Gait Of Normal Subjects Research Articles

Simulation of Paretic Gait in Normal Subjects by Loading the Ankles

Normal subjects were loaded with increasing weights (2-6 kg) applied around the ankles. During these conditions stride length increased in relation to velocity. The percentage duration of single support in relation to stride duration increased. Provided the same load was applied around both ankles increase was symmetrical. Consequently there was also an increase of swing as well as a decrease of stance and of double support. The results contrast in all respects to what was found in previous experiments when the load was carried in the hand. During these conditions stride length decreased as well as the duration of single support. The two experimental conditions differed in that with ankle loading the swing phase was loaded while in the other case stance was loaded. The two types of experiment may help to explain why some patients with paretic legs walk with short strides, while others walk with strides that are normal or slightly prolonged.

T50. Freezing of gait does not modulate neural oscillations in motor cortices

Introduction Walking abilities are severely affected in patients with freezing of gait (FOG), a common phenomenon in advanced stages of Parkinson’s disease (PD). Despite the high occurrence of FOG, little is known about the underlying mechanisms. Interestingly, it was reported that patients with FOG are still able to ride a bike (Snijders AH et al., Bicycling breaks the ice for freezers of gait, Mov Disord 2011). While similar brain networks are involved in walking and bicycling (Fukuyama H et al., Brain functional activity during gait in normal subjects: A SPECT study, Neurosci Lett 1997; Christensen LOD et al., Cerebral activation during bicycle movements in man, Exp Brain Res 2000), it is not completely understood why both types of movement are differently affected in PD patients with FOG. A recent study from our group demonstrated that the oscillatory activity within the subthalamic nucleus (STN) differs between patients with and without FOG (Storzer L et al., Bicycling suppresses abnormal beta synchrony in the Parkinsonian basal ganglia, Ann Neurol 2017). In particular, it was shown that patients with FOG present a characteristic increase of oscillatory activity at ∼18 Hz. The aim of the study was to examine movement-associated cortical oscillatory activity in PD patients with and without FOG. Methods We analyzed EEG data of 19 PD patients with FOG (65.5 ± 7.2 years), 13 PD patients without FOG (61.6 ± 8.1 years), and 16 healthy controls (63.3 ± 7.3 years). Patients were recorded OFF dopaminergic medication using a portable EEG system (Porti, TMSi, Enschede, The Netherlands). Data were recorded during unconstrained walking and bicycling on a stationary bicycle. Measurements consisted of a baseline rest period, continuous movement, and an alternating sequence of rest and movement, i.e. bicycling or walking, for 10 s each. Furthermore, measurements included 180° turns around the body axis during walking condition. Turns were rated for the occurrence of FOG episodes by two different raters. Analyses were focused on oscillatory activity in the beta band and the Cz electrode overlying the leg area of both motor cortices. Statistical testing was performed by fitting linear mixed models using package lme 1.1–13 for R. Results Bicycling and walking were associated with beta power suppression (13–35 Hz). This suppression was stronger for bicycling than for walking ( β = −0.37, p β = −0.11, p = 0.72). Furthermore, within the group of Freezers we did not find cortical differences between turns with FOG and turns without FOG either( β = 0.66, p = 0.4). Conclusion We did not observe cortical beta power changes specifically related to freezing. This finding does not support the notion that the primary motor cortex is crucially involved in generating freezing.

Estimation of effects of walking speed to vertical ground reaction force

The measurement of ground reaction force (GRF) is important in biomechanical analysis for clinical gait assessment and gait research. The GRF measured by the force plate, along with the gravity, are the only significant external forces acting on the body during gait. The purpose of this study is to show the effects of walking speed on vertical ground reaction force (VGRF) F z using Kistler quartz force platform embedded on the floor. Since considerable differences in the gait of normal subjects arises due to ‘constrained’ walking, so subject are made to walk with their self selected walking speed in the walkway. Vertical component of the GRF was analysed from the recorded data using Bioware software. It was clearly observed that with increasing walking speed VGRF increased at F z 1 and F z 3 whereas decreased at F z 2 .

The effect of simulated hamstring shortening on gait in normal subjects

The purpose of this study was to determine the effect of simulated hamstring shortening on gait in normal subjects. Six normal subjects wore an adjustable brace to simulate three different hamstring lengths. Evaluation of the physiological cost index (PCI) and gait analysis revealed that simulated hamstring shortening produced adverse affects in the gait of normal subjects. Significant effects were only observed when the popliteal angle exceeded 85° ( p < 0.001) and included increased effort of walking (PCI), decreased speed, stride and step length; decreased hip flexion and increased knee flexion in stance, increased posterior pelvic tilt, decreased pelvic obliquity and rotation and premature ankle dorsi- and plantar-flexion in stance. These results emphasise the need to consider the effects of changing the length of the hamstrings on joints other than the hip and knee when assessing patients for hamstring lengthening.

Effect of compensation procedures for velocity on repeatability and variability of gait parameters in normal subjects

Objective: To evaluate the effects of a mathematical procedure that adjusts for gait velocity on the variability seen in gait analysis. Design: Evaluation before and after compensation. Setting: Gait laboratory, Fukui University Hospital, Japan. Subjects: Fourteen normal volunteers. Outcome measures: A computerized gait analysis system with two forceplates and a light source spot measuring device was used. Gait measurement in each subject was performed on three different days. Results: The gait parameters measured on three different days were significantly different, particularly step length, stride length, velocity, the components of floor-reaction forces and hip motion. In these parameters, intraclass correlation coefficient, ICC (1,1) was not high (range 0.05-0.71). However, there was a high correlation between these parameters and velocity and high repeatability was obtained following compensation for velocity (ICC (1,1), range 0.73-0.97). In contrast, compensation of parameters whose measurement was not significantly different before compensation did not improve ICC (1,1). Variability of all parameters was acceptable, however CV (an index of variability) improved significantly after compensation compared with that before compensation in six of 15 parameters. Conclusions: Our findings suggest that low repeatability in gait parameters should be considered even when the gait of normal subjects is measured on different days. A high repeatability and more acceptable variability were obtained when the data were compensated for velocity.

Empreintes de pieds dynamiques ou statiques : calculs comparés de l'angle et de l'appui de la marche

Information derived from footprint data serves as a useful, reliable and objective component to the assessment of patients with musculoskeletal pathology. Common spatial parameters extrapolated from such data include the angle and base of gait. Previous research has described a reliable method for analysing dynamic footprint data. While this data remains fundamental, few studies, if any have documented the comparisons of dynamic and static footprints. The purpose of this study was to ascertain the differences between the angle and base of gait from dynamic and static footprint data. Twenty-five subjects provided three dynamic (mid-gait analysis) and three static footprints. Intra-rater reliability of the measurement technique for both the angle and base of gait was found to be excellent ( P >0.001) for each of the two conditions (dynamic and static). Comparisons between the dynamic and static condition revealed no significant differences ( P <0.0001) for the angle of gait, whilst significant differences were noted between the static and dynamic condition for the base of gait. Further analysis using linear regression identified that the angle of gait for the left and right foot predicted a 67 and 60% of that of a dynamic situation; a slightly lower prediction of 54% was noted for base of gait. These results suggest that static footprints do demonstrate some prediction of dynamic function when assessing the angle and base of gait in normal subjects.

Dynamic and static footprints: comparative calculations for angle and base of gait

Information derived from footprint data serves as a useful, reliable and objective component to the assessment of patients with musculoskeletal pathology. Common spatial parameters extrapolated from such data include the angle and base of gait. Previous research has described a reliable method for analysing dynamic footprint data. While this data remains fundamental, few studies, if any have documented the comparisons of dynamic and static footprints. The purpose of this study was to ascertain the differences between the angle and base of gait from dynamic and static footprint data. Twenty-five subjects provided three dynamic (mid-gait analysis) and three static footprints. Intra-rater reliability of the measurement technique for both the angle and base of gait was found to be excellent ( p > 0.001) for each of the two conditions (dynamic and static). Comparisons between the dynamic and static condition revealed no significant differences ( p < 0.0001) for the angle of gait, whilst significant differences were noted between the static and dynamic condition for the base of gait. Further analysis using linear regression identified that the angle of gait for the left and right foot predicted a 67 and 60% of that of a dynamic situation; a slightly lower prediction of 54% was noted for base of gait. These results suggest that static footprints do demonstrate some prediction of dynamic function when assessing the angle and base of gait in normal subjects.

Brain functional activity during gait in normal subjects: a SPECT study

The purpose of this study was to evaluate changes in brain activity during voluntary walking in normal subjects using technetium-99m-hexamethyl-propyleneamine oxime single photon emission computed tomography. This study included 14 normal subjects. Statistical parametric mapping analysis revealed that the supplementary motor area, medial primary sensorimotor area, the striatum, the cerebellar vermis and the visual cortex were activated. These results suggested that the cerebral cortices controlling motor functions, visual cortex, basal ganglia and the cerebellum might be involved in the bipedal locomotor activities in humans.

Effects of joint motion constraints on the gait of normal subjects and their implications on the further development of hybrid fes orthosis for paraplegic persons

In this study the effects of angular motion constraints of the lower limbs on the gait of normal subjects were investigated. An assessment orthosis was developed with a new hip coupling mechanism which allows its ratio of reciprocal flexion to extension to be altered. The knee and ankle joints of the orthosis could also be set to be free or locked in specific directions of angular motion in the sagittal plane. A total of 12 different orthosis configurations was tested on three normal subjects. The kinematic, kinetic and electromyographic (EMG) data were collected using the VICON system, two Kistler forceplates, foot switches and an eight channel EMG system. The physiological cost index of walking was assessed by measuring the heart rate and walking speed. It was found that (1) a higher hip flexion-extension ratio was associated with lower energy cost and faster walking; (2) allowing the knee to flex significantly reduced the energy cost and increased the walking speed; (3) allowing the ankle to plantarflex during early stance phase reduced the knee flexing moment. The implications of these effects on the further development of hybrid functional electrical stimulation orthotic systems are discussed.

Interaction between active and passive knee stabilizers during level walking

The gait of normal subjects and patients with varus deformities at the knee was studied by analyzing the interaction between the dynamic (muscular) and passive (ligamentous) restraints affecting lateral stability of the knee. A statistically determinant model predicted that the midstance-phase adducting moment during normal gait would cause lateral knee joint opening if either antagonistic muscle force and/or pretension in the lateral soft tissues were not present at the knee. The patient group tended to compensate for a high midstance-phase adducting moment by walking with a style of gait that demanded more muscle force (greater flexion-extension moments). This walking style reduced the chance of lateral joint opening. It can be speculated that this style of gait would help to maintain equilibrium at the knee. The higher muscle force would aid in resisting the adducting moment, keeping the joint closed laterally and thus increasing the stability of the knee.

Initiation of gait in normal subjects: a preliminary study

The initiation of gait, from standing at rest to the toe-off of the second leg, was analysed in 15 normal subjects wearing shoes. Thirty-two parameters were identified and measured. The pattern of forces, angular movement and timing in this period are described and analysed. Two groups, one of 8 female subjects and another of 7 males, were compared statistically. Sex-related differences were found in the mediolateral and vertical forces as well as in which leg was the first to leave the ground. The values of all the parameters are given, as part of a database to be used in the future for diagnostic and assessment purposes in orthopaedics.

Influence of dystonia on the response to long-term L-dopa therapy in Parkinson's disease.

The gait of normal subjects was examined electromyographically and the pattern was altered during preferential blockade of large nerve fibres to alternating activity in flexor and extensor muscles.The EMG activity was disrupted more in flexor than extensor muscles by preferential ischaemic blockade. Normal gait was associated with flexor contraction only when the foot was lifted and placed on the ground, whereas during ischaemic blockade flexor contraction continued during the interval between foot lifting and foot placement.The `freezing' or `blocking' gait in Parkinson's disease was found to be associated with coactivation of flexor and extensor muscles and this phenomenon occurred only in patients with features of flexion dystonia in the electromyographic recordings of their tonic stretch reflexes. Eight of nine patients with evidence of flexion dystonia showed a deterioration in their response to l-dopa therapy over a two year period, whereas four patients without flexion dystonia maintained their clinical improvement.