Samuel R. Pierce

Direct effect of percutaneous electric stimulation during gait in children with hemiplegic cerebral palsy: a report of 2 cases.

The feasibility of using percutaneous intramuscular functional electric stimulation (FES) in children with cerebral palsy (CP) as a method to improve ankle kinematics and kinetics during gait was investigated. Two children with right hemiplegic CP had percutaneous intramuscular electrodes implanted into the gastrocnemius and tibialis anterior muscles of the involved limb. FES was provided during the gait cycle using force-sensing foot switches to detect gait phase transitions. The children ambulated using FES under 3 conditions (gastrocnemius on, tibialis anterior on, gastrocnemius and tibialis anterior on). For each condition, two 45-minute walking sessions were conducted per day for 1 week. Immediately after each week of practice, a gait analysis was performed at the subjects self-selected walking speed for that stimulation condition and without stimulation. Both children demonstrated improvements in ankle dorsiflexion angle at initial contact, peak dorsiflexion during swing, mean dorsiflexion during swing, and ankle work during early stance with tibialis anterior stimulation alone and combined gastrocnemius and tibialis anterior stimulation. Improvements in ankle work were found during late stance for both children with all stimulation conditions. These results suggest that percutaneous intramuscular FES was effective in improving aspects of ankle kinematics and kinetics of 2 children with hemiplegic CP.

Immediate effect of percutaneous intramuscular stimulation during gait in children with cerebral palsy: a feasibility study

The feasibility of percutaneous intramuscular functional electrical stimulation (P‐FES) in children with cerebral palsy (CP) for immediate improvement of ankle kinematics during gait has not previously been reported. Eight children with CP (six with diplegia, two with hemiplegia; mean age 9 years 1 month [SD 1y 4mo; range 7y 11mo to 11y 10mo]) had percutaneous intramuscular electrodes implanted into the gastrocnemius (GA) and tibialis anterior (TA) muscles of their involved limbs. Stimulation was provided during appropriate phases of the gait cycle in three conditions (GA only, TA only, and GA/TA). Immediately after a week of practice for each stimulation condition, a gait analysis was performed with and without stimulation. A significant improvement in peak dorsiflexion in swing for the more affected extremity and dorsiflexion at initial contact for the less affected extremity were found in the GA/TA condition. Clinically meaningful trends were evident for improvements in dorsiflexion kinematics for the more and less affected extremities in the TA only and GA/TA conditions. The results suggest that P‐FES might immediately improve ankle kinematics in children with CP.

Relationship Between Age and Spasticity in Children With Diplegic Cerebral Palsy

OBJECTIVE To examine the relationship between passive torque, reflex activity, co-contraction, and age during the assessment of spasticity of knee flexors and extensors in children with spastic diplegic cerebral palsy (CP). DESIGN Retrospective. SETTING Pediatric orthopedic hospital. PARTICIPANTS Children (N=36) with spastic diplegic CP. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Spasticity of the knee flexors and knee extensors (as measured by peak passive torque, mean passive torque, reflex activity of the medial hamstrings, reflex activity of vastus lateralis, and co-contraction) was assessed during passive movements completed using an isokinetic dynamometer with concurrent electromyography. RESULTS A significant positive relationship was found between age and mean knee flexor passive torque (P<.05), while a significant negative relationship was found between age and mean percentage of the range of motion with co-contraction (P<.05). CONCLUSIONS Our results suggest that passive stiffness may play a larger role in spasticity than reflex activity as children with spastic diplegic CP age. Additional research is needed to determine whether subject age could influence the effectiveness of interventions, such as serial casting or botulinum toxin, for spasticity in children with spastic diplegic CP.

Roles of Reflex Activity and Co-contraction During Assessments of Spasticity of the Knee Flexor and Knee Extensor Muscles in Children With Cerebral Palsy and Different Functional Levels

Background and Purpose: Spasticity is a common impairment in children with cerebral palsy (CP). The purpose of this study was to examine differences in passive resistive torque, reflex activity, coactivation, and reciprocal facilitation during assessments of the spasticity of knee flexor and knee extensor muscles in children with CP and different levels of functional ability. Subjects: Study participants were 20 children with CP and 10 children with typical development (TD). The 20 children with CP were equally divided into 2 groups: 10 children classified in Gross Motor Function Classification Scale (GMFCS) level I and 10 children classified in GMFCS level III. Methods: One set of 10 passive movements between 25 and 90 degrees of knee flexion and one set of 10 passive movements between 90 and 25 degrees of knee flexion were completed with an isokinetic dynamometer at 15°/s, 90°/s, and 180°/s and concurrent surface electromyography of the vastus lateralis and medial hamstring muscles. Results: Children in the GMFCS level III group demonstrated significantly more peak knee flexor torque with passive movements at 180°/s than children with TD. Children in the GMFCS level I and level III groups demonstrated significantly more repetitions with medial hamstring muscle activity, vastus lateralis muscle activity, and co-contraction than children with TD during the assessment of knee flexor spasticity at a velocity of 180°/s. Discussion and Conclusion: Children with CP and more impaired functional mobility may demonstrate more knee flexor spasticity and reflex activity, as measured by isokinetic dynamometry, than children with TD. However, the finding of increased reflex activity with no increase in torque in the GMFCS I group in a comparison with the TD group suggests that reflex activity may play a less prominent role in spasticity.

Age and electromyographic frequency alterations during walking in children with cerebral palsy

The use of surface electromyography (sEMG) recorded during ambulation has provided valuable insight into motor development and changes with age in the pediatric population. However, no studies have reported sEMG differences with age in the children with cerebral palsy (CP). In this study, data from 50 children were divided retrospectively into four groups, representing either an older (above the age of seven years) or younger (below the age of seven years) age group with either typical development (TD) or CP. Data were analyzed from 16 children in the younger age group with TD, and eight in the older age group with TD. Data were also available from 14 in the younger age group with CP, and 12 in the older age group with CP. SEMG signals from the rectus femoris (RF) and medial hamstring (MH) were analyzed using wavelet techniques to examine time-frequency content. RF muscle activity was statistically different between all groups (p<0.001), with an elevated instantaneous mean frequency (IMNF) in the older TD group than the younger TD group, an elevated IMNF in the younger CP group than the older CP group, and elevated IMNF in both CP groups compared to both TD groups. Activity for the MH muscle followed the same pattern except for the CP young and old group comparison, which indicated no difference. The results indicate that differences in neuromuscular activation exist between younger and older groups of children with both TD and CP, and may provide new insight into muscle activity pattern changes during the development of walking.

Examination of spasticity of the knee flexors and knee extensors using isokinetic dynamometry with electromyography and clinical scales in children with spinal cord injury.

Abstract Background/Objective: To examine the role of reflex activity in spasticity and the relationship between peak passive torque, Ashworth Scale (AS), and Spasm Frequency Scale (SFS) of the knee flexors and extensors during the measurement of spasticity using an isokinetic dynamometer in children with spinal cord injury (SCI). Methods: Eighteen children with chronic SCI and 10 children of typical development (TD) participated. One set of 10 passive movements was completed using an isokinetic dynamometer at 15, 90, and 180 degrees per second (deg/s) while surface electromyographic data were collected from the vastus lateralis (VL) and medial hamstrings (MH). Spasticity was clinically assessed using the AS and SFS. Results: There were no significant differences in peak passive torque of the knee flexors and extensors at any velocity for children with SCI compared to children with TD. Children with TD demonstrated significantly more reflex activity of the MH during the assessment of knee flexor spasticity at all movement velocities than did children with SCI. Children with TD demonstrated significantly more reflex activity of the VL during the assessment of knee-extensor spasticity with movements at 180 deg/s. The relationship between peak passive torque, AS, and SFS was significant during movements at a velocity of 90 deg/s only. Conclusions: The role of increased reflexes in spasticity needs further examination. Isokinetic dynamometry may be measuring a different aspect of spasticity than the AS and SFS do in children with SCI.

Barriers to Bicycle Helmet Use in Young Children in an Urban Elementary School

Purpose. Traumatic brain injury is a leading cause of death in bicycle crashes. The factors associated with bicycle helmet use in young children with diverse ethnic and socioeconomic backgrounds have not been studied. The purpose of this study was to identify barriers to helmet use in young children in an urban elementary school. Design. Qualitative content analysis with semistructured interviews, observational field notes, and artifacts. Setting. Urban elementary school. Participants. Seventeen students whose age ranged from 5 to 7 years and whose ethnic background was identified as African American (14) or Caucasian (3). Method. Children participated in a brain safety fair that included presentations and activities. Semistructured, pre- and postexperience interviews were completed. Observations of the students participating in the activities and reflective art projects from the students were collected. Results. The analysis found the following barriers to helmet use: (a) lack of access to a helmet, (b) poor fit of helmets due to hairstyles, and (c) lack of knowledge regarding helmet use. Conclusion. The present study suggests that the issue of helmet design and comfort for younger children with variable hairstyles needs to be addressed in order to increase helmet use in this population.

The Relationship Between Spasticity and Muscle Volume of the Knee Extensors in Children With Cerebral Palsy

Purpose: The purpose of this study was to examine the relationship between spasticity and muscle volume in children with cerebral palsy (CP), using isokinetic dynamometry and magnetic resonance imaging. Methods: A retrospective sample of 8 children with diplegic CP was analyzed. One set of 10 passive knee flexion movements was completed at a velocity of 180° per second with concurrent surface electromyography of the medial hamstrings (MH) and vastus lateralis (VL) to assess knee extensor spasticity. Magnetic resonance imaging was used to measure maximum cross-sectional area and muscle volume of the quadriceps femoris. Results: The quadriceps femoris muscle volume was positively correlated with MH reflex activity, VL reflex activity, MH/VL co-contraction, and peak knee extensor passive torque (P < .05). Conclusion: The present findings suggest that higher levels of knee extensor muscle spasticity are associated with greater quadriceps muscle volume in children with spastic diplegic CP.

Incidental findings during functional magnetic resonance imaging: ethical and procedural issues.

ABSTRACTPierce SR, Lauer RT, Prosser LA, Mohamed FB, Dougherty JB, Faro SH, Betz RR: Incidental findings during fMRI: ethical and procedural issues.This purpose of this report was to describe the discovery of an incidental finding during functional magnetic resonance imaging in a child of typical development. During the completion of a functional magnetic resonance imaging protocol, an abnormality was noted by a board-certified neuroradiologist that was identified as a benign developmental arachnoid pouch. Significant ethical concerns were apparent with the discovery of an incidental finding, which included how to address the likelihood of incidental findings in the consent and assent process, how to disclose the incidental findings to the subject’s parents and primary care provider, and how to minimize subject and parental anxiety.

Effect of percutaneous electrical stimulation on ankle kinematics in children with cerebral palsy

Percutaneous intramuscular electrodes were implanted operatively into the tibialis anterior (TA) and gastrocnemius (GA) muscles of four children with cerebral palsy. An electrical stimulator was programmed to provide electrical stimulation at appropriate times using force-sensing foot switches to detect gait phase transitions. Participants practiced using the electrical stimulation under three randomly ordered conditions (GA on, TA on, and both GA and TA on). Immediately after a week of practice, a standard three-dimensional gait analysis was conducted for the practiced stimulation condition and without stimulation. Significant improvements in the degree of dorsiflexion at initial contact and the peak dorsiflexion in swing were found when comparing the TA only on and both TA and GA on conditions to off conditions. No changes were found in degree of dorsiflexion at initial contact and the peak dorsiflexion in swing were when comparing the GA only on and GA only off conditions. Preliminary data suggest that percutaneous functional electrical stimulation of the TA applied during walking improved the position of the foot at initial contact and during the swing phase of gait.