Merel-Anne Brehm

Reproducibility evaluation of gross and net walking efficiency in children with cerebral palsy

In evaluating energy cost (EC) of walking, referred to as walking efficiency, the use of net measurement protocols (i.e. net=gross‐resting) has recently been recommended. However, nothing is known about the comparative reproducibility of net protocols and the commonly used gross protocols. Ten minutes of resting and 5 minutes of walking at a self‐selected speed were used to determine gross and net EC in 13 children with spastic cerebral palsy (CP; seven males, six females; mean age 8y 7mo [SD 3y 4mo], range 4y 1mo–13y) and in 10 children (three males, seven females) with typical development. In the former, their Gross Motor Function Classification System levels ranged from Level I to Level III; and seven had hemiplegia and six diplegia. There were four repeated sessions on different days, with periods of 1 week between sessions. Reproducibility was assessed for speed, and gross and net EC, by using the standard error of measurement. The results of this preliminary study showed that EC measurements were more variable for children with CP than for children with typical development. Furthermore, in both groups there was considerably more variability in the net measurements than in the gross measurements. We conclude that, on the basis of the methodology used, the use of gross EC, rather than net EC, seems a more sensitive measure of walking efficiency to detect clinically relevant changes in an individual child with CP.

EFFECT OF CARBON-COMPOSITE KNEE-ANKLE-FOOT ORTHOSES ON WALKING EFFICIENCY AND GAIT IN FORMER POLIO PATIENTS

OBJECTIVE To investigate the effects of total-contact fitted carbon-composite knee-ankle-foot orthoses (KAFOs) on energy cost of walking in patients with former polio who normally wear a conventional leather/metal KAFO or plastic/metal KAFO. DESIGN A prospective uncontrolled study with a multiple baseline and follow-up design. Follow-up measurements continued until 26 weeks after intervention. PARTICIPANTS Twenty adults with polio residuals (mean age 55 years). INTERVENTION Each participant received a new carbon-composite KAFO, fitted according to a total-contact principle, which resulted in a rigid, lightweight and well-fitting KAFO. OUTCOME MEASURES Energy cost of walking, walking speed, biomechanics of gait, physical functioning and patient satisfaction. RESULTS The energy cost decreased significantly, by 8%, compared with the original KAFO. Furthermore, the incremention energy cost during walking with the carbon-composite KAFO was reduced by 18% towards normative values. An improvement in knee flexion, forward excursion of the centre of pressure, peak ankle moment, and timing of peak ankle power were significantly associated with the decrease in energy cost. Walking speed and physical functioning remained unchanged. CONCLUSION In patients with former polio, carbon-composite KAFOs are superior to conventional leather/metal and plastic/metal KAFOs with respect to improving walking efficiency and gait, and are therefore important in reducing overuse and maintaining functional abilities in polio survivors.

Physical strain of comfortable walking in children with mild cerebral palsy

Purpose. To evaluate the physical strain of comfortable walking in children with mild cerebral palsy ((CP)) in comparison to typically developing ((TD)) children. Physical strain was defined as the oxygen uptake during walking ((VO2walk)) expressed as a percentage of their maximal aerobic capacity ((VO2peak)). Method. Eighteen children ((aged 8–16 years)) participated, including eight ambulant children ((four girls, four boys)) with mild spastic CP ((three hemiplegia, five diplegia, GMFCS I: n  ==  7 and II: n  ==  1)) and 10 TD children. VO2walk was measured during 5 min of walking on an indoor track at comfortable walking speed. VO2peak was measured in a shuttle run test. Results. VO2walk was significantly higher in CP ((19.7 ((2.8)) ml//kg//min)) compared to TD ((16.8 ((3.6)) ml//kg//min, p  ==  0.033)), while walking speed did not differ significantly between groups. VO2peak was significantly lower in CP ((37.2 ((2.2)) ml//kg//min)) compared to TD ((45.0 ((5.3)) ml//kg//min, p  ==  0.001)). Consequently, the physical strain during walking was significantly higher in CP ((52 ((7.7)) %%)) compared to TD ((36 ((8.4)) %%, p  ==  0.001)). Conclusions. The higher physical strain during comfortable walking of children with mild CP compared to TD children may be related to reported problems with fatigue in this population, and suggest a need for physical aerobic training programmes.

Reproducibility and validity of video screen measurements of gait in children with spastic cerebral palsy

PURPOSE To determine the reproducibility and validity of video screen measurement (VSM) of sagittal plane joint angles during gait. METHODS 17 children with spastic cerebral palsy walked on a 10m walkway. Videos were recorded and 3d-instrumented gait analysis was performed. Two investigators measured six sagittal joint/segment angles (shank, ankle, knee, hip, pelvis, and trunk) using a custom-made software package. The intra- and interrater reproducibility were expressed by the intraclass correlation coefficient (ICC), standard error of measurements (SEM) and smallest detectable difference (SDD). The agreement between VSM and 3d joint angles was illustrated by Bland-Altman plots and limits of agreement (LoA). RESULTS Regarding the intrarater reproducibility of VSM, the ICC ranged from 0.99 (shank) to 0.58 (trunk), the SEM from 0.81 degrees (shank) to 5.97 degrees (trunk) and the SDD from 1.80 degrees (shank) to 16.55 degrees (trunk). Regarding the interrater reproducibility, the ICC ranged from 0.99 (shank) to 0.48 (trunk), the SEM from 0.70 degrees (shank) to 6.78 degrees (trunk) and the SDD from 1.95 degrees (shank) to 18.8 degrees (trunk). The LoA between VSM and 3d data ranged from 0.4+/-13.4 degrees (knee extension stance) to 12.0+/-14.6 degrees (ankle dorsiflexion swing). CONCLUSION When performed by the same observer, VSM mostly allows the detection of relevant changes after an intervention. However, VSM angles differ from 3d-IGA and do not reflect the real sagittal joint position, probably due to the additional movements in the other planes.

Optimising Ankle Foot Orthoses for children with cerebral palsy walking with excessive knee flexion to improve their mobility and participation; protocol of the AFO-CP study.

BackgroundAnkle-Foot-Orthoses with a ventral shell, also known as Floor Reaction Orthoses (FROs), are often used to reduce gait-related problems in children with spastic cerebral palsy (SCP), walking with excessive knee flexion. However, current evidence for the effectiveness (e.g. in terms of walking energy cost) of FROs is both limited and inconclusive. Much of this ambiguity may be due to a mismatch between the FRO ankle stiffness and the patient’s gait deviations.The primary aim of this study is to evaluate the effect of FROs optimised for ankle stiffness on the walking energy cost in children with SCP, compared to walking with shoes alone. In addition, effects on various secondary outcome measures will be evaluated in order to identify possible working mechanisms and potential predictors of FRO treatment success.Method/DesignA pre-post experimental study design will include 32 children with SCP, walking with excessive knee flexion in midstance, recruited from our university hospital and affiliated rehabilitation centres. All participants will receive a newly designed FRO, allowing ankle stiffness to be varied into three configurations by means of a hinge. Gait biomechanics will be assessed for each FRO configuration. The FRO that results in the greatest reduction in knee flexion during the single stance phase will be selected as the subject’s optimal FRO. Subsequently, the effects of wearing this optimal FRO will be evaluated after 12–20 weeks. The primary study parameter will be walking energy cost, with the most important secondary outcomes being intensity of participation, daily activity, walking speed and gait biomechanics.DiscussionThe AFO-CP trial will be the first experimental study to evaluate the effect of individually optimised FROs on mobility and participation. The evaluation will include outcome measures at all levels of the International Classification of Functioning, Disability and Health, providing a unique set of data with which to assess relationships between outcome measures. This will give insights into working mechanisms of FROs and will help to identify predictors of treatment success, both of which will contribute to improving FRO treatment in SCP in term.Trial registrationThis study is registered in the Dutch Trial Register as NTR3418.

Reliability of a Progressive Maximal Cycle Ergometer Test to Assess Peak Oxygen Uptake in Children With Mild to Moderate Cerebral Palsy

Background Rehabilitation research in children with cerebral palsy (CP) is increasingly addressing cardiorespiratory fitness testing. However, evidence on the reliability of peak oxygen uptake (V̇o2peak) measurements, considered the best indicator of aerobic fitness, is not available in this population. Objective The objective of this study was to establish the reliability of a progressive maximal cycle ergometer test when assessing V̇o2peak in children with mild to moderate CP. Design Repeated measures were used to assess test-retest reliability. Methods Eligible participants were ambulant, 6 to 14 years of age, and classified as level I, II, or III according to the Gross Motor Function Classification System (GMFCS). Two progressive maximal cycle ergometer tests were conducted (separated by 3 weeks), with the workload increasing every minute in steps of 3 to 11 W, dependent on height and GMFCS level. Reliability was determined by means of the intraclass correlation coefficient (ICC [2,1]) and smallest detectable change (SDC). Results Twenty-one children participated (GMFCS I: n=4; GMFCS II: n=12; and GMFCS III: n=5). Sixteen of them (9 boys, 7 girls; GMFCS I: n=3; GMFCS II: n=11; and GMFCS III: n=2) performed 2 successful tests, separated by 9.5 days on average. Reliability for V̇o2peak was excellent (ICC=.94, 95% confidence interval=.83–.98). The SDC was 5.72 mL/kg/min, reflecting 14.6% of the mean. Limitations The small sample size did not allow separate analysis of reliability per GMFCS level. Conclusions In children with CP of GMFCS levels I and II, a progressive maximal cycle ergometer test to assess V̇o2peak is reliable and has the potential to detect change in cardiorespiratory fitness over time. Further study is needed to establish the reliability of V̇o2peak in children of GMFCS level III.

Test-retest reliability of the 20-sec Wingate test to assess anaerobic power in children with cerebral palsy.

ObjectiveThe aim of this study was to determine the test-retest reliability of the 20-sec Wingate anaerobic test in children with cerebral palsy. DesignParticipants were 22 ambulant children with cerebral palsy, with Gross Motor Function Classification System levels I (limitations in advanced motor skills, n = 11), II (limitations in walking, n = 7), and III (walking with walking aids, n = 4), aged 7–13 yrs. All children performed two 20-sec full-out sprint tests on a bicycle ergometer within 1–3 wks. Mean power and peak power (W/kg) were calculated as an estimate of anaerobic power. Test-retest reliability was determined by calculating the intraclass correlation coefficient (ICC) and standard error of measurement (SEM). Values were shown for the total group and Gross Motor Function Classification System I and II/III separately. ResultsThe test-retest reliability of mean power output was excellent for children with Gross Motor Function Classification System level I (ICC, 0.96; SEM, 5.4%) and II/III (ICC, 0.99; SEM, 6.1%). Peak power output showed a lower reliability in both Gross Motor Function Classification System I (ICC, 0.87; SEM, 9.4%) and II/III (ICC, 0.96; SEM, 11.7%). ConclusionsAnaerobic testing using a 20-sec Wingate bicycle test is reliable in ambulant school-aged children with cerebral palsy.

Defining the Mechanical Properties of a Spring-hinged Ankle Foot Orthosis to Assess its Potential Use in Children With Spastic Cerebral Palsy

A rigid ventral shelf ankle foot orthosis (AFO) may improve gait in children with spastic cerebral palsy (SCP) whose gait is characterized by excessive knee flexion in stance. However, these AFOs can also impede ankle range of motion (ROM) and thereby inhibit push-off power. A more spring-like AFO can enhance push-off and may potentially reduce walking energy cost. The recent development of an adjustable spring-hinged AFO now allows adjustment of AFO stiffness, enabling tuning toward optimal gait performance. This study aims to quantify the mechanical properties of this spring-hinged AFO for each of its springs and settings. Using an AFO stiffness tester, two AFO hinges and their accompanying springs were measured. The springs showed a stiffness range of 0.01-1.82 N · m · deg(-1). The moment-threshold increased with increasing stiffness (1.13-12.1 N · m), while ROM decreased (4.91-16.5°). Energy was returned by all springs (11.5-116.3 J). These results suggest that the two stiffest available springs should improve joint kinematics and enhance push-off in children with SCP walking with excessive knee flexion.

Beenorthesen bij neuromusculaire aandoeningen

Dat iemand met spierzwakte niet goed loopt, is vaak in een oogopslag te zien. Maar hoe komt dat? Welke spieren functioneren niet goed? Kan een orthese het lopen verbeteren? Welke orthese is dan het best? De antwoorden op deze vragen zijn niet eenvoudig. Beenorthesen bij neuromusculaire aandoeningen is de boekuitgave van de richtlijn Beenorthesen naar maat bij neuromusculaire aandoeningen, een standaardwerk voor alle zorgprofessionals die zich bezighouden met het toepassen van beenorthesen. Het boek behandelt alle stappen in het verstrekkingsproces aan de hand van de Procesbeschrijving Hulpmiddelenzorg. Met deze procesbeschrijving wordt de hele keten van activiteiten van de patient en zorgdeskundige in de hulpmiddelenzorg in kaart gebracht; van het signaleren van het probleem van de patient, gevolgd door het bepalen van de oplossingsrichting, tot de evaluatie van het verstrekte hulpmiddel. Voor de verschillende stappen in het zorgtraject zijn werkprotocollen, bijpassende registratieformulieren en beslisschemas opgenomen. Deze kunnen worden gebruikt in het besluitvormingsproces om de keuze voor een orthese, dat het probleem van de patient zo goed mogelijk opheft, te onderbouwen, waarbij de patient nadrukkelijk wordt betrokken. Het boek geeft een praktische ondersteuning aan zorgprofessionals bij het indiceren, vervaardigen, leren gebruiken en evalueren van beenorthesen. Dit boek beoogt de eenduidigheid in het toepassen van orthesen te verbeteren om het beste functionele resultaat voor de gebruiker te bereiken. Beenorthesen bij neuromusculaire aandoeningen is geschreven voor medisch studenten, studenten van medisch hogere beroepsopleidingen, revalidatieartsen, fysiotherapeuten, andere (para)medici, orthopedisch instrumentmakers, zorgverzekeraars en patienten. Het boek kwam tot stand met medewerking van een expertgroep van deskundigen uit verschillende disciplines. De auteurs zijn verbonden aan de afdeling Revalidatie van het Academisch Medisch Centrum (AMC) Amsterdam, Merel-Anne Brehm als senior onderzoeker en Frans Nollet als hoogleraar revalidatiegeneeskunde. De afdeling Revalidatie van het AMC is gespecialiseerd in de behandeling met beenorthesen bij loopstoornissen door slappe verlammingen.

P038 Reproducibility of video screen measurement of sagittal joint and segment angles during gait in patients with spastic cerebral palsy

S72 Abstracts of the 17th Annual Meeting of ESMAC, Poster Presentations / Gait & Posture 28S (2008) S49-S118 Conclusions: Isometric strength can be reliably measured by a hand-held dynamometer in patients with cerebral palsy after MLS. Findings of this study indicate that early rehabilitation including strength training is recommendable. Introduction: Orthopaedic surgery aims at improving functional ability of children with CP, however it is known to initially reduce muscle strength, particularly in the presence of pre-existing weakness. Few studies have examined the progression of muscle strength following MLS in children with CP (1,2). This study aims at evaluating strength outcome and progression over time in this patient group after MLS. The assessment device for strength, a hand-held dynamometer, was evaluated for reliability and validity. Patients/Materials and Methods: Inclusion criteria for both studies were: hospitalization following MLS, diagnosis of spastic cerebral palsy and a GMFCS score of <4. For the reliability study, 28 children with CP (mean age 14 y2m; range 9 y6m-18 y10m) were recruited. Maximum isometric strength (M. Gastrocnemius, Mm. Vastii, M. Quadriceps, M. Hamstrings, M. Gluteus medius, M. Gluteus maximus) was evaluated by two testers using a portable hand-held dynamometer at two measurement points. To evaluate concurrent validity, muscle strength was also evaluated using the Manual Muscle Testing (MMT) of Daniels and Wothingham by the two testers. For the strength outcome study, strength measurements of 31 children (mean age 13 y11m; range 5 y9m-27 y5m) were performed before surgery, at the beginning of the rehabilitation program and at discharge. All children received conventional rehabilitation and a three times weekly strength-training program. Statistical analysis was carried out to assess the interrater reliability (Intraclass Correlation Coefficients) and concurrent validity of the dynamometer (Spearman rank correlation coefficients). To evaluate the progression of strength over time, Friedman tests were applied with post-hoc Wilcoxon signed rank tests. Results: The present study showed excellent reliability coefficients of strength measurements by use of a hand-held dynamometer in this patient group after MLS. Good to high correlation coefficients between the values of the dynamometer and those of the MMT supported the concurrent validity. Friedman tests indicated a highly significant difference in strength for all muscle groups between the three measurements (p < 0.0001). Post-hoc tests showed a highly significant decrease of strength for all muscle groups after surgery (p < 0.0001) and a highly significant increase of strength after the rehabilitation program for all muscle groups (p < 0.0001). At discharge, the strength of M. Gastrocnemius, Mm. Vastii and M. Quadriceps even reached its preoperative level. Discussion: The results of this study indicated a decrease in muscle strength after MLS, but also the possibility to increase strength already in the early rehabilitation phase. Some muscle groups even reached preoperative levels at discharge from the hospital. The more proximal muscle groups did not reach preoperative levels and probably need a longer training period to become stronger.