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Pediatric Physical Therapy:
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CRITICALLY APPRAISED TOPICS

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QUESTION: Is treadmill training an effective intervention for enhancing the development of independent walking in infants with Down Syndrome (DS)?

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Clinical Bottom Lines:

Treadmill training administrated by parents at home (eight minutes per day, five days per week) with infants with DS facilitated the onset age of 1) rising to stand, 2) walking with help, and 3) walking independently for three steps. However, treadmill training did not improve the physical growth of infants with DS after controlling for age and is not likely to be a mechanism for enhanced gross motor development.

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Summary of Key Evidence:

1. Study design: Randomized Clinical Trial. Observations were taken prior to intervention, and biweekly afterwards until all infants could walk independently. Intervention continued until all infants could walk.

2. Sample: Thirty infants with trisomy 21 form of DS entered this study if able to sit independently for 30 seconds. The average age at entry was 307.6 days (SD = 58.9 days). After randomization, groups were the same for gestational age, corrected age, Bayley Scale of Infant Development (BSID-II) raw motor score, mother’s and father’s education level, family income, and 11 anthropometric measures. The treadmill group had a great number of siblings.

3. Procedure: Infants’ physical growth measured by anthropometrics and new motor milestones determined by the BSID-II scale were evaluated by a team of researchers biweekly at home throughout the study. All infants received biweekly physical therapy. Infants in the treadmill group received additional treadmill intervention administered by parents at home eight minutes per day, five days per week, until they walked independently.

4. Outcome measures: The number of days lapsed between entry into the study and the occurrence of 1) raising up to stand, 2) walking with help, and 3) walking independently for three steps; Physical growth taken by anthropometrics of crown-heel length, thigh and calf lengths and circumferences, foot length and width, thigh, calf and umbilicus skinfold, and body weight.

5. Results: Treadmill group developed raising self to stand, walking with help, and independent walking earlier than control group with effect size d valued 0.61, 0.81, and 0.83, respectively. There were no group differences on any of the 11 anthropometric measures after the corrected age was controlled between groups.

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Appraisal and Application:

Threats: 1) intra- and inter-reliability of all measurements were not performed in the study for BSID-II scale and anthropometric measures, 2) no blind assessor, 3) no comparison on the amount of PT intervention between groups, even though parents wrote the treatment log, 4) observing interval was biweekly which increases error of determining onset of gross motor outcome up to 13 days.

Strengths: 1) randomization, 2) effect size (d) for each comparison, 3) log record for all possible confounders, 4) attrition rate was zero, 5) observation was taken in familiar environment.

Citation: Ulrich, D.A., Ulrich, B.D., Angulo-Kinzler, R.M., and Yun, J. (2001) Treadmill Training of Infants with Down Syndrome: Evidence-Based Developmental Outcomes. Pediatrics. 108(5):e84.

Prepared by: Yu-ping Chen, ScD, PT, Institute and Faculty of Physical Therapy, National Yang-Ming University, Taiwan

QUESTION: Is muscle strengthening an effective intervention for improving locomotion function in children with cerebral palsy (CP)?

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Clinical Bottom Lines:

Isotonic strengthening exercise was effective immediately after six weeks of treatment in improving walking function, but not 12 weeks after treatment stopped. Strength of lower limb muscles showed improvement immediately after treatment and at follow-up. Continued gains at the impairment level did not necessarily relate to continued gains at the functional limitation level (Nagi model).

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Summary of Key Evidence:

1. Study design: Randomized Clinical Trial with Blinded Assessor.R O X OO O O O

2. Sample: Twenty-one Austrian children aged between eight and 18 years with spastic diplegic CP were included. All walked independently with/without a gait aid before intervention. After randomization, the treatment group included children who were more physically disabled, classified by the Gross Motor Function Classification System, in comparison with the control group. Statistically, there were no differences between groups at baseline (prior to intervention) in age, gender, height, weight, strength assessment, and upright locomotion function, measured by dimensions D (standing) and E (walking, running and jumping activities) of the GMFM.

3. Procedure: The children were evaluated at baseline, immediately after the six-week intervention, and at 12 weeks after the intervention stopped (follow-up). Treatment group received isotonic strengthening exercises (three sets of eight to 10 repetitions of each muscle group, three times per week) with emphasis on ankle plantar flexors, knee extensors, and hip extensors. Load of strengthening was individualized and adjusted every other week. All children were instructed to continue their normal daily activities, including school and sports as well as PT consultation at school.

4. Outcome measures: 1) Isometric strength scores of the ankle plantar flexors, knee extensors, and hip extensors, using a hand-held dynamometer, 2) scores of dimensions D and E of the GMFM, 3) time to walk up and down three stair steps, and 4) self-selected walking speed.

5. Results: The treatment group improved more on combined strength scores of ankle plantar flexors and knee extensors and on combined scores of all extensors at six weeks and follow-up, in comparison to controls. The treatment group also improved more on the scores of dimension E of the GMFM and took a shorter time to walk up and down stairs at six weeks but not at follow-up. No difference in walking speed was found between groups at six or 18 weeks.

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Appraisal and Application:

Threats: 1) more physically disabled children were allocated to the treatment group without statistical control, 2) intra-and inter- reliability of all measurements were cited but not performed in the study for dynamometer and GMFM, 3) large standard deviation of each dependent variable implied the heterogeneity of the groups, 4) small sample size (11 in treatment group, 10 in control group).

Strengths: 1) concealed random allocation, 2) blind assessor, 3) specific inclusion criteria (spastic diplegic CP, aged between eight and 18 years, independent walking ability, no known orthopedic deformity), 4) intervention protocol clearly described, 5) participants’ compliance was quantitatively recorded and equal between groups.

Citation: Dodd, K.J., Taylor, N.T., and Graham, H.K. (2003) A randomized clinical trial of strength training in young people with cerebral palsy. Dev Med Child Neurol. 45(10):652–657.

Prepared by: Yu-ping Chen, ScD, PT, Institute and Faculty of Physical Therapy, National Yang-Ming University, Taiwan

QUESTION Is massed practice balance training an effective intervention for improving balance recovery and stability in school-age children with cerebral palsy (CP)?

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Clinical Bottom Lines:

Five consecutive days of balance training using a moveable forceplate system resulted in immediate significant improvement in the reactive balance control of children with CP. These improvements were maintained at a one-month follow-up. These improvements in impairments may have an influence on functional limitations (Nagi): three of the five children showed slight improvement on the Gross Motor Function Measure (GMFM). However, the GMFM section used measures anticipatory balance control not reactive balance control and may not reflect the true functional impact of the balance training intervention.

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Summary of Key Evidence:

1. Study design: single-subject, replicated multiple baseline experimental design using three pairs of children matched by diagnosis.O O X O O or O O O X O O

2. Sample: Six children with CP were included in the study, four boys and two girls with mean age of nine years two months (range was seven to 13 years). Four children had a diagnosis of spastic diplegia and two children had a diagnosis of spastic hemiplegia. All subjects met inclusion criteria.

3. Procedure: Each child served as his/her own control, and children were paired according to age and diagnosis. Initial baseline measurements were taken for two days, and then one child began training. The other child underwent a third baseline assessment prior to training. Five consecutive days of platform training occurred, with 100 perturbations (four to six perturbations/min) per session in forward and backward translations and rest breaks given every 20–25 perturbations. Assessments were made immediately after treatment and at 30-day follow-up.

4. Outcome Measures: 1) center of pressure area based on the force platform data, 2) time to stabilization based on force platform data, 3) score on Dimension D (standing) of the GMFM.

5. Results: All subjects showed an initial training effect as both center of pressure area and time to stabilization improved. Patterns of recovery emerged with center of pressure measure—the children with spastic hemiplegia showed a large initial effect and no within-training effect (rapid), while those with spastic diplegia showed a small initial effect and a continued within-training effect (gradual). Three of five subjects available after training showed improvement on GMFM, and improvements in all dependent variables were maintained one month after training was completed.

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Appraisal and Application:

Internal Validity: Threats: 1) reliability of outcome measures not described, 2) no control of children’s’ activities outside of training sessions.

Strengths: 1) replicated multiple baseline design and staggered training times to ensure changes due to intervention rather than external factors, 2) specific inclusion criteria listed, 3) dropouts for posttest analysis reported.

External Validity Threats: 1) small sample size and specific method of balance training decreases generalizability, 2) limited time for follow-up does not measure potential long-term effect.

Strengths: 1) generalizable to school-age children with spastic diplegic and hemiplegic CP, 2) no exclusion criteria listed to limit generalizability.

Statistical Validity Threats: 1) no intent to treat analysis for dropout.

Strengths 1) hierarchical linear modeling and two repeated measures ANOVAs performed to estimate effect size.

Other Elements: The specific balance training using a forceplate system may be difficult to replicate in clinical settings; different patterns of recovery in children with spastic diplegia vs hemiplegia may indicate need for different balance training approaches dependent on diagnosis.

Citation: Shumway-Cook, A., Hutchinson, S., Kartin, D., Price, R., Woollacott, M. (2003) Effect of balance training on recovery of stability in children with cerebral palsy. Dev Med Child Neurol. 45:591–602.

Prepared by: Kelley Kuzak, Physical Therapy Program, Sargent College of Health and Rehabilitation Sciences, Boston University, Boston, Massachusetts

QUESTION: Which factors contribute to muscle weakness in children with cerebral palsy (CP)?

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Clinical Bottom Lines:

An inability or failure to maximally activate the plantar flexors (PF) and dorsiflexors (DF) contributes to muscle weakness, with some contribution of plantarflexor co activation during dorsiflexion in children with CP.

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Summary of Key Evidence:

1. Case control study with 46 participants.

2. Sample:n = 46; 14 ambulatory children with spastic hemiplegic (SH)CP (seven males, seven females), 14 children with spastic diplegic (SD)CP (eight males, six females), 18 children as controls.

3. All children with CP were identified as being mildly-moderately affected by orthopedic surgeons or staff physiotherapists; confirmed with inclusion criteria. Informed consent obtained.

4. Procedure: One observation period per group. Torque measurements were taken on both legs of CP group and one leg in control group; three maximal isometric contractions were performed for PF (at each subject’s optimal length-tension position) and for DF (at 20° PF). EMG was recorded from soleus, medial gastrocnemius, and tibialis anterior at maximum DF and PF contractions. MRI was obtained on both legs of all subjects with ankle joint at 20° degrees PF.

5. Outcome Measures: Maximum torque (torque measuring apparatus), muscle cross-sectional area (MRI using Siemens 1.5T Megnetom Vision), muscle volume (MRI), specific tension (maximum torque divided by cross-sectional area), co activation (EMG with MEDI-TRACE Pellet Electrodes), and recruitment (EMG with “turns analysis”).

6. Results:Maximum torque: PF and DF torques (and mean torque ratio of PF to DF) were significantly lower in the CP group. Cross-sectional area: Significantly smaller areas of soleus, posterior, and anterior compartments noted in the affected legs of children with hemiplegia versus control; only the right anterior compartment had significantly smaller areas in the children with SDCP. Muscle volume: Anterior and posterior compartment volumes in the affected legs of children with SHCP were significantly smaller than the unaffected leg. Specific tension: Soleus and posterior compartments in the affected legs of the CP group had significantly lower tension than control; tension in anterior compartment was significantly lower in both legs of CP group. Co-activation: Significantly higher levels noted in CP group at medial gastrocnemius, soleus, and anterior tibialis. Recruitment: Affected leg in hemiplegic group produced significantly higher recruitment in soleus and medial gastrocnemius than control; mean amplitude of soleus in CP group was significantly lower than control; significantly higher recruitment/mean amplitude noted in tibialis anterior of CP group.

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Appraisal and Application:

Strengths: 1) specific inclusion/exclusion criteria 2) participants familiarized with torque testing procedures to ensure maximal contraction with no significant differences between groups; 3) high correlational accuracy of cross-sectional area measurements (r ≥ 0.82).

Threats: 1) reliability of ROM and torque measurements not reported; 2) unknown if testers were blinded;3) verbal/visual encouragement during torque measurements not standardized; 4) no operational definition of ambulatory status; 5) selection of volunteers as participants, 6) no tests of strength in functional movement were included as outcome measure. Applicability: Generalizes to ambulatory children 5.5 and 11 years old with SHCP or SDCP who are mildly -moderately affected. When such children present with PF or DF muscle weakness, it is likely caused by decreased muscle activation, which should be assessed via EMG to document true strength changes. Functional strength may be different from that tested via the apparatus used in this study.

Other Elements: Clinic would require EMG access, which may not be reasonable for all outpatient clinics.

Citation: Elder G.C., Kirk J., Stewart G., Cook K., Weir D., Marshall A., Leahey L. (2003) Contributing factors to muscle weakness in children with cerebral palsy. Dev Med Child Neurol. 45:542–550.

Prepared by: Kate Wolford, Physical Therapy Program, Sargent College of Health and Rehabilitation Sciences, Boston University, Boston, Massachusetts

© 2004 Lippincott Williams & Wilkins, Inc.

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