EMG-Based Characterization of Walking Asymmetry in Children with Mild Hemiplegic Cerebral Palsy.

Hemiplegia is a neurological disorder that is often detected in children with cerebral palsy. Although many studies have investigated muscular activity in hemiplegic legs, few EMG-based findings focused on unaffected limb. This study aimed to quantify the asymmetric behavior of lower-limb-muscle recruitment during walking in mild-hemiplegic children from surface-EMG and foot-floor contact features. sEMG signals from tibialis anterior (TA) and gastrocnemius lateralis and foot-floor contact data during walking were analyzed in 16 hemiplegic children classified as W1 according to Winter' scale, and in 100 control children. Statistical gait analysis, a methodology achieving a statistical characterization of gait by averaging surface-EMG-based features, was performed. Results, achieved in hundreds of strides for each child, indicated that in the hemiplegic side with respect to the non-hemiplegic side, W1 children showed a statistically significant: decreased number of strides with normal foot-floor contact; decreased stance-phase length and initial-contact sub-phase; curtailed, less frequent TA activity in terminal swing and a lack of TA activity at heel-strike. The acknowledged impairment of anti-phase eccentric control of dorsiflexors was confirmed in the hemiplegic side, but not in the contralateral side. However, a modified foot-floor contact pattern is evinced also in the contralateral side, probably to make up for balance requirements.

Is child walking conditioned by gender? Surface EMG patterns in female and male children.

EMG-based differences between females and males during walking are generally acknowledged in adults. Aim of the study was the quantification of possible gender differences in myoelectric activity of gastrocnemius lateralis (GL) and tibialis anterior (TA) during walking in school-age children. Gender-related comparison with adults was also provided to get possible novel insight in maturation of gait. To this aim, Statistical gait analysis, a recent methodology performing a statistical characterization of gait by averaging spatial-temporal and surface-EMG-based parameters over hundreds of strides, was performed in100 healthy school-age children (C-group) and in 33 healthy young adults (YA-group). On average, 301±110 consecutive strides were analyzed for each subject. In C-group, no significant differences (p>0.05) were observed between females and males in GL and TA, considering mean onset/offset instants of activation and occurrence frequency. Stratifying the C-group for age, small differences between females and males in occurrence frequency of GL arose in oldest children. In YA-group, females showed a significant propensity for a more complex recruitment of TA and GL (higher number of activations during gait cycle, quantified by occurrence frequency) compared to males. These outcomes suggest that gender-related differences in sEMG parameters do not characterize the recruitment of GL and TA during child walking in early years (6-8 years), start occurring when adolescence is approaching (10-12 years), and are acknowledged in both ankle muscles only in adults. Present findings seem to support previous studies on maturation of gait which indicate adolescence as the time-range where gait is completing its maturation path.

Normative EMG patterns of ankle muscle co-contractions in school-age children during gait.

PURPOSE: The study was designed to assess the co-contractions of tibialis anterior (TA) and gastrocnemius lateralis (GL) in healthy school-age children during gait at self-selected speed and cadence, in terms of variability of onset-offset muscular activation and occurrence frequency. METHODS: Statistical gait analysis, a recent methodology performing a statistical characterization of gait by averaging spatio-temporal and sEMG-based parameters over numerous strides, was performed in 100 healthy children, aged 6-11 years. Co-contractions were assessed as the period of overlap between activation intervals of TA and GL. RESULTS: On average, 165±27 strides were analyzed for each child, resulting in approximately 16,500 strides. Results showed that GL and TA act as pure agonist/antagonists for ankle plantar/dorsiflexion (no co-contractions) in only 19.2±10.4% of strides. In the remaining strides, statistically significant (p<0.05) co-contractions appear in early stance (46.5±23.0% of the strides), mid-stance (28.8±15.9%), pre-swing (15.2±9.2%), and swing (73.2±22.6%). This significantly increased complexity in muscle recruitment strategy beyond the activation as pure ankle plantar/dorsiflexors, suggests that in healthy children co-contractions are likely functional to further physiological tasks as balance improvement and control of joint stability. CONCLUSIONS: This study represents the first attempt for the development in healthy children of a normative dataset for GL/TA co-contractions during gait, achieved on an exceptionally large number of strides in every child and in total. The present reference frame could be useful for discriminating physiological and pathological behavior in children and for designing more focused studies on the maturation of gait.

Multiple gait patterns within the same Winters class in children with hemiplegic cerebral palsy.

BACKGROUND: Previous literature hypothesized that Winters type I are mainly characterized by a hypo-activation of dorsiflexors and type II by hyperactivation of plantarflexors around initial contact. However, it is currently not known if hemiplegic children belonging to the same Winters class really share the same muscle activation patterns, although this information might have relevant clinical implications in the patient management. METHODS: Gait data of 38 hemiplegic cerebral palsy children (16 Winters type I, 22 Winters type II) were analyzed, focusing on the foot and shank. A 2.5-minute walk test was considered, corresponding to more than 100 gait cycles for each child, analyzing the muscle activation patterns of tibialis anterior and gastrocnemius lateralis. The large stride-to-stride variability of gait data was handled in an innovative way, processing separately: 1) distinct foot-floor contact patterns, and for each specific foot-floor contact pattern 2) distinct muscle "activation modalities", averaging only across gait cycles with the same number of activations, and obtaining, in both cases, the pattern frequency-of-occurrence. FINDINGS: At least 2 representative foot-floor contact patterns within each Winters group, and up to 4-5 distinct muscle activation patterns were documented. INTERPRETATION: It cannot be defined a predominant muscle activation pattern specific for a Winters group. For a correct clinical assessment of a hemiplegic child, it is advisable to record and properly analyze gait signals during a longer period of time (2-3 min), rather than (subjectively) selecting a few "clean" gait cycles, since these cycles may not be representative of the patient's gait.

Dual task-related gait changes in patients with mild cognitive impairment.

Mild cognitive impairment (MCI) entails a high risk of developing Alzheimer's dementia. In MCI patients gait impairment, which increases the risk of falls and institutionalization, is an early motor sign. A dualtask (DT) paradigm might improve the observation of this phenomenon. The aim of this study was to investigate motor-cognitive interference in a sample of MCI patients and a group of matched healthy controls submitted to DT conditions. To this end, three different cognitive tasks were used: counting backwards, short story recall and a phonemic fluency task. Overall, the patients, compared with the healthy participants, performed worse on the cognitive tasks and showed some degree of gait impairment. In the DT conditions, both groups showed significant gait disruption independently of the concomitant cognitive task. As regards cognitive performance, counting backwards worsened during dual tasking, while short story recall improved in both groups. Overall, our results suggest that the use of a DT paradigm does not improve the early detection of MCI. Our findings of enhanced story recall during walking might have interesting implications for rehabilitation of memory function.

Dependence of gait parameters on height in typically developing children.

In clinical gait analysis is fundamental to have access to normative data, to be used as a reference in the interpretation of pathological walking. In a paediatric population this may be complicated by the dependence of gait parameters on child growth. The aim of this work is to provide the correlations of spatial-temporal gait parameters with children's height. We obtained the regression lines of cadence, double support, and gait phases, with respect to height, from a sample of 85 normally typically developing children aged 6 to 11. Our analysis of gait phases was not limited to the traditional analysis of stance and swing, but rather focused on the sub-phases of stance - heel contact, flat foot contact, push off - which proved to be an innovative approach to gait analysis. Heel contact decreased, flat foot contact increased and push off remained essentially unchanged with respect to children's height. These results may be useful in the interpretation of gait data in developing children, and the regression lines obtained may be used to normalize their gait parameters.

Gait attentional load at different walking speeds.

Gait is an attention-demanding task even in healthy young adults. However, scant evidence exists about the attentional load required at various walking speeds. The aim of this study was to investigate motor-cognitive interference while walking at spontaneous, slow and very slow speed on a treadmill while carrying out a backward counting task, in a group (n = 22) of healthy young participants. Cognitive performance was also assessed while sitting. Higher DT cost on the cognitive task was found at spontaneous and very slow walking speed, while at slow walking speed the cognitive task was prioritized with higher DT cost on the motor task. The attentional allocation during DT depends on walking speed with gait prioritization at spontaneous and very slow speed that likely represent more challenging motor conditions.

Incontinentia pigmenti: a rare pathology with complex rehabilitative aspects.

PURPOSE: Incontinentia pigmenti (IP), or Bloch-Sulzberger syndrome, is a rare X-linked dominant genetic disorder with multisystem involvement. To our knowledge, there are no previous reports about rehabilitation in IP adult with intact cognitive development. We report a 20-year-old lady with IP managed and followed into adulthood. METHOD: Patient management and rehabilitation programs from birth to the last follow-up. RESULTS: There was normal cognitive development despite magnetic resonance imaging (MRI) evidence of white matter, corpus callosum and brainstem hypoplasia. Extensor spasticity was present on both lower limbs for which she underwent rehabilitation from the age of one. Botulinum toxin injections were performed and when she was 15 years old she underwent functional surgery. CONCLUSION: The absence of mental retardation in our patient enabled us to carry out an active rehabilitation program and provide her with maximum independence in locomotion and in activities of daily living. IMPLICATIONS FOR REHABILIATION: Incontinentia pigmenti (Bloch-Sulzberger syndrome). Incontinentia pigmenti is a rare X-linked dominant genetic disorder with multisystemic involvement. Skin lesions, neurological impairments, motormental retardation, skeletal congenital defects and ophthalmologic involvement are IP most frequent manifestations. Due to the complex multisystem involvement resulting in severe long-term disability, patients with IP require a multidisciplinary team approach for rehabilitation. In IP patients, rehabilitation interventions should always take into consideration the individual phenotype expression, child's physical development and personal needs.

A combined robotic and cognitive training for locomotor rehabilitation: evidences of cerebral functional reorganization in two chronic traumatic brain injured patients.

It has been demonstrated that automated locomotor training can improve walking capabilities in spinal cord-injured subjects but its effectiveness on brain damaged patients has not been well established. A possible explanation of the discordant results on the efficacy of robotic training in patients with cerebral lesions could be that these patients, besides stimulation of physiological motor patterns through passive leg movements, also need to train the cognitive aspects of motor control. Indeed, another way to stimulate cerebral motor areas in paretic patients is to use the cognitive function of motor imagery. A promising possibility is thus to combine sensorimotor training with the use of motor imagery. The aim of this paper is to assess changes in brain activations after a combined sensorimotor and cognitive training for gait rehabilitation. The protocol consisted of the integrated use of a robotic gait orthosis prototype with locomotor imagery tasks. Assessment was conducted on two patients with chronic traumatic brain injury and major gait impairments, using functional magnetic resonance imaging. Physiatric functional scales were used to assess clinical outcomes. Results showed greater activation post-training in the sensorimotor and supplementary motor cortices, as well as enhanced functional connectivity within the motor network. Improvements in balance and, to a lesser extent, in gait outcomes were also found.

Dual task interference during gait in patients with unilateral vestibular disorders.

BACKGROUND: Vestibular patients show slower and unsteady gait; they have also been shown to need greater cognitive resources when carrying out balance and cognitive dual tasks (DT). This study investigated DT interference during gait in a middle-aged group of subjects with dizziness and unsteadiness after unilateral vestibular neuronitis and in a healthy control group. METHODS: Fourteen individuals with subacute unilateral vestibular impairment after neuronitis and seventeen healthy subjects performed gait and cognitive tasks in single and DT conditions. A statistical gait analysis system was used and spatio-temporal parameters were considered. The cognitive task, consisting of backward counting by three, was tape recorded and the number of right figures was then calculated. RESULTS: Both patients and controls showed a more conservative gait during DT and between groups significant differences were not found. A significant decrease in cognitive performance during DT was found only in the vestibular group. CONCLUSIONS: Results suggest that less attentional resources are available during gait in vestibular patients compared to controls, and that a priority is given in keeping up the motor task to the detriment of a decrease of the cognitive performance during DT.

Motor evoked potentials: prognostic value in motor recovery after stroke.

Accurate motor and functional prognosis after stroke is important for the optimal planning of a personalised rehabilitation programme, and clinical, demographic and radiological data are commonly employed for this purpose. It is becoming increasingly apparent that motor evoked potentials (MEPs), obtained through transcranial magnetic stimulation, can furnish complementary prognostic information on motor outcome after stroke, particularly when initial hand palsy is present. To evaluate the prognostic value of early MEPs together with other clinical variables, 19 subjects with first- ever stroke in the middle cerebral artery territory and hand palsy at onset, were evaluated in the acute phase. These cases were retrospectively selected out of a sample of 33 subjects. Multivariate analysis was carried out using amplitude of MEPs, National Institutes of Health Stroke Scale score (NIH) and Motricity Index as independent variables, and Medical Research Council scale score (MRC) as the dependent outcome variable at 4 months after stroke. The best model, which combined NIH and MEP data, accounted for 75.44% of the variability of the MRC. Our results suggest that the NIH and MEPs may yield information useful for predicting hand motor outcome after stroke in the presence of initial hand palsy, a condition in which a prognosis made on the basis solely of clinical data is deemed more difficult.