Brain white matter correlates of learning ankle tracking using a wearable device: importance of the superior longitudinal fasciculus II.

BACKGROUND: Wearable devices have been found effective in training ankle control in patients with neurological diseases. However, the neural mechanisms associated with using wearable devices for ankle training remain largely unexplored. This study aimed to investigate the ankle tracking performance and brain white matter changes associated with ankle tracking learning using a wearable-device system and the behavior-brain structure relationships in middle-aged and older adults. METHODS: Twenty-six middle-aged and older adults (48-75 years) participated in this study. Participants underwent 5-day ankle tracking learning with their non-dominant foot using a custom-built ankle tracking system equipped with a wearable sensor and a sensor-computer interface for real-time visual feedback and data acquisition. Repeated and random sequences of target tracking trajectories were both used for learning and testing. Ankle tracking performance, calculated as the root-mean-squared-error (RMSE) between the target and actual ankle trajectories, and brain diffusion spectrum MR images were acquired at baseline and retention tests. The general fractional anisotropy (GFA) values of eight brain white matter tracts of interest were calculated to indicate their integrity. Two-way (Sex × Time) mixed repeated measures ANOVA procedures were used to investigate Sex and Time effects on RMSE and GFA. Correlations between changes in RMSE and those in GFA were analyzed, controlling for age and sex. RESULTS: After learning, both male and female participants reduced the RMSE of tracking repeated and random sequences (both p < 0.001). Among the eight fiber tracts, the right superior longitudinal fasciculus II (R SLF II) was the only one which showed both increased GFA (p = 0.039) after learning and predictive power of reductions in RMSE for random sequence tracking with its changes in GFA [ß = 0.514, R2 change = 0.259, p = 0.008]. CONCLUSIONS: Our findings implied that interactive tracking movement learning using wearable sensors may place high demands on the attention, sensory feedback integration, and sensorimotor transformation functions of the brain. Therefore, the SLF II, which is known to perform these brain functions, showed corresponding neural plasticity after such learning, and its plasticity also predicted the behavioral gains. The SLF II appears to be a very important anatomical neural correlate involved in such learning paradigms.

Cingulum correlates of cognitive functions in patients with mild cognitive impairment and early Alzheimer's disease: a diffusion spectrum imaging study.

Diffusion spectrum imaging (DSI) of MRI can detect neural fiber tract changes. We investigated integrity of cingulum bundle (CB) in patients with mild cognitive impairment (MCI) and early Alzheimer's disease (EAD) using DSI tractography and explored its relationship with cognitive functions. We recruited 8 patients with MCI, 9 with EAD and 15 healthy controls (HC). All subjects received a battery of neuropsychological tests to access their executive, memory and language functions. We used a 3.0-tesla MRI scanner to obtain T1- and T2-weighted images for anatomy and used a pulsed gradient twice-refocused spin-echo diffusion echo-planar imaging sequence to acquire DSI. Patients with EAD performed significantly poorer than the HC on most tests in executive and memory functions. Significantly smaller general fractional anisotropy (GFA) values were found in the posterior and inferior segments of left CB and of the anterior segment of right CB of the EAD compared with those of the HC. Spearman's correlation on the patient groups showed that GFA values of the posterior segment of the left CB were significantly negatively associated with the time used to complete Color Trails Test Part II and positively correlated with performance of the logical memory and visual reproduction. GFA values of inferior segment of bilateral CB were positively associated with the performance of visual recognition. DSI tractography demonstrates significant preferential degeneration of the CB on the left side in patients with EAD. The location-specific degeneration is associated with corresponding declines in both executive and memory functions.

Impacts of audiovisual simultaneity perception on single-task and dual-task gaits in middle-aged and older adults.

BACKGROUND: While dual-task walking requires the ability to integrate sensory information from multiple ongoing sources, it remains unknown whether dual-task walking is more affected than single-task walking by the multisensory integration ability. RESEARCH QUESTION: How does the audiovisual temporal integration ability affect single-task and dual-task gaits in the aging population? METHODS: One hundred and thirty healthy middle-aged and older adults (age = 64.7 ± 6.4 years) completed an audiovisual simultaneity judgment (AVSJ) task and underwent single-task, motor dual-task, and cognitive dual-task gait assessments. In the AVSJ task, participants judged whether a flash and an auditory stimulus presented at different stimulus onset asynchronies were simultaneous. The accuracy and precision of the AVSJ performance were assessed using the point of subjective simultaneity (PSS) and the temporal binding window (δ), respectively. A lower absolute PSS and δ indicated better performance. Participants held a cup of water and performed serial-7 subtraction for motor and cognitive dual-task gait assessments, respectively. The spatiotemporal gait parameters and their variability were calculated. The influences of PSS and δ on the gait parameters of the three gaits were examined with multiple hierarchical regressions. RESULTS: Only the cognitive dual-task gait was significantly affected by PSS and δ. Greater PSS predicted a longer single support time (ß = 0.195, p = 0.024) and its variability (ß = 0.224, p = 0.011). Greater δ predicted greater step time variability (ß = 0.198, p = 0.022). SIGNIFICANCE: Declined perception of audiovisual simultaneity particularly degrades temporal control of cognitive dual-task walking, highlighting the importance of assessing and training this ability after midlife.

Age-Related Changes in Audiovisual Simultaneity Perception and Their Relationship With Working Memory.

OBJECTIVES: Perceiving simultaneity of a visual and an auditory signal is critical for humans to integrate these multisensory inputs effectively and respond properly. We examined age-related changes in audiovisual simultaneity perception, and the relationships between this perception and working memory performances with aging. METHODS: Audiovisual simultaneity perception of young, middle-aged, and older adults was measured using a simultaneity judgment (SJ) task, in which a flash and a beep were presented at 1 of 11 stimulus-onset asynchronies (SOAs). Participants judged whether these two stimuli were perceived simultaneously. Precision of simultaneity perception, the SOA corresponding to the point of subjective simultaneity (PSS), and response errors at each SOA were estimated using model fitting. The precision and PSS are associated with multisensory perception per se, whereas the response error reflects executive ability when performing the SJ task. Visual working memory of the same middle-aged and older adults was measured using the Cambridge Neuropsychological Test Automated Battery (CANTAB) beforehand. RESULTS: Compared to young adults' performances, middle-aged and older adults showed a decreased precision, a shift of PSS toward the visual-leading SOAs, and increased response errors at the visual-leading SOAs. Among these changes, only the increased response errors correlated with worse spatial recognition memory in middle-aged and older adults. DISCUSSION: Age-related decrements in audiovisual simultaneity perception start from middle age and are manifested in both perceptual and executive parameters. Furthermore, higher-order executive ability is plausibly a common cause for age-related degenerations in the audiovisual simultaneity perception and visual working memory.

Daily physical activity and its contribution to the health-related quality of life of ambulatory individuals with chronic stroke.

BACKGROUND: Participation in daily physical activity (PA) post-stroke has not previously been investigated as a possible explanatory variable of health-related quality of life (HRQL). The aims were 1) to determine the contribution of daily PA to the HRQL of individuals with chronic stroke and 2) to assess the relationship between the functional ability of these individuals to the amount of daily PA. METHODS: The amount of daily PA of forty adults with chronic stroke (mean age 66.5 +/- 9.6 years) was monitored using two measures. Accelerometers (Actical) were worn on the hip for three consecutive days in conjunction with a self-report questionnaire [the PA Scale for Individuals with Physical Disabilities (PASIPD)]. The daily physical activity was measured as the mean total accelerometer activity counts/day and the PASIPD scores as the metabolic equivalent (MET) hr/day. HRQL was assessed by the Physical and Mental composite scores of the Medical Outcomes Study Short-Form 36 (SF-36) in addition to the functional ability of the participants. Correlation and regression analyses were performed. RESULTS: After controlling for the severity of the motor impairment, the amount of daily PA, as assessed by the PASIPD and accelerometers, was found to independently contribute to 10-12% of the variance of the Physical Composite Score of the SF-36. No significant relationship was found between PA and the Mental Composite Score of the SF-36.The functional ability of the participants was found to be correlated to the amount of daily PA (r = 0.33 - 0.67, p < 0.01). CONCLUSION: The results suggest that daily PA is associated with better HRQL (as assessed by the Physical composite score of the SF-36) for people living with stroke. Daily PA should be encouraged to potentially increase HRQL. Accelerometers in conjunction with a self-report questionnaire may provide important measures of PA which can be monitored and modified, and potentially influence HRQL.

Integrity of the Prefronto-striato-thalamo-prefrontal Loop Predicts Tai Chi Chuan Training Effects on Cognitive Task-switching in Middle-aged and Older Adults.

Tai Chi Chuan (TCC) exercise has been shown to improve cognitive task-switching performance in older adults, but the extent of this positive effect varies among individuals. Past research also shows that brain white matter integrity could predict behavioral gains of cognitive and motor learning. Therefore, in this randomized controlled trial (NCT02270320), we examined whether baseline integrity of three target white matter tract groups was predictive of task-switching improvement after 12-week TCC training in middle-aged and older adults. Thirty-eight eligible participants were randomly assigned to a TCC group (n = 19) and a control group (n = 19). Cognitive task-switching and physical performances were collected before and after training. Brain diffusion spectrum MR images were acquired before training and the general fractional anisotropy (GFA) of each target white matter tract group was calculated to indicate baseline white matter integrity of that group. Correlation and regression analyses between these GFAs and post-training task-switching improvement were analyzed using adjusted p-values. After 12 weeks, significant task-switching and physical performance improvements were found only in the TCC group. Moreover, higher baseline GFA of the prefronto-striato-thalamo-prefrontal loop fibers (r = -0.63, p = 0.009), but not of the prefronto-parietal/occipital (r = -0.55, p = 0.026) and callosal (r = -0.35, p = 0.189) fiber groups, was associated with greater reductions of task-switching errors after the TCC training. Multiple regression analysis revealed that baseline GFA of the prefronto-striato-thalamo-prefrontal loop fibers was the only independent white matter integrity predictor of task-switching error reductions after TCC training (ß = -0.620, adjusted R2 change = 0.265, p = 0.009). These findings not only highlight the important role of baseline integrity of the prefronto-striatal circuits in influencing the extent of positive cognitive task-switching effects from short-term TCC training, but also implicate that preserving good white matter integrity in the aging process may be crucial in order to gain the best cognitive effects of exercise interventions.

How active are people with stroke?: use of accelerometers to assess physical activity.

BACKGROUND AND PURPOSE: Accelerometers are a unique tool used to objectively measure free-living physical activity, but their reliability for people with stroke has not been established. The primary aim was to assess the day-to-day reliability of these instruments for the paretic and nonparetic hips. The secondary aims were to measure the amount of physical activity with accelerometers that people with stroke undertake in the community and its relationship with walking capacity (6-minute walk test distance). METHODS: Forty people with stroke wore one Actical accelerometer on each hip for 3 consecutive days at home and during the 6-minute walk test in the laboratory. The accelerometer measured physical activity using total activity counts per day and energy expenditure (kcal/d). RESULTS: Excellent intraclass correlation coefficients (ICCs) for the activity counts (paretic hip ICC([1,3])=0.95, nonparetic hip ICC([1,3])=0.94) and for the energy expenditure (paretic hip ICC([1,3])=0.95, nonparetic hip ICC([1,3])=0.95) were found across the 3 consecutive days at home. Excellent ICCs were also found between the paretic versus the nonparetic hips for the activity counts (ICC([1,3])=0.98) and for the energy expenditure (ICC([1,3])=0.96). Free-living physical activity was very low and 58% of the participants did not meet recommended physical activity levels. Only moderate correlations (r=0.6 to 0.73, P<0.001) were found between the 6-minute walk test distance in the laboratory and 3-day physical activity recording at home. CONCLUSIONS: The accelerometer was found to be a reliable objective instrument. The use of accelerometers quantified the low level of free-living physical activity of people with stroke.

Efficacy of a target-matching foot-stepping exercise on proprioception and function in patients with knee osteoarthritis.

STUDY DESIGN: A randomized clinical trial design. OBJECTIVE: To investigate the efficacy of high, repetitive, target-matching foot-stepping exercise (TMFSE) performed in a sitting position on proprioception, functional score, and walking velocity for patients with knee osteoarthritis (OA). BACKGROUND: Researchers have suggested that exercises to address knee OA should include proprioceptive training. However, most patients cannot tolerate conventional proprioceptive training performed in a standing position. METHODS AND MEASURES: Forty-nine subjects (mean age +/- SD, 63.3 +/- 8.1) with knee OA were randomly assigned to the exercise or no intervention groups. The exercise group practiced TMFSE in sitting, 3 sessions weekly for 6 weeks. All subjects underwent assessments of knee reposition error, functional incapacity score, and walking velocity prior to and after intervention. RESULTS: The TMFSE significantly improved reposition error from a mean +/- SD of 3.0 degrees +/- 1.6 degrees to 1.5 degrees +/- 0.6 degree, walking velocity on ground level from 44.1 +/- 2.9 to 38.6 +/- 2.5 sec for 60 meters, time to complete a stairs task from 34.2 +/- 2.1 to 26.5 +/- 2.3 seconds, time to complete a figure-of-eight from 51.3 +/- 6.7 to 29.1 +/- 3.6 seconds, and score on a functional incapacity scale from 12.0 +/- 3.1 to 4.9 +/- 1.7, in subjects with knee OA after 6-week intervention (P <.0125). In contrast, the control group showed no change in any of the measured tests. CONCLUSION: TMFSE in sitting appears to be an option for exercise in patients with mild to moderate knee OA. This may be an especially attractive option for patients who may have pain with weight-bearing exercises. A longitudinal study with a larger sample size is needed to confirm the potential use of TMFSE for patients with knee OA.

Impaired Callosal Motor Fiber Integrity and Upper Extremity Motor Impairment Are Associated With Stroke Lesion Location.

BACKGROUND: Damage to the callosal motor fibers (CMFs) may affect motor recovery in patients with stroke. However, whether the severity of CMF impairment varies with lesion locations remains unclear. OBJECTIVE: To investigate (1) whether CMF impairment occurs after stroke and whether the impairment varies with lesion locations and (2) the associations of CMF impairment and upper extremity (UE) motor impairment. METHODS: Twenty-nine patients with lesions involving the corticospinal tract (CST) were categorized into 2 groups: lesions involving the CMFs (CMF group, n = 15), and lesions not involving the CMFs (non-CMF group, n = 14). Thirteen healthy adults served as the control group. Tract integrity, assessed by the mean generalized fractional anisotropy (mGFA) using diffusion spectrum imaging, of the CMFs and the CST above the internal capsule (CSTABOVE) of the ipsilesional hemisphere were compared. RESULTS: After accounting for the effect of lesion load on the CST, the CMF group exhibited a significantly lower mGFA of the CMFs than did the control and non-CMF groups (post hoc P = .005 and .001, respectively). No significant difference was observed between the non-CMF and control groups (post hoc P = .999). The CST and CMF impairment accounted for 56% of the variance of UE motor impairment in the CMF group ( P = .007), whereas no significant association was observed in the non-CMF group ( P = .570). CONCLUSIONS: CMF impairment after stroke depends on lesion locations and CMF integrity has an incremental contribution to the severity of UE motor impairment in the CMF group.

Task-Switching Performance Improvements After Tai Chi Chuan Training Are Associated With Greater Prefrontal Activation in Older Adults.

Studies have shown that Tai Chi Chuan (TCC) training has benefits on task-switching ability. However, the neural correlates underlying the effects of TCC training on task-switching ability remain unclear. Using task-related functional magnetic resonance imaging (fMRI) with a numerical Stroop paradigm, we investigated changes of prefrontal brain activation and behavioral performance during task-switching before and after TCC training and examined the relationships between changes in brain activation and task-switching behavioral performance. Cognitively normal older adults were randomly assigned to either the TCC or control (CON) group. Over a 12-week period, the TCC group received three 60-min sessions of Yang-style TCC training weekly, whereas the CON group only received one telephone consultation biweekly and did not alter their life style. All participants underwent assessments of physical functions and neuropsychological functions of task-switching, and fMRI scans, before and after the intervention. Twenty-six (TCC, N = 16; CON, N = 10) participants completed the entire experimental procedure. We found significant group by time interaction effects on behavioral and brain activation measures. Specifically, the TCC group showed improved physical function, decreased errors on task-switching performance, and increased left superior frontal activation for Switch > Non-switch contrast from pre- to post-intervention, that were not seen in the CON group. Intriguingly, TCC participants with greater prefrontal activation increases in the switch condition from pre- to post-intervention presented greater reductions in task-switching errors. These findings suggest that TCC training could potentially provide benefits to some, although not all, older adults to enhance the function of their prefrontal activations during task-switching.

Factors Contributing to Single- and Dual-Task Timed "Up & Go" Test Performance in Middle-Aged and Older Adults Who Are Active and Dwell in the Community.

BACKGROUND: Dual-task Timed "Up & Go" (TUG) tests are likely to have applications different from those of a single-task TUG test and may have different contributing factors. OBJECTIVE: The purpose of this study was to compare factors contributing to performance on single- and dual-task TUG tests. DESIGN: This investigation was a cross-sectional study. METHODS: Sixty-four adults who were more than 50 years of age and dwelled in the community were recruited. Interviews and physical examinations were performed to identify potential contributors to TUG test performance. The time to complete the single-task TUG test (TUGsingle) or the dual-task TUG test, which consisted of completing the TUG test while performing a serial subtraction task (TUGcognitive) or while carrying water (TUGmanual), was measured. RESULTS: Age, hip extensor strength, walking speed, general mental function, and Stroop scores for word and color were significantly associated with performance on all TUG tests. Hierarchical multiple regression models, without the input of walking speed, revealed different independent factors contributing to TUGsingle performance (Mini-Mental Status Examination score, ß=-0.32), TUGmanual performance (age, ß=0.35), and TUGcognitive performance (Stroop word score, ß=-0.40; Mini-Mental Status Examination score, ß=-0.31). LIMITATIONS: At least 40% of the variance in the performance on the 3 TUG tests was not explained by common clinical measures, even when the factor of walking speed was considered. However, this study successfully identified some important factors contributing to performance on different TUG tests, and other studies have reported similar findings for single-task TUG test and dual-task gait performance. CONCLUSIONS: Although the TUGsingle and the TUGcognitive shared general mental function as a common factor, the TUGmanual was uniquely influenced by age and the TUGcognitive was uniquely influenced by focused attention. These results suggest that both common and unique factors contribute to performance on single- and dual-task TUG tests and suggest important applications of the combined use of the 3 TUG tests.

Motor dual-task Timed Up & Go test better identifies prefrailty individuals than single-task Timed Up & Go test.

AIM: The present study investigated whether dual-task Timed Up & Go tests (TUG) could identify prefrail individuals more sensitively than the single-task TUG (TUGsingle ) in community-dwelling middle-aged and older adults. METHODS: This cross-sectional study recruited adults aged 50 years and older who actively participated in local community programs. Time taken to complete single-task TUG and dual-task TUG, carrying a cup of water (TUGmanual ) or carrying out serial-3 subtraction (TUGcognitive ) while executing TUG, was measured. Prefrailty status was defined based on Fried's phenotypic definition. RESULTS: Of the 65 participants (mean age 71.5±8.1 years), 33.3% of the 12 middle-aged (50-64 years) and 62.3% of the 53 older (≥65 years) adults were prefrail, mainly as a result of weak grip strength. The receiver operating characteristic curve analyses for differentiating prefrailty from non-frailty showed that the area under the curve (AUC) for TUGmanual (0.73, 95% CI 0.60-0.86) was better than that for TUGsingle (0.67, 95% CI 0.54-0.80), whereas the AUC value was not significant for TUGcognitive (0.60, 95% CI 0.46-0.74). The optimal cut-off points for detecting prefrailty using TUGsingle , TUGmanual and TUGcognitive were 7.7 s (sensitivity 68%), 8.2 s (sensitivity 83%), and 14.3 s (sensitivity 29%), respectively. After adjusting for age, logistic regression analyses showed that individuals with TUGmanual 8.2 s or slower were 7.2-fold more likely to have prefrailty than those with TUGmanual faster than 8.2 s. CONCLUSION: TUGmanual is more valid and sensitive than TUGsingle in identifying prefrail individuals. The TUGmanual thus could serve as a screening tool for early detection of individuals with prefrailty in community-dwelling middle-aged and older adults.

Analysis and comparison of the psychometric properties of three balance measures for stroke patients.

BACKGROUND AND PURPOSE: This study compared the psychometric properties of 3 clinical balance measures, the Berg Balance Scale (BBS), the Balance subscale of the Fugl-Meyer test (FM-B), and the Postural Assessment Scale for Stroke Patients (PASS), in stroke patients with a broad range of neurological and functional impairment from the acute stage up to 180 days after onset. METHODS: One hundred twenty-three stroke patients were followed up prospectively with the 3 balance measures 14, 30, 90, and 180 days after stroke onset (DAS). Reliability (interrater reliability and internal consistency) and validity (concurrent validity, convergent validity, and predictive validity) of each measure were examined. A comparison of the responsiveness of each of the 3 measures was made on the basis of the entire group of patients and 3 separate groups classified by degree of neurological severity. RESULTS: The FM-B and BBS showed a significant floor or ceiling effect at some DAS points, whereas the PASS did not show these effects. The BBS, FM-B, and PASS all had good reliability and validity for patients at different recovery stages after stroke. The results of effect size demonstrated fair to good responsiveness of all 3 measures within the first 90 DAS but, as expected, only a low level of responsiveness at 90 to 180 DAS. The PASS was more responsive to changes in severe stroke patients at the earliest period after stroke onset, 14 to 30 DAS. CONCLUSIONS: All 3 measures tested showed very acceptable levels of reliability, validity, and responsiveness for both clinicians and researchers. The PASS showed slightly better psychometric characteristics than the other 2 measures.

Reactive postural control deficits in patients with posterior parietal cortex lesions after stroke and the influence of auditory cueing.

OBJECTIVE: The purpose of this study was to investigate the ways in which stroke-induced posterior parietal cortex (PPC) lesions affect reactive postural responses and whether providing auditory cues modulates these responses. DESIGN: Seventeen hemiparetic patients after stroke, nine with PPC lesions (PPCLesion) and eight with intact PPCs (PPCSpared), and nine age-matched healthy adults completed a lateral-pull perturbation experiment under noncued and cued conditions. The activation rates of the gluteus medius muscle ipsilateral (GMi) and contralateral to the pull direction, the rates of occurrence of three types of GM activation patterns, and the GMi contraction latency were investigated. RESULTS: In noncued pulls toward the paretic side, of the three groups, the PPCLesion group exhibited the lowest activation rate (56%) of the GMi (P < 0.05), which is the primary postural muscle involved in this task, and the highest rate of occurrence (33%) of the gluteus medius muscle contralateral-activation-only pattern (P < 0.05), which is a compensatory activation pattern. In contrast, in cued pulls toward the paretic side, the PPCLesion group was able to increase the activation rate of the GMi to a level (81%) such that there became no significant differences in activation rate of the GMi among the three groups (P > 0.05). However, there were no significant differences in the GM activation patterns and GMi contraction latency between the noncued and cued conditions for the PPCLesion group (P > 0.05). CONCLUSIONS: The PPCLesion patients had greater deficits in recruiting paretic muscles and were more likely to use the compensatory muscle activation pattern for postural reactions than the PPCSpared patients, suggesting that PPC is part of the neural circuitry involved in reactive postural control in response to lateral perturbations. The auditory cueing used in this study, however, did not significantly modify the muscle activation patterns in the PPCLesion patients. More research is needed to explore the type and structure of cueing that could effectively improve patterns and speed of postural responses in these patients.

Diffusion MRI connectometry automatically reveals affected fiber pathways in individuals with chronic stroke.

Building a human connectome database has recently attracted the attention of many researchers, although its application to individual subjects has yet to be explored. In this study, we acquired diffusion spectrum imaging of 90 subjects and showed that this dataset can be used as a norm to examine pathways with deviant connectivity in individuals. This analytical approach, termed diffusion MRI connectometry, was realized by reconstructing patient data to a common stereotaxic space and calculating the percentile rank of the diffusion quantities with respect to those of the norm. The affected tracks were constructed with deterministic tractography using the local tract orientations with substantially low percentile ranks as seeds. To demonstrate the performance of the connectometry, we applied it to 7 patients with chronic stroke and compared the results with lesions shown on T2-weighted images, apparent diffusion coefficient (ADC) maps, and fractional anisotropy (FA) maps, as well as clinical manifestations. The results showed that the affected tracks revealed by the connectometry corresponded well with the stroke lesions shown on T2-weighted images. Moreover, while the T2-weighted images, as well as the ADC and FA maps, showed only the stroke lesions, connectometry revealed entire affected tracks, a feature that is potentially useful for diagnostic or prognostic evaluation. This unique capability may provide personalized information regarding the structural connectivity underlying brain development, plasticity, or disease in each individual subject.

Meta-analysis of type and complexity of a secondary task during walking on the prediction of elderly falls.

AIM: Dual-tasking probes divided attention and causes performance changes that are associated with an increased risk for falls in the elderly. There is no systematic review investigating the effect of task type and complexity on the prediction of elderly falls. This article synthesizes research evidence regarding this issue on the contents of dual-tasking walking. METHODS: Relevant studies were systematically identified from electronic databases of Medline, PubMed, CINAHL, Cochrane CENTRAL and PsycINFO, and the reference lists of identified articles. The selection criteria were defined a priori. Two independent reviewers classified task types based on properties for cognitive demand, assessed the methodological quality with a customized checklist, and calculated the odds ratio of fall prediction. RESULTS: There was one study of reaction time, one of discrimination and decision-making, 10 of mental tracking, three of verbal fluency and five of manual tasks. The methodological heterogeneity was manifested in the selection criteria, faller classification, tasks and measures, resulting in substantial heterogeneity (I(2) 87-92%). Meta-analyses resulted in a significant pooled odds ratio 1.33 (95% CI 1.18-1.50). The mental tracking task was the only type that yielded a significant odds ratio 3.30 (95% CI 2.00-5.44). Running meta-analyses separately for simple and difficult mental tracking task showed similar odds ratios. CONCLUSION: The mental tracking task yielded significant dual-task-related changes for fall prediction. Most studies successively used an appropriate level of task complexity specific to the specified population of interest. More research is required for definite conclusions regarding the effect of task type and complexity.

Effect of a cane on sit-to-stand transfer in subjects with hemiparesis.

OBJECTIVE: The aim of this study was to determine the effect of using a cane on movement time, joint moment, weight symmetry, and muscle activation patterns during sit-to-stand (STS) transfer in healthy subjects and subjects who have had a stroke. DESIGN: Nine subjects with hemiparesis (mean [SD] age, 61.11 [12.83] yrs) and nine healthy adults (mean [SD] age, 63.11 [10.54] yrs) were included. The subjects with hemiparesis performed STS transfer in two randomly assigned conditions: (1) without a cane and (2) with a cane. The healthy subjects performed only STS transfer without a cane. A three-dimensional motion system, force plates, and eletromyography were used to examine STS transfer. The symmetry index between the two limbs was calculated. RESULTS: The movement time of the subjects with hemiparesis in both conditions without a cane and with a cane was longer than that of the healthy subjects without a cane (P < 0.025). However, STS transfer with a cane in the subjects with hemiparesis resulted in shorter movement time, greater knee extensor moment of the paretic limb, and more symmetry of weight bearing than in those without a cane (P < 0.05). The sequence of muscle onset tended to improve with a cane in the subjects with hemiparesis. CONCLUSIONS: Cane use may promote more symmetrical STS transfers rather than compensation by the unaffected limb.

A home-based program using patterned sensory enhancement improves resistance exercise effects for children with cerebral palsy: a randomized controlled trial.

BACKGROUND: Neurologic music therapy has demonstrated improved walking performance in persons with neurologic disease; however, little evidence supports the use of music with functional resistance exercise to improve motor capacity and daily functions for children with cerebral palsy. OBJECTIVE: To investigate the effect of additional patterned sensory enhancement (PSE) music combined with exercise for children with spastic diplegia. METHODS: An assessor-blind, randomized controlled trial with 6- and 12-week follow-ups was carried out. Thirty-six children with spastic diplegia, aged 5 to 13 years, were assigned to a PSE group (n = 18) or a no-music group (n = 18). Both groups received 6-week, home-based, loaded sit-to-stand exercise, but only the PSE group exercised with prerecorded PSE music. The primary outcome was Gross Motor Function Measure (GMFM). Secondary outcomes included Pediatric Evaluation of Disability Inventory (PEDI) mobility and self-care domains, 1-repetition maximum of sit-to-stand, and walking speeds. RESULTS: Three children did not complete the program. Intention-to-treat analysis showed both groups improved in GMFM D, E, and Goal dimensions; Functional Skills Scales of PEDI mobility domain; and 1-repetition maximum of sit-to-stand at posttest and follow-ups (P ≤ .005). The PSE group improved significantly greater than the no-music group in the GMFM D and Goal dimensions (P < .005) after training, and the improvement persisted for at least 6 or 12 weeks (P ≤ .013). No significant improvements in the rest PEDI scales and walking speeds were found. CONCLUSIONS: Adding neurologic music therapy to functional resistance exercise could induce greater improvements in gross motor capacity for children with cerebral palsy.

Hierarchy of higher-level physical functions: a longitudinal investigation on a nationally representative population of community-dwelling middle-aged and elderly persons.

PURPOSE: Understanding the hierarchy of higher-level physical functions to infer disability level (mild, moderate or severe) is essential for the precise targeting of preventive interventions and has been examined previously in a cross-sectional study. Based on longitudinal data, this study evaluated the hierarchy of higher-level physical functions. METHODS: Data from a cohort of 2729 community-dwelling persons aged over 50 with no initial disability were drawn from the "Survey of Health and Living Status of the Elderly in Taiwan" from 1996 through 2007. The three-level hierarchy of eight chosen activities was examined by the median ages to disability onset with survival analyses and by Cox regressions, which examined the effects of sex and age on the development of this hierarchy. RESULTS: The progression of incident disability was as follows: mild level-running, carrying weight, and squatting; moderate level-climbing stairs, walking, and standing; and severe level-grasping and raising arms up. Women and older persons were at greater risk of developing more severe levels of disability. Another Cox regression with one index activity from each hierarchical level revealed similar results. CONCLUSIONS: The three-level hierarchy of higher-level physical functions has been validated longitudinally, suggesting rich research and clinical implications.

Immediate effects of therapeutic music on loaded sit-to-stand movement in children with spastic diplegia.

The effects of patterned sensory enhancement (PSE) music on muscle power and movement control in children with spastic diplegia (SD) during loaded sit-to-stand (LSTS) were investigated. Twenty-three children with SD aged 5 to 12 years were recruited. Individualized PSE was composed by a music therapist based on each subject's sit-to-stand (STS) movement with 50% 1-repetition maximum load. Each subject performed LSTS continuously for eight repetitions under randomly assigned music or no-music (Control) conditions while the kinematic and kinetic data were measured simultaneously. For the music condition, PSE music was played only during the first five repetitions (PSE condition), and the following three repetitions were referred to as the Continuation condition. Paired t- or Wilcoxon signed rank tests were used to compare the variables between the PSE and Control conditions, and between the Continuation and Control conditions. Compared to the Control condition, greater peak knee extensor power (P=0.009), greater total extensor power (P=0.015), and better center-of-mass smoothness (P=0.01), but less movement time (P=0.003) were found in the PSE condition. Significant effects of the PSE music on the above variables were also found for Continuation condition. The current results showed that individualized PSE music helped improve the performance of LSTS in children with SD. The associated biomechanical features also continued to exist in subsequent movement cycles after the music had ceased. These findings suggest that therapy using LSTS combined with PSE music may be beneficial for rehabilitating children with SD.