Visuospatial Skills Explain Differences in the Ability to Use Propulsion Biofeedback Post-stroke.

Gait speed is commonly used to assess walking ability in persons with stroke. Previous research related to the psychometric properties of gait speed has been conducted primarily with individuals who were able to walk independently and/or were in the later stages of recovery after stroke. The purpose of this research was to examine the test-retest reliability and minimal detectable change (MDC90) of gait speed in individuals with stroke who required varying levels of assistance to ambulate during rehabilitation. Patients who could ambulate with or without physical assistance and were undergoing inpatient rehabilitation were recruited. Gait speed was measured over the middle five meters of a nine-meter walk at a comfortable pace. Data were analyzed using the intraclass correlation coefficient (ICC2,1) and the MDC90. Thirty-five patients who were a mean 34.5 (standard deviation = 17.7) days post-stroke agreed to participate. For all the subjects combined, the ICC2,1 was 0.862 and MDC90 was 0.30 m/sec. For the 13 subjects who required physical assistance to walk, the ICC2,1 = 0.971 and MDC90 = 0.07 m/sec. For the 22 subjects who could walk without physical assistance, the ICC2,1 = 0.80 and MDC90 = 0.36 m/sec. Gait speed is a reliable measure of walking ability for a wide variety of patients undergoing rehabilitation after stroke. Gait speed is more sensitive to change in patients who require physical assistance to walk than in those who can walk without assistance. A change of more than 0.30 m/sec may be necessary in order to determine whether a change in gait speed exceeds measurement error and patient variability.

BackgroundThe relationship between different affective presentations and cognitive outcome is poorly understood and may elucidate subgroups of patients who are more at risk for decline. Here we utilized longitudinal data from subjects ≥ 60 years, enrolled in the National Alzheimer’s Coordinating Center (NACC) study for an average of 5 years and who were not demented at baseline to investigate the relationship between affective dimensions and global cognition and specific cognitive domains over time.MethodSubjects [n=17,385; mean age= 73.73 (SD= 7.72); 59.20% female] completed the 15‐item geriatric depression scale (GDS‐15) and a broad neuropsychological battery at baseline, and approximately every 12 month follow ups. Cognitive domains included episodic memory, attention, executive functions, and language. Global cognition averaged the z‐scores of the four domains. Affective dimensions were defined based on GDS‐15 factors previously described, and included dysphoric mood, Withdrawal‐Apathy –Vigor (WAV) , anxiety, hopelessness and memory complaint. Linear mixed models (LMM) analysis was used to assess associations between the five affective dimensions with global cognition and each cognitive domain. Analyses adjusted for baseline age, sex, race/ethnicity, years of education, baseline Functional Assessment Questionnaire (FAQ), indicators for history of diabetes, hypertension, and hypercholesterolemia.ResultAt baseline, our sample had low reported depressive symptoms (GDS‐15=1.66; SD= 2.23) and were non‐demented (MMSE= 28.34; SD=2.01). Reported subjective memory complaint and hopelessness were associated with faster decline in all cognitive domains (all p<0.001) and , attention and executive function (all p<0.001), but not with episodic memory or language. In contrast, dysphoria and anxiety were not associated with a faster decline in global cognition or any of the cognitive domains.ConclusionIn our large clinical sample of initially non‐demented older adults, different affective dimensions had different degree of associations with the rate of cognitive decline, suggesting distinct pathophysiology and need for more targeted interventions.

While gait has been linked with cognition, few studies have contrasted the strength of the relationships between gait speed and cognitive domains in people with cognitive impairment (CI). Investigate the association between gait speed and global cognitive function and cognitive domains in older people with CI. Three-hundred-and-nine community-dwelling people with CI (mean age 82 years, 47% female, and mean gait speed 0.62±0.23 m/s) were included using baseline data from the Intervention-Falls in Older Cognitively Impaired Study (iFOCIS). Usual gait speed (m/s) was measured over 2.4 m. Global cognitive function and individual cognitive domains (attention; memory; verbal fluency; language; visuospatial ability) were assessed using the Addenbrooke's Cognitive Examination-III (ACE-III). Additionally, executive function was assessed using the Frontal Assessment Battery (FAB). Participants mean±standard deviation ACE-III and FAB scores were 62.8±19.3 and 11.4±4.6, respectively. In separate multiple linear regression analyses adjusting for confounders, global cognitive function, and each cognitive domain, was significantly associated with gait speed. Executive function demonstrated the strongest association (FAB: standardized β= 0.278, p < 0.001, adjusted R2 = 0.431), and remained significantly associated with gait speed when adjusted for attention, memory, language, and visuospatial ability. In this large study of older people with CI, global cognition and each cognitive domain were associated with gait speed. Executive function had the strongest association, possibly reflecting the higher-level cognitive processes and complex motor task responses required for gait control. Future longitudinal studies are needed to explore the temporal relationships between declines in executive function and gait, and whether the facilitation of executive function lessens gait decline.

<title>Abstract</title> <bold>Background.</bold> Post-stroke walking deficits are closely associated with impaired forward propulsion from the affected leg. We developed a real-time training system using an instrumented split-belt treadmill that provides phase-specific adaptive belt speed modulation (propulsion-facilitating mode, PF) during late stance and visual biofeedback (VB) of the affected leg’s propulsive (anterior ground reaction) force. This study investigated the effects of VB, PF, and VB + PF on gait propulsion, kinematics, and muscle activity in individuals post-stroke. <bold>Methods.</bold> Thirteen adults with chronic hemiparetic stroke completed three randomized, counterbalanced treadmill trials: VB alone, PF alone, and VB + PF. Each trial consisted of the baseline (30 steps, without intervention), the training (100 steps, assigned modality), and the post-training (30 steps, without intervention) periods. All outcome measures were obtained from the affected leg, including peak propulsive force, stride length, peak knee and ankle extension, and electromyographic activity of the major ankle and knee extensors (i.e., medial gastrocnemius, soleus, vastus medialis, and rectus femoris). <bold>Results.</bold> Significant main effects of modality, period, and their interaction were observed for all outcome measures (P &lt; 0.0001). During the training period, VB + PF resulted in the greatest improvements across all outcome measures (i.e., peak propulsive force, stride length, peak knee and ankle extension, and electromyographic activity in the ankle and knee extensor muscles) compared with either VB or PF alone. PF alone demonstrated moderate improvements, whereas VB alone showed smaller yet statistically significant improvements. Regardless of modality, the improvements achieved during the training period were retained during the post-training period. <bold>Conclusion.</bold> In individuals post-stroke, combining real-time visual biofeedback with phase-specific adaptive belt speed modulation resulted in the greatest and most substantial improvements in affected-leg propulsion, lower-limb kinematics, and electromyographic activity in the ankle and knee extensor muscles. These findings demonstrate the effectiveness of multimodal, adaptive treadmill training in engaging the affected-leg propulsion reserve and inform the development of scalable rehabilitation protocols that integrate perceptual feedback with task-specific mechanical facilitation for stroke gait rehabilitation.

Transcranial direct current stimulation (tDCS) has mixed effects on walking performance in individuals poststroke. This is likely the result of variations in tDCS electrode montages and individualized responses. The purpose of this study was to quantify the effects of a single session of tDCS using various electrode montages on poststroke walking performance. Individuals with chronic stroke ( n = 16) participated in a double-blind, randomized cross-over study with sham stimulation and three tDCS electrode montages. Gait speed, paretic step ratio, and paretic propulsion were assessed prestimulation and poststimulation at self-selected and fastest comfortable speeds. Changes in muscle activation patterns with self-selected walking were quantified by the number of modules derived from nonnegative matrix factorization of EMG signals for hypothesis generation. There was no significant effect of active stimulation montages compared with sham. Comparisons between each participant's best response to tDCS and sham show personalized tDCS may have a positive effect on fastest comfortable overground gait speed ( P = 0.084), paretic step ratio ( P = 0.095) and paretic propulsion ( P = 0.090), and self-selected paretic step ratio ( P = 0.012). Participants with two or three modules at baseline increased module number in response to the all experimental montages and sham, but responses were highly variable. A single session of tDCS may affect clinical and biomechanical walking performance, but effects seem to be dependent on individual response variability to different electrode montages. Findings of this study are consistent with responses to various tDCS electrode montages being the result of underlying neuropathology, and the authors recommend examining how individual factors affect responses to tDCS.

Comprehensive Assessment of Cognitive Function in Patients with Sickle Cell Disease Reveals Deficits in Memory and Processing Speed

Cerebral microbleeds (CMB), suspected markers of hemorrhage-prone microangiopathy, are common in patients with cerebrovascular disease and in those with cognitive impairment. Their longitudinal relationship with cognitive decline and incident dementia in non-demented community-dwelling older individuals has been insufficiently examined. 302 adults aged 70-90 participating in the population-based Sydney Memory and Ageing Study underwent a susceptibility-weighted imaging (SWI) MRI sequence. The relationship of CMB with performance on neuropsychological tests was examined both cross-sectionally and longitudinally, over a mean of 4years. The association with cases of incident dementia during this period was also examined. The prevalence of CMB was 20%. In cross-sectional analysis, after adjusting for demographics and vascular risk factors, there was a significant association between the presence of CMB and poorer executive function. CMB were not associated with global cognition or other cognitive domains. On longitudinal analysis, after adjusting for demographics and vascular risk factors, there was a greater decline in visuospatial ability in those with CMB compared to those without. The presence of CMB was not associated with increased progression to dementia. CMB are associated with impairments in specific cognitive domains: executive function and decline in visuospatial ability, independent of other markers of CVD including white matter hyperintensities. This suggests a direct contribution of CMB to cognitive impairment although no significant difference in incident dementia rates was observed.

Handgrip strength asymmetry and cognitive impairment risk: Insights from a seven-year prospective cohort study.

Improving walking remains the most important goal of rehabilitation, and the effectiveness of previously proposed methods of practicing the motor skill requires further improvement.The aim of the work is to evaluate the results of walking training according to «the period of support» in the comprehensive rehabilitation of patients with central hemiparesis in the early recovery period of ischemic stroke, as well as to identify factors concomitant with gait improvement.Material and methods. 49 patients with central hemiparesis (mild and moderate in the foot) in the early recovery period of ischemic stroke were examined. The patients were randomized into the main group of 28 patients and the comparison group of 21 patients. The patients of the main group in addition to the standards of care were trained with visual biofeedback on the period of support. Functional testing, assessment of biomechanical indicators of walking and taking surface electromyograms from the thigh and lower leg muscles were performed twice. The training course consisted of 10 sessions of 15 [10;20] minutes each.Results. Training with the use of biofeedback in patients in the early recovery period of stroke was accompanied by improvement of walking as a daily activity and optimization of biomechanical indices of support period, step cycle length, double support, lateral deviation of the foot, as well as neurophysiological — EMG amplitude of EMG m.Quadriceps femoris.Conclusion. In patients with central hemiparesis in the early recovery period of ischemic stroke, walking training was accompanied by its improvement simultaneously with an increase in the dynamic component of balance.

Rehabilitation research for individuals with chronic stroke is increasingly addressing spatiotemporal asymmetries (STA). Understanding the reliability of STA between sessions is essential for determining whether treatment responses exceed day-to-day variation. The purpose of this study was to determine the minimal detectable change (MDC) and test-retest reliability in STA and gait speed measures for individuals with chronic stroke. Twenty-six individuals with chronic (>6 months) stroke participated in 2 visits. At each visit, participants walked across a 14-ft (4.3-m) GAITRite mat at comfortable gait speed (CGS) and fast gait speed (FGS). Spatiotemporal asymmetries ratios (paretic/nonparetic limb) were calculated for step length, stance time, and swing time. Intraclass correlation coefficients (ICC, 2,1) were calculated to determine reliability between sessions. Minimal detectable change values were calculated to determine the smallest change that is considered "real." Spatiotemporal asymmetry measures were consistent between sessions, with ICCs ranging from 0.93 to 0.98. Asymmetry ratio MDC values were calculated for step length (CGS: 0.15; FGS: 0.19), swing time (CGS: 0.26; FGS: 0.20), and stance time (CGS: 0.09; FGS: 0.10). Gait speed MDC was 0.20 m/s and 0.22 m/s, respectively, for the CGS and FGS walking conditions. There were considerable differences among MDC values for the various STA measures, suggesting that larger changes will be necessary to show improvement for certain measures (eg, swing time asymmetry). These data will assist with setting clinical goals for patients with chronic stroke and will be useful for evaluating interventions designed to minimize temporal and spatial interlimb asymmetries during walking.

BackgroundGrip strength and gait speed, indicators of frailty, have been associated with poor cognitive outcomes. Whether there are differences in these associations by race/ethnicity is unknown. In the Kaiser Healthy Aging and Diverse Life Experiences (KHANDLE) Study, we examined the cross‐sectional associations of grip strength and gait speed with cognition.MethodKHANDLE aimed to evaluate how race/ethnicity and life‐course health influence late‐life brain health among community‐dwelling adults ages 65+ living in Northern California. Analysis included 1,353 Asian (24%), Black (26%), Latino (18%), and White (32%) participants. Grip strength (kg) was measured using a hand‐held dynamometer and gait speed measured a timed 4‐meter walk (m/s). Cognitive domains of verbal episodic memory, semantic memory, and executive function were measured using the Spanish and English Neuropsychological Assessment Scales (SENAS). Z‐standardized test scores were averaged for a global z‐score. Linear regression was used to assess the associations of grip strength and gait speed with cognition. Models were adjusted for demographic (age, education, income), physical (waist circumference), and behavioral risk factors (physical activity, smoking status, alcohol consumption). Gender and race/ethnicity interactions were tested separately.ResultParticipants had a mean age of 76 (SD=7) years and 58% were women. The associations of grip strength and gait speed with cognition did not differ by gender. A standard deviation (SD) increase in grip strength was associated with better global cognition [β=0.11(0.06, 0.15)]. This association did not differ by race/ethnicity and was similar across cognitive domains [executive β=0.07(0.03, 0.12); semantic β=0.12(0.07, 0.17); verbal β=0.06(0.01, 0.11)]. A SD decrease in gait speed was associated with worse global cognition [β=‐0.09(‐0.12, ‐0.06)] and associations were consistent across domains [executive β=‐0.08(‐0.11, ‐0.05); semantic β=‐0.08(‐0.11, ‐0.05); verbal β=‐0.06(‐0.09, ‐0.02)]. There were significant race/ethnicity interactions on the associations of gait speed with global cognition (p=0.001), executive function (p=0.02), and semantic memory (p=0.0004). Decreased gait speed was associated with worse cognition in these domains for Asians, Latinos, and Whites, but not associated in Blacks.ConclusionGrip strength and gait speed were cross‐sectionally associated with cognition. There were race/ethnicity differences in the association of gait speed with executive function, semantic memory, as well as global cognition.

Research has highlighted the relationship between impaired cognitive function and physical mobility measures in older adults. This relationship may also exist in older survivors of breast cancer, however, specific cognitive domains like executive function or visuospatial ability may influence physical mobility. The purpose of this study is to describe associations between cognitive function and mobility in a group of community-dwelling older females with a history of breast cancer. Cross-sectional data of performance on cognitive and physical mobility measures from 38 older adults with a history of breast cancer were analyzed. Pearson’s correlation coefficient was used to examine relationships between measures. Significant inverse relationships were found between TMT-A and usual gait speed (r = -.662, p&amp;lt;.001), fast gait speed (r = -.409, p = .012), and dual-task gait speed (r = -.631, p&amp;lt;.001), suggesting that as visuospatial ability became more impaired, gait speed decreased. Significant relationships were found between TMT-A and performance on the TUG (r = .664, p&amp;lt;.001), TUG-cognitive (r = .635, p&amp;lt;.001), and TUG-manual (r = .653, p&amp;lt;.001). Results indicate that visuospatial ability, as measured with the TMT-A, is associated with physical mobility measures in older survivors of breast cancer. While previous research has reported impairments in executive function in this population, impaired visuospatial ability may also play a role, suggesting that clinicians should include a visuospatial task when working on improving gait in older survivors of breast cancer.

Patients who undergo bone marrow transplantation (BMT) often report cognitive problems following treatment. This study used cognitive tests and a self-report measure of subjective cognitive complaints to determine (1) the rate of objective cognitive impairment in a sample of 65 BMT patients, and (2) the correspondence of patients' cognitive complaints to their actual cognitive performance. At 6 months following BMT, patients were assessed in seven cognitive domains--attention, verbal learning, verbal memory, visual memory, simple executive function, complex executive function, and psychomotor speed. Cognitive complaints were likewise assessed. In all, 51% had at least mild impairment (-1 standard deviation (s.d.) below published norms) in one or more cognitive domains, with 28% demonstrating moderate-to-severe impairment (-2 s.d.). Older patients and patients with lower IQ were more likely to score in the impaired range on objective cognitive tests, with males and the less educated showing trends toward scores in the impaired range. Younger patients made significantly more cognitive complaints. Total cognitive complaints were unrelated to average cognitive performance, and complaints in specific cognitive domains were largely unrelated to objective performance on corresponding domains. Findings suggest that patients who complain about their cognitive performance following BMT differ from those who experience actual deficits.

To study the association between poststroke cognitive impairment and defining a specific resting functional marker. The resting-state functional connectivity 6 months after an ischemic stroke in 56 patients was investigated. Twenty-nine of the patients who had an impairment of one or several cognitive domains were compared to 27 without any cognitive deficit. We studied the whole-brain connectivity using 2 complementary approaches: graph theory to study the functional network organization and network-based statistics to explore connectivity between brain regions. We assessed the potential cortical atrophy using voxel-based morphometry analysis. The overall topological organization of the functional network was not altered in cognitively impaired stroke patients, who had the same mean node degree, average clustering coefficient, and global efficiency as cognitively healthy stroke patients. Network-based statistics analysis showed that poststroke cognitive impairment was associated with dysfunction of a whole-brain network composed of 167 regions and 178 connections, and functional disconnections between superior, middle, and inferior frontal gyri and the superior and inferior temporal gyri. These regions had connections that were specifically and positively correlated with cognitive domain scores. No intergroup differences in overall gray matter thickness and ischemic infarct topography were observed. To assess the effect of prestroke white matter hyperintensities on connectivity, we included the initial Fazekas scale in the regression model for a second network-based analysis. The resulting network was associated with the same key alterations but had fewer connections. The observed functional network alterations suggest that the appearance of a cognitive impairment following stroke may be associated with a particular functional alteration, shared specifically between cognitive domains.

Ultra-processed food (UFP) consumption accounts for more than 50% of energy intake in the US, steadily increasing among older adults over the decade. UPF consumption is associated with cognitive decline, but fewer studies have examined the association between UPF consumption and individual cognitive domains. In this study, we examined associations between UPF consumption and impairment in memory, executive function, language, visuospatial, and orientation in the nationally representative Health and Retirement Study (HRS) of adults aged ≥50. Participants without dementia or memory problems at baseline (2012 HRS) were included (n = 1,408). Dietary intake was assessed using the food frequency questionnaire from 2013 Health Care and Nutrition Study (HCNS). UPF was classified using the NOVA categorization. The percentage of energy intake from UPF was grouped into sex-specific quintiles (Q). Cognitive impairment was assessed from the 2016 Harmonized Cognitive Assessment Protocol (HCAP) based on cognitive domain scores, defined as &amp;gt; 1.5 SDs below the mean or a T-score=35. Weighted multivariate-logistic regression was used to estimate the associations between UPF consumption and cognitive outcomes. In the analytic sample, median UPF intake was 42.3% energy/day. After adjustment for baseline sociodemographic and health characteristics, higher UPF consumption was associated with greater impairment in executive function (Q4 vs Q1, OR 2.12, 95% CI 1.17-3.83; Q5 vs Q1, OR 1.77 95% CI 0.98-3.17; P-trend=0.04). UPF consumption was not associated with impairment in other cognitive domains in multivariate models. Our findings highlight the need for support in reducing UPF intake for better cognitive health among older adults.