Search

Background Agenesis of the corpus callosum (ACC) is a rare congenital brain defect that produces a wide variety of cognitive and motor impairments. Literature regarding the response of pediatric populations with ACC to physical rehabilitation is scarce. Treadmill-based gait training (TT) has been shown to improve walking ability in some pediatric populations but has not been investigated in children with ACC. Objective The purpose of this study was to investigate the effect of a novel treadmill intervention paradigm on the gait parameters of a child with ACC. Design A single-participant design with 2 phases was used. Methods The settings were the participant's home and the laboratory. The participant was a 13-year-old girl who had ACC and cortical visual impairment and who ambulated independently using a reverse walker for household and short community distances. A home-based TT intervention (2 phases of 3 months of training over 6 months) was implemented, and a laboratory-based gait analysis was conducted at 4 time points: baseline, after each of the 2 training phases, and 3 months after the cessation of training. The intervention consisted of weekly bouts of TT. Phase I incorporated forward, backward, and incline walking for 15 minutes each; in phase II, this protocol was continued, but short-burst interval training for 10 minutes was added. Data collected at each laboratory visit included spatiotemporal parameters and kinematics (joint angles) during overground and treadmill walking. Results After both phases of training, increased step length, decreased step width, and foot progression angle and decreased variability of most spatiotemporal parameters were observed for the participant. Further, after phase II, increased peak extension at the hip, knee, and ankle, decreased crouched gait, and improved minimum foot clearance during overground walking were observed. Most gait improvements were retained for 3 months after the cessation of the intervention. Limitations The small sample size of this study and wide variety of presentations within individuals with ACC limit the generalizability of our findings. Conclusions TT may be a safe and effective treatment paradigm for children with ACC. Future research should investigate the effect of intervention dosage on gait improvements and generalization in individuals with ACC. [ABSTRACT FROM AUTHOR]

Background: Studies have typically treated the first and second floor-to-stair transition steps (TS1 and TS2) as one stride. However, because the foot is devoid of plantar cutaneous input from the stair surface at TS1, these steps may have different toe spatiotemporal profiles, and resultantly, different susceptibilities to a trip and/or a fall. This study compared vertical toe clearance, forward velocity, and their respective variability magnitudes between TS1 and TS2 when ascending stairs of different heights. Methods: Twenty young adults (seven males and 13 females) (21.68 ± 2.49 years; 169.70 ± 9.56 cm; 63.91 ± 9.62 kg) negotiated an intervening three-step staircase placed midpoint on a 10 m walkway. There were three stair heights: low stairs (LS), medium stairs (MS), and high stairs (HS). Vertical toe clearance, forward velocity, and their variability magnitudes were calculated. Results: Vertical toe clearance was only higher (P < 0.05) at TS1 than TS2 in the medium and high stairs. Vertical toe clearance was more variable (P < 0.05) in the low compared to medium stairs. Also, forward toe velocity was greater at TS1 than TS2, but was lower in the medium and high stairs. Conclusion: The locomotor system appeared cautious by exaggerating vertical toe clearance at both TS1 and TS2 only in low stairs, possibly due to higher forward toe velocity. If the exaggeration strategy consistently persists, this finding may suggest decreased trip or fall risk at both TS1 and TS2 only when transitioning onto low stairs. [ABSTRACT FROM AUTHOR]

Highlights: [•] We study postural response in children using unilateral Achilles tendon vibration. [•] Both 6- and 10-year-old children show a directionally specific postural response. [•] Both 6- and 10-year-old children display an adult-like timing of postural response. [•] Only 10-year-old children show some adult-like spatial pattern in the AP direction. [ABSTRACT FROM AUTHOR]

Highlights: [•] We study vertical GRF and impulse of treadmill walking in children with DS and TD. [•] Children with DS produce less efficient propulsion during treadmill walking. [•] A faster speed helps children with DS increase propulsive duration and impulse. [•] External ankle load helps children with DS increase propulsive force and impulse. [ABSTRACT FROM AUTHOR]

Models of human gait are based on adult locomotion. C. E. Bauby and A. D. Kuo (2000) proposed that adults rely on passive mechanisms at the spinal level to control motion in the anteroposterior direction and rely on direct monitoring of postural control in the lateral direction. The authors' purpose in this study was to determine if that model applies to control at the onset of walking in typically developing toddlers (n = 9) and in toddlers with Down syndrome (n = 6). Their longitudinal data suggested that toddlers control gait in a distinctly different manner than adults do. An adult pattern of control emerges with experience. In addition, the effect of experience on the emergence of that pattern is magnified by task-specific early intervention. The present data support the emergence and discovery of efficient patterns of control in this fundamental human behavior. [ABSTRACT FROM AUTHOR]

This study investigated the development of adaptive gait of toddlers in obstacle negotiation. Three groups were studied: toddlers with typical development (TD, N = 9), toddlers at risk for cerebral palsy without treadmill training (RC, N = 5), and toddlers at risk for CP who received treadmill training (RE, N = 5). Infants at risk for CP were recruited at about 9 months of age and randomly assigned to either RC or RE group. A home-based treadmill training was provided for the RE group until the child walked 3 steps independently (walking onset). Then, at about 1 and months after walking onset, all three groups were brought into our lab to collect gait data. A 5-cm-high obstacle was placed perpendicular to the travel path on the floor at Visits 1 and 2, and was also raised to 10% of the child's leg length at Visit 2. All the trials were recorded with a video camera. A GaitRite mat was used to record footprints and to calculate spatiotemporal gait variables (step length, step width, and step time). Results showed that all three groups preferably walked over the obstacle starting at Visit 1. However, in terms of the second preferred strategy at Visit 1, the TD group tried to step over the obstacle but failed, whereas both RC and RE groups equally crawled or fell over the obstacle. Also at Visit 2, all three groups decreased step length sequentially in the three steps prior to the obstacle, and then increased step length and step time for the leading foot crossing the obstacle (all p 0.05). However, such locomotor adjustment patterns were observed only in TD and RE groups at Visit 1. These preliminary results suggest that all three groups are able to predominately walk over the obstacle at 1 month after walking onset, and produce locomotor adjustment while negotiating an obstacle at 4 months after walking onset. Furthermore, treadmill training appears to facilitate earlier development of locomotor adjustment in obstacle negotiation in infants at risk for CP. [ABSTRACT FROM AUTHOR]

It has been reported that children produce more variability in head movement during level walking than young adults. However, how the variability in head movement is used to regulate head control during gait has not been investigated between healthy children and young adults. The uncontrolled manifold (UCM) hypothesis provides theoretical framework to partition the variability of the joint configuration into two orthogonal subspaces: task-relevant (VUCM) and task-irrelevant (VORT). A greater VUCM and a smaller VORT implies a more stably controlled body movement. This study investigated how healthy children and young adults make use of available variability in head control at two gait events: heel strike and toe off. Three healthy populations were studied: young children (YC, 6 years, N = 7), old children OC, 10 years, N = 7), and young adults (YA, 20 years, N = 7). Kinematic data were collected using a Vicon Peak motion capture system, and 5 trials were collected for each subject at the preferred walking speed. The left and right temple markers were used to represent head movement and were analyzed along the horizontal and vertical directions in the sagittal plane. A ratio VUCM/(VUCM + VORT) was used to quantify how much variability was partitioned to the task-relevant subspace. Results showed that at both heel strike and toe off, the YC group produced significantly greater SD than both OC and YA groups in the horizontal and vertical directions, respectively (all p < 0.05). However, the ratios from the UCM analysis were not significantly different among the three groups in both directions at heel strike. At toe off, the ratios produced by the YC group in both directions were significantly smaller than those for the OC and YA groups (all p < 0.05). These results suggest that OC group produces adultlike gait patterns in both the amount and the partition of variability, whereas the YC group partitions more variability in task-relevant subspace like young adults at heel strike but not at toe off although the YC group produces greater amount of variability at both gait events. [ABSTRACT FROM AUTHOR]

Challenging children with Down syndrome to walk fast and with external ankle load has demonstrated acute adjustments, such as increased step length and decreased step width, and improved joint stability. However, it is unknown to what extent these task constraints affect gait stability. Assessing dynamic gait stability through margin-of-stability not only quantifies adjustments related to balance control, but also informs safety considerations. Twenty-four children with and without Down syndrome participated in this study. Subjects walked overground at two speed conditions: self-selected (normal) and as fast as possible (fast); and two ankle load conditions: no load and ankle load of 2% body mass. We assessed margin-of-stability in the anteroposterior and mediolateral directions, separately, at three gait events of toe-off, mid-swing, and heel strike. Children with Down syndrome walked with greater mediolateral margin-of-stability than typically developing children. Children with Down syndrome demonstrated less anteroposterior margin-of-stability than typically developing children only before heel-strike at normal speed but increased anteroposterior margin-of-stability at fast speed. The ankle load increased the mediolateral margin-of-stability in both groups but did not impact the anteroposterior margin-of-stability. In addition, children with Down syndrome took shorter and wider steps for more lateral placement of mediolateral margin-of-stability. Children with Down syndrome were capable of adjusting their margin-of-stability for fast walking and ankle-load conditions. However, children with Down syndrome walked with less mediolateral stability and anteroposterior mobility than typically developing children. Children with Down syndrome overcompensate the mediolateral foot placement to recapture their margin-of-stability and maintain gait stability. • Children with Down syndrome walked with a distinct joint pattern compared to peers. • Increased walking speed improved ankle kinematics, but challenged knee kinematics. • Ankle load improved hip and knee kinematics, but challenged ankle plantarflexion. • Intervention design can consider the manipulation of walking speed and ankle load. [ABSTRACT FROM AUTHOR]

Background: Backward walking and fast walking have distinctive gait patterns in adults; however, there is minimal literature describing these gait modifications in typically developing children. Additionally, most of previous research focused on overground backward walking, but not on a treadmill.Research Question: How do typically developing children adapt their gait patterns, including spatiotemporal parameters, joint kinematics, and muscle activation, to changes in direction and speed during treadmill walking?Methods: We recruited 19 children (10 M/9 F) aged 6-12 years. Treadmill conditions included forward and backward walking at three speeds: slow (75 % of normal speed), normal speed, and fast (125 % of normal speed). Subjects completed a 2-minute trial under each condition. Spatiotemporal, kinematic, kinetic and electromyography data were collected and analyzed. Correlations between forward and time-reversed backward walking were calculated for joint angles and vertical ground reaction force.Results: During backward walking, children (a) decreased step lengths and increased step widths and foot clearance, (b) decreased peak hip and knee flexion and increased peak ankle dorsiflexion, and (c) increased muscle activity at the vastus lateralis, rectus femoris, and tibialis anterior. At faster speeds, children increased step lengths and inconsistently increased overall muscle activity. Both the hip and knee showed high correlation between forward and time-reversed backward walking, while correlation at the ankle was low.Significance: Overall, children adapt their gait to changes in direction and speed of treadmill walking in similar ways to adults. However, notable differences emerged in that children limited their ankle range of motion. Our results suggest that, while many aspects of gait are mature enough by this age to adapt to backward walking on a treadmill, neuromuscular control at the ankle may still be lacking in children while walking backward on a treadmill. [ABSTRACT FROM AUTHOR]

Background: The Wartenberg pendulum test is a common clinical test that is used to measure stiffness about the knee in persons with and without disabilities such as cerebral palsy and Down syndrome (DS). Adults and adolescents with DS show fewer number of swing cycles and a lower relaxation index than healthy controls. However, it is not clear if children with DS show a similar trend compared to typically developing (TD) children.Research Question: Was the knee joint kinematics different between children with and without DS during the pendulum test?Methods: Thirteen children with DS and 13 TD children participated in this study. There were two load conditions: no load (NL) and with ankle load (AL) equal to 2 % of the subject's body weight. Five trials of a pendulum test were collected for each condition.Results: The DS group showed a smaller first flexion excursion, a lower relaxation index, lower mean and peak velocities and accelerations during the first and second flexion and extension, and greater variability of acceleration during the first flexion than the TD group across both load conditions. This suggests that the DS group may have greater stiffness of the knee than the TD group to compensate for joint instability.Significance: The pendulum test appears to be a valid test to evaluate the passive stiffness of the knee in children with DS. The lower relaxation index in children with DS suggests that larger bursts of quadriceps may be activated during a pendulum test, particularly in the first flexion excursion, to assure the knee joint stability. [ABSTRACT FROM AUTHOR]

Background: Children with Down syndrome (DS) often show underdeveloped motor ability and adaptation. Stair ascent is a common task to examine locomotor function and external ankle load is often used to perturb the stability of a system and observe the emergence of new patterns.Research Question: How do stair height and external ankle load affect locomotor adjustments in 5-to-11-year-old children with typical development (TD) and with DS during stair ascent?Methods: Fourteen children with DS and 14 age- and sex-matched children with TD participated in this study. They walked along a 5-m walkway and ascended 3-step staircases of different heights (low, moderate, and high) with or without ankle load. A 3D motion capture system was used for data collection. Dependent variables included stance time and toe-to-stair distance before stair ascent, and vertical toe clearance and horizontal toe velocity during stair ascent. Mixed ANOVAs with repeated measures were conducted for statistical analysis.Results: The DS group presented a longer stance time and a shorter toe-to-stair distance than the TD group before stair ascent. External ankle load affected, to a greater extent, the DS group than the TD group in stance time and toe-to-stair distance. During stair ascent, while the TD group generally maintained toe clearance and decreased horizontal toe velocity with the increase of stair height, the DS group decreased toe clearance and maintained horizontal toe velocity. Particularly, the DS group displayed a greater toe clearance than the TD group in the LS condition but a smaller toe clearance in the HS condition. In addition, external ankle load increased toe clearance and decreased horizontal toe velocity in both groups.Significance: Children with DS display underdeveloped locomotor adjustments during stair ascent. External ankle load appears to help the DS group regulate toe clearance and horizontal toe velocity for different stair heights. [ABSTRACT FROM AUTHOR]

Whole-body vibration (WBV) is a relative new intervention paradigm that could reduce spasticity and improve motor function in children with cerebral palsy (CP). We investigated neuromuscular response to a single session of side-alternating WBV with different amplitudes in children with CP. Ten children with spastic CP aged 7–17 years at GMFCS level I-III participated in this pilot study. Participants received two sessions of side-alternating WBV with the same frequency (20 Hz) but different amplitudes (low-amplitude: 1 mm and high-amplitude: 2 mm). Each session included six sets of 90 s of WBV and 90 s of rest. Before and after each WBV session, we used (a) the modified Ashworth scale to evaluate the spasticity of the participants' leg muscles, (b) a quiet standing task to analyze center-of-pressure (CoP) pattern and postural control, and (c) overground walking trials to assess spatiotemporal gait parameters and joint range-of-motion (RoM). Both WBV sessions similarly reduced the spasticity of the ankle plantarflexors, improved long-range correlation of CoP profile during standing, and reduced muscle activity of tibialis anterior during walking. The high-amplitude WBV further increased ankle RoM during walking. This study demonstrates that a single session of WBV with either a low or a high amplitude can reduce spasticity, enhance standing posture, and improve gait patterns in children with CP. It suggests that low-amplitude WBV may induce similar neuromuscular response as high-amplitude WBV in children with spastic CP and can provide positive outcomes for those who are not able to tolerate stronger vibration. • A single session of whole-body vibration benefits children with cerebral palsy. • Both high- and low-amplitude vibration reduce leg muscle spasticity. • Both vibration sessions improve long-range correlation of standing posture. • Both vibration sessions reduce muscle activity of tibialis anterior during walking. • Only high-amplitude vibration increases the ankle range of motion during walking. [ABSTRACT FROM AUTHOR]

Background: Increasing walking speed and including bilateral external ankle load have been shown to improve aspects of the gait pattern of children with Down syndrome (DS). However, it is unknown if speed and ankle load improves the cycle-to-cycle variability in a similar way.Research Question: How do changes of walking speed and external ankle load impact spatiotemporal variability during treadmill walking in children with and without DS?Methods: Thirteen children with DS (aged 7-10 years) and thirteen age- and sex-matched typically developing (TD) children participated in this study. Subjects completed two bouts of 60-second treadmill walking at two different speeds (slow and fast) and two load conditions (no load and ankle load equaling to 2% bodyweight at each side). Kinematic data was captured using a Vicon motion capture system. Mean and coefficient of variance of spatiotemporal gait variables were calculated and compared between children with and without DS.Results and Significance: Across all conditions, the DS group took shorter and wider steps than the TD group, but walked with a similar swing percentage, double support percentage, and foot rotation angle. Further, the DS group demonstrated greater variability of all spatiotemporal parameters, except for step width and foot rotation angle. Our results indicated that children with DS can modulate their spatiotemporal gait pattern accordingly like their TD peers when walking faster on a treadmill and/or with an external ankle load. Smaller step width variability in the DS group suggests that mediolateral stability may be prioritized during treadmill walking to safely navigate the treadmill and complete walking tasks. Similar temporal parameters but distinct spatial parameters in the DS group suggest that they may have developed similar rhythmic control but are confined by their spatial movement limitations. [ABSTRACT FROM AUTHOR]