B.C. McDowell

The variability of goniometric measurements in ambulatory children with spastic cerebral palsy

This study assessed the variability of six goniometric measurements commonly used in the assessment of children with cerebral palsy (CP). Three experienced paediatric physiotherapists recorded three consecutive measurements of six joint ranges from 12 children with spastic CP. A fourth measurement was recorded 1 week later. The order of measurement with regards to both joint measurement and tester, was randomised to ensure a balanced experimental design. A blinded procedure was adopted with masked goniometers and a second assessor present to record the measurement. Results, analysed using generalizability theory, showed same day and different day measurement error of +/-10-14 degrees (95% confidence limits) for the foot/thigh angle, abduction and internal rotation of the hip. The source of this was child-assessor and residual error. For ankle dorsiflexion and the popliteal angles, same day measurement error was similar. However, for joint ranges recorded on different days, error ranged from +/-18-28 degrees. The major source of this was systematic differences in measurements recorded on different days. Results show a need for caution when using goniometric measurements in clinical decision making, particularly in the more tone dependent biarticular muscles after an initial assessment.

Validity of a 1 minute walk test for children with cerebral palsy

The concurrent validity of a 1 minute walk test at a childs maximum walking speed was assessed in children with bilateral spastic cerebral palsy (BSCP). The distance covered during the 1 minute walk test was compared with the childrens gross motor function as assessed by the Gross Motor Function Measure (GMFM). Twenty-four male and 10 female children with CP (mean age 11y, range 4 to 16y) participated in the study. Gross Motor Function Classification System (GMFCS) levels were; level I (n=3), level II (n=17), level III (n=10), and level IV (n=4). Participants had clinical diagnoses of symmetrical diplegia (n=19), asymmetrical diplegia (n=14), and quadriplegia (n=1). Results showed a significant correlation between GMFM score and the distance covered during the 1 minute walk (r=0.92; p<0.001). There was also a significant decrease in the distance walked with increasing GMFCS level (p<0.001). We concluded that the 1 minute walk test is a valid measure for assessing functional ability in children with ambulatory BSCP. Its cost-effectiveness and user friendliness make it a potentially useful tool in the clinical setting. Further study needs to address its reliability and ability to detect change over time.

Electrical stimulation in cerebral palsy: a review of effects on strength and motor function

Interest in the area of cerebral palsy (CP) and electrical stimulation continues to grow because it has potential as a passive, non-invasive, home-based therapy, which is claimed to result in gains in strength and motor function. If proved effective it might provide an alternative to resistive exercise techniques for children with poor selective muscle control, or indeed it might improve treatment compliance in those children who find exercise programmes difficult. Unfortunately, early reports on the efficacy of this intervention are undermined by poor methodology. A lack of consensus on optimal treatment parameters and variation in the physical abilities of the participants further confound interpretation of the literature.

Further evidence of validity of the Gait Deviation Index.

In this paper, the relationship of the Gait Deviation Index (GDI) to gross motor function and its ability to distinguish between different Gross Motor Function Classification System (GMFCS) levels was determined. A representative sample of 184 ambulant children with CP in GMFCS levels I (n=57), II (n=91), III (n=22) and IV (n=14) were recruited as part of a population-based study. Representative gait cycles were selected following a 3D gait analysis and gross motor function was assessed using the Gross Motor Function Measure (GMFM). GDI scores were calculated in Matlab. Valid 3D kinematic data were obtained for 173 participants and both kinematic and GMFM data were obtained for 150 participants. A substantial relationship between mean GDI and GMFM-66 scores was demonstrated (r=0.70; p<0.001) with significant differences in mean GDI scores between GMFCS levels (p<0.001) indicating increasing levels of gait deviation in subjects less functionally able. The relationship between the GDI, GMFM and GMFCS in a representative sample of ambulators, lends further weight to the validity of the GDI scoring system. Furthermore it suggests that the subtleties of gait may not be wholly accounted for by gross motor function evaluation alone. Gait specific tools such as the GDI more likely capture both the functional and aesthetic components of walking.

Age-related changes in energy efficiency of gait, activity, and participation in children with cerebral palsy

Aim  The aim of this study was to use a prospective longitudinal study to describe age‐related trends in energy efficiency during gait, activity, and participation in ambulatory children with cerebral palsy (CP).

Energy efficiency in gait, activity, participation, and health status in children with cerebral palsy

The aim of the study was to establish if a relationship exists between the energy efficiency of gait, and measures of activity limitation, participation restriction, and health status in a representative sample of children with cerebral palsy (CP). Secondary aims were to investigate potential differences between clinical subtypes and gross motor classification, and to explore other relationships between the measures under investigation. A longitudinal study of a representative sample of 184 children with ambulant CP was conducted (112 males, 72 females; 94 had unilateral spastic C P, 84 had bilateral spastic C P, and six had non‐spastic forms; age range 4‐17y; Gross Motor Function Classification System Level I, n=57; Level II, n=91; Level III, n=22; and Level IV, n=14); energy efficiency (oxygen cost) during gait, activity limitation, participation restriction, and health status were recorded. Energy efficiency during gait was shown to correlate significantly with activity limitations; no relationship between energy efficiency during gait was found with either participation restriction or health status. With the exception of psychosocial health, all other measures showed significant differences by clinical subtype and gross motor classification. The energy efficiency of walking is not reflective of participation restriction or health status. Thus, therapies leading to improved energy efficiency may not necessarily lead to improved participation or general health.

Electrical stimulation in cerebral palsy: a randomized controlled trial.

A randomized placebo-controlled trial was carried out to investigate the efficacy of neuromuscular electrical stimulation (NMES) and threshold electrical stimulation (TES) in strengthening the quadriceps muscles of both legs in children with cerebral palsy (CP). Sixty children (38 males, 22 females; mean age 11y [SD 3y 6mo]; age range 5-16y) were randomized to one of the following groups: NMES (n=18), TES (n=20), or placebo (n=22). Clinical presentations were diplegia (n=55), quadriplegia (n=1), dystonia (n=1), ataxia (n=1), and non-classifiable CP (n=2). Thirty-four children walked unaided, 17 used posterior walkers, six used crutches, and the remaining three used sticks for mobility. Peak torque of the left and right quadriceps muscles, gross motor function, and impact of disability were assessed at baseline and end of treatment (16wks), and at a 6-week follow-up visit. No statistically significant difference was demonstrated between NMES or TES versus placebo for strength or function. Statistically significant differences were observed between NMES and TES versus placebo for impact of disability at the end of treatment, but only between TES and placebo at the 6-week follow-up. In conclusion, further evidence is required to show whether NMES and/or TES may be useful as an adjunct to therapy in ambulatory children with diplegia who find resistive strengthening programmes difficult.

Reducing the variability of oxygen consumption measurements

The oxygen consumption (O(2)) of 10 able-bodied adults each walking at a variety of cadences and hence speeds was measured. The effect on variability of subtracting the resting oxygen rate from gross measurements and of normalising walking speed to the subjects height was investigated. Both of these were indeed found to reduce variability. A total reduction of more than 40% in the variability of O(2) cost measurements was observed. Using these techniques it was found that, at walking speeds below the average, nett O(2) cost per height was very nearly independent of walking speed.

Recruitment Bias in a Population-Based Study of Children with Cerebral Palsy

OBJECTIVE. The purpose of this analysis was to assess recruitment bias in a population-based study of locomotor ability in children with cerebral palsy. METHOD. A population-based case register was used as a sampling frame and was considered a highly ascertained record of children with the condition. A twin track approach to recruitment for the Locomotor Study was adopted through: (1) a specialist orthopedic service and (2) a community pediatric network on behalf of the case register. The subjects included children with cerebral palsy aged 4 to 16 years in 2003, able to walk ≥10 m, and a resident in Northern Ireland, as well as their parents. RESULTS. The Orthopaedic Service identified clinically distinct children with cerebral palsy in terms of type, severity, age, and geographic residence. More families responded to an invitation, and more were ultimately recruited into the study via the Orthopaedic Service compared with a case register using community pediatric contacts. Overall, 37.8% of the eligible cerebral palsy population participated in the Locomotor Study, but there was no evidence of any systematic biases in demographic or key clinical characteristics when compared with nonparticipants. One follow-up reminder led to an increase in recruitment of 10%. CONCLUSIONS. Care must be taken in the recruitment of children with cerebral palsy through clinic-based populations, although these routes may prove more successful in follow-up. Provided they are comprehensive, case registers have a valuable contribution to make to clinical research by providing a sampling frame including information on baseline characteristics of an affected population.

Interobserver agreement of the Gross Motor Function Classification System in an ambulant population of children with cerebral palsy

Gross Motor Function Classification System (GMFCS) level was reported by three independent assessors in a population of children with cerebral palsy (CP) aged between 4 and 18 years (n=184; 112 males, 72 females; mean age 10y 10mo [SD 3y 7mo]). A software algorithm also provided a computed GMFCS level from a regional CP registry. Participants had clinical diagnoses of unilateral (n=94) and bilateral (n=84) spastic CP, ataxia (n=4), dyskinesia (n=1), and hypotonia (n=1), and could walk independently with or without the use of an aid (GMFCS Levels I‐IV). Research physiotherapist (n=184) and parent/guardian data (n=178) were collected in a research environment. Data from the childs community physiotherapist (n=143) were obtained by postal questionnaire. Results, using the kappa statistic with linear weighting (κ1w), showed good agreement between the parent/guardian and research physiotherapist (κ1w=0.75) with more moderate levels of agreement between the clinical physiotherapist and researcher (κ1w=0.64) and the clinical physiotherapist and parent/guardian (κ1w=0.57). Agreement was consistently better for older children (>2y). This study has shown that agreement with parent report increases with therapists’experience of the GMFCS and knowledge of the child at the time of grading. Substantial agreement between a computed GMFCS and an experienced therapist (κ1w=0.74) also demonstrates the potential for extrapolation of GMFCS rating from an existing CP registry, providing the latter has sufficient data on locomotor ability.