Is the objective assessment of cerebral palsy gait reproducible?

Motion analysis for the evaluation of muscle overactivity: A point of view

Muscle overactivity is a general term for pathological increases in muscle activity such as spasticity. It is caused by damage to the central nervous system at the cortical, subcortical or spinal levels, leading to an upper motor neuron syndrome. In routine clinical practice, muscle overactivity, which induces abnormal muscle tone, is usually evaluated by using the Modified Ashworth Scale or the Tardieu Scale. However, both of these scales involve testing in passive conditions that do not always reflect muscle activity during dynamic tasks such as gait or reaching. To determine appropriate treatment strategies, muscle overactivity should be evaluated by using objective measures in dynamic conditions. Instrumental motion analysis systems that include 3-D motion analysis and electromyography are very useful for this purpose. The method can be used to identify patterns of abnormal muscle activity that can be related to abnormal kinematic patterns. It allows for objective and accurate assessment of the effects of treatments to reduce muscle overactivity on the movement to be improved. The aim of this point-of-view article is to describe the utility of instrumental motion analysis and to outline both its numerous advantages in evaluating muscle overactivity and to present the current limitations for its use (e.g., cost, the need for an engineer, errors relating to marker placement and cross talk between electromyography sensors).

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.

Measurement properties of gait-related outcomes in youth with neuromuscular diagnoses: a systematic review

BACKGROUND

Sound measurement properties of outcome tools are essential when evaluating outcomes of an intervention, in clinical practice and in research.

PURPOSE

The purpose of this study was to review the evidence on reliability, measurement error, and responsiveness of measures of gait function in children with neuromuscular diagnoses.

DATA SOURCES

The MEDLINE, CINAHL, EMBASE, and PsycINFO databases were searched up to June 15, 2012.

STUDY SELECTION

Studies evaluating reliability, measurement error, or responsiveness of measures of gait function in 1- to 18-year-old children and youth with neuromuscular diagnoses were included.

DATA EXTRACTION

Quality of the studies was independently rated by 2 raters using a modified COnsensus-based Standards for the selection of health status Measurement INstruments (COSMIN) checklist. Studies with a fair quality rating or better were considered for best evidence synthesis.

DATA SYNTHESIS

Regarding the methodological quality, 32 out of 35 reliability studies, all of the 13 measurement error studies, and 5 out of 10 responsiveness studies were of fair or good quality. Best evidence synthesis revealed moderate to strong evidence for reliability for several measures in children and youth with cerebral palsy (CP) but was limited or unknown in other diagnoses. The Functional Mobility Scale (FMS) and the Gross Motor Function Measure (GMFM) dimension E showed limited positive evidence for responsiveness in children with CP, but it was unknown or controversial in other diagnoses. No information was reported on the minimal important change; thus, evidence on measurement error remained undetermined.

LIMITATIONS

As studies on validity were not included in the review, a comprehensive appraisal of the best available gait-related outcome measure per diagnosis is not possible.

CONCLUSIONS

There is moderate to strong evidence on reliability for several measures of gait function in children and youth with CP, whereas evidence on responsiveness exists only for the FMS and the GMFM dimension E.

Classification of the reduced vertical component of the ground reaction force in late stance in cerebral palsy gait

Children with cerebral palsy (CP) often experience significant problems supporting their bodyweight (BW) and decelerating the downward velocity of the centre of mass (CoM) in late stance. This is seen as a decreased second peak of vertical ground reaction force (GRF) nominated FZ(2). This study categorises gait data by the degree of reduced FZ(2). Kinetic data were analysed from a CP database. Data from 129 patients, able to walk barefoot unaided, were investigated. Of these, 84 had kinetic data, 59 diplegics (both legs) and 15 hemiplegics (affected leg only), thus providing data from 133 legs. A reduced FZ(2) was observed in 116 legs (87%). Of the 133 legs, 44% failed to generate FZ(2)>BW. By including the Type 2 data this figure rises to, a staggering 66% who are having difficulty supporting BW at this stage of the stance phase. Only 12% of the legs showed a normal pattern (FZ(2) approximately equal to FZ(1)). In conclusion, the majority of CP children referred to the gait laboratory exhibited some degree of reduced FZ(2) and can be categorised as having a 'Ben Lomonding' gait pattern. 'Ben Lomonding,' is the term used to describe this phenomenon of reduced FZ(2), as the shape of the GRF graph resembles the shape of the Scottish mountain, Ben Lomond, which has two peaks, the second peak being much smaller than the first. Crucially, clinicians should be aware that nearly half of the CP children in this study were in difficulty supporting their BW in late stance and must use compensatory mechanisms to prevent collapse of the affected limb.

Analogy versus explicit learning of a modified basketball shooting task: performance and kinematic outcomes

The effects of differential instructional sets on motor skill acquisition were investigated using performance outcome and kinematic measures. Participants were provided with a single analogical instruction (analogy learning), a set of eight explicit (technical) instructions (explicit learning), or were not instructed (control). During a learning phase, participants (n=9 for each condition) performed a modified basketball shooting task over 3 days (160 trials per day). On the fourth day, participants performed a test phase consisting of two 40-trial retention tests, separated by a 40-trial secondary task transfer test, and completed a verbal protocol describing in detail the techniques that they had used to perform the task. No performance differences were found during the two retention tests, indicating similar amounts of learning for all groups. During the transfer test, performance deteriorated for both the explicit and control conditions, but not for the analogy condition. Participants in the analogy condition reported significantly fewer technical rules. Although no group differences were reported for kinematic variables, identification of movement components supported the claim that explicit learners exert conscious control over their movements, whereas analogy learners use a more implicit (unconscious or automatic) mode of movement control.

Evaluation of the longer-term use of the David Hart Walker Orthosis by children with cerebral palsy: a 3-year prospective evaluation

PURPOSE

To evaluate a walking device, the David Hart Walker Orthosis (HW), that was designed to allow children with severe cerebral palsy to ambulate with hands-free support.

METHOD

A pre-/post-test prospective one-group study evaluated outcomes three years after receiving the HW. Physical therapy assessment, parent interview and satisfaction questionnaire provided details on outcomes.

RESULTS

The HW remained the sole walking device for 13 of 20 children at 3 years. Six of seven children who discontinued use were over 12-years-old and had outgrown its maximum size. Twelve of 13 children who still used the HW were assessed. GMFM Stand and Walk Dimension mean score increases of about 3% points for the 1- 3-year follow-up were not significant (P > 0.16). Timed walk scores were unchanged. Steering ability gains were demonstrated on a directional mobility assessment (from 12.0 to 27.9% [P= 0.02]). Despite its eventual height limitations, parents considered HW use to be worthwhile (mean satisfaction = 8.2/10).

CONCLUSIONS

Sixty-five percent of the children continued to use the HW as their sole walking device, and demonstrated improved ability overall to manoeuvre it during functional ambulation. The primary reason for discontinuation was inability to accommodate taller children.

Step-to-step reproducibility and asymmetry to study gait auto-optimization in healthy and cerebral palsied subjects

OBJECTIVE

The purpose of our study was to compare plantar pressure asymmetry and step-to-step reproducibility in both able-bodied persons and two groups of hemiplegics. The relevance of the research was to determine the efficiency of asymmetry and reproducibility as indexes for diagnosis and rehabilitation processes.

MATERIAL AND METHOD

This study comprised 31 healthy young subjects and 20 young subjects suffering from cerebral palsy hemiplegia assigned to two groups of 10 subjects according to the severity of their musculoskeletal disorders. The peaks of plantar pressure and the time to peak pressure were recorded with an in-shoe measurement system. The intra-individual coefficient of variability was calculated to indicate the consistency of plantar pressure during walking and to define gait stability. The effect size was computed to quantify the asymmetry and measurements were conducted at eight footprint locations.

RESULTS

Results indicated few differences in step-to-step reproducibility between the healthy group and the less spastic group while the most affected group showed a more asymmetrical and unstable gait.

CONCLUSION

From the concept of self-optimisation and depending on the neuromotor disorders the organism could make priorities based on pain, mobility, stability or energy expenditure to develop the best gait auto-optimisation.

The Development and Validity of the Salford Gait Tool: An Observation-Based Clinical Gait Assessment Tool

OBJECTIVES

To develop the construct, content, and criterion validity of the Salford Gait Tool (SF-GT) and to evaluate agreement between gait observations using the SF-GT and kinematic gait data.

DESIGN

Tool development and comparative evaluation.

SETTING

University in the United Kingdom.

PARTICIPANTS

For designing construct and content validity, convenience samples of 10 children with hemiplegic, diplegic, and quadriplegic cerebral palsy (CP) and 152 physical therapy students and 4 physical therapists were recruited. For developing criterion validity, kinematic gait data of 13 gait clusters containing 56 children with hemiplegic, diplegic, and quadriplegic CP and 11 neurologically intact children was used. For clinical evaluation, a convenience sample of 23 pediatric physical therapists participated.

INTERVENTIONS

We developed a sagittal plane observational gait assessment tool through a series of design, test, and redesign iterations. The tool's grading system was calibrated using kinematic gait data of 13 gait clusters and was evaluated by comparing the agreement of gait observations using the SF-GT with kinematic gait data.

MAIN OUTCOME MEASURES

Criterion standard kinematic gait data.

RESULTS

There was 58% mean agreement based on grading categories and 80% mean agreement based on degree estimations evaluated with the least significant difference method.

CONCLUSIONS

The new SF-GT has good concurrent criterion validity.

The role of gait analysis in the orthopaedic management of ambulatory cerebral palsy

PURPOSE OF REVIEW

The literature was reviewed to describe the role of gait analysis in the orthopaedic management of ambulatory children with cerebral palsy and examine the current best evidence to support these roles.

RECENT FINDINGS

Gait laboratory analysis is superior to visual or observational analysis of gait because it provides an objective record of gait that is able to quantify the magnitude of deviations of pathologic gait from normal and also explain these abnormalities. Recognizable gait patterns can be classified and used for making treatment decisions, the effectiveness of which can be assessed using gait analysis as a measure of gait outcomes. There are many sources of variability, however, including patients themselves, the gait laboratories and testing processes, interpretation of data and surgeons' surgical recommendations.

SUMMARY

Although gait analysis has been shown to alter decision making, there is little evidence that the decisions based on gait analysis lead to better outcomes. Consequently, clinical gait analysis remains controversial, with wide variation in the rates of utilization of gait analysis in the management of children with ambulatory cerebral palsy. The time is ripe for clinical trials and cohort studies to provide the evidence to establish the appropriate utilization of this technology.

Biomechanical and electromyographic evaluation of ankle foot orthosis and dynamic ankle foot orthosis in spastic cerebral palsy

This study evaluated the biomechanical and electromyographic effects of conventional ankle foot orthoses (AFOs) and dynamic ankle foot orthoses (DAFOs) on gait in patients with spastic cerebral palsy (CP). Thirteen patients with dynamic equinus underwent motion analysis with electromyography. Both AFOs and DAFOs provided longer stride length, permitted pre-positioning for initial contact, and successfully controlled the excessive plantarflexion during the swing phase. Median frequency (MF) of EMG signal indicated that extremely high firing was found in the patient's lower limbs compared to controls that resulted in tiredness. The DAFOs allowed a significantly larger total ankle range of motion than the AFOs. However, AFOs significantly reduced the MF while DAFOs did not. The reduced MF seen when wearing AFOs suggested an improvement of walking endurance. The DAFO had the advantage of less restriction on ankle movement, which avoids muscular atrophy and improves orthotic compliance.

Kinematic and kinetic evaluation of the ankle joint before and after tendo achilles lengthening in patients with spastic diplegia

Fourteen patients, at a mean age of 9.1 years (range 4.1-16.6 years), who had spastic diplegic cerebral palsy were evaluated before and after tendo Achilles lengthening (TAL). Follow-up (by gait analysis) after TAL ranged from 8 to 30 months. A Vicon motion analysis system with six CCD cameras and two AMTI force plates provided three-dimensional measurements of joint motion and moments. The TAL procedure resulted in normal passive dorsiflexion of the ankle joint with the knee at 0 degrees of extension and 90 degrees of flexion, reduced plantarflexion during swing phase, and reduced premature plantarflexor moment. However, 10 degrees greater than normal dorsiflexion of the ankle joint during mid-stance phase was indicative of a mild calcaneal gait pattern. The TAL procedure improved lower extremity function as documented by both kinematic and kinetic analysis in cerebral palsy.

Gait in children with cerebral palsy: observer reliability of Physician Rating Scale and Edinburgh Visual Gait Analysis Interval Testing scale

The aim of this study was to test the inter- and intraobserver reliability of the Physician Rating Scale (PRS) and the Edinburgh Visual Gait Analysis Interval Testing (GAIT) scale for use in children with cerebral palsy (CP). Both assessment scales are quantitative observational scales, evaluating gait. The study involved 24 patients ages 3 to 10 years (mean age 6.7 years) with an abnormal gait caused by CP. They were all able to walk independently with or without walking aids. Of the children 15 had spastic diplegia and 9 had spastic hemiplegia. With a minimum time interval of 6 weeks, video recordings of the gait of these 24 patients were scored twice by three independent observers using the PRS and the GAIT scale. The study showed that both the GAIT scale and the PRS had excellent intraobserver reliability but poor interobserver reliability for children with CP. In the total scores of the GAIT scale and the PRS, the three observers showed systematic differences. Consequently, the authors recommend that longitudinal assessments of a patient should be done by one observer only.

Harmonic analysis of force platform data in normal and cerebral palsy gait

BACKGROUND

Examination of force platform data during gait is usually carried out in the time domain and is limited to selected points on the force-time graphs. Harmonic analysis allows examination of the whole waveform and has a greater potential for assessing the effects of treatment options. Therefore, the objectives of this study were to show the benefits of using harmonic analysis to determine the variability and symmetry of force platform data in normal and cerebral palsy gait.

METHODS

Harmonic analysis was carried out on the foot to ground reaction force data recorded from a group of cerebral palsy children and a matched control group when they walked at their preferred walking speed. Statistical tests were used to assess this frequency domain data and to validate the reconstructed force-time curves.

FINDINGS

The differences in the frequency domain parameters between the cerebral palsy and control groups were significant. The mediolateral force was the most variable and asymmetric parameter in the control group. Cerebral palsy gait was more variable and more asymmetric than normal gait.

INTERPRETATION

This study has shown that the force platform data derived from clinical gait analysis can reveal more useful information in the frequency domain than the limited time domain information commonly used for analysing this type of data.

[The effect of similar speed's walking and functional classification of foot contact on variability of the vertical ground reaction force]

INTRODUCTION

The variability of the normal ground reaction force (F(z)) is a restrictive factor for the clinical analyse of kinetics parameters recorded during walking.

OBJECTIVE

The aim of this study is the decrease of the inter-individual variability of the normal ground reaction force: F(z).

MATERIAL AND METHOD

The method tested consists in imposing a similar speed to the subjects during walking tests, then to class foot according to their function: loading or propulsive foot. A group of seven young adults walk at spontaneous speed (VSpon) for the first walking test then at similar speed (Vsim = N(Fr) x square root of (g x li); where N(Fr) is the Froud's number, g is the gravitational acceleration and li is the length of the lower limb) for the second walking test. Two forces platforms register the F(z) of two consecutive steps. The normal ground reaction force and the mean coefficient of variability are retained to test for speed (VSim and VSpon) and functional classification effects.

RESULTS

The CoV of F(z) decreases from 13% to 8% when the subjects walk at similar speed rather than at spontaneously chosen speed. The variability decreases by 1-1.5% when the data are classified according to functional criterion. The inter-individual variability of the F(z) significantly reduces when the tests are performed at similar speed and when the loading or propulsive factors are used for functional classification.

CONCLUSION

The coupling of the methods described must permit to the clinician to constitute a data base which, tainted of less variability, should make easier the detection of pathology affecting the ground reaction force.

Quantifying the variability of a complex motor task specifically studying the gait of dyskinetic CP children

Lately, more and more interest has been directed towards the variability of complex motor tasks and its diagnostic value in motion disorders. However, there is no standardized way of quantifying variability of motion. In this respect, the purpose of this study is to explore the usefulness of variability computations derived from three-dimensional (3D) motion trajectories. A mathematical and computational algorithm was defined to first extract and overlay the 3D data for the trajectories. As an example for the application, the trajectories of the ankle marker representing the motion during swing were chosen. The method was used to determine the variability during swing for CP children with and without dyskinesia (n=31). A group of healthy adult normals served as control (n=8). The results were validated against the visual rating of swing variability by experienced clinical observers. The calculated values were superior to the previously used pelvic span/ankle spread ratio. The proposed method of quantifying the variability of a complex, repetitive motor task proved to be valid and useful. It has no limitation with regard to reprocessing previously collected data, or as to which equipment is used to gather the 3D coordinates during the motion.

Measurement of plantar pressure distribution in hemiplegic children: changes to adaptative gait patterns in accordance with deficiency

OBJECTIVE

A comparison of plantar pressure distribution in hemiplegic children with a healthy control group was performed to illustrate the link between the changing dynamics during the stance phase and the degree of deficiency.

DESIGN

Twenty three healthy control subjects and two groups of six hemiplegic children with minor and major spasticity were tested.

BACKGROUND

In previous studies, it was shown that the musculoskeletal dysfunction due to spasticity disturbed the hemiplegic gait pattern, for example reduced walking speed and step length. However, plantar pressure measurements which would help to understand the pathological gait mechanisms have not been studied.

METHODS

The stance phase parameters measured included spatio-temporal data and the relative impulse measurements during consecutive gait cycles. The relative impulses under eight plantar areas were determined with an in-shoe plantar pressure measurement device.

RESULTS

Each group had a specific plantar pressure distribution profile that varied with the degree of deficiency. The most significant differences were found beneath the midfoot, the first metatarsal head and the hallux.

CONCLUSION

The neuromuscular disorders and foot deformities due to the cerebral lesion modified the contact of the foot with the ground, and led to specific plantar pressure distribution profiles. The equinovarus, with clawed-toe deformity due to greater spasticity, seemed to be an important factor in disturbances of the terminal stance phase. However, the spastic hemiplegic subjects seemed to adopt a gait pattern required for optimal stability.

RELEVANCE

From previous work, comparable data were available only for the hemiparetic adult patients. In-shoe pressure data from spastic hemiplegic children can provide detailed information specific to each region of contact for the support of diagnosis, a clinical decision or the prescription of appropriate footwear, braces or othoses. Both peak pressure and local impulse have proven to be valuable for the understanding of foot function, lower extremity dysfunctions and walking strategies.

[Asymmetries in dynamic plantar pressure distribution measurement in able-bodied gait: application to the study of the gait asymmetries in children with hemiplegic cerebral palsy]

OBJECTIVES

The aim of this study was to analyse, firstly, the plantar pressure distribution in healthy subjects in order to validate or invalidate the previous studies results on the asymmetrical profile of the stance phase. The studies of asymmetries was based on the identification of a propulsive foot and a loading foot from a concept introduced by Viel. Secondly, the approach was applied to the study of gait asymmetries in two children with hemiplegic cerebral plasy.

MATERIAL AND METHOD

Thirty healthy control subjects and two hemiplegic children (H1 and H2) performed a walking test at self selected speed. The recordings of dynamic parameters were realized thanks to an in-shoe plantar pressure analysis system (Parotec, by Paromed Medizintechnik, GMBH, Germany). The pressure peaks were determined from the recording of pressures under eight footprint locations. A program calculated the sum of forces under the heel and determined the loading foot. By defect, the second foot is the propulsive foot.

RESULTS

The asymmetrical profile of the human normal stance phase was validated. Under the heel, the pressure peaks lower by 28 % were noticed beneath the loading foot compared to the propulsive foot. Inversely, under the metatarsal heads and the hallux, the pressure peaks were greater by 32 % beneath the propulsive foot. For the two hemiplegic children, the plantar pressure profile equally highlighted significant differences between the unaffected and affected feet. The pressure peaks under the affected heel were respectively lower by 21 % and 97 % for H1 and H2. The loading function was found and associated to the affected limb. The propulsive function was not systematically found under the unaffected foot.

DISCUSSION

The analysis of plantar pressure measurements during able-bodied gait showed differences between the two lower limbs. These dynamic asymmetries are the results of a natural functional organization of the supports differentiating a loading foot and a propulsive foot and corroborating the concept proposed by Viel. The hemiplegic gait also presented dynamic asymmetries partially agreement with a personalized functional logic of loading and propulsion. However, the asymmetrical profile can also result a gait self-optimization strategy compensating biomechanical, anatomical and physiological disorders linked to the cerebral deficiency.

Intrasubject repeatability of gait analysis data in normal and spastic children

OBJECTIVE

To evaluate intrasubject repeatability of data obtained from computer-aided motion analysis in normal and spastic children.

DESIGN

Prospective controlled study.

BACKGROUND

Information from gait analysis is used in selecting therapeutic interventions for gait improvement in cerebral palsy. While there are several studies regarding repeatability of normal gait, there are no studies evaluating the repeatability of spastic gait.

METHODS

Forty children (20 normal, 20 with diplegic type of cerebral palsy) were subjected to gait analysis. Kinematic, kinetic and time distance parameters obtained from gait analysis were studied for intrasubject variability within-day and between-day using statistical measures.

RESULTS

Normal children had lower variability in time distance parameters than spastic children both within and between days. The repeatability of kinetics was better than those of kinematics, and values for normal children were better than those for spastic children. Within-day repeatability of kinematics and kinetics was better in normal children. Between-day repeatability of kinematics was better in normal children, while spastic children showed better repeatability for kinetics.

CONCLUSIONS

We found lower repeatability of gait analysis data in spastic children compared to normal children. Restricted joint range of motion due to spasticity in the group of cerebral palsy patients may be responsible for the lower repeatability of data. Some errors due to marker placement are inadvertent and contribute to the lower between-day repeatability.

RELEVANCE

The results of this study should be of interest to clinicians who make therapeutic decisions in patients with cerebral palsy using gait analysis data, and for scientists studying normal and pathological gait.

Botulinum toxin type A in the treatment of lower limb spasticity in cerebral palsy

OBJECTIVES

To determine whether botulinum toxin (BtA) is an effective and safe treatment for lower limb spasticity in children with cerebral palsy. Functional outcomes are of particular interest.

SEARCH STRATEGY

Studies for inclusion in the review were identified using the Movement Disorders Review Group trials register, the Cochrane Controlled Trials Register, MEDLINE, pharmaceutical company databases, communication with other researchers in the field and reference lists of papers found using above search strategies.

SELECTION CRITERIA

Studies were considered eligible for inclusion in the review if they evaluated the efficacy of BtA for the treatment of leg spasticity in children with cerebral palsy. They must have been randomised and include a concurrent control group receiving another intervention.

DATA COLLECTION AND ANALYSIS

A paper pro forma was used to collect data from the included studies using double extraction by two independent reviewers. Each trial was assessed for internal validity by each of the two reviewers. Meta-analysis was not possible because results were presented in an incompatable form. A Peto odds ratio was calculated where this was appropriate, otherwise a descriptive summary of the results of the individual studies was compiled.

MAIN RESULTS

Three eligible studies were found each with small numbers of subjects. They were short term, used single injection sessions with follow-up of between 4 and 26 weeks. One study (Koman), of twelve ambulant children, compared BtA with injection of a placebo and found non-significant improvements in gait in the BtA group compared to the placebo group. Two studies (Corry, Flett) compared BtA with the use of casts. Each included 20 ambulant children and found improvements in gait, range of ankle movement and muscle tone in both the BtA and cast groups. However there were no significant differences between the groups in either trial. One of these trials (Flett) also assessed motor function using the gross motor function measure (GMFM) (Russell, 1989) and found significant improvements in each group compared to baseline but no significant differences between the groups. The other trial (Corry) performed 3D gait analysis on those children able to co-operate. Maximal plantar flexion and maximal dorsiflexion during walking were both found to be significantly greater in the BtA group compared to the cast group. In all other dimensions there were no significant differences between the groups.

REVIEWER'S CONCLUSIONS

This systematic review has not revealed strong controlled evidence to support or refute the use of BtA for the treatment of leg spasticity in cerebral palsy. Ongoing randomised controlled trials are likely to provide useful data on the short term effects of BtA for leg spasticity. Future research should also assess the longer term use of BtA. Ideally studies should be pragmatic in their approach to dose and distribution of toxin to reflect practise. Outcome measures assessing function and disability would give the most useful information.

The variability of force platform data in normal and cerebral palsy gait

OBJECTIVE

To determine the natural variability and symmetry of force platform parameters in normal and cerebral palsy gait.

DESIGN

Force platform data has been analysed using coefficient of variation, analysis of variances and symmetry index.

BACKGROUND

It is important to establish the natural variability of force platform data so that changes in gait due to natural variability and those due to intervention can be determined.

METHODS

Force platform data and walking speed were recorded in 15 normal volunteers and 11 children with cerebral palsy on 3 consecutive days. Five recordings were made of each leg on each day.

RESULTS

The force platform parameters in both groups showed greater asymmetry in the horizontal plane. In the cerebral palsy group significant asymmetry was found in all 3 directions. The variation of the vertical ground reaction force peaks (Fz1 and Fz3) and of the anterior-posterior negative peak (Fy3) for both groups was low. Fz3 was the most reproducible force parameter. The other force parameters showed high variability and are not considered reliable measures of gait. The temporal parameters and the walking speed were reproducible measures.

CONCLUSIONS

Only selected ground reaction force parameters showed acceptable stability and reproducibility. Therefore caution has to be taken in the selection of these parameters, when assessing the effects of any intervention on cerebral palsy gait.