Clinical characteristics of COVID-19 infection in polyhandicapped persons in France.

AIM: Little is known about the clinical profile of COVID-19 infection in polyhandicapped persons. This study aimed to describe the characteristics of this infection among individuals with polyhandicap. METHOD: This was a retrospective observational study. Polyhandicap was defined by the combination of motor deficiency, profound mental retardation, and age at onset of cerebral lesion younger than 6 years. A positive COVID-19 status was considered for patients with a positive COVID-19 laboratory test result, or patients presenting with compatible symptoms and living in an institution or at home with other patients or relatives who had laboratory-confirmed COVID-19 infection. Data collection included sociodemographic data, clinical and paraclinical characteristics, as well as the management and treatment for COVID-19 infection. RESULTS: We collected 98 cases, with a sex ratio of 0.98 and a mean age of 38.5 years (3 months to 73 years). COVID-19 infection was paucisymptomatic in 46% of patients, 20.6% of patients presented with dyspnea, while the most frequent extra-respiratory symptoms were digestive (26.5%) and neurological changes (24.5%); 18 patients required hospital admission, four adults died. The mean duration of infection was longer for adults than for children, and the proportion of taste and smell disorders was higher in older patients. CONCLUSION: These findings suggest that PLH persons often develop paucisymptomatic forms of COVID-19 infection, although they may also experience severe outcomes, including death. Clinicians should be aware that COVID-19 symptoms in PLH persons are often extra-respiratory signs, mostly digestive and neurologic, which may help in the earlier identification of COVID-19 infection in this particular population of patients.

Reliability outcomes and inter-limb differences in ankle joint stiffness in children with unilateral cerebral palsy depend on the method of analysis.

Children with cerebral palsy (CP) present increased passive ankle joint stiffness, measured as the slope of the torque-angle curve relationship. However, large discrepancies in results exist among studies, likely because of various methodologies used. The purpose of this study was to determine the influence of different calculation methods on the outcomes and their inter-session reliability in children with unilateral CP (UCP). Thirteen children (mean age: 9.8 years) with spastic UCP underwent passive ankle mobilization at 2°/s on both legs using a dynamometer, on two occasions separated by one week. Passive ankle joint stiffness was calculated as the slope of the torque-angle curve using linear regression on three different relative ranges of torque (i.e. 30%-100%, 20-80% and 50-90% of maximal torque for method 1, 2 and 3, respectively) for both the paretic and non-paretic legs. Inter-session reliability was significantly lower on paretic leg (mean CV = 13.8%, ICC = 0.62) when compared to non-paretic leg (mean CV = 6%, ICC = 0.85), and method 3 presented lower reliability outcomes (mean CV = 11.7%, ICC = 0.75) than methods 1 (mean CV = 7.5%, ICC = 0.78) and 2 (mean CV = 6.6%, ICC = 0.79). Paretic values (0.24 Nm/°) were not different from the non-paretic leg (0.25 Nm/°), although significantly higher when considering the same angular sector (0.18 Nm/°). Passive ankle joint stiffness measurement can be reliably performed in children with UCP using method 1 and 2 while method 3 should be avoided. The non-paretic leg may be used for comparison with the paretic leg when taking into account differences in maximal dorsiflexion angle between legs. ClinicalTrials.gov Identifier: NCT02960932.

Quality of life and functional outcome in early school-aged children after neonatal stroke: a prospective cohort study.

BACKGROUND: Quality of life (QoL) is recognized internationally as an efficient tool for evaluating health interventions. To our knowledge, QoL has not been specifically assessed in children after neonatal arterial ischemic stroke (AIS). AIM: To study the QoL of early school-aged children who suffered from neonatal AIS, and QoL correlation to functional outcome. METHOD: We conducted a multicenter prospective cohort study as part of a larger study in full-term newborns with symptomatic AIS. Participating families were sent anonymous QoL questionnaires (QUALIN). Functional outcome was measured using the Wee-FIM scale. Healthy controls in the same age range were recruited in public schools. Their primary caregivers filled in the QUALIN questionnaires anonymously. We used Student's t-test and a rank test to compare patients and controls' QoL and functional outcomes. RESULTS: 84 children with neonatal AIS were included. The control group was composed of 74 children, of which ten were later excluded due to chronic conditions. Mean ages and QUALIN median scores did not differ between patients and controls. Median Wee-FIM scores were lower in hemiplegic children than in non-hemiplegic ones (p < 0.001). QoL scores did not seem correlated to functional outcome. INTERPRETATION: Those results could support the presence of a "disability paradox" in young children following neonatal AIS.

Efficiency of flexible derotator in walking cerebral palsy children.

INTRODUCTION: The flexible derotator is one of the therapeutic resources used to combat primary and secondary abnormalities in walking cerebral palsy children. It was developed to reduce abnormal femoral and tibial torsions and lessen the latter's negative functional impact. OBJECTIVE: To determine the effect of wearing a flexible derotator on anatomic and functional parameters in walking cerebral palsy children. METHODS: We performed a retrospective study of walking cerebral palsy children by gathering data on bone-related parameters (femoral and tibial torsion) and functional parameters (distance and speed gait, and the energy expenditure index (EEI)). Fifteen walking cerebral palsy children were treated with the flexible derotator for one year and 15 untreated walking cerebral palsy children were included as controls. The two groups were compared in terms of the various parameters' change over time between the initial examination (the last examination prior to the start of the study or prior to use of the flexible derotator) and the final examination (after one year of follow-up). RESULTS: Right femoral anteversion and right and left external tibial torsion improved. There was a significant increase in distance and speed gait and a decrease in the EEI in walking cerebral palsy children. CONCLUSION: Our retrospective study revealed a significant improvement in functional parameters in children with cerebral palsy, as a result of wearing the flexible derotator for at least 6 hours a day for a year. Bone parameters only improved slightly. Use of the flexible derotator could improve these children's quality of life.

Tibial intercondylar eminence fractures in children: The long-term perspective.

PURPOSE OF THE STUDY: To analyze objective and subjective results on medium-term follow-up of intercondylar fractures of the tibia in children. MATERIAL AND METHODS: A retrospective, single-center study of 32 fractures (17 boys, 14 girls) was performed. Fractures were itemized on the Meyers and McKeever classification as modified by Zaricznyj: there were eight type-I, 17 type-II, five type-III and two type-IV fractures. Treatment was conservative for type-I and II fractures (with mild displacement) and for the others surgical. Seven patients were lost to follow-up and one had insufficient follow-up for inclusion. Thirteen patients were assessed on a KT 1000 arthrometer and a dynamometer, and on the IKDC and ARPEGE scoring systems. Ten patients chose to answer only the subjective IKDC questionnaire, by mail. RESULTS: The mean IKDC score of subjects answering by mail was 91 and of those with clinical examination was 80. Mean ARPEGE score was 8.3. Subjective IKDC score classified four patients as A, four as B, four as C and one as D. Mean difference in tibial anterior translation between affected and unaffected knees was 0.88mm for type I fractures, 0.82mm for type II and 0.30mm for types III and IV together. DISCUSSION: The mean difference in tibial anterior translation between affected and unaffected knees was greater in patients with conservative treatment (0.96mm for conservative vs. 0.29mm for surgical treatment). Seventy per cent of patients reported pain at follow-up. Only two had pathological knee laxity. Twelve out of thirteen had returned to sport activity, half of them at the same level as before injury. CONCLUSION: The cases treated surgically had a better objective result than those treated conservatively. Nevertheless there was no correlation between subjective evaluation and degree of knee laxity. Overall, intercondylar fractures of the tibial eminence in children have good long-term prognosis, at least subjectively. This study shows that, in spite of a very satisfactory subjective result for most patients, results were not so good on objective measures. LEVEL OF EVIDENCE: Level IV: retrospective study.

[New developments in spastic unilateral cerebral palsy]. / Hémiplégie cérébrale infantile: épidémiologie, aspects étiologiques et développements thérapeutiques récents.

INTRODUCTION: Hemiplegic (or spastic unilateral) cerebral palsy accounts for about 30% of all cases of cerebral palsy. With a population prevalence of 0.6 per 1000 live births, it is the most common type of cerebral palsy among term-born children and the second most common type after diplegia among preterm infants. STATE OF THE ART: Many types of prenatal and perinatal brain injury can lead to congenital hemiplegia and brain MRI is the most useful tool to classify them with accuracy and to provide early prognostic information. Perinatal arterial ischemic stroke thus appears as the leading cause in term infants, whereas encephalopathy of prematurity is the most common cause in premature babies. Other causes include brain malformations, neonatal sinovenous thrombosis, parenchymal hemorrhage (for example due to coagulopathy or alloimmune thrombocytopenia) and the more recently described familial forms of porencephaly associated with mutations in the COL4A1 gene. PERSPECTIVES: In adjunction with pharmacologic treatment (botulinium neurotoxin injection), new evidence-based rehabilitational interventions, such as constraint-induced movement therapy and mirror therapy, are increasingly being used.

[Exercise therapy and myopathies]. / Thérapie par l'exercice et myopathies.

Since the first consensus papers published early in the 2000s, a growing number of recent publications has shown that adapted physical activity is not only safe in the context of myopathy but also potentially effective as a therapeutic tool. After a short recall of the different exercise modalities, the mechanical strain they induce and the expected muscular benefits, the present paper reviews the different studies related to exercise therapy in myopathic patients and provides a critical analysis of the topic. Myopathies are rare diseases with many different etiologies and a large number of training modalities which could be useful for the different muscular challenges have been proposed. We have chosen to focus on several specific training modalities and to discuss the results from the most recent papers. The purpose of this review is to, firstly, update physical training guidelines for patients with myopathy and, secondly, highlight some common pitfalls associated with this strategy. This is particularly important for medical and allied professionals involved in prescribing and managing exercise therapy protocols.

[Proximal femoral resection in nonambulatory multiply handicapped child]. / Résection fémorale supérieure chez l'enfant polyhandicapé grabataire.

INTRODUCTION: Hip dislocation in nonambulatory multiply handicapped children (particularly in cerebral palsy [CP]) is a common and severe problem involving painful transportation and uneasy positioning, usually resulting from major anatomical osteoarticular and soft tissue disorders. Therefore, proximal femoral resection is seen as a salvage procedure whose primary purpose is to provide children and their caregivers with better comfort during activities of daily living thus allowing improved sitting tolerance in the wheelchair and painless nursing care. MATERIALS AND METHODS: A series of 21 proximal femoral resections performed on 16 patients with a mean age at surgery of 12 years, and a follow-up period of 21 years (from 1984 to 2005) were retrospectively reviewed. All patients suffered from painful dislocation of the hip. Sixteen of the hips (76%) had been managed previously with bony and soft tissue surgery. Femoral resection was performed in the basicervical region in eight hips and distal to the lesser trochanter in 13 hips. RESULTS: At a mean follow-up of five years and eight months, 18 of the 21 painful hips reported to be painless (86%). All preoperative stiffness and deformity of the hip joints was corrected, resulting in floppy, mobile hips with an increased range of motion after surgery. Femoral stump, regarding the acetabulum was above in three hips, at the same level in 18 and never below. The proximal end of the femoral shaft could often been palpated but did not reveal any skin irritation. The formation of heterotopic bone was discernible in five hips (24%). However, it did not affect the functional outcomes. DISCUSSION: Soft-tissue releases combined with femoral and pelvic osteotomies have reported poor results with regard to their long-term inefficacy in children. The outcomes of our series support these findings, since surgical procedures had been performed previously in 76% of the hips. Therefore, we believe that proximal femoral resection is a promising and reliable surgical treatment option to address such failures, in case of severe and painful deformities of the hip. The success of our series corroborates Widemann, Mc Carthy and Abu-Rajab encouraging results on proximal femoral resection. Postoperatively, we advise placement of a hip spica cast immobilization with a soft cotton lining to prevent pressure sores from developing. This surgical procedure seems to be an appropriate management in nonambulatory multiply handicapped children reporting more promising results than other surgical treatment options such as rotational osteotomy, arthrodesis or even arthroplasty.

BCL-2 counteracts Doppel-induced apoptosis of prion-protein-deficient Purkinje cells in the Ngsk Prnp(0/0) mouse.

The pro-apoptotic factor BAX has recently been shown to contribute to Purkinje cell (PC) apoptosis induced by the neurotoxic prion-like protein Doppel (Dpl) in the prion-protein-deficient Ngsk Prnp(0/0) (NP(0/0)) mouse. In view of cellular prion protein (PrP(c)) ability to counteract Dpl neurotoxicity and favor neuronal survival like BCL-2, we investigated the effects of the anti-apoptotic factor BCL-2 on Dpl neurotoxicity by studying the progression of PC death in aging NP(0/0)-Hu-bcl-2 double mutant mice overexpressing human BCL-2 (Hu-bcl-2). Quantitative analysis showed that significantly more PCs survived in NP(0/0)-Hu-bcl-2 double mutants compared with the NP(0/0) mutants. However, number of PCs remained inferior to wild-type levels and to the increased number of PCs observed in Hu-bcl-2 mutants. In the NP(0/0) mutants, Dpl-induced PC death occurred preferentially in the aldolase C-negative parasagittal compartments of the cerebellar cortex. Activation of glial cells exclusively in these compartments, which was abolished by the expression of Hu-bcl-2 in the double mutants, suggested that chronic inflammation is an indirect consequence of Dpl-induced PC death. This partial rescue of NP(0/0) PCs by Hu-bcl-2 expression was similar to that observed in NP(0/0):Bax(-/-) double mutants with bax deletion. Taken together, these data strongly support the involvement of BCL-2 family-dependent apoptotic pathways in Dpl neurotoxicity. The capacity of BCL-2 to compensate PrP(c) deficiency by rescuing PCs from Dpl-induced death suggests that the BCL-2-like property of PrP(c) may impair Dpl-like neurotoxic pathways in wild-type neurons.

Training programs for children: literature review.

INTRODUCTION: Training programs are increasingly being prescribed for occupational therapy for adults affected by chronic illness and/or handicap, but their use is more recent for children and teenagers. OBJECTIVE: A review of the literature to synthesize information concerning training programs for children, whether healthy or with disease or handicap, considering the target population, methodology, the results and limitations. METHODS: We searched the Medline database with use of the key words retraining, training, training programs, physical activity, physical training, fitness program, sport, children, disability, and handicap. We also searched references of the selected articles for appropriate studies. DISCUSSION/CONCLUSION: Physical activity seems to be a good means of primary preventing adverse health in the healthy child and secondary prevention in children with chronic disease or handicap. Thus, training programs could be adapted and integrated into the global treatment of sick or handicapped children in the health care situation or in the home. These programs are feasible and do not undermine children's health, but few studies have shown clear data on the methods of the programs. The suggested training programs, not always validated, included two to five sessions from 30 to 60 min/week, for 6-16 weeks, of variable activity and intensity, adapted to the condition and the objectives of therapy. Training programs adapted to children should be validated to allow their accessibility by health care professionals dealing with children with chronic disease and/or handicap.

BAX contributes to Doppel-induced apoptosis of prion-protein-deficient Purkinje cells.

Research efforts to deduce the function of the prion protein (PrPc) in knock-out mouse mutants have revealed that large deletions in the PrPc genome result in the ectopic neuronal expression of the prion-like protein Doppel (Dpl). In our analysis of one such line of mutant mice, Ngsk Prnp0/0 (NP0/0), we demonstrate that the ectopic expression of Dpl in brain neurons induces significant levels of cerebellar Purkinje cell (PC) death as early as six months after birth. To investigate the involvement of the mitochondrial proapoptotic factor BAX in the Dpl-induced apoptosis of PCs, we have analyzed the progression of PC death in aging NP0/0:Bax-/- double knockout mutants. Quantitative analysis of cell numbers showed that significantly more PCs survived in NP0/0:Bax-/- double mutants than in the NP0/0:Bax+/+ mutants. However, PC numbers were not restored to wildtype levels or to the increased number of PCs observed in Bax-/- mutants. The partial rescue of NP0/0 PCs suggests that the ectopic expression of Dpl induces both BAX-dependent and BAX-independent pathways of cell death. The activation of glial cells that is shown to be associated topographically with Dpl-induced PC death in the NP0/0:Bax+/+ mutants is abolished by the loss of Bax expression in the double mutant mice, suggesting that chronic inflammation is an indirect consequence of Dpl-induced PC death.

Influence of speed variation and age on ground reaction forces and stride parameters of children's normal gait.

The aim of this study was to assess the influence of both age and speed on ground reaction forces and temporal parameters during normal gait in children. Fifteen children aged 4-6 years (group 1), 16 aged 6-8 years (group 2), and 16 aged 8-10 years (group 3) walked at 2.7 km/h, 3.6 km/h, and 4.5 km/h on a treadmill. For each child thirty successive steps were recorded. The influence of speed and age on normalized gait parameters was examined with two-way analysis of variance. The first vertical peak force (Fz1) and all the antero-posterior forces of group 1 were higher than those of the other groups for the three speeds. The minimum vertical force (Fz2), the second vertical peak force (Fz3), and the duration of stride and stance were significantly higher in groups 2 and 3. For all the groups, Fz1 and all the antero-posterior forces increased with the speed while Fz2, stride, stance, and double-stance duration decreased. Fz3 was not influenced by speed variation. The results of this study show that age and walking speed influence ground reaction forces and stride time parameters in 4- to 10-year-old children.

[Hemiplegia and a hiking tour of Mont Blanc: from hope to reality]. / Hémiplégie et tour du Mont Blanc: de l'espoir à la réalité.

INTRODUCTION: At the end of an endurance training program for stroke patients with hemiplegia, we offered a hiking tour around the Mont Blanc Pedestrian Tour. We found no publication describing a similar experience and no scientific data in the literature to determine the physiological characteristics required for this performance, particularly regarding cardiac and vascular capacities, level of impairment, and functional abilities. OBJECTIVE: To complete a part of the Mont Blanc Pedestrian Tour over six days, with a group of adults with hemiparesis and aphasia due to stroke. POPULATION: Seven of 20 subjects with right hemiparesis and aphasia were selected on the basis of results of physiological tests, after an endurance training program and two tests hikes at medium altitude. Mean age was 51.71 +/- 7.13 years, mean VO(2max) 19.76 +/- 3.46 ml.g(-1).mm(-1), mean P(max) 90 +/- 22.68 and mean walking speed 3.60 +/- 1.30 km/hour. ORGANIZATION: Organization involved setting up the itinerary, recruiting accompanying personnel (9 people), and arranging security. No specific adaptations for accessibility were available, and no specific equipment was used, except for standard walking sticks. RESULTS: During this pedestrian tour, the subjects demonstrated strong motivation, as well as exceptional physical and functional performance, despite significant changes in elevation (up to 1500 m per day) and long walking times (from 5 to 9 hours per day). DISCUSSION: This experience has enriched our reflection about the medical, functional, and psychological conditions required for this type of physical effort, both from patients and accompanying personnel. In the absence of reports on similar experiences with this patient population, we thought it interesting, six months after this challenge, to present our observations as well as the patients' point of view. This may encourage other rehabilitation teams to offer intensive walking activities for stroke patients.

Extra-articular subtalar arthrodesis. A long-term follow-up in patients with cerebral palsy.

Of 23 children (35 feet) with cerebral palsy who had undergone a Grice extra-articular subtalar arthrodesis for a valgus hindfoot between 1976 and 1981, we reviewed 17 (26 feet), at a mean of 20 years (17 years 3 months to 22 years 4 months) after operation. Seven were quadriplegic, eight spastic diplegic, and two hemiplegic. They were all able to walk at the time of operation. Thirteen patients (20 feet) were pleased with the Grice procedure, 13 had no pain and 15 (23 feet) were still able to walk. The clinical results were satisfactory for most feet. Radiography showed that the results had been maintained over time but 14 feet developed a mean ankle valgus of 11 degrees (6 to 18) with a compensatory hindfoot varus in 12 feet. No deformity of the talus or arthritis of adjacent joints was noted. The Grice procedure gives good long-term results in children with cerebral palsy.

[Isokinetic assessment of muscular strength in subjects with acute inflammatory demyelinating polyradiculoneuropathy]. / Evaluation isocinétique de la force musculaire de patients atteints de polyradiculonévrite aiguë.

OBJECTIVE: To evaluate the feasibility and the interest of isokinetic measures tests in subjects with inflammatory demyelinating polyradiculoneuropathy or Guillain-Barré syndromes (GBS). METHODS: Nine patients with GBS are tested at the beginning and after 6 months of recovery stage. They benefit from (1) isokinetic assessment of muscular strength of knee, elbow, ankle: flexion/extension and shoulder abduction/adduction ranging 30 per s at 180 per s angular velocity; (2) isometric assessment of the same muscular groups; (3) manual muscle testing; (4) functional independence measure. RESULTS: Isokinetic tests were tolerated at 60 and 120 per s. Fatigability appears since the third second of isometric test. The relationships between isokinetic, manual tests and isometric tests are variables (0.29 < r < 0.97). The evaluation after 6 months of recovery showed a good sensibility of isokinetic test. CONCLUSION: The continuation of this motor isokinetic evaluation, in a large population, will permit to establish longitudinal and evolutive profile of each patient and will facilitate to chose the rehabilitation program.

[Backpack and spinal disease: myth or reality?]. / Cartable et pathologie rachidienne. Légende ou réalité?

Back pain has become a real public health concern both for adults and children. In general, patients complain of moderate pain. While the topic was long ignored by the scientific community, the number of publications has increased over the last three Years. We reviewed the literature to separate real evidence from speculations. Recognized risk factors for spinal pain are: female gender, poor general status, family history of back pain, particular psychological patterns, time spent sitting watching television, history of spinal trauma, intense physical activity, practicing competition sports, and age (more frequent in adolescents than children). Several recent papers have drawn attention to the role of the weight of the school backpack in children, particularly when its weight exceeds 20% of the child's body weight. Many children carry heavy backpacks which for some may weigh 30% to 40% of their body weight. Several groups have estimated that the maximum should be 10% of the body weight. It appears that time spent carrying the backpack as well as its weight is an important factor favoring back pain. Backpacks can injury the head or face, as well as the hands, the elbow, the wrist, the shoulder, the foot and the ankle. Back trauma is observed as the sixth most common injury. The 'weak point' is the shoulder and not the back. A poorly positioned backpack can modify posture and gait. Carrying the backpack with two shoulder straps affects posture and gait less than carrying it on one shoulder. The posture of the spine changes when the weight of the backpack increases. This is probably one of the reasons why many parents who consult believe that there is a relationship between the weight of the backpack and scoliosis or kyphosis, observed in many of their children. It is proven that adolescents who suffer from back pain will probably have chronic back pain as adults, but there is not evidence to our knowledge demonstrating a relationship between the development of spinal deviation and the weight of the backpack. Recent studies have been conducted to design backpacks allowing a better weight distribution and comfort. This type of backpack appears to have a limited benefit. Furthermore, the question of mode must not be ignored for children and adolescents. Backpacks with one sack in front and one in back certainly provide better weight distribution but are they acceptable for children and adolescents?

Dantrolene and pleural effusion: case report and review of literature.

STUDY DESIGN: Single-subject case (a quadriplegic female, 56 years). OBJECTIVES: To describe a new case of eosinophilic pleural effusion induced by dantrolene chronic administration. SETTING: Physical medicine and rehabilitation unit in a teaching hospital, France. METHODS: Diagnosis of an eosinophilic pleural effusion induced by dantrolene without any respiratory symptoms, except a decrease of breath sounds on the right lung base. RESULTS: Chest radiograph revealed a right-sided pleural effusion, and blood cell count a significant peripheral eosinophilia. Thoracenthesis contained 85% of eosinophils. The other explorations eliminated other causes of pleural effusion. The diagnosis of drug-induced effusion was almost sure and led us to discontinue the dantrolene. After 3 months, she had completely recovered. These characteristics, similar to the eight other cases described in the literature, are essential for the diagnosis of pleural effusion induced by dantrolene. CONCLUSION: Dantrolene, a long-acting skeletal muscle relaxant, is well known to induce liver side effects but it can also induce pleural pericarditis. The pathogenesis is still not clearly identified, but similarities of chemical structures of dantrolene and nitrofurantoine make us think that it could be the same mechanism. The association between dantrolene and nitrofurantoine may have contributed to the expression of the pleural effusion.

[Influence of speed variation and age on the intrasubject variability of ground reaction forces and spatiotemporal parameters of children's normal gait]. / Influence de la vitesse et de l'âge sur la variabilité intrasujet des forces de réaction et des paramètres spatiotemporels de la marche de l'enfant sain.

OBJECTIVE: To assess the effect of age and speed on the variability of ground reaction forces (GRF) and stride parameters of gait in normal children. MATERIAL AND METHOD: Forty-seven children aged 4-10 years were split into three age groups. Each child walked at three constant speeds on a treadmill. Thirty consecutive steps of each leg were recorded. For each child, the mean parameters of the 30 steps were calculated. The mean parameter of each child was taken to calculate the mean parameters of the group. The variability was evaluated by the coefficient of variation (CV). The influence of both age and speed on the variability was examined with a to-way analysis of variance. RESULTS: The cross effect of age and speed on the variability was not significant. The variability of the parameters decreased significantly with age between 4 and 8 years. The variability of vertical forces increased significantly with speed (between 2.7 and 4.5 km/h), while the variability of antero-posterior forces, the stride and the stance decreased between 2.7 and 3.6 km/h. However, the variability of double stance was not influenced by walking speed between 2.7 and 4.5 km/h. Except the time of production of the vertical force of propulsion (Tz3), the variability of temporal vertical parameters decreased significantly with speed between 2.7 and 4.5 km/h and the variability of temporal antero-posterior parameters decreased significantly between 2.7 and 3.6 km/h. DISCUSSION-CONCLUSION: The variability of the GRF and spatio-temporal parameters in children was influenced by age between 4 and 8 years old and by speed between 2.7 and 3.6 km/h. Moreover, the effect of age on the GRF persists up to 8 years. The variabilities of the time of production of the antero-posterior force of propulsion (Ty2) and stance duration were lower than the variabilities of the others parameters. These two variables could be the most reliable parameters when assessing gait in children aged 4-10 years, walking at speeds between 2.7 and 4.5 km/h.