Association of renal function with ambulation in mild acute stroke patients

Background: Renal dysfunction has affected the functional outcome after stroke. However, the association of renal function with walking endurance after stroke is poorly understood.

Objectives: This study aimed to investigate the relationship between renal function and walking endurance and speed in mild acute stroke patients.

Methods: Eighty-nine patients with mild acute stroke were enrolled. Walking endurance and speed were assessed by the 6-minute walk test (6MWT) and comfortable and maximal 10-meter walk tests (10MWT) within 7 days of hospital admission. Stroke severity was assessed using the National Institutes of Health stroke scale (NIHSS) on admission. The estimated glomerular filtration rate (eGFR) was calculated based on creatinine levels as a renal function. Pearson’s correlation coefficients were calculated between eGFR and walking ability. Multivariate regression analysis was used to investigate the relationship between eGFR and walking ability in mild acute stroke patients.

Results: The 6MWT distance was significantly correlated with eGFR (r = 0.212, p = .046). On multivariate regression analysis, the 6MWT was significantly associated with age (p = .029), body mass index (p = .020), NIHSS score (p = .016), and eGFR (p = .028), whereas the comfortable 10MWT was significantly associated with the NIHSS score alone (p = .009) and the maximal 10MWT was significantly associated with age (p = .032) and NIHSS score (p = .007).

Conclusion: The eGFR based on creatinine levels of acute stroke patients may be important factor to predict the walking endurance in mild acute stroke patients.     

Walking ability and predictors of performance on the 6‐minute walk test in adults with spastic cerebral palsy

Aim To describe walking ability and identify factors predicting walking capacity in adults with spastic cerebral palsy (CP) assessed with the 6‐minute walk test (6MWT). Method A cross‐sectional clinical study as part of the recruitment process for a randomized controlled trial on the effects of botulinum toxin A. Data analysed were the 6MWT, Timed Up and Go (TUG) test, Borg Scale, spasticity, muscle strength, popliteal angle, pain, fatigue, type of CP, foot deformity, Gross Motor Function Classification System (GMFCS) levels, Functional Mobility Scale (FMS) scores, a gait questionnaire, interview, and demographic data. Results In total, 126 persons were included (53 males, 73 females; mean age 39y [SD 12y]; 59 with unilateral and 67 with bilateral spastic CP; GMFCS level I, n=12; level II, n=94; level III, n=20). Mean distance on the 6MWT was 485m (SD 95m) with FMS scores reflecting independent walking performance in daily life. Multiple regression analysis identified sex, type of CP, popliteal angle, pain, and TUG values as significant predictors, with TUG values as the strongest predictor (standardized regression coefficient =?0.57, p<0.001). Interpretation Our results demonstrate that 39% of the participants had declined one GMFCS level from adolescence to their present age, and that the TUG was the strongest predictor for the 6MWT. This implicates the importance of focusing specifically on the different elements of functional mobility in further studies.     

The effects of treadmill walking combined with obstacle-crossing on walking ability in ambulatory patients after stroke: a pilot randomized controlled trial

Background and objective: Treadmill walking training (TWT) provides greater amount and intensity of stepping practice than conventional walking training in patients with chronic stroke. However, there is not any conclusive evidence regarding the effects of TWT for ambulatory post-stroke patients. This study investigated the effects of treadmill walking combined with obstacle-crossing on the walking ability of ambulatory post-stroke patients.

Methods: Twenty-nine subjects from a university hospital-based rehabilitation center were randomly assigned to one of the following: experimental group (15 subjects) or control group (14 subjects). All subjects underwent 30 min of active/passive exercises and 30 min of gait training in the form of treadmill walking. The subjects in the experimental group underwent simultaneous training in obstacle-crossing while walking on the treadmill for 30 min/day, 5 times/week, for 4 weeks. Main measures were the 10-m walk test (10MWT), 6-min walk test (6MWT), Berg Balance Scale (BBS), timed “Up & Go” (TUG) test, and Activities-specific Balance Confidence (ABC) scale used before and after the intervention.

Results: The changed values of the 6MWT and BBS were significantly higher in the experimental group than in the control group after adjusting for each baseline value, with large effects of 1.12 and 0.78, respectively, but not in the 10MWT, TUG, and ABC scale scores. Both groups showed a significant difference in all variables before and after the intervention.

Conclusion: Treadmill walking combined with obstacle-crossing training may help improve the walking ability of patients with hemiplegic stroke and can possibly be used as an adjunct to routine rehabilitation therapy as a task-oriented practice based on community ambulation.     

Standardized assessment of walking capacity after spinal cord injury: the European network approach

OBJECTIVES: After a spinal cord injury (SCI), walking function is an important outcome measure for rehabilitation and new treatment interventions. The current status of four walking capacity tests that are applied to SCI subjects is presented: the revised walking index for spinal cord injury (WISCI II), the 6 minute walk test (6MinWT), 10 meter walk test (10MWT) and the timed up and go (TUG) test. Then, we investigated which categories of the WISCI II apply to SCI subjects who participated in the European Multicenter Study of Human Spinal Cord Injury (EM-SCI), and the relationship between the 10MWT and the TUG. METHODS: In the EM-SCI, the walking tests were applied 2 weeks and 1, 3, 6 and 12 months after SCI. We identified the WISCI II categories that applied to the EM-SCI subjects at each time point and quantified the relationship between the 10MWT and the TUG using Spearman's correlation coefficients (rho) and linear regression. RESULTS: Five WISCI II categories applied to 71% of the EM-SCI subjects with walking ability, while 11 items applied to 11% of the subjects. The 10MWT correlated excellently with the TUG at each time point (rho>0.80). However, this relationship changed over time. One year after SCI, the time needed to accomplish the TUG was 1.25 times greater than the 10MWT time. DISCUSSION: Some categories of the WISCI II appear to be redundant, while some discriminate to an insufficient degree. In addition, there appear to be ceiling effects, which limit its usefulness. The relationship between the 10MWT and TUG is high, but changes over time. We suggest that, at present, the 10MWT appears to be the best tool to assess walking capacity in SCI subjects. Additional valuable information is provided by assessing the needs for walking aids or personal assistance. To ensure comparability of study results, proposals for standardized instructions are presented.     

Comparison of the Mini-Balance Evaluations Systems Test with the Berg Balance Scale in relationship to walking speed and motor recovery post stroke*

Background: The Mini-BESTest is a recently developed balance assessment tool that incorporates challenging dynamic balance tasks. Few studies have compared the psychometric properties of the Mini-BESTest to the commonly used Berg Balance Scale (BBS). However, the utility of these scales in relationship to post stroke walking speeds has not been explored.

Objectives: The purpose of this study was to compare the sensitivity and specificity of the Mini-BESTest and BBS to evaluate walking speeds in individuals with stroke.

Design: A retrospective exploratory design.

Methods: Forty-one individuals with chronic stroke were evaluated with the Mini-BESTest, BBS, and 10-meter self-selected walk test (10MWT). Based on their self-selected gait speeds (below or above 0.8 m/s), participants were classified as slow and fast walkers.

Results: Significant linear correlations were observed between the Mini-BESTest vs. BBS (r = 0.72, p ≤ 0.001), Mini-BESTest vs. 10MWT (r = 0.58, p ≤ 0.001), and BBS vs. 10MWT (r = 0.30, p = 0.05). Independent t-tests comparing the balance scores for the slow and fast walkers revealed significant group differences for the Mini-BESTest (p = 0.003), but not for the BBS (p = 0.09). The Mini-BESTest demonstrated higher sensitivity (93%) and specificity (64%) compared to the BBS (sensitivity 81%, specificity 56%) for discriminating participants into slow and fast walkers.

Conclusions: The Mini-BESTest has a greater discriminative ability than the BBS to categorize individuals with stroke into slow and fast walkers.     

Effects of a group circuit progressive resistance training program compared with a treadmill training program for adolescents with cerebral palsy

ABSTRACT

Objective: To determine whether goal-directed group circuit progressive resistance exercise training (GT) can improve motor function in adolescents with cerebral palsy (CP) and to compare outcomes with a treadmill training (TT) intervention. Methods: In a multi-centered matched pairs study, 95 adolescents with spastic CP (GMFCS II-III) were allocated to GT or TT interventions for 30 bi-weekly one hour training. Outcome measures of GMFM-66, GMFM-D%, GMFM-E%, TUG, 10 meter walk test (10 MWT), and 6 minute walk test (6 MWT) were made at baseline (T1), after interventions (T2) and 6 months post training (T3). Results: Both training programs induced significant improvement in all outcome measures (T2–T1) that were mostly retained at T3. At the end of the intervention, the GT group showed an advantage in all measured changes compared to the TT group and in percentage changes. Differences were significant (p < 0.02) for GMFM-66, GMFM-D%, GMFM-E% and TUG. The advantage trend for the GT group was less apparent at follow up (T3–T1). Conclusion: Both programs were effective in improving motor function in adolescents with cerebral palsy. The GT program had generally greater benefits based on the functional measures.     

Repeated Use of 6-min Walk Test with Immediate Knowledge of Results for Walking Capacity in Chronic Stroke: Clinical Trial of Fast versus Slow Walkers

Aim: This study aimed to determine the effects of repeated use of the 6-minute walk test (6MWT) with immediate knowledge of results (KR) on the walking capacity by comparing fast and slow walkers in patients with chronic hemiparesis. Methods: Twenty-five subjects were allocated to 2 groups depending on their walking speed¹: Group 1 (fast walkers, n₁ = 11): greater than equal to .8 m/s and² Group 2 (slow walkers, n₂ = 14): less than .8 m/s. All subjects underwent the 6MWT once a day, 5 days a week, for 4 weeks (a total of 20 sessions). The 6MWT was performed on a 30-m path with immediate KR; subjects informed the time taken to walk each 30-m path. Outcome measures included the 6MWT and 10-meter walk test (10MWT). Measurements were taken before and after 4 weeks. Results of within-group comparisons showed significant improvements in the 10MWT and 6MWT for both groups pre- and post-test (P < .05). Furthermore, in between-group comparison, results of Group 1 differences were greater between pre- and post-test in the 10MWT and 6MWT values as compared to Group 2 (P < .05). These findings indicate that repeated use of the 6MWT with immediate KR may be beneficial to enhance walking capacity in patients with chronic stroke, with more favorable changes in better poststroke walking speed.     

‘Timed up and go’ and brain atrophy: a preliminary MRI study to assess functional mobility performance in multiple sclerosis

Motor and cognitive disabilities are related to brain atrophy in multiple sclerosis (MS). ‘Timed up and go’ (TUG) has been recently tested in MS as functional mobility test, as it is able to evaluate ambulation/coordination-related tasks, as well as cognitive function related to mobility. The objective of this study is to evaluate the relationship between brain volumes and TUG performances. Inclusion criteria were a diagnosis of MS and the ability to walk at least 20 m. TUG was performed using a wearable inertial sensor. Times and velocities of TUG sub-phases were calculated by processing trunk acceleration data. Patients underwent to a brain MRI, and volumes of whole brain, white matter (WM), grey matter (GM), and cortical GM (C) were estimated with SIENAX. Sixty patients were enrolled. Mean age was 41.5 ± 11.6 years and mean EDSS 2.3 ± 1.2. Total TUG duration was correlated to lower WM (ρ = 0.358, p = 0.005) and GM (ρ = 0.309, p = 0.017) volumes. A stronger association with lower GM volume was observed for intermediate (ρ = 0.427, p = 0.001) and final turning (ρ = 0.390, p = 0.002). TUG is a useful tool in a clinical setting as it can not only evaluate patients’ disability in terms of impaired functional mobility, but also estimate pathological features, such as grey atrophy.     

Independently ambulant,community–dwelling stroke survivors have reduced cardiorespiratory fitness,mobility and knee strength compared to an age- and gender-matched cohort

Background: Most exercise interventions for stroke survivors are designed for those who have substantial motor and functional disabilities. There remains a group of well-recovered stroke survivors who have yet to be investigated in terms of their physical capacity and fitness levels.

Objective: To assess and compare the physical capacities of independently ambulant, community-dwelling stroke survivors to age- and gender-matched comparison participants.

Methods: Data were obtained from 17 stroke survivors participating in the How FITSS? Trial, all with functional ambulatory category of ≥4 and a self-selected walking speed ≥0.8 m s^?1. An additional 17 healthy control participants were recruited. Cardiorespiratory fitness (CRF) was measured using oxygen consumption (VO_2peak), and additional measures of walking speed (m s^?1), leg strength and body composition were also assessed. Differences between groups were assessed by matched pairs t-tests. Effect sizes were calculated using Cohen’s d.

Results: There were no significant differences in age, BMI, muscle mass or body fat between groups (p > 0.05). Peak VO₂ was lower in the stroke group for the shuttle walk test (p = 0.037) and progressive cycle test (p = 0.019), as were all CRF test performance measures (p < 0.05). Stroke survivors walked significantly (p < 0.001) slower at both self-selected and fast speeds. Effect sizes of group differences for all leg strength variables were medium to large, with peak torque lower in the stroke group for all trials.

Conclusions: Despite being independently ambulant and community dwelling, the CRF, walking speed and leg strength of this group were reduced compared to non-stroke comparison participants. These patients may benefit from undertaking targeted exercise programmes.     

Subjective cognitive complaints and neuropsychological performance in former smokers with and without chronic obstructive pulmonary disease

Objective: This study examined the association of perceived cognitive difficulties with objective cognitive performance in former smokers. We hypothesized that greater perceived cognitive difficulties would be associated with poorer performance on objective executive and memory tasks.

Method: Participants were 95 former smokers recruited from the COPDGene study. They completed questionnaires (including the Cognitive Difficulties Scale [CDS] and the Hospital Anxiety and Depression Scale [HADS]), neuropsychological assessment, and pulmonary function testing. Pearson correlations and t-tests were conducted to examine the bivariate association of the CDS (total score and subscales for attention/concentration, praxis, delayed recall, orientation for persons, temporal orientation, and prospective memory) with each domain of objective cognitive functioning (memory recall, executive functioning/processing speed, visuospatial processing, and language). Simultaneous multiple linear regression was used to further examine all statistically significant bivariate associations. The following covariates were included in all regression models: age, sex, pack-years, premorbid functioning (WRAT-IV Reading), HADS total score, and chronic obstructive pulmonary disease (COPD) status (yes/no based on GOLD criteria).

Results: In regression models, greater perceived cognitive difficulties overall (using CDS total score) were associated with poorer performance on executive functioning/processing speed tasks (b = ?0.07, SE = 0.03, p = .037). Greater perceived cognitive difficulties on the CDS praxis subscale were associated with poorer performance on executive functioning/processing speed tasks (b = ?3.65, SE = 1.25, p = .005), memory recall tasks (b = ?4.60, SE = 1.75, p = .010), and language tasks (b = ?3.89, SE = 1.39, p = .006).

Conclusions: Clinicians should be aware that cognitive complaints may be indicative of problems with the executive functioning/processing speed and memory of former smokers with and without COPD.     

Self-efficacy Mediates the Relationship between Balance/Walking Performance,Activity, and Participation after Stroke

Background: Many outcome measures (OM) that assess individuals’ ability or beliefs in their ability to perform tasks exist to evaluate activity and participation after stroke; however, the relationship between various OM and activity/participation is unclear.

Objective: The purpose of this study was to explore the relationships between different OM and activity and participation in people after stroke.

Methods: Fifty-nine subjects post stroke participated in an assessment including self-selected walking speed, 6 minute walk test, Timed “Up and Go” test, Berg Balance Scale, Functional Gait Assessment, Walk 12, and Activity-specific Balance Confidence Scale. Step Watch Activity Monitoring (SAM) was used as a measure of activity and Stroke Impact Scale-Participation (SIS-P) as a measure of participation. Exploratory Factor Analysis was performed including all measures except SAM and SIS-P. Two factors were extracted and termed performance based (PB) and self-efficacy (SE). A path analysis assessed the role of SE as a mediator in the relationships of PB and SAM/SIS-P.

Results: In the path analysis, PB significantly predicts SE (p < 0.001, b = 0.44), but not SAM or SIS-P (p > 0.05, b = 0.25, and b = 0.11, respectively). SE significantly predicts both SAM and SIS-P (p < 0.001, b = 0.46, and b = 0.59, respectively). The indirect effects of PB on SAM and SIS-P were significant (p < 0.001; b = 0.20, and b = 0.26, respectively).

Conclusion: These results suggest that SE mediates the relationship between PB and activity and participation after stroke, reinforcing that improving activity and participation is more complicated than only targeting performance. Clinicians should administer SE and PB measures to determine the most accurate view of patients after stroke and seek to improve SE through interventions.     

Feasibility of single session high-intensity interval training utilizing speed and active recovery to push beyond standard practice post-stroke

Background: Improvement in overground walking speed reduces dependency and is a central focus in post-stroke rehabilitation. Previous studies have shown that high-intensity interval training (HIT) can significantly improve functional and health-related outcomes in neurologically health individuals more so than traditional approaches. Emerging evidence suggests the same may be true post-stroke.

Objective: The purpose of this study was to assess the feasibility of a single session, novel HIT design.

Methods: Participants walked on a treadmill, alternating between one minute at high-intensity and one minute at low-intensity for 20 minutes, adjusting the speed of the treadmill to dictate intensity. Treadmill speeds were determined from overground self-selected walking speed (SSWS).

Results: No adverse events occurred during the training sessions. High-intensity treadmill speeds were significantly faster than treadmill SSWS (standard practice; +227%; p < 0.0001) and overground SSWS (+142%; p = 0.003). 15 of the 21 subjects were able to walk on the treadmill at 150% of overground SSWS; with the remaining individuals (n = 6) walking at 123% of overground SSWS. Average peak heart rate during HIT was 90% of age-predicted max.

Conclusions: These results demonstrate the feasibility of this single session HIT design and suggest that individuals following stroke are capable of prolonged training at speeds significantly faster than standard practice. Additionally, this training intensity elicited heart rate responses in the upper range of vigorous exercise. Future studies are needed to investigate a progressive HIT intervention applying this design and its effects on functional outcomes as well as cardiovascular fitness.     

Depressive symptoms and muscular fitness contribute independently to the ability to perform daily life activities in people with bipolar disorder

Background: Compared with healthy controls, people with bipolar disorder experience muscle weakness. The extent to which muscle weakness influences the performance of daily life activities such as walking in people with bipolar disorder requiring hospitalization is unclear. Aims: The primary aim of the current study was to explore whether depressive symptoms and muscular fitness independently contribute to the walking capacity in people with bipolar disorder. A secondary aim was to identify variables that could explain the variability in muscular fitness. Methods: Forty-two inpatients with bipolar disorder performed a standing broad jump test (SBJ), a measure of muscular performance, and the six minute walk test (6MWT) in addition to the International Physical Activity Questionnaire (IPAQ), the Depressive Symptomatology Self Report (QIDS) and a full-fasting metabolic screening. Results: The correlation between the 6MWT (595.0?±?127.3m) and SBJ (126.2?±?48.6m) was high (r?=?0.72, p?Conclusions: Depressive symptoms and muscular fitness contribute independently to daily life functioning in people with bipolar disorder. Thus, muscular rehabilitation strategies might offer a strategy for improving performance of daily life activities in this group.     

Effect of depression on cognition after mild traumatic brain injury in adults

Objective: The current study examined the effect of depression on cognitive test performance in a sample of adults seeking treatment for a mild traumatic brain injury (MTBI). We hypothesized that patients with greater depressive symptoms would perform worse on tasks of fluid cognition compared to those without depression, after controlling for potential confounds.

Method: Patients (N = 76) completed a brief cognitive test battery (NIH Toolbox Cognition Battery; NIHTB-CB) and a depression screening questionnaire (PHQ-9) at 11.7-weeks post injury (SD = 6.3 range 2–26). Cognitive scores were adjusted for age, education, gender, and race/ethnicity. Depressive symptoms were examined continuously and dichotomized as: (1) total PHQ-9 score of ≥ 10, the optimal cut-off for Major Depressive Disorder caseness from prior research, and (2) five or more symptoms of depression, including either depressed mood or anhedonia (i.e. DSM-5-based definition).

Results: Twenty-seven patients (35.5%) met DSM-5-based criteria for depression and 42 (55.3%) met criteria based on PHQ-9 > 10. Depression symptom severity correlated with lower fluid cognition composite scores [r = ?.22, p = .05] and contributed to the prediction of fluid cognition performance in a model that controlled for time since injury and crystallized cognitive abilities [F(3, 72) = 7.49, p < .001; R² = 20.6%]. Examining specific NIHTB-CB fluid subtests, the largest group differences were seen on processing speed (d = .40–.49), cognitive flexibility (d = .32–.36), and episodic memory (d = .20–.34). Depression severity was strongly associated with overall post-concussion symptom burden (r = .77, p < .001).

Conclusion: Depression is a common comorbidity and an important factor to consider when interpreting neurocognitive test performance in adults with concussion in a clinical setting.     

Efficacy and safety of nabiximols (Sativex<Superscript>®</Superscript>) on multiple sclerosis spasticity in a real-life Italian monocentric study

Multiple sclerosis (MS) patients frequently suffer from limb spasticity and pain despite antispastic treatments. To investigate nabiximols efficacy and safety in a real-world monocentric Italian cohort, the following data were collected at baseline, week 4, 14 and 48: Ambulation Index (AI), 10-min walking test (10MWT), combined Modified Ashworth scale (cMAS), scores at numerical rating scale for spasticity (sNRS) and pain (pNRS). Responder status was defined as a ≥20 % reduction in sNRS after 4 weeks of treatment. 144 MS patients (123 progressive and 21 relapsing-remitting) complaining of moderate-to-severe spasticity (mean sNRS: 7.5) were included: 138 (95.8 %) completed the first month of therapy and were classified as follows—23.2 % were non-responders, 5.1 % were responders but discontinued treatment due to side effects, 71.7 % were responders with a mean 32 % reduction in sNRS (p < 0.001). In responders sNRS further decreased between 4 and 14 weeks (p = 0.03). Similarly, pNRS improvement was seen during the first month and between 4 and 14 weeks (p < 0.001 and p = 0.004, respectively). Moreover, at 4 weeks responders showed a significant (p < 0.05) improvement in cMAS, AI and 10MWT, which was maintained at 14 weeks. At 1-year follow-up, a benefit was still evident on spasticity and painful symptoms with a low drop-out rate. Confusion/ideomotor slowing, fatigue and dizziness were the most frequent side effects; no major adverse events were reported. Shorter disease duration at treatment start was associated with better response. This real-world study confirms nabiximols efficacy and safety in the treatment of MS-related spasticity and pain, which is maintained up to 48 weeks.     

The use of virtual reality for balance among individuals with chronic stroke: a systematic review and meta-analysis

Background: Virtual reality (VR) is becoming a popular alternative to traditional upper and lower limb rehabilitation following a stroke.

Objective: To conduct a systematic review and meta-analysis on the effectiveness of VR interventions for improving balance in a chronic stroke (≥6 months) population.

Data sources: A literature search of Pubmed, Scopus, CINAHL, Embase, Psycinfo, and Web of Science databases was conducted.

Study selection: English randomized controlled trials published up to September 2015 assessing balance with VR in chronic stroke participants.

Data extraction: Mean and standard deviations from outcome measures were extracted. Pooled standard mean differences ± standard error were calculated for the Berg Balance Scale (BBS) and the Timed Up and Go test (TUG).

Results: In total, 20 studies were selected which assessed the Nintendo^® Wii Fit balance board (n = 7), treadmill training and VR (n = 7), and postural training using VR (n = 6). Significant improvements were found for VR interventions evaluating the BBS (n = 12; MD = 2.94 ± 0.57; p < 0.001) and TUG (n = 13; MD = 2.49 ± 0.57; p < 0.001). Sub-analyses revealed postural VR interventions had a significant effect on BBS (n = 5) and TUG (n = 3) scores (BBS: MD = 3.82 ± 0.79; p < 0.001 and TUG: MD = 3.74 ± 0.97; p < 0.001). VR and treadmill training (n = 5) had a significant effect on TUG scores (MD = 2.15 ± 0.89, p = 0.016).

Conclusion: Overall, VR interventions compared to conventional rehabilitation had significant improvements. The meta-analyses also suggest that the Nintendo^® Wii Fit balance board may not be effective, although further confirmatory studies are necessary. Results should be interpreted with caution due to differences in therapy intensities and effect sizes within the included studies.     

Performance on a 1-week delayed recall task is associated with medial temporal lobe structures in neurologically normal older adults

Objective: Traditional episodic memory tests employ a delayed recall length ranging from 10 to 30 min. The neurobiological process of memory consolidation extends well beyond these time intervals, however, raising the possibility that these tests might not be fully sensitive to the subtle neurocognitive changes found in early disease or age-related decline. We aimed to determine the sensitivity of a 1-week delayed recall paradigm to medial temporal lobe (MTL) structure among neurologically normal older adults. Methods: One hundred and forty functionally intact, older adults (mean age = 75.8) completed a story recall test in which participants learned to 90% criterion. Recall was tested after 30-min and 1-week. Participants also completed a standardized list learning task with a 20-min delay (n = 129) and a structural brain MRI. The MTL, including the parahippocampal gyrus, hippocampus, and entorhinal, was our primary region of interest. Results: Controlling for age, education, gender and total intracranial volume, the standard 20- and 30-min recalls showed no significant relationship with MTL. In contrast, 1-week recall was uniquely associated with MTL structure (partial r = .24, p = .006), specifically entorhinal (partial r = .27; p = .001) and hippocampal (partial r = .21, p = .02) volumes. Conclusion: Memory paradigms that utilize 1-week delays are more sensitive than standard paradigms to MTL volumes in neurologically normal older adults. Longer delay periods may improve detection of memory consolidation abilities associated with age-related, and potentially pathological, neurobehavioral change.     

Vagus nerve stimulation improves working memory performance

Vagus nerve stimulation (VNS) is used for treating refractory epilepsy and major depression. While the impact of this treatment on seizures has been established, its impact on human cognition remains equivocal. The goal of this study is to elucidate the immediate effects of vagus nerve stimulation on attention, cognition, and emotional reactivity in patients with epilepsy. Twenty patients (12 male and 8 female; 45 ± 13 years old) treated with VNS due to refractory epilepsy participated in the study. Subjects performed a computer-based test of executive functions embedded with emotional distractors while their brain activity was recorded with electroencephalography. Subjects’ cognitive performance, early visual event-related potential N1, and frontal alpha asymmetry were studied when cyclic vagus nerve stimulation was on and when it was off. We found that vagus nerve stimulation improved working memory performance as seen in reduced errors on a subtask that relied on working memory, odds ratio (OR) = 0.63 (95% confidence interval, CI [0.47, 0.85]) and increased N1 amplitude, F(1, 15) = 10.17, p = .006. In addition, vagus nerve stimulation resulted in longer reaction time, F(1, 16) = 8.23, p = .019, and greater frontal alpha asymmetry, F(1, 16) = 11.79, p = .003, in response to threat-related distractors. This is the first study to show immediate improvement in working memory performance in humans with clinically relevant vagus nerve stimulation. Furthermore, vagus nerve stimulation had immediate effects on emotional reactivity evidenced in behavior and brain physiology.     

The six-minute walk test predicts cardiorespiratory fitness in individuals with aneurysmal subarachnoid hemorrhage

Background: Peak oxygen uptake (VO_2peak) established during progressive cardiopulmonary exercise testing (CPET) is the “gold-standard” for cardiorespiratory fitness. However, CPET measurements may be limited in patients with aneurysmal subarachnoid hemorrhage (a-SAH) by disease-related complaints, such as cardiovascular health-risks or anxiety. Furthermore, CPET with gas-exchange analyses require specialized knowledge and infrastructure with limited availability in most rehabilitation facilities.

Objectives: To determine whether an easy-to-administer six-minute walk test (6MWT) is a valid clinical alternative to progressive CPET in order to predict VO_2peak in individuals with a-SAH.

Methods: Twenty-seven patients performed the 6MWT and CPET with gas-exchange analyses on a cycle ergometer. Univariate and multivariate regression models were made to investigate the predictability of VO_2peak from the six-minute walk distance (6MWD).

Results: Univariate regression showed that the 6MWD was strongly related to VO_2peak (r = 0.75, p < 0.001), with an explained variance of 56% and a prediction error of 4.12 ml/kg/min, representing 18% of mean VO_2peak. Adding age and sex to an extended multivariate regression model improved this relationship (r = 0.82, p < 0.001), with an explained variance of 67% and a prediction error of 3.67 ml/kg/min corresponding to 16% of mean VO_2peak.

Conclusions: The 6MWT is an easy-to-administer submaximal exercise test that can be selected to estimate cardiorespiratory fitness at an aggregated level, in groups of patients with a-SAH, which may help to evaluate interventions in a clinical or research setting. However, the relatively large prediction error does not allow for an accurate prediction in individual patients.     

Physical function and muscle strength in sporadic inclusion body myositis

Introduction: In this study, self‐reported physical function, functional capacity, and isolated muscle function were investigated in sporadic inclusion body myositis (sIBM) patients. Methods: The 36‐item Short Form (SF‐36) Health Survey and 2‐min walk test (2MWT), timed up & go test (TUG), and 30‐s chair stand performance were evaluated. In addition, patients were tested for knee extensor muscle strength (isokinetic dynamometer) and leg extension power (Nottingham power rig). Results: TUG performance was the strongest predictor of self‐reported physical function (r ² = 0.56, P < 0.05). Knee extension strength and between‐limb strength asymmetry were the strongest multi‐regression indicators of TUG performance (r ² = 0.51, P < 0.05). Strength asymmetry showed the strongest single‐factor (negative) association with 2MWT performance (r ² = 0.49, P < 0.05). Discussion: TUG assessment appears to sensitively predict self‐perceived physical function in sIBM patients. Notably, between‐limb asymmetry in lower limb muscle strength had a substantial negative impact on motor tasks involving gait function. Muscle Nerve 56 : E50–E58, 2017