Evaluación en miembros inferiores con un análisis 3D

An evaluation of lycra garments in the lower limb using 3-D gait analysis and functional assessment (PEDI)

Abstract

Whole body lycra garments were assessed in eight children using gait analysis, the paediatric evaluation of disability index (PEDI), and a questionnaire of parental acceptance. Seven of the children had cerebral palsy and one Duchennes muscular dystrophy. After initial assessment and fitting of the garment, there was a 2-week introduction period followed by 6 weeks of wearing the garment for at least 6 h everyday, following which they were re-assessed. The root mean square error (RMSE) was used as a measure of variability over three separate passes through the gait laboratory and was a reference figure for gait stability. Proximal stability around the pelvis improved for five children and distal stability improved for three. Five children improved in     at least one aspect of the PEDI scale. Although the parents and children detected these improvements, they did not outweigh the disadvantages of wearing the suit and as a consequence only one out of eight families considered continuing with the lycra   garment. © 2000 Elsevier Science B.V. All rights reserved.

Introduction

Gait is an important functional activity [1]. Patholo- gies such as cerebral palsy and muscular dystrophy can have a detrimental effect on the functional ability of the individual [2,3]. Recent studies have suggested that the use of dynamic lycra garments provide patients with an immediate and continuing improvement in balance, proximal joint stability and postural readiness for movement. Furthermore, it has been suggested  that  they inhibit increased tone, soft tissue contracture and involuntary movements [4,5]. However, other re- searchers and clinicians have questioned the efficacy and claims of these studies [6].

To date, evaluation of lycra garments has been through subjective video interpretation  and  rating  scales of functional improvement. Although helpful, these approaches have problems with re-test and inter- rater reliability due to their subjective nature and are open to bias. Additionally, the functional improve- ments reported were not founded on any validated assessment tools such as the Gross Motor Function Measure [1,7,8] or the Paediatric Evaluation of Disabil- ity Index (PEDI) [9,10]. Consequently, the efficacy of their findings may be limited. We therefore undertook an objective, quantitative assessment of the  garment  gait using a 3-D motion analysis system, the PEDI and compliance using a parental/carer questionnaire.

Children and method

Eight children aged from 5 to 11 years (mean 8.13 years) were studied. Seven had cerebral palsy (CP) and one Duchenne muscular dystrophy (DMD) (Table 1).  No patients had previously worn a lycra garment and none had received Botulinum toxin injections or ortho- paedic surgery in the year before the study. Each child could walk unsupported for 5 m. Consent was obtained from the children (where appropriate) or their parents. The study was approved by the local ethics committee. No change in the physiotherapy or orthotic manage- ment of the children was permitted during the study. Each child was assessed at the same time of day by the same assessors to minimise any order effects at the follow up assessment.

Each child was assessed on two occasions 8 weeks  apart. Their gait was analysed using a 6-camera motion analysis system (Elite, BTS Milan), which sampled at a rate of 100 Hz and the marker protocol of Davis [11]. The root mean square error (RMSE) was used as a measure of stability as it indicates the degree of vari-  ability over the total number of walking trials (in degrees). High RMSE values indicate that the individ- ual has poor stability and therefore experiences prob-  lems reproducing the same motion over a number of trials. Conversely, lower RMSE values suggest a good level of stability. For the purpose of differentiation between proximal and distal stability, the collective RMSE values for the pelvis defined proximal stability (saggital, coronal and transverse right and left, total 6) whereas, those for the hip, knee and ankle joints deter- mined distal stability (saggital plane only right and left, total 6).

After gait analysis the child’s function was evaluated with the PEDI. Each child was then measured for their Lycra garment by a registered orthotist for Kendall– Camp Orthopaedic. The garments were full body suits which extended from the ankles to the neck and from the neck to the wrist joints. There was no additional plastic boning to reinforce the suit.

A 2 week familiarisation period was incorporated within the study, to allow the child to gradually in- crease the time in the garment to a maximum  of  6  hours a day. This was maintained for 6 weeks and the gait and function measures were then repeated whilst  wearing the lycra garment. Parents also completed a questionnaire on the practicality and compliance of  using the garment.

Results

Dynamic postural stability

The raw RMSE values (Tables 3 and 4) suggest a trend following use of the lycra garment. Five of the eight children showed reductions in their RMSE values around the pelvis when using the lycra garment and therefore an improvement in their level of proximal stability. Improvements in proximal stability were par- ticularly noticeable in child 4 who had athetoid CP and child 8 who had proximal weakness secondary  to  DMD. An example of such an improvement is illus- trated by Fig. 2 and Fig. 3. Each figure shows the mean angle of anterior pelvic tilt for three separate walking trials, coupled with the RMSE. As gait is a cyclical process one would expect to see a high level of consis- tency between each separate trial. Such consistency is clearly evident in the gait pattern of a  normal  child (Fig. 1). When Fig. 1 and Fig. 2 are compared it is clear that child 4 who had athetoid CP showed more vari- ability, had a higher RMSE and was therefore less  stable proximally. A reduction in the RMSE is evident following use of the lycra garment. This is shown in  Fig. 3 where there is a notable convergence of the traces indicative of more proximal stability.

Improvements in proximal stability were not uniform. Child 3, whose predominant motor impairments were spasticity, weakness and hypotonia, demonstrated an increase in the degree of variability about the pelvis. This suggests that the lycra garment affected this child’s proximal stability.

There was less improvement in distal than proximal stability when the lycra garment was worn. Only the children 1, 4 and 5 had an improvement in their distal joint stability. Fig. 5 and Fig. 6 illustrate the distal improvement in stability at the ankle of one child (sagittal plane). Interestingly, child 3, who demonstrated the most variability at the pelvis also showed   the largest deterioration in their distal stability.

There was no statistically significant change in the RMSE before and after use of the garment (Wilcoxon test).

Functional Improvement

Change in the functional ability of the children over the 8-week period was recorded by the  PEDI.  There was no significant change in self-care, mobility, social function for the child or the level of caregiver assistance required for self care, mobility or social function (Wilcoxon test). Although there was no significant im- provement in function in the group as a whole, some children did improve. Child 3 showed improved scores in all aspects of self-care, mobility or social function. Children 2 and 4 also showed improvements in two of the three functional scores. No change in any func- tional score was noted in children 4, 5 or 8

Compliance questionnaire

The majority of parents found the suits  relatively  easy to get on their children, and only the parent of  child 4 reported difficulties. No concerns were raised by the parents over the health and well being of the children whilst wearing the lycra garments. There were no respiratory problems and only one parent reported   an increase in frequency of dribbling in their child. One area which gave concern to the parents and children, was that of toileting and six out of eight experienced difficulties. No child became constipated by wearing the garment. However, two children namely (children 1  and 5) had a decrease in the frequency of urination and bowel movements. Some children did experience an increase in frequency of urination (children 2, 6, 7). The parent  of  child  2  reported  an  improvement  in  the child’s confidence whilst mobilising whereas five parents noted a positive change in their child’s walking pattern. No parents reported that their child  enjoyed  wearing the garment. Seven of the eight parents reported that they would not consider using the lycra garment  for their child again in the future. The parent of child 3 was undecided.

Discussion

The aim of this study was to evaluate the effect of lycra garments on the gait and function of children with neurodisability. The study did not show any statistically significant improvement from the garment on proximal or distal stability. However, the small sample size, coupled with the heterogeneous nature of the popula- tion studied, may have diluted any perceptible differ- ences making the collective statistical analysis insignificant. Blair et al. [4] found that successful out- comes with a lycra garment was often dependent on the individual’s pathology, motivation,  age,  and  attitude. In this study the pelvic RMSE scores in all three planes of motion during walking improved in five out of eight children. This trend reinforces those proposed by Blair  et al. [4] and Hylton et al. [5] who suggested that lycra garments can promote proximal joint stability.

It is well recognised that improvement in proximal stability is essential for motor control and is often the main focus of therapy [12]. However, the trend towards improved proximal stability did not correspond with improvements distally and only three children improved their collective RMSE scores distally. Not all children showed an improvement in distal stability if they exhib- ited more pelvic variability. In addition not all children who improved proximally improved distally. This was clearly demonstrated in child 8 who had proximal weakness secondary to DMD showed good proximal improvement but was significantly more variable dis- tally whilst wearing the garment.

The reason why improvements in proximal control did not affect motor control distally may have been because the duration of the study was too short. Addi- tionally, the manufacturing process of the garments predisposes a bias towards proximal improvement over distal. The foot and most of the ankle is not covered by the garment. and this may reduce its efficacy for distal control. It is also possible that by improving proximal stability may place less demand at the ankle and foot  and be reflected in an unchanged RMSE for distal stability.

There were no statistically significant changes in the PEDI in the study. This may have been due mainly to  the small sample size and heterogeneity, but may also  be attributable to the assessment tool used. The PEDI, although a well-validated form of assessment [9,10], may not have been sensitive enough to detect functional change over a short time. Individual scores for  the  PEDI were highly variable. However, the autonomy of the majority of children studied generally improved  and, conversely, the level of caregiver assistance re- mained relatively static. This suggests that the func- tional improvements seen in some children  were  not due to increased support by the caregiver.

It was interesting to note that improvements in the variability of the gait pattern did not necessarily trans- late into functional gains as measured by the PEDI. For example children 4 and 5 demonstrated improve- ments in proximal and distal stability but neither showed any functional change after using the lycra garment. This is probably because the RMSE only  indicates the degree of variability and not a trend towards a more ‘normal’ gait pattern.

Another factor which may have detracted from the efficacy of this study’s findings was the practicality and compliance of wearing the garment. Parents particu- larly noted problems of ‘toileting’. Some children were reported as having a decreased frequency of toilet use, which was attributed to fear of soiling the garment or    to the embarrassment of needing assistance when in the garment. Parents also complained of wear and tear over the knees and elbows and occasionally of skin chaffing over joint lines. As the trial was performed over the summer period some children also found the suits uncomfortably warm, occasionally leading excessive perspiration and subsequent dehydration.

There were no ill effects reported whilst wearing the lycra garment. No parent reported problems with con- stipation, peripheral cyanosis or respiratory dysfunc- tion, which differs from those of Blair et al. [4]. The lack of adverse events within this study is probably due to the design of the garments. Blair et al. evaluated the Second Skin Lycra® garments, which have plastic bon- ing for extra support. In comparison, the garments manufactured by Kendall– Camp Orthopaedic have no such plastic boning and may prove a little less restric- tive to respiratory and bowel movement.

Seven of the eight parents did not wish for their child to continue with the garment as they found the prob- lems of toileting, excess heat and child’s comfort in the garment outweighed any apparent gain in mobility or function.

The use of lycra garments to promote proximal stability remains an exciting development in the man- agement of children with neurodisability. However, for it to fulfil its true potential, researchers must strive to evaluate the mechanisms by which the garments work and overcome the practical problems of their daily use. Failure to do so will undoubtedly lead to indifferent outcomes and a parental perception that the negative concerns of everyday wear outweigh any possible posi- tive gains for their child’s mobility or function.