Erratum to "Effects of wearing a foot orthosis on ankle function in children with idiopathic toe walking during gait." [Heliyon 8(10) (October 2022) e11021].

[This corrects the article DOI: 10.1016/j.heliyon.2022.e11021.].

Ankle Kinematics Characterization in Children with Idiopathic Toe Walking: Does the Foot Model Change the Clinical Evaluation?

Idiopathic toe walking (ITW) is a gait deviation characterized by forefoot contact with the ground, sometimes observed in children, that alters ankle kinematics, possibly leading to health-related issues. When studying foot and ankle gait deviations, the adoption of a single-segment foot model entails a significant simplification of foot and ankle movement, and thus may potentially mask some important foot dynamics. Differences in ankle kinematics between single- (conventional gait model, PiG, or Davis) and multi-segment (Oxford foot model, OFM) foot models were investigated in children with ITW. Fourteen participants were enrolled in the study and underwent instrumented gait analysis. Children were asked to walk barefoot and while wearing a foot orthosis that modified the ankle movement pattern toward a more physiological one without blocking foot intrinsic motion. ITW gait abnormalities, e.g., the absence of heel rocker and the presence of anticipated forefoot rocker, were found/not found according to the foot model. Walking conditions significantly interacted with the foot model effect. Finally, the different characterization of gait abnormalities led to a different classification of ITW, with a possible impact on the clinical evaluation. Due to its closer adhesion to ankle anatomy and to its sensitivity to ITW peculiarities, OFM may be preferable for instrumented gait analysis in this population.

Effects of wearing a foot orthosis on ankle function in children with idiopathic toe walking during gait.

Background: Idiopathic toe walking (ITW) is a gait deviation characterized by forefoot contact with the ground, possibly enhancing the risk of falling and causing Achilles' tendon shortening and psychological discomfort. Between possible treatments, foot orthosis may limit ITW when worn. With these premises, the effects of a novel foot orthosis (A.Dyn.O.®) on ankle function were analyzed in children with ITW during gait. Methods: Twenty-one children were recruited in the study after ITW diagnosis. At follow-up assessment after a habituation period of at least two weeks, participants walked in barefoot condition and while wearing A.Dyn.O.®. Kinetics and kinematics were derived from a multi-segment foot model using an optoelectronic system. Gait spatiotemporal parameters, ankle kinetic and kinematic and rockers timing were analyzed. Lastly, ITW severity was classified according to Alvarez classification. Differences between conditions were verified with paired t-test. Statistical parametric mapping was used to evaluate differences in the entire kinematic and kinetic waveforms. Findings: Wearing A.Dyn.O.®, step cadence was reduced, step length, stance phase and stride duration increased; physiological heel rocker was present, thus postponing the timing of ankle and forefoot rockers; ankle dorsiflexion angular excursion, range of motion, maximal dorsiflexor and plantarflexor moments together with maximal power absorption and production were all amplified. Interpretation: While wearing it, A.Dyn.O.® limited gait deviations typical of ITW and improved ITW severity classification for most of the participants. These findings suggest that the use of A.Dyn.O.® may assist ITW treatment, preventing children from toe walking and thus limiting its side effects.

A wearable gait analysis protocol to support the choice of the appropriate ankle-foot orthosis: A comparative assessment in children with Cerebral Palsy.

BACKGROUND: Cerebral Palsy is, nowadays, the most common cause of pediatric disabilities, particularly debilitating for daily living activities. While the adoption of ankle-foot orthoses is very well established as gait treatment, the choice of the most appropriate orthotic configuration is not strongly supported by scientific evidence. The aim of this study was to develop an instrumented assessment protocol based on wearable gait analysis to support clinicians in ankle-foot orthoses configuration selection. METHODS: Ten children with spastic diplegic Cerebral Palsy were assessed (7 males, aged 4 to 11 years; all functionally classified as Gross Motor Function Classification System I or II, with clinical indication of conservative treatment through use of ankle-foot orthoses). They performed a 10Meter Walk Test in three conditions: barefoot and wearing alternatively a polypropylene hinged and solid ankle-foot orthosis accommodated in the same off-the-shelf shoe model, after 20 days of daily use of each configuration. An instrumented assessment protocol based on body-mounted magneto-inertial sensors was devised to derive spatio-temporal, gait stability and symmetry biomechanical parameters within an observational pre and post cross over design. FINDINGS: The analysis at the individual level quantitatively revealed how different patients benefited differently from the two orthoses. No general indications were obtained in favour of or against a specific configuration for the sample as a whole. INTERPRETATION: The proposed instrumented protocol represents a quantitative and useful tool to support the clinical selection of an appropriate orthotic treatment and, potentially, in evaluating its effectiveness.

Reduced short term adaptation to robot generated dynamic environment in children affected by Cerebral Palsy.

BACKGROUND: It is known that healthy adults can quickly adapt to a novel dynamic environment, generated by a robotic manipulandum as a structured disturbing force field. We suggest that it may be of clinical interest to evaluate to which extent this kind of motor learning capability is impaired in children affected by cerebal palsy. METHODS: We adapted the protocol already used with adults, which employs a velocity dependant viscous field, and compared the performance of a group of subjects affected by Cerebral Palsy (CP group, 7 subjects) with a Control group of unimpaired age-matched children. The protocol included a familiarization phase (FA), during which no force was applied, a force field adaptation phase (CF), and a wash-out phase (WO) in which the field was removed. During the CF phase the field was shut down in a number of randomly selected "catch" trials, which were used in order to evaluate the "learning index" for each single subject and the two groups. Lateral deviation, speed and acceleration peaks and average speed were evaluated for each trajectory; a directional analysis was performed in order to inspect the role of the limb's inertial anisotropy in the different experimental phases. RESULTS: During the FA phase the movements of the CP subjects were more curved, displaying greater and variable directional error; over the course of the CF phase both groups showed a decreasing trend in the lateral error and an after-effect at the beginning of the wash-out, but the CP group had a non significant adaptation rate and a lower learning index, suggesting that CP subjects have reduced ability to learn to compensate external force. Moreover, a directional analysis of trajectories confirms that the control group is able to better predict the force field by tuning the kinematic features of the movements along different directions in order to account for the inertial anisotropy of arm. CONCLUSIONS: Spatial abnormalities in children affected by cerebral palsy may be related not only to disturbance in motor control signals generating weakness and spasticity, but also to an inefficient control strategy which is not based on a robust knowledge of the dynamical features of their upper limb. This lack of information could be related to the congenital nature of the brain damage and may contribute to a better delineation of therapeutic intervention.

Neurophysiological changes induced by the botulinum toxin type A injection in children with cerebral palsy.

In the last few years botulinum toxin type A (BTX-A) has been widely used in the management of spasticity in children with cerebral palsy in order to reduce hypertonicity and improve functional outcomes enhancing motor skill development. The botulinum toxin injection seems to interact with intrafusal and extrafusal fibers producing a reduction of hypertone both through synaptic blockade and inhibition of stretch reflex loop and these changes may influence not only the spinal cord but also the central nervous system (CNS). The purpose of our study was to determine the neurophysiological changes induced by the BTX-A through an evaluation of cortical somatosensory Evoked Potential (SEP) and Soleus H wave, that is the index of excitability of stretch reflex loop. Eighteen children with Cerebral Palsy (CP), aged between 5 and 12, were recruited at Children's Hospital "Bambino Gesù" of Rome. All children were evaluated with appropriate clinical scales before and 1 month after the BTX-A injection. Neurophysiological measurements were performed before, and 1 month after botulinum toxin injection through lower limb SEPs, M-wave and Soleus H wave recording. After the injection the results showed a statistically significant improvement both of clinical scales and the neurophysiological variables. These findings suggest that spasticity itself can be considered as a factor affecting the cortical SEPs. And even though it seems that BTX-A does not have any direct central effect on sensory pathways we suppose an indirect mechanism on modulation of afferent fibers Ia due to the modification induced by BTX-A to central loop reflex.

Robot-mediated and clinical scales evaluation after upper limb botulinum toxin type A injection in children with hemiplegia.

OBJECTIVE: The aim of this pilot study was to examine changes in different aspects of impairment, including spasticity in the upper limbs, of hemiplegic children following botulinum toxin type A intervention. Progress was assessed using standard clinical measurements and a robotic device. DESIGN: Pre-post multiple baseline. SUBJECTS: Six children with hemiplegia. METHODS: Botulinium toxin type A injections were administered into the affected upper limb muscles. Outcomes were evaluated before and one month after the injection. Outcome assessments included: Melbourne Scale, Modified Ashworth Scale (MAS) and Passive Range of Motion. Furthermore, a robotic device was employed as an evaluation tool. RESULTS: Patients treated with botulinum toxin type A had significantly greater reduction in spasticity (MAS, p < 0.01), which explains an improvement in upper limb function and quality movement measured with the Melbourne Scale (p < 0.01). These improvements are consistent with robot-based evaluation results that showed statistically significant changes (p < 0.01) following botulinum toxin type A injections. CONCLUSION: The upper limb performs a wide variety of movements. The multi-joint nature of the task during the robot-mediated evaluation required active control of joint interaction forces. There was good correlation between clinical scales and robotic evaluation. Hence the robot-mediated assessment may be used as an additional tool to quantify the degree of motor improvement after botulinum toxin type A injections.

Visual recognition and visually guided action after early bilateral lesion of occipital cortex: a behavioral study of a 4.6-year-old girl.

We report the case of a 4.6-year-old girl born pre-term with early bilateral occipital damage. It was revealed that the child had non-severely impaired basic visual abilities and ocular motility, a selective perceptual deficit of figure-ground segregation, impaired visual recognition and abnormal navigating through space. Even if the child's visual functioning was not optimal, this was the expression of adaptive anatomic and functional brain modifications that occurred following the early lesion. Anatomic brain structure was studied with anatomic MRI and Diffusor Tensor Imaging (DTI)-MRI. This behavioral study may provide an important contribution to understanding the impact of an early lesion of the visual system on the development of visual functions and on the immature brain's potential for reorganisation related to when the damage occurred.

Stepping over obstacles of different heights: kinematic and kinetic strategies of leading limb in hemiplegic children.

Twelve hemiplegic children (HC) and five normally developing children (NDC) were instructed to walk barefoot over a level surface and to cross obstacles of various heights (0%, 10%, 15% and 20% of their leg lengths). Kinematic and kinetic strategies of their leading limb were mainly examined. For the starting position of the trials HC was adjusted so that the affected limb was the leading one, while NDC step over the obstacle with their preferred selection of leading and trailing limb. The results demonstrated that the crossing speed was decreased and the crossing swing phase was increased in both groups. The toe vertical clearance augmented with the presence of the obstacle, but it remained constant with obstacle heights. The toe and heel horizontal distances of the leading limb remained constant with all obstacle heights. The toe horizontal distances of the trailing limb in HC increased with obstacle heights outlying a peculiar strategy. A comparison of joint angles and power variations revealed substantial differences in height changes between the two groups: HC exhibited a preferential modulation of pelvis and hip joints and a reduced modulation of knee and ankle joints. The knee flexor limitation in HC was accomplished by knee power variations near the toe-off. HC showed also an increased ankle involvement of the support limb, i.e. the almost normal limb. Collectively, the results provided insights into multijoint variations of locomotor act caused by visible obstacle in HC and indicate that a correct rehabilitation treatment should be focused on the use of dynamic constraints preferentially at the plegic knee.

A continuous loading apparatus for measuring three-dimensional stiffness of ankle-foot orthoses.

This paper describes a novel device to evaluate the mechanical properties of ankle foot orthoses (AFOs). The apparatus permits the application to AFOs of continuous three-dimensional (3D) movements between specified and settable endpoints. Using an x-y robot with a rotary stage and a six-component load cell, characteristic displacement versus reaction force curves can be generated and consequently the ankle moments can be determined as a function of dorsi/plantar flexion, inv/eversion and int/external rotation. Representative curves for two polypropylene lateral leaf AFOs, different in shape but produced for the same leg by a skilled orthotist, are presented to illustrate the capabilities of the novel testing system. The metrological investigation showed that the apparatus creates a highly repeatable data set (uncertainty < or = 1% FSO).

Gait analysis in patients operated on for sacrococcygeal teratoma.

BACKGROUND: Long-term follow-up of sacrococcygeal teratoma (SCT) is well established; however, little is known about the effects of extensive surgery in the pelvic and perineal region, which involves disruption of muscles providing maximal support in normal walking. METHODS: Thirteen patients operated on at birth for SCT with extensive muscle dissection underwent gait studies with a Vicon 3-D motion analysis system with 6 cameras. Results were compared with 15 age-matched controls. Statistical analysis was performed with Mann-Whitney test; correlations were sought with Spearman's correlation coefficient. RESULTS: All subjects were independent ambulators, and no statistically significant differences were seen in walking velocity and stride length. However, in all patients, toe-off occurred earlier (at 58% +/- 1.82% of stride length) than controls (at 65.5% +/- 0.52%; P <.05). On kinetics, all patients exhibited, on both limbs, a significant reduction of hip extensory moment (-0.11 +/- 0.11 left; -0.16 +/- 0.15 right v 1.19 +/- 0.08 Newtonmeter/kg; P <.05) and of ankle dorsi/plantar moment (-0.07 +/- 0.09 right; -0.08 +/- 0.16 v -0.15 +/- 0.05 Nm/kg, p < 0.05). Knee power was also significantly reduced (0.44 +/- 0.55 right, 0.63 +/- 0.45 left v 0.04 +/- 0.05 W/kg), whereas ankle power was increased (3 +/- 1.5 right; 2.8 +/- 0.9 left v 1.97 +/- 0.2 W/kg; P <.05). No statistically significant correlation was found between tumor size and either muscle power generation or flexory/extensory moments. CONCLUSIONS: Patients operated on for SCT exhibit nearly normal gait patterns. However, this normal pattern is accompanied by abnormal kinetics of some ambulatory muscles, and the extent of these abnormalities appears to be independent of tumor size. A careful follow-up is warranted to verify if such modifications are stable or progress over the years, thereby impairing ambulatory potential or leading to early arthrosis.