determined primary outcome and end point was a comparison of the change in steps/day between the 3 intervention groups from pre- to post-intervention. Adverse events were tracked after randomization. All randomized participants were included in the intent-to-treat analysis.

RESULTS

Participants were enrolled from July 18, 2016, to November 16, 2021. Of 2385 participants initially screened, 250 participants were randomized (mean [SE] age, 63 [0.80] years; 116 females/134 males), with 89 assigned to FAST, 81 to SAM, and 80 to FAST+SAM. Steps/day significantly increased in both the SAM (mean [SE], 1542 [267; 95% CI, 1014-2069] P<0.001) and FAST+SAM group (1307 [280; 95% CI, 752-1861] P<0.001) but not in the FAST group (406 [238; 95% CI, -63 to 876] P=0.09). There were no deaths or serious study-related adverse events.

CONCLUSIONS

Only individuals with chronic stroke who completed a step activity monitoring behavioral intervention with skilled coaching and goal progression demonstrated improvements in physical activity (steps/day).

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT02835313.

Examining Psychological Factors as Contributors to Pain, Disability, and Physical Function in Geriatric Chronic Low Back Pain: A Prospective Analysis of the Delaware Spine Studies Cohort

In younger populations, risk factors from psychologically-focused theoretical models have become accepted as primary drivers behind the persistence of low back pain (LBP), but these risk factors have not been thoroughly assessed in older adult populations (60-85 years). To address this knowledge gap, we sought to examine longitudinal associations between both general and pain-related psychological risk factors and future pain intensity, LBP-related disability, and physical function (gait speed) outcomes in older adults with chronic LBP (n = 250). Questionnaires for general (ie, depressive symptoms) and pain-related psychological risk factors (ie, fear-avoidance beliefs, pain catastrophizing, and kinesiophobia) were collected at baseline. Questionnaire values were entered into principal component analysis to yield a combined psychological component score. LBP intensity (pain thermometers), LBP-related disability (Quebec Back Pain Disability Scale), and gait speed were measured at baseline and 12-month follow-up. Multiple linear regression was used to examine adjusted associations between baseline psychological component scores and each prospective outcome. The baseline psychological component score failed to independently predict 12-month LBP-related disability and gait speed after adjustment for baseline outcomes. Though the psychological component score was associated with 12-month LBP intensity after adjusting for baseline LBP intensity, this association diminished with full adjustment for other baseline characteristics. Cumulatively, general and pain-related psychological risk factors did not independently predict longitudinal pain, disability, and physical function outcomes in this cohort. Compared to younger populations with this condition, general and pain-related psychological risk factors may have less influence on the maintenance of chronic LBP in older adults. PERSPECTIVE: This article failed to establish consistent independent relationships between psychological factors and worse longitudinal pain, disability, and physical function outcomes in older adults with chronic LBP. The findings highlight a need to determine other age-specific biopsychosocial risk factors that may impact the maintenance of chronic pain in this patient population.

How should the margin of stability during walking be expressed to account for body size?

When expressing the margin of stability as a distance, it does not directly estimate the perturbation magnitude needed to change stability states. Additionally, it is unknown how body size may influence this measure. Therefore, we propose other expressions of stability margins, including that of an impulse, a change in center of mass velocity, and a scaled, unitless impulse. The purpose of this study was to determine the influence of body size on these margin expressions using walking data from children and adults. We anticipated that margins expressed as an impulse would have strong correlations with body mass and height, as well as large between-group differences. We predicted that scaling this impulse value would result in small correlations and between-group effect sizes. We calculated each stability margin at minimum lateral values and in the anteroposterior directions at mid-swing and foot strike. In the lateral direction, margins expressed as an impulse had strong correlations with body size (r≥0.58, p<0.01) and large between-group differences (|d|≥1.07, p<0.01). The other expressions did not have strong positive correlations (|r|≤0.20) or large between-group effects (|d|≤0.44). In the anteroposterior directions, impulse margins had strong correlations with body size (|r|≥0.83, p<0.01) and large between-group differences (|d|≥1.74, p<0.01). The scaled, unitless impulse margin was the only variable that resulted in small, non-significant differences (|r|≤0.22, p≥0.24) as well as small between-group effect sizes (|d|≤0.46, p≥0.22). We propose expressing stability margins as an impulse. If scaling is needed, we encourage using the scaled, unitless impulse.

Vascular determinants of hippocampal viscoelastic properties in healthy adults across the lifespan

Arterial stiffness and cerebrovascular pulsatility are non-traditional risk factors of Alzheimer's disease. However, there is a gap in understanding the earliest mechanisms that link these vascular determinants to brain aging. Changes to mechanical tissue properties of the hippocampus (HC), a brain structure essential for memory encoding, may reflect the impact of vascular dysfunction on brain aging. We tested the hypothesis that arterial stiffness and cerebrovascular pulsatility are related to HC tissue properties in healthy adults across the lifespan. Twenty-five adults underwent measurements of brachial blood pressure (BP), large elastic artery stiffness, middle cerebral artery pulsatility index (MCAv PI), and magnetic resonance elastography (MRE), a sensitive measure of HC viscoelasticity. Individuals with higher carotid pulse pressure (PP) exhibited lower HC stiffness (β = -0.39, r = -0.41, p = 0.05), independent of age and sex. Collectively, carotid PP and MCAv PI significantly explained a large portion of the total variance in HC stiffness (adjusted R2 = 0.41, p = 0.005) in the absence of associations with HC volumes. These cross-sectional findings suggest that the earliest reductions in HC tissue properties are associated with alterations in vascular function.

Clinically Relevant Subgroups Among Athletes Who Have Ruptured Their Anterior Cruciate Ligaments: A Delaware-Oslo Cohort Study

OBJECTIVE

To identify subgroups of individuals with anterior cruciate ligament (ACL) injuries based on patient characteristics, self-reported outcomes, and functional performance at baseline, and to associate subgroups with long-term outcomes after ACL rupture.

METHODS

A total of 293 participants (45.7% male, mean ± SD age 26.2 ± 9.4 years, days from injury 58 ± 35) were enrolled after effusion, pain, and range of motion impairments were resolved and quadriceps strength was at least 70% of the uninvolved limb. Mixture modeling was used to uncover latent subgroups without a prior group classification using probabilistic assignment. Variables include demographics, functional testing, and self-reported outcome measures. Radiographic evidence of osteoarthritis (OA; i.e., Kellgren/Lawrence grade of ≥1) in the involved knee at 5 years after injury was the primary outcome of interest. Chi-square tests assessed differences in the presence of radiographic OA in the involved knee between subgroups at 5 years after ACL rupture. Secondary outcomes of interest included radiographic OA in the uninvolved knee, return to preinjury sport by 2 years, operative status, and clinical OA (classified using Luyten et al criteria) at 5 years.

RESULTS

Four distinct subgroups exist after ACL rupture (younger good self-report, younger poor self-report, older poor self-report, older good self-report) with 30%, 31%, 47%, and 53%, respectively, having involved knee OA. The percentage of radiographic OA was not significantly different between the groups (P = 0.059).

CONCLUSION

The prevalence of OA in all subgroups is highly concerning. These results suggest there are unique subgroupings of individuals that may guide treatment after ACL rupture and reconstruction by providing support for developing a patient-centered approach.

Effects of an Acute High Intensity Exercise Bout on Retention of Explicit, Strategic Locomotor Learning in Individuals With Chronic Stroke

BACKGROUND

Exercise priming, pairing high intensity exercise with a motor learning task, improves retention of upper extremity tasks in individuals after stroke, but has shown no benefit to locomotor learning. This difference may relate to the type of learning studied. Upper extremity studies used explicit, strategic tasks; locomotor studies used implicit sensorimotor adaptation (split-belt treadmill). Since walking is an important rehabilitation goal, it is crucial to understand under which circumstances exercise priming may improve retention of a newly learned walking pattern.

OBJECTIVE

Determine the impact of exercise priming on explicit, strategic locomotor learning task retention in chronic stroke survivors.

METHODS

Chronic stroke survivors (>6 months) performed 2 treadmill walking sessions. Visual feedback was used to train increased step length. Participants were assigned to control group (no exercise), continuous exercise (5 minutes high intensity), or long-interval exercise (15 minutes high/moderate intervals). After day 1 learning, participants either rested or performed exercise. On day 2, retention of the learned walking pattern was tested.

RESULTS

All groups learned on day 1 (P < .001). The 2 priming groups showed significant changes in blood lactate and heart rate after exercise priming, the resting control group did not (P < .001). On day 2, there was no significant between-group difference in cued or un-cued task retention (P = .963 and .287, respectively).

CONCLUSIONS

Exercise priming did not affect retention of an explicit locomotor task in chronic stroke survivors. Further work should explore subgroups of individuals for whom priming may have selective clinical benefit to locomotor learning.ClinicalTrials.gov Identifier: NCT03726047.

Adults with lower-limb amputation: Reduced multifidi muscle activity and extensor muscle endurance is associated with worse physical performance

Trunk muscles may be an overlooked region of deficits following lower-limb amputation (LLA). This study sought to determine the extent that trunk muscle deficits are associated with physical function following amputation. Sedentary adults with a unilateral transtibial- (n = 25) or transfemoral-level (n = 14) amputation were recruited for this cross-sectional research study. Participants underwent a clinical examination that included ultrasound imaging of the lumbar multifidi muscles, the modified Biering-Sorensen Endurance Test (mBSET), and performance-based measures, that is, the Timed Up and Go (TUG), Berg Balance Scale (BBS), and 10-m Walk Test (10mWT). Associations between trunk muscle metrics and performance were explored with regression modeling, while considering covariates known to impact performance postamputation (p ≤ 0.100). Average ultrasound-obtained, lumbar multifidi activity was 14% and 16% for transfemoral- and transtibial-level amputations, respectively, while extensor endurance was 37.34 and 12.61 s, respectively. For TUG, nonamputated-side multifidi activity and an interaction term (level x non-amputated-side multifidi activity) explained 9.4% and 6.2% of the total variance, respectively. For 10mWT, beyond covariates, non-amputated-side multifidi activity and the interaction term explained 6.1% and 5.8% of the total variance, respectively. For TUG, extensor endurance and an interaction term (level x mBSET) explained 11.9% and 8.3% of the total variance beyond covariates; for BBS and 10mWT, extensor endurance explained 11.2% and 17.2% of the total variance, respectively. Findings highlight deficits in lumbar multifidi activity and extensor muscle endurance among sedentary adults with a LLA; reduced muscle activity and endurance may be important factors to target during rehabilitation to enhance mobility-related outcomes.

Increasing activity after stroke: a randomized controlled trial of highintensity walking and step activity intervention

Background

Physical inactivity in people with chronic stroke profoundly affects daily function and increases recurrent stroke risk and mortality, making physical activity improvements an important target of intervention. We compared the effects of a highintensity walking intervention (FAST), a step activity monitoring behavioral intervention (SAM), or a combined intervention (FAST+SAM) on physical activity (i.e., steps per day). We hypothesized the combined intervention would yield the greatest increase in steps per day.

Methods

This assessor-blinded multi-site randomized controlled trial was conducted at four university/hospital-based laboratories. Participants were 21-85 years old, walking without physical assistance following a single, unilateral non-cerebellar stroke of ≥6 months duration, and randomly assigned to FAST, SAM, or FAST+SAM for 12 weeks (2-3 sessions/week). FAST training consisted of walking-related activities for 40 minutes/session at 70-80% heart rate reserve, while SAM received daily feedback and goal-setting of walking activity (steps per day). Assessors and study statistician were masked to group assignment.The a priori-determined primary outcome and primary endpoint was change in steps per day from pre- to post-intervention. Adverse events (AEs) were tracked after randomization. All randomized participants were included in the intent-to-treat analysis.This study is registered at ClinicalTrials.gov, NCT02835313.

Findings

Participants were enrolled from July 18, 2016-November 16, 2021. Of 250 randomized participants (mean[SE] age 63[0.80], 116F/134M), 89 were assigned to FAST, 81 to SAM, and 80 to FAST+SAM. Steps per day significantly increased in both the SAM (mean[SE] 1542[267], 95%CI:1014-2069, p<0.001) and FAST+SAM groups (1307[280], 752-1861, p<0.001), but not in the FAST group (406[238], 63-876, p=0.09). There were no deaths or serious study-related AEs and all other minor AEs were similar between groups.

Interpretation

Only individuals with chronic stroke who completed a step activity monitoring behavioral intervention with skilled coaching and goal progression demonstrated improvements in physical activity (steps per day).

Construct validity of movement-evoked pain operational definitions in older adults with chronic low back pain

OBJECTIVE

Movement-evoked pain (MeP) may predispose the geriatric chronic low back pain (LBP) population to health decline. As there are differing operational definitions for MeP, the question remains as to whether these different definitions have similar associations with health outcomes in older adults with chronic LBP.

DESIGN

Cross-sectional analysis of an observational study.

SETTING

Clinical research laboratory.

SUBJECTS

226 older adults with chronic LBP.

METHODS

This secondary analysis used baseline data from a prospective cohort study (n = 250). LBP intensity was collected before and after the repeated chair rise test, stair climbing test, and 6-minute walk test; MeP change scores (ie, sum of pretest pain subtracted from posttest pain) and aggregated posttest pain (ie, sum of posttest pain) variables were calculated. LBP-related disability and self-efficacy were measured by the Quebec Back Pain Disability Scale (QBPDS) and Low Back Activity Confidence Scale (LOBACS), respectively. Physical function was measured with the Health ABC Performance Battery. Robust regression with HC3 standard errors was used to evaluate adjusted associations between both MeP variables and disability, self-efficacy, and physical function.

RESULTS

Greater aggregated posttest MeP was independently associated with worse disability (b = 0.593, t = 2.913, P = .004), self-efficacy (b = -0.870, t = -3.110, P = .002), and physical function (b = -0.017, t = -2.007, P = .039). MeP change scores were not associated with any outcome (all P > .050).

CONCLUSIONS

Aggregate posttest MeP was linked to poorer health outcomes in older adults with chronic LBP, but MeP change scores were not. Future studies should consider that the construct validity of MeP paradigms partially depends on the chosen operational definition.

Reliability of Continuous Shear Wave Elastography in the Pathological Patellar Tendon

OBJECTIVES

Patellar tendon injuries occur via various mechanisms such as overuse, or due to surgical graft harvest for anterior cruciate ligament reconstruction (ACLR). Quantified patellar tendon stiffness after injury may help guide clinical care. Continuous shear wave elastography (cSWE) allows for the assessment of viscosity and shear modulus in tendons. The reliability of the measure, however, has not been established in the patellar tendon. The purpose of this study was to investigate the interrater reliability, intrarater reliability, and between-day stability of cSWE in both healthy and pathological patellar tendons.

METHODS

Participants with patellar tendinopathy (n = 13), history of ACLR using bone-patellar tendon-bone autograft (n = 9), and with no history of patellar tendon injury (n = 13) were recruited. cSWE was performed 4 times by multiple raters over 2 days. Intraclass correlations (ICC) and minimum detectable change (MDC_95% ) were calculated.

RESULTS

Good to excellent between-day stability were found for viscosity (ICC = 0.905, MDC_95%  = 8.3 Pa seconds) and shear modulus (ICC = 0.805, MDC_95%  = 27.4 kPa). The interrater reliability measures, however, were not as reliable (ICC = 0.591 and 0.532).

CONCLUSIONS

cSWE is a reliable assessment tool for quantifying patellar tendon viscoelastic properties over time. It is recommended, however, that a single rater performs the measure as the interrater reliability was less than ideal.

Differences in Recovery of Tendon Health Explained by Midportion Achilles Tendinopathy Subgroups: A 6-Month Follow-up

OBJECTIVES: To (1) evaluate whether the defining characteristics of previously reported Achilles tendinopathy subgroups were reproducible in a cohort with midportion Achilles tendinopathy and (2) compare recovery trajectories and outcomes. DESIGN: Prospective single cohort study. METHODS: Participants (n = 114; 57 women; age [mean ± standard deviation]: 47 ± 12 years) received the Silbernagel protocol and were evaluated at baseline, and at 8, 16, and 24 weeks. Subgroups were identified using mixture modeling. Main effects of group and time, and interaction effects were evaluated using linear mixed models for 23 outcome measures representing symptoms, lower extremity function, tendon structure, psychological factors, and patient-related factors. Recovery trajectories were reported descriptively to reflect clinically meaningful change for outcomes. RESULTS: Activity-Dominant (n = 34), Function-Dominant (n = 38), Psychosocial-Dominant (n = 27), and Structure-Dominant (n = 15) subgroups were identified. There were significant effects of group and time for all primary outcome measures, except heel-rise and viscosity limb symmetry indexes. The Activity- and Function-Dominant subgroups achieved functional recovery despite persisting symptoms. The Psychosocial-Dominant subgroup reported the greatest impairments in symptom and foot- and ankle-related quality of life at all time points. The Structure-Dominant subgroup experienced delayed improvement in symptoms and was the only subgroup to not achieve structural recovery. No subgroup met our criteria for complete recovery. CONCLUSION: The defining characteristics of Achilles tendinopathy subgroups were reproduced in a cohort with midportion Achilles tendinopathy. The Activity- and Function-Dominant subgroups had superior outcomes compared to the Psychosocial- and Structure-Dominant subgroups for symptomatic, functional, and structural recovery. J Orthop Sports Phys Ther 2023;53(4):1-18. Epub: 23 January 2023. doi:10.2519/jospt.2023.11330.

Movement-Evoked Pain Versus Widespread Pain: A Longitudinal Comparison in Older Adults With Chronic Low Back Pain From the Delaware Spine Studies

It is currently unknown which pain-related factors contribute to long-term disability and poorer perceived health among older adults with chronic low back pain (LBP). This investigation sought to examine the unique influence of movement-evoked pain (MeP) and widespread pain (WP) on longitudinal health outcomes (ie, gait speed, perceived disability, and self-efficacy) in 250 older adults with chronic LBP. MeP was elicited with 3 standardized functional tests, while presence of WP was derived from the McGill Pain Map. Robust regression with HC3 standard errors was used to examine associations between these baseline pain variables and health outcomes at 12-month follow-up. Covariates for these models included age, sex, body mass index, resting and recall LBP intensity, LBP duration, depression, pain catastrophizing, and baseline outcome (eg, baseline gait speed). Greater MeP was independently associated with worse 12-month LBP-related disability (b = .384, t = 2.013, P = .046) and poorer self-efficacy (b = -.562, t = -2.074, P = .039); but not gait speed (P > .05). In contrast, WP and resting and recall LBP intensity were not associated with any prospective health outcome after adjustment (all P > .05). Compared to WP and resting and recall LBP intensity, MeP is most strongly related to longitudinal health outcomes in older adults with chronic LBP. PERSPECTIVE: This article establishes novel independent associations between MeP and worse perceived disability and self-efficacy at 12-months in older adults with chronic LBP. MeP likely has biopsychosocial underpinnings and consequences and may therefore be an important determinant of health outcomes in LBP and other geriatric chronic pain populations.

Gait asymmetry is associated with performance-based physical function among adults with lower-limb amputation

BACKGROUND

Adults with lower-limb amputation walk with an asymmetrical gait and exhibit poor functional outcomes, which may negatively impact quality-of-life.

OBJECTIVE

To evaluate associations between gait asymmetry and performance-based physical function among adults with lower-limb amputation.

METHODS

A cross-sectional study involving 38 adults with a unilateral transtibial (N = 24; 62.5 ± 10.5 years) or transfemoral amputation (N = 14; 59.9 ± 9.5 years) was conducted. Following gait analysis (capturing step length and stance time asymmetry at self-selected (SSWS) and fast walking speeds (FWS)), participants completed performance-based measures (i.e. Timed Up and Go (TUG), the 10-Meter Walk Test (10mwt), and the 6-Minute Walk Test (6MWT)).

RESULTS

Step length and stance time asymmetry (at SSWS and FWS) were significantly correlated with each performance-based measure (p < .001 to p = .035). Overall, models with gait measures obtained at SSWS explained 40.1%, 46.8% and 40.1% of the variance in TUG-time (p = .022), 10mwt-speed (p = .003) and 6MWT-distance (p = .010), respectively. Models with gait measures obtained at FWS explained 70.0%, 59.8% and 51.8% of the variance in TUG-time (p < .001), 10mwt-speed (p < .001), and 6MWT-distance (p < .001), respectively.

CONCLUSIONS

Increases in step length or stance time asymmetry are associated with increased TUG-time, slower 10mwt-speed, and reduced 6MWT-distance. Findings suggest gait asymmetry may be a factor in poor functional outcomes following lower-limb amputation.

Structure-Function Dissociations of Human Hippocampal Subfield Stiffness and Memory Performance

Aging and neurodegenerative diseases lead to decline in thinking and memory ability. The subfields of the hippocampus (HCsf) play important roles in memory formation and recall. Imaging techniques sensitive to the underlying HCsf tissue microstructure can reveal unique structure-function associations and their vulnerability in aging and disease. The goal of this study was to use magnetic resonance elastography (MRE), a noninvasive MR imaging-based technique that can quantitatively image the viscoelastic mechanical properties of tissue to determine the associations of HCsf stiffness with different cognitive domains across the lifespan. Eighty-eight adult participants completed the study (age 23-81 years, male/female 36/51), in which we aimed to determine which HCsf regions most strongly correlated with different memory performance outcomes and if viscoelasticity of specific HCsf regions mediated the relationship between age and performance. Our results revealed that both interference cost on a verbal memory task and relational memory task performance were significantly related to cornu ammonis 1-2 (CA1-CA2) stiffness (p = 0.018 and p = 0.011, respectively), with CA1-CA2 stiffness significantly mediating the relationship between age and interference cost performance (p = 0.031). There were also significant associations between delayed free verbal recall performance and stiffness of both the dentate gyrus-cornu ammonis 3 (DG-CA3; p = 0.016) and subiculum (SUB; p = 0.032) regions. This further exemplifies the functional specialization of HCsf in declarative memory and the potential use of MRE measures as clinical biomarkers in assessing brain health in aging and disease.SIGNIFICANCE STATEMENT Hippocampal subfields are cytoarchitecturally unique structures involved in distinct aspects of memory processing. Magnetic resonance elastography is a technique that can noninvasively image tissue viscoelastic mechanical properties, potentially serving as sensitive biomarkers of aging and neurodegeneration related to functional outcomes. High-resolution in vivo imaging has invigorated interest in determining subfield functional specialization and their differential vulnerability in aging and disease. Applying MRE to probe subfield-specific cognitive correlates will indicate that measures of subfield stiffness can determine the integrity of structures supporting specific domains of memory performance. These findings will further validate our high-resolution MRE method and support the potential use of subfield stiffness measures as clinical biomarkers in classifying aging and disease states.

Relationships between tendon structure and clinical impairments in patients with patellar tendinopathy

The clinical relevance of altered tendon structure in patellar tendinopathy is contested since structural change persists after symptom resolution. The purpose of this study was to explore the relationships between tendon structure and clinical impairments in patellar tendinopathy. In this retrospective, secondary analysis of individuals with patellar tendinopathy (n = 41), tendon structure (thickness, cross-sectional area [CSA], shear modulus, and viscosity), symptom severity, lower extremity function (counter-movement jump [CMJ] height), and quadriceps muscle performance (knee extension force and central activation ratio [CAR]) were recorded for the symptomatic limb. Relationships among structure, symptom severity, lower extremity function, and quadriceps muscle performance were examined using sequential regression models. Adjusting for age, sex, body mass index, and pain levels, there were significant positive relationships for thickness (p < 0.001, β = 0.718) and viscosity (p = 0.006, β = 0.496) with CMJ height. There were significant negative relationships between CSA with both CMJ height (p = 0.001, β = -0.538) and CAR (p = 0.04, β = -0.517). This is the first study to demonstrate relationships between tendon structure and lower extremity function or quadriceps muscle performance in patients with patellar tendinopathy. Clinical significance: Since structural changes persist after symptom resolution, addressing these changes may assist in restoring lower extremity function and quadriceps muscle performance.

Relationships Among Environmental Variables, Physical Capacity, Balance Self-Efficacy, and Real-World Walking Activity Post-Stroke

BACKGROUND

Social and physical environmental factors affect real-world walking activity in individuals with stroke. However, environmental factors are often non-modifiable, presenting a challenge for clinicians working with individuals with stroke whose real-world walking is limited due to environmental barriers.

OBJECTIVE

The purpose of this work was to test a model hypothesizing the relationships among environmental factors (specifically, living situation and area deprivation), modifiable factors, and real-world walking activity to understand opportunities for intervention. We hypothesized that balance self-efficacy would mediate the relationship between the environment and real-world walking and that physical capacity would moderate this mediation.

METHODS

This was a cross-sectional study of 282 individuals with chronic (≥6 months) stroke. We tested the indirect effect to determine if mediation was present. Multiple group structural equation modeling was used to test if physical capacity moderated this mediation. A χ² difference test was used to compare the moderation model against the null (no moderation) model.

RESULTS

Balance self-efficacy mediated the relationship between area deprivation and real-world walking (indirect effect: β = -0.04, P = .04). Both the moderation and null models fit the data equally well statistically (χ²(5) = 6.9, P = .23). We therefore accepted the simpler (null) model and concluded that the mediation was not moderated.

CONCLUSIONS

Targeting balance self-efficacy may be an effective approach to improving real-world walking in persons with stroke who experience barriers within the physical environment. A stroke survivor's physical capacity may not impact this approach. Future work should consider utilizing more specific measures of the social and physical environment to better understand their influences on real-world walking activity in individuals with stroke. However, the results of this work provide excellent targets for future longitudinal studies targeting real-world walking activity in stroke.

Tendon loading in runners with Achilles tendinopathy: Relations to pain, structure, and function during return-to-sport

We aimed to (1) compare pain, tendon structure, lower limb function, and Achilles tendon loads while running between limbs in runners with Achilles tendinopathy, and (2) explore the relations of pain, tendon structure, and lower limb function to Achilles tendon loads while running. Twenty runners with Achilles tendinopathy participated in this pilot study. Pain was assessed with questionnaires, quantitative sensory testing, and functional testing. Tendon morphology and mechanical properties were evaluated with ultrasound imaging, continuous shear wave elastography, and ultrasound imaging combined with dynamometry. Lower limb function was assessed with an established test battery. Achilles tendon loads were estimated from biomechanical data acquired during running. Compared to the least symptomatic limb, the most symptomatic limb had lower scores on the Victorian Institute of Sports Assessment - Achilles questionnaire and worse pain during drop countermovement jumping, hopping, and running. Tendon thickness and cross-sectional area were greater, and Young's modulus, drop countermovement jump height, and plyometric quotient during hopping were lower on the most symptomatic limb. Side-to-side differences in drop countermovement jump height were significantly associated with side-to-side differences in Achilles tendon peak forces and average loading rates during running. Various measures of pain, structure, and function differ between limbs in runners with Achilles tendinopathy during return-to-sport. Tendon forces, however, do not differ between limbs during comfortable running. In addition to measures that differ between limbs, measures of performance during drop countermovement jumping may aid in clinical decision-making during return-to-sport because they are associated with tendon forces while running.

Residual and sound limb hip strength distinguish between sedentary and nonsedentary adults with transtibial amputation

Following a transtibial amputation (TTA), physical activity has known benefits for health and quality of life. Adults post-TTA, however, demonstrate reduced physical activity, predisposing them to adverse health outcomes. Identifying adults at the risk of sedentarism post-TTA via commonly used, objective clinical measures may enhance clinical decisions, including prosthesis prescription. The study's purpose was to determine whether residual and sound limb hip strength distinguishes between sedentary and nonsedentary adults post-TTA. A secondary analysis of a cross-sectional dataset (n = 44) was conducted. Participant residual and sound limb hip flexion, extension, abduction and adduction strength were assessed via handheld dynamometry. Physical activity was monitored for 7 days and participants were classified as sedentary (<5000 steps/day; n = 13) or nonsedentary (≥5000 steps/day; n = 31). Receiver operating curves revealed that residual and sound limb hip extension, abduction and adduction strength distinguished between sedentary and nonsedentary adults post-TTA (P < 0.050). Preliminary cut-points for hip strength measures to classify adults at the risk of sedentarism were determined. A hip strength composite score (0-6) estimates a 2.2× increased odds of being sedentary with each additional hip strength deficit. Post-TTA, residual and sound limb hip strength can help identify adults at risk of sedentarism to aid clinical decision making, including prosthesis prescription.

Altered Brain Functional Connectivity in the Frontoparietal Network following an Ice Hockey Season

AbstractSustaining sports-related head impacts has been reported to result in neurological changes that potentially lead to later-life neurological disease. Advanced neuroimaging techniques have been used to detect subtle neurological effects resulting from head impacts, even after a single competitive season. The current study used resting-state functional magnetic resonance imaging to assess changes in functional connectivity of the frontoparietal network, a brain network responsible for executive functioning, in collegiate club ice hockey players over one season. Each player was scanned before and after the season and wore accelerometers to measure head impacts at practices and home games throughout the season. We examined pre- to post-season differences in connectivity within the frontoparietal and default mode networks, as well as the relationship between the total number of head impacts sustained and changes in connectivity. We found a significant interaction between network region of interest and time point (p = 0.016), in which connectivity between the left and right posterior parietal cortex seed regions increased over the season (p < 0.01). Number of impacts had a significant effect on frontoparietal network connectivity, such that more impacts were related to greater connectivity differences over the season (p = 0.042). Overall, functional connectivity increased in ice hockey athletes over a season between regions involved in executive functioning, and sensory integration, in particular. Furthermore, those who sustained more impacts had the greatest changes in connectivity. Consistent with prior findings in resting-state sports-related head impact literature, these findings have been suggested to represent brain injury.

Aberrant Lumbopelvic Movements Predict Prospective Functional Decline in Older Adults with Chronic Low Back Pain

OBJECTIVE

To investigate if clinically observable aberrant lumbopelvic movements are associated with physical function at 12-month follow-up in older adults with chronic low back pain (CLBP), both directly and indirectly through baseline physical function.

DESIGN

Secondary analysis of a yearlong prospective cohort study.

SETTING

Clinical Research Laboratory.

PARTICIPANTS

Community-dwelling older adults with CLBP (N=250).

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Data from 239 participants were analyzed. Participants were screened at baseline for aberrant lumbopelvic movements during active trunk flexion; total observable aberrant movements were recorded and summed (range 0-4). Latent constructs of physical function were developed from an array of perception-based and performance-based outcome measures at baseline and 12 months, respectively. Structural Equation Modeling was used to assess the direct effect of baseline aberrant movement score on the latent construct of 12-month physical function, and its indirect effect through baseline physical function.

RESULTS

Aberrant movements were present in most participants (64.7%) and had a significant negative total effect on 12-month physical function (γ= -0.278, P<.001). Aberrant movement score's direct effect and indirect effect, through baseline functioning, were significantly negatively associated with physical function at 12-months, after adjusting for covariates (γ=-0.068, P=.038; γ= -0.210, P<.001, respectively).

CONCLUSIONS

Aberrant lumbopelvic movements are associated with decreased physical function at 12-month follow-up in older adults with CLBP, independent of baseline physical function and covariates. Future studies should evaluate if screening for aberrant movements may inform prognostic and interventional efforts in this patient population.

Vibration Sensitivity Is Associated With Functional Balance After Unilateral Transtibial Amputation

Objectives

To evaluate differences in vibration perception thresholds between adults with transtibial amputation and age-matched adults without amputation and to examine associations between vibration perception thresholds and balance performance. We hypothesized that adults with transtibial amputation would demonstrate lower thresholds compared with adults without amputation and that lower thresholds would be associated with better functional balance.

Design

Prospective cross-sectional study.

Setting

National conference, clinical practice, and university laboratory.

Participants

Adults (N=34) with a nondysvascular, unilateral, transtibial amputation and 43 age-matched controls without amputation.

Interventions

Participants' vibration perception thresholds were evaluated bilaterally by applying a vibration stimulus to the midpatella and recording their verbal response to conscious perception of stimulus. Functional balance was assessed with the Berg Balance Scale and the Four Square Step Test.

Main Outcome Measures

Residual and sound limb (right and left for controls) vibration perception thresholds, Berg Balance Scale, and Four Square Step Test.

Results

For participants with transtibial amputation and controls, there were no significant between-group (P=.921) or interlimb (P=.540) differences in vibration perception thresholds. Overall, robust regression models explained 35.1% and 19.3% variance in Berg Balance Scale scores and Four Square Step Test times, respectively. Among adults with transtibial amputation, vibration perception thresholds were negatively associated with Berg Balance Scale scores (P=.009) and positively associated with Four Square Step Test times (P=.048). Among controls, average vibration perception thresholds were not significantly associated with functional balance (P>.050).

Conclusions

Adults with nondysvascular, transtibial-level amputation demonstrated similar vibration detection compared with adults with intact limbs, indicating that vibration detection is preserved in the amputated region postamputation. These findings suggest a unique relationship between vibration perception and functional balance post-transtibial amputation.

Fluid Cognition Relates to Locomotor Switching in Neurotypical Adults, Not Individuals After Stroke

BACKGROUND AND PURPOSE

The ability to switch between walking patterns (ie, locomotor switching) is vital for successful community navigation and may be impacted by poststroke impairments. Thus, the purpose of this work was to examine locomotor switching and the relationship between locomotor switching and fluid cognition in individuals after stroke compared with neurotypical adults.

METHODS

Twenty-nine individuals more than 6 months after stroke and 18 neurotypical adults participated in a 2-day study. On day 1, participants were taught a new walking pattern on the treadmill and then locomotor switching was assessed by instructing participants to switch between the new walking pattern and their usual walking pattern. The change between these 2 patterns was calculated as the switching index. On day 2, the NIH Toolbox Cognition Battery was administered to obtain the Fluid Cognition Composite Score (FCCS), which reflected fluid cognition. The switching index was compared between groups using an analysis of covariance, and the relationship between locomotor switching and fluid cognition was assessed with regression.

RESULTS

Individuals after stroke had significantly lower switching indexes compared with neurotypical adults (P = 0.03). The regression showed a significant interaction between group and FCCS (P = 0.002), with the FCCS predicting the switching index in neurotypical adults but not in individuals after stroke.

DISCUSSION AND CONCLUSIONS

Individuals after stroke appear to have deficits in locomotor switching compared with neurotypical adults. The relationship between fluid cognition and locomotor switching was significant in neurotypical adults but not in individuals after stroke. Future work to understand the relationship between specific cognitive domains and locomotor switching is needed (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A361).

A Standardized Assessment of Movement-evoked Pain Ratings Is Associated With Functional Outcomes in Older Adults With Chronic Low Back Pain

OBJECTIVE

Despite high prevalence estimates, chronic low back pain (CLBP) remains poorly understood among older adults. Movement-evoked pain (MeP) is an understudied factor in this population that may importantly contribute to disability. This study investigated whether a novel MeP paradigm contributed to self-reported and performance-based function in older adults with CLBP.

MATERIALS AND METHODS

This secondary analysis includes baseline data from 230 older adults with CLBP in the context of a prospective cohort study. The Repeated Chair Rise Test, Six Minute Walk Test, and Stair Climbing Test were used to elicit pain posttest LBP ratings were aggregated to yield the MeP variable. Self-reported and performance-based function were measured by the Late Life Function and Disability Index (LLFDI) scaled function score and Timed Up-and-Go Test (TUG), respectively. Robust regression with HC3 standard errors was used to model adjusted associations between MeP and both functional outcomes; age, sex, body mass index, and pain characteristics (ie, intensity, quality, and duration) were utilized as covariates.

RESULTS

MeP was present in 81.3% of participants, with an average rating of 5.09 (SD=5.4). Greater aggregated posttest MeP was associated with decreased LLFDI scores (b=-0.30, t=-2.81, P=0.005) and poorer TUG performance (b=0.081, t=2.35, P=0.020), independent of covariates. LBP intensity, quality and duration were not associated with the LLFDI or TUG, (all P>0.05).

DISCUSSION

Aggregated posttest MeP independently contributed to worse self-reported and performance-based function among older adults with CLBP. To understand long-term consequences of MeP, future studies should examine longitudinal associations between MeP and function in this population.

The Manual Therapy and Strengthening for the Hip (MASH) Trial: Protocol for a Multisite Randomized Trial of a Subgroup of Older Adults With Chronic Back and Hip Pain

OBJECTIVE

Chronic low back pain (CLBP) is a disabling and costly condition for older adults that is difficult to properly classify and treat. In a cohort study, a subgroup of older adults with CLBP who had elevated hip pain and hip muscle weakness was identified; this subgroup differentiated itself by being at higher risk for future mobility decline. The primary purpose of this clinical trial is to evaluate whether a hip-focused low back pain (LBP) treatment provides better disability and physical performance outcomes for this at-risk group compared with a spine-focused LBP treatment.

METHODS

This study is a multisite, single-blinded, randomized controlled, parallel arm, Phase II trial conducted across 3 clinical research sites. A total of 180 people aged between 60 and 85 years with CLBP and hip pain are being recruited. Participants undergo a comprehensive baseline assessment and are randomized into 1 of 2 intervention arms: hip-focused or spine-focused. They are treated twice weekly by a licensed physical therapist for 8 weeks and undergo follow-up assessments at 8 weeks and 6 months after randomization. Primary outcome measures include the Quebec Low Back Disability Scale and the 10-Meter Walk Test, which are measures of self-report and performance-based physical function, respectively.

IMPACT

This multicenter, randomized clinical trial will determine whether a hip-focused or spine-focused physical therapist intervention results in improved disability and physical performance for a subgroup of older adults with CLBP and hip pain who are at increased risk of mobility decline. This trial will help further the development of effective interventions for this subgroup of older adults with CLBP.

Depressive Symptoms Moderate the Relationship Among Physical Capacity, Balance Self-Efficacy, and Participation in People After Stroke

OBJECTIVE

It was previously found that balance self-efficacy mediated the relationship between physical capacity and participation after stroke. The effect of other factors that influence participation, such as depression, on this relationship has not been explored. This study examined the effect of symptoms of depression on the mediated relationship between physical capacity and participation by balance self-efficacy in individuals after stroke.

METHODS

In this cross-sectional study, 282 persons with chronic stroke (>6 months) were classified as having either low or high Geriatric Depression Scale scores. This study used a multiple group structural equation model to test moderated mediation by comparing a constrained model (indicating no effect of depression on the mediation) and an unconstrained model (indicating an effect of depression on the mediation). The models were compared using a chi-squared difference test.

RESULTS

The chi-squared difference test suggested that the unconstrained model was a better fit, indicating that depressive symptoms moderated the mediated relationship between physical capacity and participation (χ2(3, N = 282) = 9.0). In the Low Depression group, a significant indirect effect indicated that balance self-efficacy did mediate the relationship between physical capacity and participation. There was no significant indirect effect in the High Depression group.

CONCLUSION

The results suggest the relationship between physical capacity and participation appears to be mediated by balance self-efficacy in individuals after stroke with low reports of depressive symptoms, but in those with high reports of depressive symptoms, physical capacity and balance self-efficacy are unrelated to participation.

IMPACT

Targeting balance self-efficacy to improve post-stroke participation may be beneficial only for individuals with low reports of depression. In individuals after stroke with high reports of depression, treatment should include and emphasize the treatment of those depressive symptoms. Additional work further examining these complex relationships is warranted.

Classification of Geriatric Low Back Pain Based on Hip Characteristics With a 12-Month Longitudinal Exploration of Clinical Outcomes: Findings From Delaware Spine Studies

OBJECTIVE

The purpose of this study is to identify geriatric chronic low back pain (LBP) subgroups based on the presence of potentially modifiable hip impairments, using Latent Variable Mixture Modeling (LVMM), and to examine the prospective relationship between these subgroups and key outcomes over time.

METHODS

Baseline, 3-month, 6-month, and 12-month data were collected from a prospective cohort of 250 community-dwelling older adults with chronic LBP. Comprehensive hip (symptoms, strength, range of motion, and flexibility), LBP (intensity and disability), and mobility function (gait speed and 6-Minute Walk Test) examinations were performed at each timepoint. Baseline hip measures were included in LVMM; observed classes/subgroups were compared longitudinally on LBP and mobility function outcomes using mixed models.

RESULTS

Regarding LVMM, a model with 3 classes/subgroup fit best. Broadly speaking, subgroups were differentiated best by hip strength and symptom presence: subgroup 1 = strong and nonsymptomatic, subgroup 2 = weak and nonsymptomatic, and subgroup 3 = weak and symptomatic (WS). Regarding longitudinal mixed models, all subgroups improved in most outcomes over time. Specifically, over 12 months, the nonsymptomatic subgroups had lower LBP intensity and disability levels compared with the WS subgroup, whereas the strong and nonsymptomatic subgroup had better mobility function than the 2 "weak" subgroups.

CONCLUSION

These subgroup classifications may help in tailoring specific interventions in future trials. Special attention should be given to the WS subgroup given their consistently poor LBP and mobility function outcomes.

IMPACT

Among older adults with chronic low back pain, there are 3 hip subgroups: "strong and nonsymptomatic," "weak and nonsymptomatic," and "weak and symptomatic." People in these subgroups demonstrate different outcomes and require different treatment; proper identification will result in tailored interventions designed to benefit individual patients. In particular, people in the WS subgroup deserve special attention, because their outcomes are consistently poorer than those in the other subgroups.

Hip Range of Motion and Strength Predict 12-Month Physical Function Outcomes in Older Adults With Chronic Low Back Pain: The Delaware Spine Studies

Objective

The objective of this study was to investigate whether poor hip range of motion (ROM) and strength predict 12‐month physical function decline among older adults with chronic low back pain (LBP) and whether hip osteoarthritis modifies those relationships.

Methods

At baseline, passive ROM and strength measurements were taken for hip flexion, extension, abduction, adduction, internal rotation, and external rotation; ultrasound images and self‐reported symptoms were used to evaluate hip osteoarthritis presence (eg, osteophytes and hip pain). At baseline and 12 months, performance‐based (repeated chair rise, self‐selected gait speed, 6‐minute walk test [6MWT]) and self‐reported (Quebec LBP Disability Questionnaire, Late‐Life Function & Disability Instrument [LLFDI] basic and advanced lower extremity scales) physical function outcomes were assessed. Regression models were constructed for each outcome predicted by baseline hip ROM and strength measures, with adjustment for potential covariates. To avoid collinearity, hip ROM and strength measures with the strongest unadjusted correlations were included in final models. The hip osteoarthritis presence by hip ROM/strength interaction was also explored.

Results

Hip abduction strength predicted repeated chair rise (β = −0.297, P < 0.001), gait speed (β = 0.160, P = 0.003), 6MWT (β = 0.159, P ≤ 0.001), Quebec LBP Disability Questionnaire (β = −0.152, P = 0.003), and LLFDI basic lower extremity scale (β = 0.171, P = 0.005) outcomes. Regarding hip ROM, extension predicted repeated chair rise (β = −0.110, P = 0.043) and LLFDI advanced lower extremity scale (β = 0.090, P = 0.007) outcomes, external rotation predicted gait speed (β = 0.122, P = 0.004) outcomes, and abduction predicted LLFDI basic lower extremity scale (β = 0.114, P = 0.026) outcomes. The hip osteoarthritis interaction was not significant for any model.

Conclusion

Reduced hip strength and ROM predict physical function decline; hip osteoarthritis presence may not modify these relationships.

The Dynamic Motor Control Index as a Marker of Age-Related Neuromuscular Impairment

Biomarkers that can identify age-related decline in walking function have potential to promote healthier aging by triggering timely interventions that can mitigate or reverse impairments. Recent evidence suggests that changes in neuromuscular control precede changes in walking function; however, it is unclear which measures are best suited for identifying age-related changes. In this study, non-negative matrix factorization of electromyography data collected during treadmill walking was used to calculate two measures of the complexity of muscle co-activations during walking for 36 adults: (1) the number of muscle synergies and (2) the dynamic motor control index. Study participants were grouped into young (18–35 years old), young-old (65–74 years old), and old–old (75+ years old) subsets. We found that the dynamic motor control index [χ²(2) = 9.41, p = 0.009], and not the number of muscle synergies [χ²(2) = 5.42, p = 0.067], differentiates between age groups [χ²(4) = 10.62, p = 0.031, Nagelkerke R² = 0.297]. Moreover, an impairment threshold set at a dynamic motor control index of 90 (i.e., one standard deviation below the young adults) was able to differentiate between age groups [χ²(2) = 9.351, p = 0.009]. The dynamic motor control index identifies age-related differences in neuromuscular complexity not measured by the number of muscle synergies and may have clinical utility as a marker of neuromotor impairment.

The Impact of the Degree of Kinesiophobia on Recovery in Patients With Achilles Tendinopathy

OBJECTIVE

Kinesiophobia has been proposed to influence recovery in individuals with Achilles tendinopathy. However, whether there are differences in outcomes in individuals with different levels of kinesiophobia is unknown. The purpose of this study was to compare the characteristics of patients at baseline and recovery over time in individuals with Achilles tendinopathy and various levels of kinesiophobia.

METHODS

This study was a secondary analysis of a prospective observational cohort study of 59 individuals with Achilles tendinopathy. The participants were divided into 3 groups on the basis of scores on the Tampa Scale for Kinesiophobia (TSK) (those with low TSK scores [≤33; low TSK group], those with medium TSK scores [34-41; medium TSK group], and those with high TSK scores [≥42; high TSK group]). All participants were evaluated with self-reported outcomes, clinical evaluation, tendon morphology, viscoelastic property measurements, and a calf muscle endurance test at baseline, 6 months, and 12 months. No treatment was provided throughout the study period.

RESULTS

There were 16 participants (8 women) in the low TSK group (age = 51.9 [SD = 15.3] years, body mass index [BMI] = 24.3 [22.3-25.4]), 28 participants (13 women) in the medium TSK group (age = 52.7 [SD = 15.2] years, BMI = 26.4 [22.5-30.8]), and 15 participants (8 women) in the high TSK group (age = 61.1 [SD = 11.1] years, BMI = 28.1 [25.2-33.6]). Among the groups at baseline, the high TSK group had significantly greater BMI and symptom severity and lower quality of life. All groups showed significant improvement over time for all outcomes except tendon viscoelastic properties and tendon thickening when there was an adjustment for baseline BMI. The high and medium TSK groups saw decreases in kinesiophobia at 6 months, but there was no change for the low TSK group.

CONCLUSION

Despite the high TSK group having the highest BMI and the worse symptom severity and quality of life at baseline, members of this group showed improvements in all of the outcome domains similar to those of the other groups over 12 months.

IMPACT

Evaluating the degree of kinesiophobia in individuals with Achilles tendinopathy might be of benefit for understanding how they are affected by the injury. However, the degree of kinesiophobia at baseline does not seem to affect recovery; this finding could be due to the patients receiving education about the injury and expectations of recovery.

Markers of Cardiovascular Health in Older Adults with and Without Chronic Low Back and Radicular Leg Pain: A Comparative Analysis

OBJECTIVES

There is considerable overlap in risk profiles between chronic low back pain with radiculopathy (CLBPR) and cardiovascular health among older adults; obesity and smoking are related to both conditions and may largely drive the potential relationship. We sought to explore the impact of CLBPR on cardiovascular health outcomes, independent of body mass index (BMI) and current smoking status.

METHODS

Age- and sex-matched older adults (60-85 years of age) with (n = 21) and without (n = 21) CLBPR were recruited. Current smokers were excluded. Blood samples were collected to measure cholesterol levels and pro-inflammatory markers (i.e., C-reactive protein and interleukin-6). Vascular endothelial function, a marker of cardiovascular health, was evaluated by measuring brachial artery flow-mediated dilation (FMD). General linear models with multifactorial designs were evaluated; group membership, BMI, education, and their respective two-way interaction terms were included as independent variables.

RESULTS

Older adults with CLBPR had significantly higher BMIs (P = 0.004) and lower educational levels (P = 0.013) than did those without pain. There was a significant group-by-education interaction effect (P = 0.049) for endothelial function. Older adults without pain who were highly educated had higher FMD values, indicating better endothelial function (9.2%), whereas the following combinations all had lower FMD values: no pain plus low education, CLBPR plus high education, and CLBPR plus low education (5.9%, 6.1%, and 6.6%, respectively).

CONCLUSIONS

Among older adults, CLBPR is linked with worse endothelial function, regardless of educational level and independent of BMI and smoking. These findings suggest that older adults with CLBPR may be at a higher risk of cardiovascular disease.

Fluid Cognitive Abilities Are Important for Learning and Retention of a New, Explicitly Learned Walking Pattern in Individuals After Stroke

BACKGROUND

There is significant variability in poststroke locomotor learning that is poorly understood and affects individual responses to rehabilitation interventions. Cognitive abilities relate to upper extremity motor learning in neurologically intact adults, but have not been studied in poststroke locomotor learning.

OBJECTIVE

To understand the relationship between locomotor learning and retention and cognition after stroke.

METHODS

Participants with chronic (>6 months) stroke participated in 3 testing sessions. During the first session, participants walked on a treadmill and learned a new walking pattern through visual feedback about their step length. During the second session, participants walked on a treadmill and 24-hour retention was assessed. Physical and cognitive tests, including the Fugl-Meyer-Lower Extremity (FM-LE), Fluid Cognition Composite Score (FCCS) from the NIH Toolbox -Cognition Battery, and Spatial Addition from the Wechsler Memory Scale-IV, were completed in the third session. Two sequential regression models were completed: one with learning and one with retention as the dependent variables. Age, physical impairment (ie, FM-LE), and cognitive measures (ie, FCCS and Spatial Addition) were the independent variables.

RESULTS

Forty-nine and 34 participants were included in the learning and retention models, respectively. After accounting for age and FM-LE, cognitive measures explained a significant portion of variability in learning (R² = 0.17, P = .008; overall model R² = 0.31, P = .002) and retention (ΔR² = 0.17, P = .023; overall model R² = 0.44, P = .002).

CONCLUSIONS

Cognitive abilities appear to be an important factor for understanding locomotor learning and retention after stroke. This has significant implications for incorporating locomotor learning principles into the development of personalized rehabilitation interventions after stroke.

Hip osteoarthritis signs and symptoms are associated with increased fall risk among community-dwelling older adults with chronic low back pain: a prospective study

Background

Older adults with concurrent low back and hip pain are predisposed to reductions in physical performance and health-related quality of life. Yet no study to date has assessed whether or not coexisting hip impairments increase fall risk in older adults with chronic low back pain (CLBP). The objective of this study was to determine if hip osteoarthritis (OA) signs and symptoms per American College of Rheumatology (ACR) criteria are associated with fall risk over a 1-year span.

Methods

Falls were prospectively monitored for 1 year via fall calendars. Age, sex, body mass index (BMI), anxiolytic use, balance confidence, LBP-related disability, and prior fall history were identified as covariates. Hip pain, pain with hip internal rotation (IR), hip IR range of motion (ROM) ≥ 15°, and morning stiffness lasting ≤ 60 min were evaluated at baseline and summed to represent hip OA impairment burden. A generalized linear model with a Poisson distribution and log link function assessed the association between ACR criteria and fall risk beyond established covariates. As a secondary analysis, binary logistic regression assessed ACR criteria and the odds of falling two or more times within a year.

Results

Data from two-hundred and ten participants were analyzed. Hip OA signs and symptoms were present in 97.1% of the participants, and hip OA impairment burden was significantly greater (p < 0.050) in participants who fell ≥ 2 times compared to single and non-fallers. Higher hip OA impairment burden was associated with significantly increased fall risk (p = 0.001, risk ratio = 1.23, 95% CI 1.09–1.38) and odds of falling multiple times (p < 0.05, odds ratio = 1.41, 95% CI 1.01–1.95) after adjustment for covariates.

Conclusions

Older adults with CLBP and concomitant hip impairments are an at-risk group for falling. Healthcare professionals should employ falls screening and preventive measures to avoid negative sequelae in this vulnerable population.

Pain-guided activity modification during treatment for patellar tendinopathy: a feasibility and pilot randomized clinical trial

BACKGROUND

Activity modification is a key component of patellar tendinopathy treatment but there is a lack of evidence guiding activity modification prescription. Use of activity modification in treatment studies has varied widely and the impact of those recommendations has not been directly investigated or compared. The purpose of this study was to assess (1) the feasibility of using pain-guided activity modification during treatment for patellar tendinopathy and (2) if our outcome measures are responsive to changes in tendon health over the course of treatment.

METHODS

This was an unblinded, randomized two-arm pilot and feasibility study randomized clinical trial with parallel assignment, conducted in Newark, DE. Individuals between the ages of 16 and 40 years old with patellar tendinopathy were included. Participants were randomly assigned to a pain-guided activity (PGA) or pain-free activity (PFA) group using a spreadsheet-based randomization scheme. All participants received standardized treatment using a modified version of the heavy-slow resistance protocol 3×/week for 12 weeks. For the first 6 weeks, the PGA group used the Pain-Monitoring Model to guide activity outside of treatment and the PFA group was restricted from running, jumping, or activities that provoked their patellar tendon pain. Feasibility outcomes included recruitment, enrollment, randomization, compliance, and retention percentages. Clinical evaluations were conducted at baseline, 6, and 12 weeks to assess symptom severity, psychological factors, tendon morphology and mechanical properties, lower extremity function, and quadriceps muscle performance.

RESULTS

In a ~ 13-month period, 108 individuals were screened, 47/108 (43.5%) were eligible for participation, and 15/47 (32.0%) of those were enrolled (9 PGA, 6 PFA). The recruitment rate was 1.15 participants/month. The mean ± SD compliance with treatment was PGA: 86.1 ± 13.0% and PFA: 67.1 ± 30.7%. There was one missed evaluation session and two adverse events, which were not due to study interventions. Changes exceeding the smallest detectable change were observed for at least one outcome in each domain of tendon health.

CONCLUSIONS

Use of pain-guided activity modification during exercise therapy for patellar tendinopathy was found to be feasible, and the proposed outcome measures appropriate. Computer-based allocation concealment, blinding of evaluators, and greater recruitment of high-level athletes should be implemented in future trials.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03694730 . Registered 3rd of October, 2018.

Posterior fall-recovery training applied to individuals with chronic stroke: A single-group intervention study

BACKGROUND

To assess the effects of the initial stepping limb on posterior fall recovery in individuals with chronic stroke, as well as to determine the benefits of fall-recovery training on these outcomes.

METHODS

This was a single-group intervention study of 13 individuals with chronic stroke. Participants performed up to six training sessions, each including progressively challenging, treadmill-induced perturbations from a standing position. Progressions focused on initial steps with the paretic or non-paretic limb. The highest perturbation level achieved, the proportion of successful recoveries, step and trunk kinematics, as well as stance-limb muscle activation about the ankle were compared between the initial stepping limbs in the first session. Limb-specific outcomes were also compared between the first and last training sessions.

FINDINGS

In the first session, initial steps with the non-paretic limb were associated with a higher proportion of success and larger perturbations than steps with the paretic limb (p = 0.02, Cohen's d = 0.8). Paretic-limb steps were wider relative to the center of mass (CoM; p = 0.01, d = 1.3), likely due to an initial standing position with the CoM closer to the non-paretic limb (p = 0.01, d = 1.4). In the last training session, participants recovered from a higher proportion of perturbations and advanced to larger perturbations (p < 0.05, d > 0.6). There were no notable changes in kinematic or electromyography variables with training (p > 0.07, d < 0.5).

INTERPRETATION

The skill of posterior stepping in response to a perturbation can be improved with practice in those with chronic stroke, we were not able to identify consistent underlying kinematic mechanisms behind this adaptation.

Effect of Aging on the Viscoelastic Properties of Hippocampal Subfields Assessed with High-Resolution MR Elastography

Age-related memory impairments have been linked to differences in structural brain parameters, including the integrity of the hippocampus (HC) and its distinct hippocampal subfields (HCsf). Imaging methods sensitive to the underlying tissue microstructure are valuable in characterizing age-related HCsf structural changes that may relate to cognitive function. Magnetic resonance elastography (MRE) is a noninvasive MRI technique that can quantify tissue viscoelasticity and may provide additional information about aging effects on HCsf health. Here, we report a high-resolution MRE protocol to quantify HCsf viscoelasticity through shear stiffness, μ, and damping ratio, ξ, which reflect the integrity of tissue composition and organization. HCsf exhibit distinct mechanical properties-the subiculum had the lowest μ and both subiculum and entorhinal cortex had the lowest ξ. Both measures correlated with age: HCsf μ was lower with age (P < 0.001) whereas ξ was higher (P = 0.002). The magnitude of age-related differences in ξ varied across HCsf (P = 0.011), suggesting differential patterns of brain aging. This study demonstrates the feasibility of using MRE to assess HCsf microstructural integrity and suggests incorporation of these metrics to evaluate HC health in neurocognitive disorders.

Readiness to Change is Related to Real-World Walking and Depressive Symptoms in Chronic Stroke

BACKGROUND AND PURPOSE

The transtheoretical model is a health behavior model used to understand an individual's readiness to change their behavior. This study aims to apply the transtheoretical model in understanding a person with stroke's readiness to change their activity level, as it relates to physical capacity, physical health, depressive symptoms, self-efficacy, and daily stepping activity.

METHODS

This was a cross-sectional analysis of baseline data from a clinical trial. Participants' readiness to change their activity levels was measured via self-report and daily stepping activity was measured using a step activity monitor. Robust regression (M-estimation with robust standard errors) was used to test the relationship between readiness to change and measures of physical capacity (6-minute walk test, self-selected walking speed), physical health (body mass index, age-adjusted Charlson Comorbidity Index), depressive symptoms (Patient Health Questionnaire-9), self-efficacy (Activities-Specific Balance Confidence Scale), and daily stepping (steps per day).

RESULTS

A total of 274 individuals were included in the analysis. Adjusted for age, readiness to change was positively related to daily stepping (β = 0.29, P < 0.001) and negatively related to depressive symptoms (β = -0.13, P = 0.01). Readiness to change was not significantly associated with measures of physical capacity, physical health, or self-efficacy.

DISCUSSION

These results suggest that individuals with stroke in the later stages of change may demonstrate greater daily stepping activity and lower depressive symptoms compared with those in earlier stages.

CONCLUSIONS

Understanding the relationship between readiness to change, daily stepping, and depressive symptoms will help clinicians implement appropriate stage-specific intervention strategies and facilitate greater improvement in activity levels.Video Abstract available for more insights from the authors (see the Video, Supplemental Digital Content 1, available at: http://links.lww.com/JNPT/A333).

Early Weight Gain Forecasts Accelerated Eruption of Deciduous Teeth and Later Overweight Status during the First Year

OBJECTIVES

To determine whether early diet and weight gain velocity have independent or interactive effects on deciduous teeth emergence and overweight status during the first year.

STUDY DESIGN

Monthly measures of anthropometry and teeth eruption were collected during a 1-year trial (0.5-12.5 months) on formula-fed infants in which the type of randomized infant formula (cow milk or extensively hydrolyzed protein) diet significantly affected early (0.5-4.5 months) weight gain velocity. Generalized linear mixed models determined whether early diet and weight gain velocity had independent or interactive effects on timing and pattern of teeth eruption. Data from a trial on breastfed infants were used to explore effects of breast milk vs infant formula diets on teeth eruption and overweight status at 10.5 months.

RESULTS

Independent of infant formula diet, velocities of weight gain had direct effects on the age of first deciduous tooth (P < .04) and number of erupted teeth over time (P < .002). Greater velocity of weight gain from 0.5 to 4.5 months caused earlier and more frequent eruption of deciduous teeth from 4.5 to 12.5 months. Exploratory follow-up analyses on the breastfed and formula-fed diet groups found early weight gain velocity (P = .001), but not diet or its interaction, had significant effects. Infants in the upper quartile for weight gain velocity had more primary teeth (P = .002), and a greater proportion of them were overweight (P < .001) at 10.5 months.

CONCLUSIONS

Faster weight gain accretion forecasted accelerated primary teeth eruption and increased percentage of children who were overweight-risk factors for dental caries and obesity.

TRIAL REGISTRATION

ClinicalTrials.govNCT01700205 [2012-2015] and NCT01667549 [2012-2015].

Standard-space atlas of the viscoelastic properties of the human brain

Standard anatomical atlases are common in neuroimaging because they facilitate data analyses and comparisons across subjects and studies. The purpose of this study was to develop a standardized human brain atlas based on the physical mechanical properties (i.e., tissue viscoelasticity) of brain tissue using magnetic resonance elastography (MRE). MRE is a phase contrast‐based MRI method that quantifies tissue viscoelasticity noninvasively and in vivo thus providing a macroscopic representation of the microstructural constituents of soft biological tissue. The development of standardized brain MRE atlases are therefore beneficial for comparing neural tissue integrity across populations. Data from a large number of healthy, young adults from multiple studies collected using common MRE acquisition and analysis protocols were assembled (N = 134; 78F/ 56 M; 18–35 years). Nonlinear image registration methods were applied to normalize viscoelastic property maps (shear stiffness, μ, and damping ratio, ξ) to the MNI152 standard structural template within the spatial coordinates of the ICBM‐152. We find that average MRE brain templates contain emerging and symmetrized anatomical detail. Leveraging the substantial amount of data assembled, we illustrate that subcortical gray matter structures, white matter tracts, and regions of the cerebral cortex exhibit differing mechanical characteristics. Moreover, we report sex differences in viscoelasticity for specific neuroanatomical structures, which has implications for understanding patterns of individual differences in health and disease. These atlases provide reference values for clinical investigations as well as novel biophysical signatures of neuroanatomy. The templates are made openly available (github.com/mechneurolab/mre134) to foster collaboration across research institutions and to support robust cross‐center comparisons.

Social and physical environmental factors in daily stepping activity in those with chronic stroke

BACKGROUND, PURPOSE/OBJECTIVE

Walking behavior in the chronic stroke population is multi-factorial. Previous work focused on the role of physical and biopsychosocial factors in understanding daily stepping post stroke. However, qualitative evidence suggests that social and physical environmental factors also affect daily stepping in those with stroke. The purpose of this study was to understand the role of social and physical environmental factors in daily stepping after stroke.

METHODS

A total of 249 individuals ≥6 months post stroke were included in this cross-sectional analysis (129 females, mean age 62.98 years, SD 11.94). The social environment included living situation, work status, and marital status. The physical environment included the Area Deprivation Index (ADI) and Walk Score. At least 3 days of stepping was collected using an accelerometry-based device. Predictors were entered sequentially into a regression model: demographic characteristics, social environmental factors, and physical environmental factors.

RESULTS

After adjusting for demographic factors, social environmental factors explained 6.2% (p =.017) of the variance in post stroke daily stepping. The addition of physical environmental factors improved the model (ΔR² =.029, p =.024). The final model explained 9.2% (p =.003) of the variance in daily stepping. Lower area deprivation (ADI β = -0.178, p =.015) and working (working vs. retired β = -0.187, p = .029 and working vs. unemployed β = -0.227, p =.008) were associated with greater daily stepping.

DISCUSSION/CONCLUSION

Social and physical environmental factors predicted daily stepping and should be considered when setting expectations relative to the effects of rehabilitation on daily stepping in individuals poststroke.

Hippocampal stiffness in mesial temporal lobe epilepsy measured with MR elastography: Preliminary comparison with healthy participants

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Hippocampal stiffness in MTLE is measured with magnetic resonance elastography.

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The epileptogenic hippocampus is stiffer than non-epileptogenic hippocampus in MTLE.

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Hippocampal stiffness ratio is higher in MTLE patients than in healthy participants.

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Stiffness ratio provides additional diagnostic information to hippocampal volume.

Mesial temporal lobe epilepsy (MTLE) is the most common form of refractory epilepsy. Common imaging biomarkers are often not sensitive enough to identify MTLE sufficiently early to facilitate the greatest benefit from surgical or pharmacological intervention. The objective of this work is to establish hippocampal stiffness measured with magnetic resonance elastography (MRE) as a biomarker for MTLE; we hypothesized that the epileptogenic hippocampus in MTLE is stiffer than the non-epileptogenic hippocampus. MRE was used to measure hippocampal stiffness in a group of patients with unilateral MTLE (n = 12) and a group of healthy comparison participants (n = 13). We calculated the ratio of hippocampal stiffness ipsilateral to epileptogenesis to the contralateral side for both groups. We found a higher hippocampal stiffness ratio in patients with MTLE compared with healthy participants (1.14 v. 0.99; p = 0.004), and that stiffness ratio differentiated MTLE from control groups effectively (AUC = 0.85). Hippocampal stiffness ratio, when added to volume ratio, an established MTLE biomarker, significantly improved the ability to differentiate the two groups (p = 0.038). Stiffness measured with MRE is sensitive to hippocampal pathology in MTLE and the addition of MRE to neuroimaging assessments may improve detection and characterization of the disease.

Antioxidant cocktail following a high-sodium meal does not affect vascular function in young, healthy adult humans: a randomized controlled crossover trial

Chronic high sodium intake is a risk factor for cardiovascular disease as it impairs vascular function through an increase in oxidative stress. The objective of this study was to investigate the acute effects of a high-sodium meal (HSM) and antioxidant (AO) cocktail on vascular function. We hypothesized that a HSM would impair endothelial function, and increase arterial stiffness and wave reflection, while ingestion of the AO cocktail would mitigate this response. Healthy adults ingested either an AO cocktail (vitamin C, E, alpha-lipoic acid) or placebo (PLA) followed by a HSM (1500 mg) in a randomized crossover blinded design. Blood pressure (BP), endothelial function (flow-mediated dilation; FMD) and measures of arterial stiffness (pulse wave velocity; PWV) and wave reflection (augmentation index; AIx) were made at baseline and 30, 60, 90, and 120 min after meal consumption. Forty-one participants (20M/21W; 24 ± 1 years; BMI 23.4 ± 0.4 kg/m²) completed the study. Mean BP increased at 120 min relative to 60 min (60 min: 79 ± 1; 120 min: 81 ± 1 mmHg; time effect P = .01) but was not different between treatments (treatment × time interaction P = .32). AIx decreased from baseline (time effect P < .001) but was not different between treatments (treatment × time interaction P = .31). PWV (treatment × time interaction, P = .91) and FMD (treatment × time interaction P = .65) were also not different between treatments. In conclusion, a HSM does not acutely impair vascular function suggesting young healthy adults can withstand the acute impact of sodium on the vasculature and therefore, the AO cocktail is not necessary to mitigate the response.

Tendon Morphology and Mechanical Properties Are Associated With the Recovery of Symptoms and Function in Patients With Achilles Tendinopathy

Background:

Achilles tendinopathy is a debilitating overuse injury characterized by pain, altered Achilles tendon structure, and impaired functional performance. Evaluating tendon structure as part of the physical examination may help establish a well-defined prognosis. However, the usefulness of measuring tendon structure for developing a prognosis has been questioned since structural abnormalities can exist without symptoms.

Purpose:

To determine whether initial measures of tendon morphology and mechanical properties were associated with patient-reported symptoms and calf muscle endurance at baseline, 6-month follow-up, and 1-year follow-up by prospectively following a cohort of individuals with Achilles tendinopathy.

Study Design:

Cohort study; Level of evidence, 2.

Methods:

A total of 59 participants with midportion or insertional Achilles tendinopathy completed an initial assessment and follow-up assessments at 6 months and 1 year. At the initial assessment, patient-reported symptoms, calf muscle endurance, and Achilles tendon thickening were evaluated, and Achilles tendon mechanical properties were estimated. At the 6-month and 1-year follow-up assessments, patient-reported symptoms and calf muscle endurance were reevaluated.

Results:

Greater Achilles tendon thickening at the initial assessment was consistently associated with worse patient-reported symptoms and calf muscle endurance at each assessment. Changes in symptoms over the year were moderated by the initial shear modulus of the tendon, with a lower shear modulus associated with less improvement in symptoms. Lower viscosity at the initial assessment was also associated with worse calf muscle endurance at each assessment.

Conclusion:

Measures of tendon morphology and mechanical properties appear to be associated with patient-reported symptoms and calf muscle function for patients with Achilles tendinopathy.

Relationship between mechanical properties (shear modulus and viscosity), age, and sex in uninjured Achilles tendons

Tendon mechanical properties have been proposed as a biomarker of tendon health to track response to injury and treatment. Prior to utilizing these properties in an injured population, it is critical to understand how these are influenced by age and sex in an uninjured population. A retrospective analysis was conducted of 118 uninjured Achilles tendons to evaluate the relationship between tendon mechanical properties, age and sex. Mechanical properties (shear modulus and viscosity) were assessed using continuous shear wave elastography. A moderator regression analysis was completed to examine the relationship between tendon mechanical properties, age and sex, after adjusting for body mass index and physical activity level. There was an interaction between age and sex for shear modulus (p=0.049, R² change=0.034). Females had a negative relationship between age and shear modulus (p=0.030, β=-0.350) but no relationship was observed for males (p=0.78, β=0.031). A positive relationship was found between age and viscosity (p=0.034, β=0.214). Increased viscosity was related to increased age with no difference between sexes. The effect of aging on shear modulus differed between men and women and may help explain sex specific injury risks and their differing response to mechanical load.