The Walk Aide (Innovative Neurotronics, Austin, Texas) is a small (8.2 cm × 6.1 cm × 2.1 cm, 87.9 g) device that delivers asymmetrical biphasic surface electrical stimulation (ES) in a synchronized manner to stimulate active ankle dorsiflexion during the swing phase of gait. During a gait cycle, the Walk Aide stimulates the common fibular/peroneal nerve, which innervates the tibialis anterior and other ankle dorsiflexors.
The device was attached just below the knee with a cuff, and could be removed and replaced, as required, by parents and children. The device's sensors detected changes in the position of the shank and triggered ES to activate ankle dorsiflexion during the swing phase of gait. The device was initially manually synchronized with each child's individual walking pattern.
The first author was responsible for the initial setup of the FES device, with technical support from Orthopaedic Appliances Pty Ltd available if required. Once the appropriate timing had been determined, the program was saved to the device so that the stimulation was always delivered and terminated at a particular shank angle. Pulse width was set to a maximum of 300 μs and frequency to a maximum of 33 Hz. Users could adjust intensity (mA) using a dial on the device. The device recorded hours of use and the total number of stimulations. Dorsiflexion was achieved by common fibular/peroneal nerve stimulation with 1 electrode at the head of fibula and the other on the main muscle belly of the tibialis anterior. Stimulation parameters are shown in Table 3. Electrodes were replaced every 2 to 3 weeks. The position of the cuff and electrodes on the leg was marked on the skin with a permanent marker, and parents were asked to refresh the markings throughout the week. The principal investigator trained parents and children to test the quality of the contraction manually to ensure dorsiflexion without excessive eversion. They were asked to do this each time they used the device.
Children were provided with the FES device 1 week before the commencement of the FES intervention phase, to accommodate them to the sensation of the stimulation (at home only for a maximum of 15 minutes a day) and to enable them to practice putting the cuff on in the correct position. During the FES intervention phase, children were asked to use the device for at least 1 hour a day, 6 days a week for 8 weeks. Children wore their AFOs during the pre-FES phase but not during FES and post-FES phases.
Clinical Assessment and Outcome Measures
The outcome measures were routinely used in the community setting. As part of best practice and ongoing clinical care, bilateral measures were taken to monitor adverse changes (increases in spasticity or clinically significant loss of range). However, only the ankle ROM and spasticity measures on the affected side were used for reported comparisons. All testing in all phases of the study occurred without AFOs.
Range of Motion
The first author took passive ankle dorsiflexion measures (with the knee extended) in subtalar neutral with the child in the supine position. Passive measures of popliteal angle, dorsiflexion with knee flexion, ankle eversion in plantigrade, and knee extension were taken bilaterally to ensure no loss of range. A goniometer was used for all measures because of excellent reliability in children with CP.16
Dynamic ROM (Modified Tardieu Scale) was measured in the supine position described earlier concurrently with passive ROM measurement to determine the first point of catch.17 The Australian Spasticity Assessment Scale18 was also used to measure spasticity in the gastrocnemius muscle (Table 4). This 5-point ordinal scale considers the angle of the point of catch, as well as the presence of any resistance throughout the remaining available passive range. This scale was chosen because it is easy to administer in the clinical setting, it is a more valid and reliable measure of spasticity than the Modified Ashworth Scale, and can be performed concurrently with passive and dynamic ROM testing.18
Ankle dorsiflexion strength was measured using handheld dynamometry (Lafayette Nicolas Manual Muscle Tester Model 01160 with output in kilogram, Lafayette Instruments, Lafayette, Indiana). The stabilization test position for ankle dorsiflexion followed the protocol described by Crompton et al19 to improve reliability and reduce measurement error. Three measurements were taken for each side, and median scores were calculated for affected and unaffected sides. Single-limb heel raises were used to measure functional ankle plantar flexion strength because handheld dynamometry for ankle plantar flexion is an unreliable measure.19,20 The procedure followed the description provided by Yocum et al,20 but with 2 adaptations. As this was a community-based study, it was not possible to use a laser pointer to measure heel raise height, and so a heel raise was accepted if the child could rise onto the metatarsal heads with knee extended. Because of contracture and spasticity, children were also permitted to touch the wall with their forearm on the affected side, not merely their fingertips as in the original method.20 The maximum number of heel raises was recorded.
Selective Motor Control
Selective motor control assessment of ankle dorsiflexion described by Boyd and Graham17 was used. This 5-point ordinal scale is commonly used in clinical practice and quickly and simply performed with children as young as 4 years of age.
The single-limb balance assessment was used because of excellent test-retest reliability21 and because single-limb stance is associated with ankle stability.22 Single-limb balance with eyes open was measured using a stopwatch, with the child standing barefoot on a firm and level surface. Instructions were: “Stand on your left/right foot for as long as you can or until I tell you to stop.” The maximum of 3 trials was recorded.
The Observational Gait Scale (OGS), a modification of the Physician's Rating Scale that places a greater emphasis on the foot and knee,17 was the most appropriate tool available in the community setting for measuring changes at the level of the foot and ankle. The scale items include knee and foot position in midstance, initial foot contact, timing of heel rise, and base of support.17 Silicon Coach Pro7 (Siliconcoach Ltd, Dunedin, New Zealand), a software program that enables frame-by-frame analysis of limb position, was used for video analysis. Markers were placed on the medial epicondyles, lateral epicondyles, patella, medial malleoli, lateral malleoli, head of the fifth metatarsal, and calcaneus. Two video cameras capturing sagittal and coronal views (1080p50) were positioned 5 m away from a marked central 1 m × 1 m square. Each child was video-recorded while walking barefoot at a self-selected speed without the Walk Aide in all 3 phases. Videos of walking without the Walk Aide were presented in randomized order to a blinded assessor, who gave each child a OGS score out of 20. The OGS is normally scored out of 22, but the final question regarding a change in the overall gait pattern was omitted to preserve blinding.
Self-reported Toe Drag and Falls
No published qualitative or quantitative scale is reported that rates the incidence of toe drag and falling for this population, and so a 5-point ordinal scale questionnaire was developed (Table 5), including an option for written comments. Test-retest reliability was moderate for toe drag (κ = 0.41) and good for falls (κ = 0.71).
Potential participants and their parents attended an initial appointment at The Centre for Cerebral Palsy to become familiar with the device and to determine whether FES would be an appropriate intervention. All children who attended this appointment entered the study and completed all phases.
All outcomes were measured weekly throughout the 20-week study period, except for the 2-dimensional gait analysis and toe drag and falling self-report, which were assessed every 3 weeks (totaling 7 probes throughout the study). Measures were taken by the first author at home or school to encourage children to incorporate the use of the device in their home and community settings. These appointments provided the opportunity to address any problems with the device, monitor electrode integrity and replace electrodes if necessary, check for skin condition at the point of stimulation, probe for adverse effects, assess for quality and timing of contractions, and make any necessary parameter and timing adjustments.
Families completed a weekly diary, which included recording the hours of usage of the device each day (see Table 3), intensity level, skin integrity, and any other observations. Each week, the first author collected the diaries and downloaded hours of usage and the number of stimulations from the device. The first author completed all measurements, except for the rating of gait analysis videos. It was not possible to blind either the child or the principle investigator to phases of the study. Because of budget constraints, the same person administered the intervention and took the measurements.
Means and standard deviations for interval data or medians and ranges for ordinal data were calculated for each outcome measure for each child on the affected side. Comparisons between pre-FES and FES intervention phases and between pre-FES and post-FES phases were made for each child individually, using (a) visual analysis for changes in level, (b) the 2 standard deviation band (2SD) method (for interval data) or the percentage of nonoverlapping data method (for ordinal data) to assess change in level,23 and (c) the C-statistic to assess change in slope/trend.24 Statistical significance was reached in the 2SD band method if 2 consecutive data points lay outside the 2SD band in the FES or post-FES phases.25 In the percentage of nonoverlapping data method, a median line was drawn from the baseline data, and the strength of change depended upon the percentage of points in the FES and post-FES phases that lay above and below this line (as indicated in the Supplemental Digital Content Tables 6 through 12 available at http://links.lww.com/PPT/A65).23 The C-statistic assessed trend in the pre-FES phase, and if no significant trend was found, the C-statistic was computed for the combined pre-FES and FES phases. If this result was significant, a treatment effect was found. This process was repeated for the pre-FES and post-FES phases.25 Autocorrelation was calculated for each outcome measure to ensure that serial dependency would not influence our interpretation of the visual analysis and the 2SD band method. Autocorrelation can decrease the variability in the data and increase the likelihood of concluding incorrectly that a difference exists between phases when using visual analysis and the 2SD band method.25,26 When autocorrelation is found, these methods need to be applied with more caution. As the sample was relatively homogeneous and larger than usual for a single-subject design, we undertook a secondary analysis of the grouped data.23,27 The medians for each phase were calculated, and Wilcoxon signed rank tests were used to compare performance between the pre-FES phase and the 2 other phases. For the C-statistic and Wilcoxon signed rank test, α was .05.
Weekly diaries indicated that all children wore the device at least 1 hour a day, 6 days a week, with no reported side effects. Walk Aide usage data were successfully downloaded from all devices, except for participant 12. However, the weekly diary indicated 185 hours of device wear over 8 weeks (mean of 3.3 hours a day) for this child. Weekly measures were taken on all children with 3 exceptions: (a) no measure was taken for participant 7 in week 3 of the post-FES phase because of a sprained ankle, (b) no handheld dynamometry measure was taken for participant 2 in week 1 of the FES phase because of the unavailability of the dynamometer, and (c) heel raises for participant 8 were not taken until the final week of the pre-FES phase because participant 8 was the first child to be tested and the decision to include heel raises as an outcome measure was not made until that point. Gait analysis and toe drag and falls data were complete for all participants. Clinical measures of hamstrings, knee extension, and ankle eversion indicated no loss of range or increases in spasticity. Measures taken on the unaffected side indicated no clinically adverse changes. Gait in all participants was classified in level I or II according to Winters Gage and Hicks classification.28
Range of Motion
Six children improved their passive range of ankle dorsiflexion in the FES phase when compared with the pre-FES phase and 8 children improved in the post-FES phase compared with the pre-FES phase on at least 2 of the tests (Supplemental Digital Content Table 6, available at http://links.lww.com/PPT/A65). Although the baseline ROM values for 7 children fluctuated by more than 5°, the group as a whole improved significantly between both the pre-FES and FES phases (P < .01) and the pre- and post-FES phases (P = .01). Throughout the study, loss of range was noted in 2 children (1.7° and 2.1°) between the pre- and post-FES phases.
Compared to the pre-FES phase, 7 children improved their dynamic ankle range on at least 2 of the 3 tests in the FES phase and 8 children demonstrated improvement in the post-FES phase (see Supplemental Digital Content Table 7, available at http://links.lww.com/PPT/A65). The baseline values varied by more than 5° for all but 1 child. However, the group as a whole improved significantly between the pre-FES and FES phases (P < .01) and the pre- and post-FES phases (P < .01).
Three children demonstrated a decrease in spasticity assessed on the Australian Spasticity Assessment Scale in the FES and post-FES phases when compared with the pre-FES phase (see Supplemental Digital Content Table 8, available at http://links.lww.com/PPT/A65). As a group, a significant reduction in Australian Spasticity Assessment Scale scores was found between the pre-FES and FES phases (P = .03), as well as between the pre- and post-FES phases (P < .01). Median scores and ranges are shown in Supplemental Digital Content Table 8, available at http://links.lww.com/PPT/A65. Of the 12 participants, 9 received 6-monthly BoNT-A to the gastrocnemius muscle. At the end of this study, 5 of the 9 children did not require their scheduled 6-monthly BoNT-A as it was not clinically indicated.
Ten children improved their ankle dorsiflexion strength during the FES and post-FES phases when compared with the pre-FES phase on at least 2 of the 3 tests (see Supplemental Digital Content Table 9, available at http://links.lww.com/PPT/A65). The group as a whole improved significantly between the pre-FES and FES phases (P < .01) and between the pre- and post-FES phases (P < .01). The Figure demonstrates a typical graph for this outcome measure in this study. Six children performed a greater number of heel raises in the FES and post-FES phases when compared with the pre-FES phase on at least 2 of the 3 tests (see Supplemental Digital Content Table 10, available at http://links.lww.com/PPT/A65). The group as a whole improved significantly between the pre-FES and FES phases (P < .01) and between the pre- and post-FES phases (P < .01).
Selective Motor Control
Six children improved their ankle SMC in the FES and post-FES phases when compared with the pre-FES phase, on at least 2 of the 3 tests (see Supplemental Digital Content Table 11, available at http://links.lww.com/PPT/A65). The group as a whole improved significantly between the pre-FES and FES phases (P = .02) and between the pre- and post-FES phases (P < .01). Median and ranges are shown in Supplemental Digital Content Table 11, available at http://links.lww.com/PPT/A65.
Improved balance was seen between the pre-FES and FES phases in 1 child and in 6 children between the pre- and post-FES phases on at least 2 of the 3 tests (see Supplemental Digital Content Table 12, available at http://links.lww.com/PPT/A65). As a group, no significant change was found between the pre-FES and FES phases (P = .16). A significant improvement was found between the pre- and post-FES phases (P < .01).
Observational Gait Score and Self-reported Toe Drag and Falls
As a group, no statistically significant change in OGS scores was found between the pre-FES and FES phases (P = .73) and the pre- and post-FES phases (P = .45). A significant reduction was found in self-reported frequency of falling (P = .03) and toe dragging when walking (P = .02) between the pre-FES and FES phases. Between the pre- and post-FES phases, a significant reduction was found in falling (P < .01) and toe dragging/tripping when walking (P = .02).
Low levels of autocorrelation were found, and these are indicated in Supplemental Digital Content Tables 6 to 12, available at http://links.lww.com/PPT/A65. These tables show autocorrelation in only 5% of participants across the outcomes measures at baseline. Visual analysis of baseline data identified a trend in 17% to 33% of participants across variables. Where this occurred, the 2SD band method was not used. Baseline stability was not achieved in 17% to 25% of participants for the last 5 variables, as shown in Supplemental Digital Content Tables 8 to 12, available at http://links.lww.com/PPT/A65. Moreover, considerable baseline instability was observed for passive dorsiflexion ROM (58%) and dynamic ankle range (92%), where any variation exceeding 5° was rated as unstable, as shown in Supplemental Digital Content Tables 6 and 7, available at http://links.lww.com/PPT/A65. Baseline stability results are shown in Supplemental Digital Content Tables 6 to 12, available at http://links.lww.com/PPT/A65. On the basis of the combined results of visual analysis, 2SD band method, percentage of nonoverlapping data, and C-statistic, 60% of all possible comparisons for children classified in GMFCS level I showed a change and only 34% of comparisons for children classified in GMFCS level II showed a change.
The results support the hypothesis that FES would improve ankle dorsiflexion SMC, ROM, and dorsiflexion strength, and reduce gastrocnemius muscle spasticity and the frequency of toe drag and falls during an 8-week FES intervention period. The OGS scores and balance did not improve as the result of the FES intervention.
The improvements in ROM and associated reductions in spasticity during ES have been reported previously.14,29 The mechanism for spasticity reduction and ROM improvements following ES is not well understood, but a possible hypothesis involves reciprocal inhibition, proposing ES reduces muscle cocontraction at the ankle joint by addressing impaired reciprocal inhibition.30–32 In the case of the Walk Aide, stimulation of the tibialis anterior muscle would cause inhibition of the gastrocnemius muscle, thereby enabling better prepositioning of the foot for the stance phase of gait. It is possible that this reciprocal inhibition coupled with increased awareness caused by the stimulation30,33 might also account for the observed improvements in SMC of the ankle joint. Although previous literature has reported that ES improves both passive and active ROM,14,29 to our knowledge, no studies have reported the effects of ES on SMC, which is defined as an “impaired ability to isolate the activation of muscles in a selected pattern in response to demands of a voluntary posture or movement.”34 (p2162) The development of interventions to address ankle SMC impairments is an important clinical goal, as in our experience, the ankle joint is typically more impaired than more proximal joints and can significantly affect motor function and response to therapy interventions.32,35 This study provides preliminary data supporting the use of FES to improve ankle ROM and reduce spasticity, which in turn may facilitate improvements in SMC.
Electrical stimulation is commonly used in rehabilitation to improve strength of the stimulated muscle,36 by improving muscle synaptic efficiency through selective recruitment of type II muscle fibers.37 The tibialis anterior muscle is typically weak in children with unilateral spastic CP and may be confounded by a restriction in ROM and SMC at the ankle joint due to spasticity and contracture.11 The results from this study support the use of FES to improve the strength of the stimulated muscle, which may have also been facilitated by the positive clinical effect of FES on ROM, spasticity, and SMC. Daichman et al36 similarly found that the use of ES increased agonist muscle strength that was coupled with decreased antagonist spasticity. They speculated that ES might have enabled stronger contractions that increased joint excursion, resulting in increased motor unit activation and motor learning. Given that this treatment was well tolerated by the children in the present study, FES applied during gait presents an efficient and viable option for addressing strength, spasticity, SMC, and ROM impairments concurrently. The interplay and possible relationships between these variables may account for the greater apparent response in children at GMFCS level I in our sample. This study was not designed to compare the differences between children at GMFCS levels I and II. Given the greater apparent response in children classified in GMFCS level I and the small number of children classified in GMFCS level II in this study, further investigation comparing the outcomes of these 2 groups is required.
The significant improvement in ankle plantar flexion strength during the FES phase was an unexpected finding because the plantar flexors were not electrically stimulated. The increase in strength may be partially attributed to the removal of the AFOs, which typically block ankle plantar flexion during gait.7,10 Ankle plantar flexors are weak in children with unilateral spastic CP, producing only one-third of the force generation demonstrated in gait by individuals who are healthy,5 hence the possibility of a greater potential improvement and response to intervention. Prosser et al7 who used the same FES device provided kinematic data that supported the preservation of ankle plantar flexion at toe off in children with unilateral spastic CP. This finding highlighted the potential for synchronized FES to also influence stance phase kinematics.
McNee et al38 demonstrated that ankle plantar flexion strengthening exercises in children with CP could significantly increase the number of heel raises that could be performed following a 10-week training period. Participants in the present study were not given formal plantar flexion strengthening exercises. Therefore, the significant increase in the number of heel raises during the FES phase can be attributed to only the combination of FES to preposition the foot during swing (thereby facilitating the ankle rocker mechanisms) and the removal of AFOs for an 8-week period of daily FES use. Further investigation is warranted as improvements in plantar flexion strength may have implications for gait efficiency39 and muscle volume/growth.38
Reports in the literature of the effects of FES on participation are scarce, limited to only a handful of anecdotal reports on improvements in sport participation30,40 and reduction in falls.29,30 In the current study, we did not measure participation, but we did collect some preliminary data on direct ankle dorsiflexion activation by the ES in the swing phase of gait that may have resulted in reductions in self-reported toe drag and falls. This was previously described as an orthotic effect.12 The reductions in toe drag and falls were not reflected in the OGS measures, possibly because of poor OGS sensitivity and the lack of quantitative measurements during gait. Given that a change of the ankle joint of as little as 2° can significantly alter foot clearance,41 the OGS would not have been able to account for such a small difference and may have underestimated the direct effect of FES on foot clearance for the reduction in toe drag and falls. However, it is also possible that the discrepancy between self-reported toe drag and falls and the blinded OGS score might reflect an expectation on the part of the children and their families rather than a real change. This is consistent with previous studies that investigated the effects of ES where positive parent report was not supported by clinical data, highlighting the importance for blinded and extensive assessments.42
The continued reduction in toe drag and falls, improvements in ankle dorsiflexion SMC, ROM, ankle dorsiflexion and plantar flexion strength, and gastrocnemius muscle spasticity in the 6-week follow-up phase supports the second hypothesis. The carryover is commonly referred to as the therapeutic effect and suggests the possible role of motor learning.12,40 Functional electrical stimulation applied during gait has the potential to address the requirements for motor learning. Best practice guidelines dictate that treatment needs to be applied frequently with adequate dosages of task-specific opportunities to practice in environmentally relevant contexts, at the limit of performance.43 Continued reduction in toe drag and falls and improvements in single-limb balance in the post-FES phase support this recommendation. In the post-FES phase, participants no longer had their Walk Aide or AFO. It is possible that this may have challenged the ambulation and balance requirements for activity and participation, accounting for the significant improvements in single-limb balance noted only in the post-FES phase and for the ongoing reduction of toe drag and falls. Results from this study are consistent with previous reports that support the role of high-intensity, task-specific training for high-functioning children with CP.44 Therefore, FES may be a plausible treatment for improving activity and participation, based on motor learning principles.
Children are encouraged to wear their AFOs throughout the day to prevent the loss of ROM at the ankle. In this study, we noted an improvement of ankle ROM with reductions in gastrocnemius muscle spasticity in the FES and post-FES phases. This suggests that time spent walking without an AFO while the Walk Aide was being used did not result in a loss of ankle ROM. This supported the conclusion derived by Hazlewood et al14 that ES can be an appropriate home-based intervention for improving ankle dorsiflexion ROM. The delay in BoNT-A injections by 3 to 6 months in 5 children in the current study warrants further investigation concerning the effect of FES on ROM and spasticity, as this may have implications for BoNT-A scheduling.
Several limitations of this study are notable. All but 3 criteria on the quality rating scale for single-subject research designs were met, scoring 11 of 14 (strong).45 The 3 unmet criteria were (a) assessment of interrater or intrarater reliability of dependent measures before and during each phase, (b) blinding of the assessor, and (c) stability of baseline data. The assessor's reliability was not evaluated during the study because previously established protocols were followed, and all but SMC have been shown to have at least moderate intrarater reliability. The rating of the OGS was the only blinded component, which raises the possibility that the other measures were influenced by the assessor's expectations. To prevent this bias, the assessor followed strict protocols and avoided looking at previous results. The alteration of OGS scoring to preserve blinding has not been previously reported, and this may have implications for its validity. Baseline stability was established for most participants on most variables. However, stability for passive or dynamic ankle dorsiflexion ROM was not achieved because of the true variability in children's day-to-day ROM. Other limitations arose from the fact that this was a community-based study. Two-dimensional gait analysis was used because of its accessibility and cost-effectiveness, but the OGS may not have been sensitive enough to evaluate change. There are also obvious limitations to 2-dimensional gait analysis, and 3-dimensional data for ankle kinematics and kinetic information for ankle power profiles would have strengthened this study. To our knowledge, no valid measures of toe drag and falls have been reported for this population, so we developed our own questionnaire for this study, which has not been validated; thus, results must be interpreted with caution. An adequately powered, randomized controlled trial addressing all levels of the International Classification of Functioning, Disability and Health for Children and Youth Version46 is recommended.
This study supports the use of FES to address the main impairments affecting gait in children with unilateral spastic CP, during and beyond treatment periods. This is true particularly for children functioning at GMFCS level I. These results must be interpreted with some caution because of the limitations mentioned earlier. Functional electrical stimulation was well accepted in this study, with all children adhering to the recommended dosage. Functional electrical stimulation offers the potential for high-frequency, individualized treatments in contextually relevant environments, which is believed to facilitate motor learning through specificity of intervention. This study documents a carryover effect for a minimum of 6 weeks. This suggests that intermittent and short-term use of FES can be a potentially efficient, economical (as devices can be shared) and effective treatment strategy for community clinical practice.
We thank the children and families who participated in this study for their cooperation. We also thank Georgina Jones, Michael Chan, Noula Gibson, Sarah Love, Tomie Pfieffer, and Catherine Elliott for their support and assistance with this research. We thank the journal's 2 anonymous reviewers for their very helpful advice. For this study, the Walk Aides were donated by Orthopaedic Appliances Pty Ltd.
1. Rosenbaum P, Paneth N, Leviton A, et al. A report: the definition and classification of cerebral palsy
April 2006. Dev Med Child
2. Palisano RJ, Hanna SE, Rosenbaum PL, et al. Validation of a model of gross motor function for children with cerebral palsy
. Phys Ther. 2000;80(10):974–985.
3. Beckung E, Carlsson G, Carlsdotter S, Uvebrant P. The natural history of gross motor development in children with cerebral palsy
aged 1 to 15 years. Dev Med Child
5. Riad J, Haglund-Akerlind Y, Miller F. Power generation in children with spastic hemiplegic cerebral palsy
6. Rodda J, Graham HK. Classification of gait
patterns in spastic hemiplegia and spastic diplegia: a basis for a management algorithm. Eur J Neurol. 2001;8(3):98–108.
7. Prosser LA, Curatalo LA, Alter KE, Damiano DL. Acceptability and potential effectiveness of a foot drop stimulator in children and adolescents with cerebral palsy
. Dev Med Child
8. Gibson N, Graham HK, Love S. Botulinum toxin A in the management of focal muscle overactivity in children with cerebral palsy
. Disabil Rehabil. 2007;29(23):1813–1822.
9. Molenaers G, Van Campenhout A, Fagard K, De Cat J, Desloovere K. The use of botulinum toxin A in children with cerebral palsy
, with a focus on the lower limb. J Child
10. Romkes J, Brunner R. Comparison of a dynamic and a hinged ankle-foot orthosis by gait
analysis in patients with hemiplegic cerebral palsy
11. Wiley ME, Damiano DL. Lower extremity strength profiles in spastic cerebral palsy
. Dev Med Child
12. Stein RB, Everaert DG, Thompson AK, et al. Long-term therapeutic and orthotic effects of a foot drop stimulator on walking performance in progressive and nonprogressive neurological disorders. Neurorehabil Neural Repair. 2010;24(2):152–167.
13. Reed B. The physiology of neuromuscular electrical stimulation. Pediatr Phys Ther. 1997;9:96–102.
14. Hazlewood ME, Brown JK, Rowe PJ, Salter P. The use of therapeutic electrical stimulation in the treatment of hemiplegic cerebral palsy
. Dev Med Child
15. Wright PA, Durham S, Ewins DJ, Swain ID. Neuromuscular electrical stimulation for children with cerebral palsy
: a review. Arch Dis Child
16. Allington NJ, Leroy N, Doneux C. Ankle joint range of motion measurements in spastic cerebral palsy
children: intraobserver and interobserver reliability and reproducibility of goniometry and visual estimation. J Pediatr Orthop B. 2002;11(3):236–239.
17. Boyd R, Graham HK. Objective measurement of clinical findings in the use of botulinum toxin type A for the management of children with cerebral palsy
. Eur J Neurol. 1999;6(suppl) (4):S23–S35.
18. Love S, Gibson N, Cole J, Williams N, Blair E. The reliability of the Australian Spasticity
Assessment Scale (Abstract). In: Proceedings of the Australasian Academy of Cerebral Palsy
and Developmental Medicine Conference; April 10-13, 2008; Brisbane, Queensland, Australia.
19. Crompton J, Galea MP, Phillips B. Hand-held dynamometry for muscle strength
measurement in children with cerebral palsy
. Dev Med Child
20. Yocum A, McCoy SW, Bjornson KF, Mullens P, Burton GN. Reliability and validity of the standing heel-rise test. Phys Occup Ther Pediatr. 2010;30(3):190–204.
21. Atwater SW, Crowe TK, Deitz JC, Richardson PK. Interrater and test-retest reliability of two pediatric balance tests. Phys Ther. 1990;70(2):79–87.
22. Tropp H, Odenrick P. Postural control in single limb stance. J Orthop Res. 1988;6:833–839.
23. Nugent WR. Analyzing Single System Design Data. New York, NY: Oxford University Press; 2010.
24. Backman C, Harris SR. Case studies, single subject research and n of 1 randomized trials: comparisons and contrasts. Am J Phys Med Rehabil. 1999;78(2):170–176.
25. Nourbakhsh M, Ottenbacher K. Statistical analysis of single subject data: a comparative examination. Phys Ther. 1994;74(8):768–776.
26. Bloom M, Fischer J, Orme JG. Evaluating Practice: Guidelines for the Accountable Professional. 6th ed. Boston, MA: Pearson; 2009.
27. Kazdin AE. Single Case Research Designs: Methods for Clinical and Applied Settings. 2nd ed. New York, NY: Oxford University Press; 2011.
28. Winters TF, Gage JR, Hicks R. Gait
patterns in spastic hemiplegia in children and young adults. J Bone Joint Surg Am. 1987;69(3):437–441.
29. Carmick J. Clinical use of neuromuscular electrical stimulation for children with cerebral palsy
, part 1: lower extremity. Phys Ther. 1993;73(8):505–513; discussion 523-527.
30. Comeaux P, Patterson N, Rubin M, Meiner R. Effect of neuromuscular electrical stimulation during gait
in children with cerebral palsy
. Pediatr Phys Ther. 1997;9:103–109.
31. Postans NJ, Granat MH. Effect of functional electrical stimulation applied during walking, on gait
in spastic cerebral palsy
. Dev Med Child
32. Fowler EG, Staudt LA, Greenberg MB. Lower-extremity selective voluntary motor control in patients with spastic cerebral palsy
: increased distal motor impairment. Dev Med Child
33. Mäenpää H, Jaakkola R, Sandström M, Von Wendt L. Effect of sensory-level electrical stimulation of the tibialis anterior muscle during physical therapy on active dorsiflexion of the ankle of children with cerebral palsy
. Pediatr Phys Ther. 2004;16(1):39–44.
34. Sanger TD, Chen D, Delgado MR, Gaebler-Spira D, Hallett M, Mink JW. Definition and classification of negative motor signs in childhood. Pediatrics. 2006;118(5):2159–2167.
35. Ostensjø S, Carlberg EB, Vøllestad NK. Motor impairments in young children with cerebral palsy
: relationship to gross motor function and everyday activities. Dev Med Child
36. Daichman J, Johnston TE, Evans K, Tecklin JS. The effects of a neuromuscular electrical stimulation home program on impairments and functional skills of a child
with spastic diplegic cerebral palsy
: a case report. Pediatr Phys Ther. 2003;15(3):153–158.
37. Kerr C, McDowell B, McDonough S. Electrical stimulation in cerebral palsy
: a review of effects on strength and motor function. Dev Med Child
38. McNee AE, Gough M, Morrissey MC, Shortland AP. Increases in muscle volume after plantarflexor strength training in children with spastic cerebral palsy
. Dev Med Child
39. Sawicki GS, Lewis CL, Ferris DP. It pays to have a spring in your step. Exerc Sport Sci Rev. 2009;37(3):130–138.
40. Van der Linden ML, Hazlewood ME, Hillman SJ, Robb JE. Functional electrical stimulation to the dorsiflexors and quadriceps in children with cerebral palsy
. Pediatr Phys Ther. 2008;20(1):23–29.
41. Winter D. Foot trajectory in human gait
: a precise and multifactorial motor control task. Phys Ther. 1992;72:45–66.
42. Dali CÍ, Hansen FJ, Pedersen SA, et al. Threshold electrical stimulation (TES) in ambulant children with CP: a randomized double-blind placebo-controlled clinical trial. Dev Med Child
43. Merrill DR. Review of electrical stimulation in cerebral palsy
and recommendations for future directions. Dev Med Child
Neurol. 2009;51(suppl 4):154–165.
44. Brien M, Sveistrup H. An intensive virtual reality program improves functional balance and mobility of adolescents with cerebral palsy
. Pediatr Phys Ther 2011;23(3):258–266.
45. Romeiser Logan LR, Hickman RR, Harris SR, Heriza CB. Single-subject research design: recommendations for levels of evidence and quality rating. Dev Med Child
46. Jeglinsky I, Salminen A-L, Carlberg EB, Autti-Rämö I. Rehabilitation planning for children and adolescents with cerebral palsy
. J Pediatr Rehabil Med. 2012;5(3):203–215.
accidental; adolescent; cerebral palsy; child; electrical stimulation therapy; falls; gait; motor activity/physiology; muscle strength; postural balance; spasticity; spastic unilateral
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