The impact of walking speed on interlimb coordination in individuals with Parkinson's disease.

[Purpose] Interlimb coordination can be affected by the symptoms associated with Parkinson's disease and may result in an increased risk of falls. The purpose of the current study was to compare changes in interlimb coordination in individuals with Parkinson's disease to healthy older adults while systematically manipulating walking speed. [Subjects and Methods] Participants walked on a treadmill while systematically increasing and decreasing the walking speed between 0.22 and 1.30 m/s. Kinematic data were collected by means of a three dimensional motion capture system. Dependent variables included the phase relation between arm and leg movements as well as between pelvic and thoracic rotation. [Results] Compared to healthy controls, an increased variability in relative phase between left and right arm swing, and smaller amplitude with arm, leg as well as less variability for the phase relation between thoracic and pelvic rotations were shown in individuals with Parkinson's disease. [Conclusion] The increased variability of phase relation between left and right arm swing may be related to the reduced out-of-phase forcing of the arm movements at the shoulders as a result of axial rigidity in Parkinson's disease. It deserves further investigation whether the improvement of the coordination between arms could result in the normalization of parkinsonian gait.

Effects of Parkinson's disease on optic flow perception for heading direction during navigation.

Visuoperceptual disorders have been identified in individuals with Parkinson's disease (PD) and may affect the perception of optic flow for heading direction during navigation. Studies in healthy subjects have confirmed that heading direction can be determined by equalizing the optic flow speed (OS) between visual fields. The present study investigated the effects of PD on the use of optic flow for heading direction, walking parameters, and interlimb coordination during navigation, examining the contributions of OS and spatial frequency (dot density). Twelve individuals with PD without dementia, 18 age-matched normal control adults (NC), and 23 young control adults (YC) walked through a virtual hallway at about 0.8 m/s. The hallway was created by random dots on side walls. Three levels of OS (0.8, 1.2, and 1.8 m/s) and dot density (1, 2, and 3 dots/m(2)) were presented on one wall while on the other wall, OS and dot density were fixed at 0.8 m/s and 3 dots/m(2), respectively. Three-dimensional kinematic data were collected, and lateral drift, walking speed, stride frequency and length, and frequency, and phase relations between arms and legs were calculated. A significant linear effect was observed on lateral drift to the wall with lower OS for YC and NC, but not for PD. Compared to YC and NC, PD veered more to the left under OS and dot density conditions. The results suggest that healthy adults perceive optic flow for heading direction. Heading direction in PD may be more affected by the asymmetry of dopamine levels between the hemispheres and by motor lateralization as indexed by handedness.

Comparison of the Utrecht Scale for Evaluation of Rehabilitation-Participation with the ICF Measure of Participation and Activities Screener and the WHO Disability Assessment Schedule II in persons with spinal cord injury.

OBJECTIVE: To validate the Utrecht Scale for Evaluation of Rehabilitation-Participation (USER-Participation) in persons with spinal cord injury (SCI) using 2 International Classification of Functioning, Disability and Health (ICF)-based instruments: the ICF Measure of Participation and Activities-Screener (IMPACT-S) and the World Health Organization Disability Assessment Schedule II (WHODAS II). DESIGN: Validation study. Score distributions, internal consistency, and concurrent and discriminant validity were evaluated. SETTING: The community. PARTICIPANTS: Convenience sample of persons (N=157) with long-term SCI living in The Netherlands. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: USER-Participation, IMPACT-S, and WHODAS II. RESULTS: No instruments showed floor effects, and 3 out of 6 WHODAS II domains showed ceiling effects. Most scores showed adequate internal consistency (α≥.70), except for the USER-Participation frequency scale (.51) and 2 WHODAS II domains (.58-.60). Spearman correlation coefficients between the segregate USER-Participation scales were <.60 (range, .39-.46), showing that they cover separate aspects of participation. Concurrent validity of the USER-Participation was shown because >75% (83.3%) of the 24 hypotheses (Spearman correlation coefficients above or below .60) with the other measurement instruments were confirmed. Concurrent validity between the IMPACT-S and WHODAS II was not shown (53.8% of 13 hypotheses confirmed). All scores except 4 WHODAS II domains showed significant differences in participation between persons with paraplegia and tetraplegia. CONCLUSIONS: The USER-Participation showed generally satisfactory psychometric properties in Dutch persons with long-term SCI living in the community. The IMPACT-S showed the best psychometric properties, and the WHODAS II showed less favorable results. Future research on the USER-Participation should focus on validation in other languages and different diagnostic groups.

Computer-adaptive balance testing improves discrimination between community-dwelling elderly fallers and nonfallers.

OBJECTIVES: To build an item response theory-based computer adaptive test (CAT) for balance from 3 traditional, fixed-form balance measures: Berg Balance Scale (BBS), Performance-Oriented Mobility Assessment (POMA), and dynamic gait index (DGI); and to examine whether the CAT's psychometric performance exceeded that of individual measures. DESIGN: Secondary analysis combining 2 existing datasets. SETTING: Community based. PARTICIPANTS: Community-dwelling older adults (N=187) who were aged ≥65 years (mean age, 75.2±6.8y, 69% women). INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: The BBS, POMA, and DGI items were compiled into an initial 38-item bank. The Rasch partial credit model was used for final item bank calibration. CAT simulations were conducted to identify the ideal CAT. CAT score accuracy, reliability, floor and ceiling effects, and validity were examined. Floor and ceiling effects and validity of the CAT and individual measures were compared. RESULTS: A 23-item bank met model expectations. A 10-item CAT was selected, showing a very strong association with full item bank scores (r=.97) and good overall reliability (.78). Reliability was better in low- to midbalance ranges as a result of better item targeting to balance ability when compared with the highest balance ranges. No floor effect was noted. The CAT ceiling effect (11.2%) was significantly lower than the POMA (40.1%) and DGI (40.3%) ceiling effects (P<.001 per comparison). The CAT outperformed individual measures, being the only test to discriminate between fallers and nonfallers (P=.007), and being the strongest predictor of self-reported function. CONCLUSIONS: The balance CAT showed excellent accuracy, good overall reliability, and excellent validity compared with individual measures, being the only measure to discriminate between fallers and nonfallers. Prospective examination, particularly in low-functioning older adults and clinical populations with balance deficits, is recommended. Development of an improved CAT based on an expanded item bank containing higher difficulty items is also recommended.

Effect of body-scaled information on reaching in children with hemiplegic cerebral palsy: a pilot study.

PURPOSE: This study examined body-scaled information that specifies the reach patterns of children with hemiplegic cerebral palsy and children with typical development. METHODS: Nine children with hemiplegic cerebral palsy (3-5 years) and 9 age-matched children with typical development participated in the study. They were required to reach and grasp 10 different pairs of cubes. Reach data were coded as either a 1-handed reach or a 2-handed reach. Dimensionless ratios were calculated by dividing the cube size by the maximal aperture between the index finger and thumb. A critical ratio was used to establish the shift from a 1-handed to an exclusive 2-handed reach. RESULTS: The critical ratio was not significantly different for either preferred or nonpreferred arms within and between groups. All children used an exclusive 2-handed reach at a similar dimensionless ratio. CONCLUSION: Our study provides evidence of the "fit" between environment (cube size) and the individual's capabilities (finger aperture) for reaching for both groups.

Self-management rehabilitation and health-related quality of life in Parkinson's disease: a randomized controlled trial.

The purpose of this randomized controlled trial was to determine whether increasing hours of self-management rehabilitation had increasing benefits for health-related quality of life (HRQOL) in Parkinson's disease beyond best medical treatment, whether effects persisted at 2 and 6 months of follow-up, and whether targeted compared with nontargeted HRQOL domains responded more to rehabilitation. Participants on best medication therapy were randomly assigned to one of three conditions for 6 weeks intervention: 0 hours of rehabilitation; 18 hours of clinic group rehabilitation plus 9 hours of attention control social sessions; and 27 hours of rehabilitation, with 18 in clinic group rehabilitation and 9 hours of rehabilitation designed to transfer clinic training into home and community routines. Results (N = 116) showed that at 6 weeks, there was a beneficial effect of increased rehabilitation hours on HRQOL measured with the Parkinson's Disease Questionnaire-39 summary index (F(1,112) = 6.48, eta = 0.23, CI = 0.05-0.40, P = 0.01). Benefits persisted at follow-up. The difference between 18 and 27 hours was not significant. Clinically relevant improvement occurred at a greater rate for 18 and 27 hours (54% improved) than for 0 hours (18% improved), a significant 36% difference in rates (95% CI = 20-52% difference). Effects were largest in two targeted domains: communication and mobility. More concerns with mobility and activities of daily living at baseline predicted more benefit from rehabilitation.

Changes in walking activity and endurance following rehabilitation for people with Parkinson disease.

OBJECTIVE: To investigate changes in walking activity and endurance after interdisciplinary rehabilitation in people with Parkinson disease (PD). DESIGN: Randomized controlled trial. SETTING: Clinic, home, and community. PARTICIPANTS: Mild to moderate PD (Hoehn and Yahr stage 2-3). INTERVENTIONS: Three experimental conditions lasting 6 weeks in duration: (1) no active rehabilitation; (2) 3.0 hours of interdisciplinary rehabilitation a week; or (3) 4.5 hours of interdisciplinary rehabilitation a week. Participants had stable medication regimes during the study. MAIN OUTCOME MEASURES: Walking activity was estimated with an activity monitor (AM) (time spent walking and number of 10-second walking periods) in the home and community settings over a 24-hour period. Walking endurance was measured in the clinic with the two-minute walk test (2MWT). Linear contrast analyses were applied to examine changes in walking activity and endurance after higher doses of rehabilitation, and 2-way analysis of variance models with interaction were applied to examine the effect of high and low baseline walking levels on changes. RESULTS: The 2MWT was completed by 108 people with PD (mean age, 66.53y; with PD, 6.59y), and AM data were used from 74 of these people (mean age, 66.7y; with PD, 5.8y). Improvement in AM measures and the 2MWT did not significantly change across increasing dosages of interdisciplinary rehabilitation. Higher doses of rehabilitation resulted in significant improvements in the 2MWT for subjects with low baseline walking endurance (P=.001), and in AM measures for subjects with high baseline walking activity (P<.02). CONCLUSIONS: Interdisciplinary rehabilitation can improve walking activity and endurance depending on baseline walking levels.

Test-retest reliability of 24 hours of activity monitoring in individuals with Parkinson's disease in home and community.

BACKGROUND/OBJECTIVE: This study examined the test-retest reliability of an activity monitor (AM) in home and community settings in individuals with Parkinson's disease (PD). METHODS: Nine independent community dwellers with idiopathic PD were recruited (8 males and 1 female; median age = 66 years, range 46-71; Hoehn & Yahr score 2). Patients wore the AM for 3 separate sessions in the home and community with 7 days between each session. The first 2 sessions lasted 24 hours each, and the third session lasted 48 hours. Reliability indices and measures of variability were obtained by using intraclass correlation coefficients (ICC) and generalizability coefficients. The functional activity measures included the percentage of time spent in sleeping positions, sitting, standing, and walking; the number of transitions between sit and stand; the total number of transitions; the number of walking periods lasting 5 and 10 seconds; and stride frequency. RESULTS: The ICCs for functional activities between the first and second consecutive days for the 48-hour session (third session) ranged from .76 to .92. The ICCs for the 7- and 14-day intervals ranged from .45 to .96, with walking-related measures showing the highest ICCs (range = .81 to .96). Across the three 24-hour periods (sessions 1 and 2, and the first 24 hours of session 3), the ICCs for walking-related measures were again high ranging from .87 to .92. Walking-related measures demonstrated the highest generalizability coefficients, indicating these measures have the highest test-retest reliability in comparison to other functional activity measures. CONCLUSIONS: The present study shows that 24 hours of recording with an AM is a sufficient duration of time to reliably record patients' functional activity in the home and community settings. In addition, the highest test-retest reliability for activities across 7- and 14-day intervals were found for walking-related measures in individuals with PD, indicating these measures have the highest stability compared to the other measures of functional activity.

Arm constraint and walking in healthy adults.

The aim of the present study was to examine the functional adaptations in inter-segmental coordination when constraining one arm in healthy adults during treadmill walking at different velocities. Subjects were instructed to walk on a motorized treadmill at different walking velocities (range: 0.22-1.52 m/s) during three experimental conditions, i.e.: (1) no arm constraint, (2) dominant arm constrained, and (3) non-dominant arm constrained. Movements of body segments were recorded with a 3D motion analysis system. A comparison between walking with one arm constrained and normal walking revealed decreased, transverse pelvic, thoracic, and trunk rotation, however there were slight increases in non-constrained arm movement amplitude. Reduced arm movement amplitude did result in altered frequency and phase relations between the arm and leg. Persons with upper extremity movement dysfunction may walk slower due to atypical coordination between upper and lower body movement at higher walking velocities. Future studies should focus on examining the underlying dynamics of adaptations in inter-limb and trunk coordination during walking in both healthy adults and persons with upper extremity movement disorders.

The effects of auditory rhythms and instruction on walking patterns in individuals post stroke.

The objective was to investigate the effects of auditory rhythms and arm movement on inter-segmental coordination during walking in persons who have suffered a stroke. Eleven subjects walked on a treadmill: (1) during systematic increases in velocity (0.22-1.52 m/s), (2) with instructions to 'step to the beat' during systematic increases in metronome frequency (1-2.2 Hz), and (3) with instructions: 'move the arms and legs to the beat' during systematic increases in metronome frequency (1-2.2 Hz). Movement amplitude of upper and lower body segments, frequency coordination between arm and leg movements, phase relation between upper and lower body segments were measured. Moving the arms and legs to the beat resulted in increased arm swing along with 1:1 frequency coordination between the arm and leg, and a more out-of-phase relation between transverse pelvic and thoracic rotation was observed with larger pelvic and thoracic rotations. Verbal instructions to move the arms to the beat of a metronome leads to increased arm swing, increased stride length, but further study is needed to examine the dynamics of the changes in arm movement, to enhance understanding of how upper extremity movement dysfunction affects inter-segmental coordination during walking.

Changes in axial stiffness of the trunk as a function of walking speed.

Research suggests that abnormal coordination patterns between the thorax and pelvis in the transverse plane observed in patients with Parkinson's disease and the elderly might be due to alteration in axial trunk stiffness. The purpose of this study was to develop a tool to estimate axial trunk stiffness during walking and to investigate its functional role. Fourteen healthy young subjects participated in this study. They were instructed to walk on the treadmill and kinematic data was collected by 3D motion analysis system. Axial trunk stiffness was estimated from the angular displacement between trunk segments and the amount of torque around vertical axis of rotation. The torque due to arm swing cancelled out the torque due to the axial trunk stiffness during walking and the thoracic rotation was of low amplitude independent of changes in walking speeds within the range used in this study (0.85-1.52 m/s). Estimated axial trunk stiffness increased with increasing walking speed. Functionally, the suppression of axial rotation of thorax may have a positive influence on head stability as well as allowing recoil between trunk segments. Furthermore, the increased stiffness at increased walking speed would facilitate the higher frequency rotation of the trunk in the transverse plane required at the higher walking speeds.

Gait characteristics of elderly people with a history of falls: a dynamic approach.

BACKGROUND AND PURPOSE: This study investigated changes in the kinematics of elderly people who experienced at least one fall 6 months prior to data collection. The authors hypothesized that, in order to decrease variability of walking, people with a history of falls would show different kinematic adaptations of their walking patterns compared with elderly people with no history of falls. SUBJECTS AND METHODS: Twenty-one elderly people who had fallen within the previous 6 months ("fallers"; mean age=72.1 years, SD=4.9) and 27 elderly people with no history of falls ("nonfallers"; mean age=73.8 years, SD=6.4) walked at their preferred stride frequency (STF) as treadmill speed was gradually increased (from 0.18 m/s to 1.52 m/s) and then decreased in steps of 0.2 m/s. Gait parameter measurements were recorded, and statistical analysis was applied using walking speed and STF as independent variables. RESULTS: Fifty-seven percent of the fallers were unable to walk at the fastest speed, whereas all nonfallers walked comfortably at all walking speeds. Although the fallers showed significantly greater STF, smaller stride lengths, smaller center-of-mass lateral sway, and smaller ankle plantar flexion and hip extension during push-off, they showed increased variability of kinematic measures in their coordination of walking compared with the nonfallers. DISCUSSION AND CONCLUSION: Although the fallers' adaptations were expected to reduce variability in the coordination of walking, they showed less stable gait patterns (ie, greater variability) compared with the nonfallers. Increased variability of walking patterns may be an important gait risk factor in elderly people with a history of falls.

Functional electrical stimulation changes dynamic resources in children with spastic cerebral palsy.

BACKGROUND AND PURPOSE: Children with cerebral palsy (CP) often are faced with difficulty in walking. The purpose of this experiment was to determine the effects of functional electrical stimulation (FES) applied to the gastrocnemius-soleus muscle complex on the ability to produce appropriately timed force and reduce stiffness (elastic property of the body) and on stride length and stride frequency during walking. SUBJECTS AND METHODS: Thirteen children with spastic CP (including 4 children who were dropped from the study due to their inability to cooperate) and 6 children who were developing typically participated in the study. A crossover study design was implemented. The children with spastic CP were randomly assigned to either a group that received FES for 15 trials followed by no FES for 15 trials or a group that received no FES for 15 trials followed by FES for 15 trials. The children who were having typical development walked without FES. Kinematic data were collected for the children with CP in each walking condition and for the children who were developing typically. Impulse (force-producing ability) and stiffness were estimated from an escapement-driven pendulum and spring system model of human walking. Stride length and stride frequency also were measured. To compare between walking conditions and between the children with CP and the children who were developing typically, dimensional analysis and speed normalization procedures were used. RESULTS: Nonparametric statistics showed that there was no significant difference between the children with CP in the no-FES condition and the children who were developing typically on speed-normalized dimensionless impulse. In contrast, the children with CP in the FES condition had a significantly higher median value than the children who were developing typically. The FES significantly increased speed-normalized dimensionless impulse from 10.02 to 16.32 when comparing walking conditions for the children with CP. No significant differences were found between walking conditions for stiffness, stride length, and stride frequency. DISCUSSION AND CONCLUSION: The results suggest that FES is effective in increasing impulse during walking but not in decreasing stiffness. The effect on increasing impulse does not result in more typical spatiotemporal gait parameters.

Modulation of force transmission to the head while carrying a backpack load at different walking speeds.

This study was designed to investigate the capability of the joints and segments to reduce transmission of forces during load carriage. Eleven subjects were required to carry a backpack loaded with 40% of their body weight and to walk at 6 speeds increasing from 0.6 to 1.6 ms(-1) in increments of 0.2 ms(-1), and then decreasing in the same manner. Subjects were filmed in 3-dimensions, but analysis of shock transmission ratio (TR) was limited to the sagittal plane. Shock transmission was measured as the ratio of peak vertical accelerations (ankle:head, ankle:knee, and knee:head) measured immediately following foot strike. TR for all ratios increased significantly as a function of increasing speed. TR from the ankle to the head showed no significant increase as a function of load carriage, but did increase as a function of load in transmission from knee to head. A significant interaction effect revealed that during load carriage at the higher speeds the acceleration of the ankle and knee decreased below that for the unloaded conditions. These findings suggest that the potentially injurious effects of previously observed increased ground reaction forces and increased joint stiffness while walking with loads are offset by adaptations in the gait pattern that maintain force transmission at acceptable levels. Increased variability in the acceleration of the head and in the transmission ratios suggest a potentially destabilizing effect of load carriage on the head trajectory.

Musculoskeletal stiffness changes linearly in response to increasing load during walking gait.

Development of biologically inspired exoskeletons to assist soldiers in carrying load is a rapidly expanding field. Understanding how the body modulates stiffness in response to changing loads may inform the development of these exoskeletons and is the purpose of the present study. Seventeen subjects walked on a treadmill at a constant preferred walking velocity while nine different backpack loading conditions ranging from 12.5% to 40% bodyweight (BW) were introduced in an ascending and then descending order. Kinematic data were collected using Optotrak, a 3D motion analysis system, and used to estimate the position of the center of mass (COM). Two different estimates of stiffness were computed for the stance phase of gait. Both measures of stiffness were positively and linearly related to load magnitudes, with the slopes of the relationships being larger for the descending than the ascending conditions. These results indicate that changes in mechanical stiffness brought about in the musculoskeletal system vary systematically during increases in load to ensure that critical kinematic variables measured in a previous publication remain invariant (Caron et al., 2013). Changes in stiffness and other kinematics measured at the 40% BW condition suggest a boundary in which gait stiffness control limit is reached and a new gait pattern is required. Since soldiers are now carrying up to 96% of body weight, the need for research with even heavier loads is warranted. These findings have implications on the development of exoskeletons to assist in carrying loads.

Effects of augmented exercise therapy time after stroke: a meta-analysis.

BACKGROUND AND PURPOSE: To present a systematic review of studies that addresses the effects of intensity of augmented exercise therapy time (AETT) on activities of daily living (ADL), walking, and dexterity in patients with stroke. SUMMARY OF REVIEW: A database of articles published from 1966 to November 2003 was compiled from MEDLINE, CINAHL, Cochrane Central Register of Controlled Trials, PEDro, DARE, and PiCarta using combinations of the following key words: stroke, cerebrovascular disorders, physical therapy, physiotherapy, occupational therapy, exercise therapy, rehabilitation, intensity, dose-response relationship, effectiveness, and randomized controlled trial. References presented in relevant publications were examined as well as abstracts in proceedings. Studies that satisfied the following selection criteria were included: (1) patients had a diagnosis of stroke; (2) effects of intensity of exercise training were investigated; and (3) design of the study was a randomized controlled trial (RCT). For each outcome measure, the estimated effect size (ES) and the summary effect size (SES) expressed in standard deviation units (SDU) were calculated for ADL, walking speed, and dexterity using fixed and random effect models. Correlation coefficients were calculated between observed individual effect sizes on ADL of each study, additional time spent on exercise training, and methodological quality. Cumulative meta-analyses (random effects model) adjusted for the difference in treatment intensity in each study was used for the trials evaluating the effects of AETT provided. Twenty of the 31 candidate studies, involving 2686 stroke patients, were included in the synthesis. The methodological quality ranged from 2 to 10 out of the maximum score of 14 points. The meta-analysis resulted in a small but statistically significant SES with regard to ADL measured at the end of the intervention phase. Further analysis showed a significant homogeneous SES for 17 studies that investigated effects of increased exercise intensity within the first 6 months after stroke. No significant SES was observed for the 3 studies conducted in the chronic phase. Cumulative meta-analysis strongly suggests that at least a 16-hour difference in treatment time between experimental and control groups provided in the first 6 months after stroke is needed to obtain significant differences in ADL. A significant SES supporting a higher intensity was also observed for instrumental ADL and walking speed, whereas no significant SES was found for dexterity. CONCLUSIONS: The results of the present research synthesis support the hypothesis that augmented exercise therapy has a small but favorable effect on ADL, particularly if therapy input is augmented at least 16 hours within the first 6 months after stroke. This meta-analysis also suggests that clinically relevant treatment effects may be achieved on instrumental ADL and gait speed.

Increased musculoskeletal stiffness during load carriage at increasing walking speeds maintains constant vertical excursion of the body center of mass.

The primary objective of this research was to determine changes in body and joint stiffness parameters and kinematics of the knee and body center of mass (COM), that result from wearing a backpack (BP) with a 40% body weight load at increasing speeds of walking. It was hypothesized that there would be speed and load-related increases in stiffness that would prevent significant deviations in the COM trajectory and in lower-extremity joint angles. Three independent biomechanical models employing kinematic data were used to estimate global lower-extremity stiffness, vertical stiffness and knee joint rotational stiffness in the sagittal plane during walking on a treadmill at speeds of 0.6-1.6 ms(-1) in 0.2 ms(-1) increments in BP and no backpack conditions. Kinematic data were collected using an Optotrak, three-dimensional motion analysis system. Knee angles and vertical excursion of the COM during the compression (loading phase) increased as a function of speed but not load. All three estimates of stiffness showed significant increases as a function of both speed and load. Significant interaction effects indicated a convergence of load-related stiffness values at lower speeds. Results suggested that increases in muscle-mediated stiffness are used to maintain a constant vertical excursion of the COM under load across the speeds tested, and thereby limit increases in metabolic cost that would occur if the COM would travel through greater vertical range of motion.

Effect of duration of upper- and lower-extremity rehabilitation sessions and walking speed on recovery of interlimb coordination in hemiplegic gait.

BACKGROUND AND PURPOSE: The effects of different durations of rehabilitation sessions for the upper extremities (UEs) and lower extremities (LEs) on the recovery of interlimb coordination in hemiplegic gait in patients who have had a stroke were investigated. SUBJECTS AND METHODS: Fifty-three subjects who had strokes involving their middle cerebral arteries were assigned to rehabilitation programs with (1) an emphasis on the LEs, (2) an emphasis on the paretic UE, or (3) a condition in which the paretic arm (UE) and leg (LE) were immobilized with an inflatable pressure splint (control treatment). The 3 treatment regimens were applied for 30 minutes, 5 days a week, during the first 20 weeks after onset of stroke. All subjects also participated in a rehabilitation program 5 days a week that consisted of 15 minutes of UE exercises and 15 minutes of LE exercises in addition to a weekly 11/2-hour session of training in activities of daily living. A repeated-measures design was used. Differences among the 3 treatment regimens were evaluated in terms of comfortable and maximal walking speeds. In addition, mean continuous relative phase (CRP) between paretic arm and leg (PAL) movements and nonparetic arm and leg (NAL) movements and standard deviations of CRP of both limb pairs as a measurement of stability (variability) were evaluated. RESULTS: Comfortable walking speed improved in the group that received interventions involving the LEs compared with the group that received interventions involving the UEs and the group that received the control treatment. No differences among the 3 treatment conditions were found for the mean CRP of NAL and PAL as well as the standard deviation of CRP of both limb pairs. DISCUSSION AND CONCLUSION: With the exception of an improved comfortable walking speed as a result of a longer duration of rehabilitation sessions, no differential effects of duration of rehabilitation sessions for the LEs and UEs on the variable we measured related to hemiplegic gait were found. Increasing walking speed, however, resulted in a larger mean CRP for both limb pairs, with increased stability and asymmetry of walking, indicating that walking speed influences interlimb coordination in hemiplegic gait.

Interaction between serum BDNF and aerobic fitness predicts recognition memory in healthy young adults.

Convergent evidence from human and non-human animal studies suggests aerobic exercise and increased aerobic capacity may be beneficial for brain health and cognition. It is thought growth factors may mediate this putative relationship, particularly by augmenting plasticity mechanisms in the hippocampus, a brain region critical for learning and memory. Among these factors, glucocorticoids, brain derived neurotrophic factor (BDNF), insulin-like growth factor-1 (IGF-1), and vascular endothelial growth factor (VEGF), hormones that have considerable and diverse physiological importance, are thought to effect normal and exercise-induced hippocampal plasticity. Despite these predictions, relatively few published human studies have tested hypotheses that relate exercise and fitness to the hippocampus, and none have considered the potential links to all of these hormonal components. Here we present cross-sectional data from a study of recognition memory; serum BDNF, cortisol, IGF-1, and VEGF levels; and aerobic capacity in healthy young adults. We measured circulating levels of these hormones together with performance on a recognition memory task, and a standard graded treadmill test of aerobic fitness. Regression analyses demonstrated BDNF and aerobic fitness predict recognition memory in an interactive manner. In addition, IGF-1 was positively associated with aerobic fitness, but not with recognition memory. Our results may suggest an exercise adaptation-related change in the BDNF dose-response curve that relates to hippocampal memory.

The impact of body-scaled information on reaching.

BACKGROUND: Environmental and task modifications are powerful methods used to affect action in rehabilitation and are frequently used by therapists. OBJECTIVE: The purpose of this study was to examine and quantify the relationship between hand size (person characteristics) and object size (environmental characteristics) and the effect of this relationship on the emergent reaching patterns for children and adults with typical development. DESIGN: This was a cross-sectional prospective study. METHODS: Seventeen children and 20 adults participated and were required to reach and grasp 10 pairs of cubes of different sizes. The dimensionless ratios were calculated by dividing the cube size by the aperture between index finger and thumb to quantify emergent reach and grasp patterns. A critical ratio was used to establish the shift from a 1-handed to an exclusive 2-handed reach pattern. RESULTS: The results demonstrated no significant difference in the mean critical ratios between the 2 groups. However, a 2-handed reach was used more frequently than a 1-handed reach at a significantly smaller ratio for children in comparison with adults. LIMITATIONS: The relational metrics between the cube and hand are only one contribution to the emergent reaching and grasping patterns. CONCLUSIONS: Children had more variability of reaching patterns than adults. A personal constraint, such as experience, and a task constraint of accuracy may account for the variability. The results encourage further research on body-scaled information for individuals with different personal constraints (eg, children with cerebral palsy) and the impact of body-scaled information on emergent actions.