Case reports: the influence of selective voluntary motor control on gait after hamstring lengthening surgery

Selective voluntary motor control influences knee joint torque, work and power in children with spastic cerebral palsy

BACKGROUND

Children with spastic cerebral palsy (CP) have damage to the corticospinal tracts that are responsible for selective motor control (SMC). Force, velocity and timing of joint movement are related biomechanical features controlled by the corticospinal tracts (CSTs) that are important for skilled movement.

RESEARCH QUESTION

Does SMC influence knee joint biomechanics in spastic CP?

METHODS

In this prospective study, relationships between SMC and knee biomechanics (peak torque, total work, average power) across a range of velocities (0-300 deg/s) were assessed using an isokinetic dynamometer in 23 children with spastic CP. SMC was assessed using Selective Control Assessment of the Lower Extremity (SCALE). Logistic and linear regression models were used to evaluate relationships between SCALE and biomechanical measures.

RESULTS

The ability to produce knee torque diminished with increasing velocity for both Low (0-4 points) and High (5-10 points) SCALE limb score groups (p < 0.01). More knees in the High group produced extension torque at 300 deg/s (p < 0.05) and flexion torque at 30, 90,180, 240 and 300 deg/s (p < 0.05). The ability to produce torque markedly decreased above 180 deg/s for Low group flexion. For knees that produced torque, significant positive correlations between SCALE limb scores and joint torque (0 and 120 deg/s), work (120 deg/s) and power (120 deg/s) were found (p < 0.05). Greater knee torque, work and power for the High group was found for the extensors at most velocities and the flexors for up to 120 deg/s (p < 0.05). Few Low group participants generated knee flexor torque above 120 deg/s limiting comparisons.

SIGNIFICANCE

Biomechanical impairments found for children with low SMC are concerning as skilled movements during gait, play and sport activities occur at high velocities. Differences in SMC should be considered when designing individualized assessments and interventions.

Improved Myelination following Camp Leg Power, a Selective Motor Control Intervention for Children with Spastic Bilateral Cerebral Palsy: A Diffusion Tensor MRI Study

BACKGROUND AND PURPOSE

Children with spastic cerebral palsy have motor deficits associated with periventricular leukomalacia indicating WM damage to the corticospinal tracts. We investigated whether practice of skilled lower extremity selective motor control movements would elicit neuroplasticity.

MATERIALS AND METHODS

Twelve children with spastic bilateral cerebral palsy and periventricular leukomalacia born preterm (mean age, 11.5 years; age range, 7.3-16.6 years) participated in a lower extremity selective motor control intervention, Camp Leg Power. Activities promoted isolated joint movement including isokinetic knee exercises, ankle-controlled gaming, gait training, and sensorimotor activities (3 hours/day, 15 sessions, 1 month). DWI scans were collected pre- and postintervention. Tract-Based Spatial Statistics was used to analyze changes in fractional anisotropy, radial diffusivity, axial diffusivity, and mean diffusivity.

RESULTS

Significantly reduced radial diffusivity (P < . 05) was found within corticospinal tract ROIs, including 28.4% of the left and 3.6% of the right posterior limb of the internal capsule and 14.1% of the left superior corona radiata. Reduced mean diffusivity was found within the same ROIs (13.3%, 11.6%, and 6.6%, respectively). Additionally, decreased radial diffusivity was observed in the left primary motor cortex. Additional WM tracts had decreased radial diffusivity and mean diffusivity, including the anterior limb of the internal capsule, external capsule, anterior corona radiata, and corpus callosum body and genu.

CONCLUSIONS

Myelination of the corticospinal tracts improved following Camp Leg Power. Neighboring WM changes suggest recruitment of additional tracts involved in regulating neuroplasticity of the motor regions. Intensive practice of skilled lower extremity selective motor control movements promotes neuroplasticity in children with spastic bilateral cerebral palsy.

Reliability and validity of the Turkish version of the Selective Control Assessment of the Lower Extremity (SCALE) in children with spastic cerebral palsy

PURPOSE

This study aims to translate the Selective Control Assessment of the Lower Extremity (SCALE) into Turkish language, assess its reliability and validity in children with spastic cerebral palsy.

MATERIALS AND METHODS

Fifty-two children with CP (mean age 9 years 8 months, range 4-18 years) included in this cross-sectional study. Intra- and interrater reliability was assessed by intraclass correlation coefficient (ICC). The SCALE was correlated with the Gross Motor Function Classification System (GMFCS), the Physician's Rating Scale (PRS), and Gross Motor Function Measurement (GMFM) to assess validity.

RESULTS

Intra- and interrater reliability of the SCALE were excellent (ICC > 0.75). SCALE and GMFCS (r = -0.786, p < 0.001), SCALE and PRS (r = 0.761, p < 0.001), SCALE and GMFM (r = 0.863, p < 0.001) were highly correlated. SCALE scores differed significantly between GMFCS levels and between types of spastic CP.

CONCLUSIONS

The Turkish version of the SCALE appears to be a valid and reliable tool to assess selective voluntary motor control of the lower limbs in children with spastic CP.IMPLICATIONS FOR REHABILITATIONThe Turkish version of the Selective Control Assessment of the Lower Extremity is a valid and reliable assessment for children with spastic CP.The SCALE scores differed significantly between Gross Motor Function Classification System levels I versus II and levels II versus III as well as between types of spastic CP.The current study suggests that the SCALE is a quick and easy outcome measure to assess selective motor control in patients with spastic CP.

Playfully Assessing Lower Extremity Selective Voluntary Motor Control in Children With Cerebral Palsy: Psychometric Study

BACKGROUND

Objective measures specifically assessing selective voluntary motor control are scarce. Therefore, we have developed an interval-scaled assessment based on accelerometers.

OBJECTIVE

This study provided a preliminary evaluation of the validity and reliability of this novel gamelike assessment measuring lower limb selective voluntary motor control in children with cerebral palsy (CP).

METHODS

Children with CP and their neurologically intact peers were recruited for this psychometric evaluation of the assessgame. The participants played the assessgame and steered an avatar by selective hip, knee, or ankle joint movements captured with accelerometers. The assessgame's scores provide information about the accuracy of the selective movement of the target joint and the amplitude and frequency of involuntary movements occurring in uninvolved joints. We established discriminative validity by comparing the assessgame scores of the children with CP with those of the neurologically intact children, concurrent validity by correlations with clinical scores and therapists' opinions, and relative and absolute test-retest reliability.

RESULTS

We included 20 children with CP (mean age 12 years and 5 months, SD 3 years and 4 months; Gross Motor Function Classification System levels I to IV) and 31 neurologically intact children (mean age 11 years and 1 month, SD 3 years and 6 months). The assessgame could distinguish between the children with CP and neurologically intact children. The correlations between the assessgame's involuntary movement score and the therapist's rating of the occurrence of involuntary movements during the game were moderate (Spearman ρ=0.56; P=.01), whereas the correlations of the assessgame outcomes with the Selective Control Assessment of the Lower Extremity and Gross Motor Function Classification System were low and not significant (|ρ|≤0.39). The intraclass correlation coefficients were >0.85 and indicated good relative test-retest reliability. Minimal detectable changes amounted to 25% (accuracy) and 44% (involuntary movement score) of the mean total scores. The percentage of children able to improve by the minimal detectable change without reaching the maximum score was 100% (17/17) for the accuracy score and 94% (16/17) for the involuntary movement score.

CONCLUSIONS

The assessgame proved reliable and showed discriminative validity in this preliminary evaluation. Concurrent validity was moderate with the therapist's opinion but relatively poor with the Selective Control Assessment of the Lower Extremity. We assume that the assessment's gamelike character demanded various other motor control aspects that are less considered in current clinical assessments.

Gait changes following robot-assisted gait training in children with cerebral palsy

This study investigated changes of gait pattern induced by a 4-week robot-assisted gait training (RAGT) in twelve ambulatory spastic diparesis children with cerebral palsy (CP) aged 10.4+/-3.2 years old by using computerized gait analysis (CGA). Pre-post intervention CGA data of children with CP was contrasted to the normative data of typically developing children by using cross-correlation and statistically evaluated by a Wilcoxon test. Significant pre-post intervention changes (p<0.01) include: decreased muscle activity of biceps femoris, rectus femoris, and tibialis anterior; a decrease in range of internal hip joint rotation, higher cadence, step length, and increased stride time. This study suggests that RAGT can be used in muscle reeducation and improved hip joint motion range in ambulatory children with CP.

Selective Motor Control is a Clinical Correlate of Brain Motor Tract Impairment in Children with Spastic Bilateral Cerebral Palsy

BACKGROUND AND PURPOSE

Selective voluntary motor control is an important factor influencing gross motor function, interjoint coordination, and the outcome of hamstring-lengthening surgery in spastic cerebral palsy. Using DTI, we investigated whether selective voluntary motor control would show strong correlations with WM motor tract microstructure and whether selective voluntary motor control is more sensitive to global WM impairment than gross motor function.

MATERIALS AND METHODS

Children with spastic bilateral cerebral palsy born preterm and typically developing children were recruited. The Selective Control Assessment of the Lower Extremity (SCALE) and Gross Motor Function Measure (GMFM) were assessed in participants with cerebral palsy. Participants underwent brain MR imaging to collect DWI data. Tract-Based Spatial Statistics was used to analyze the WM for between-group differences and correlations with SCALE and GMFM. ROI analyses compared motor regions.

RESULTS

Twelve children with cerebral palsy (mean age, 11.5 years) and 12 typically developing children (mean age, 10.3 years) participated. Altered DTI outcomes were found throughout the whole brain for the cerebral palsy group. SCALE, developed to evaluate selective voluntary motor control in cerebral palsy, showed significant positive correlations with fractional anisotropy in more WM voxels throughout the whole brain and for motor regions, including the corticospinal tract and corpus callosum, compared with GMFM. A significant negative correlation between radial diffusivity and SCALE, but not GMFM, was found within the corpus callosum.

CONCLUSIONS

SCALE was a more sensitive clinical correlate of motor and whole-brain WM tract impairment in children with spastic bilateral cerebral palsy, suggesting greater anisotropy and myelination in these regions for those with higher selective voluntary motor control.

Differentiating Between Idiopathic Toe Walking and Cerebral Palsy: A Systematic Review

PURPOSE

The purpose of this systematic review is to identify evidence-based examination components that enable a clinician to distinguish between participants with idiopathic toe walking (ITW) and cerebral palsy (CP) to accurately categorize them into their respective movement system diagnosis.

SUMMARY OF KEY POINTS

Five articles were used that compared key clinical findings, walking characteristics, and muscle firing patterns of participants with CP and ITW. Differences in these components allow participants with CP and ITW to be classified into different movement system diagnoses to better target plan of care.

CONCLUSIONS AND RECOMMENDATIONS FOR CLINICAL PRACTICE

The authors recommend that clinicians perform specific evidence-based tests and measures in accordance with the International Classification of Functioning, Disability and Health model.

Selective motor control correlates with gait abnormality in children with cerebral palsy

Children with bilateral cerebral palsy (CP) commonly have limited selective motor control (SMC). This affects their ability to complete functional tasks. The impact of impaired SMC on walking has yet to be fully understood. Measures of SMC have been shown to correlate with specific characteristics of gait, however the impact of SMC on overall gait pattern has not been reported. This study explored SMC data collected as part of routine gait analysis in children with bilateral CP. As part of their clinical assessment, SMC was measured with the Selective Control Assessment of the Lower Extremities (SCALE) in 194 patients with bilateral cerebral palsy attending for clinical gait analysis at a single centre. Their summed SCALE score was compared with overall gait impairment, as measured by Gait Profile Score (GPS). Score on SCALE showed a significant negative correlation with GPS (r_s=-0.603, p<0.001). Cerebral injuries in CP result in damage to the motor tracts responsible for SMC. Our results indicate that this damage is also associated with changes in the development of walking pattern in children with CP.

Dynamic motor control is associated with treatment outcomes for children with cerebral palsy

AIM

To estimate the impact of dynamic motor control on treatment outcomes in children with cerebral palsy.

METHOD

We used multiple regression on a retrospective cohort of 473 ambulatory children with cerebral palsy who underwent conservative treatment, single-level orthopaedic surgery, single-event multi-level orthopaedic surgery, or selective dorsal rhizotomy. Outcomes included gait pattern, gait speed, energy cost of walking, and the Pediatric Outcomes Data Collection Instrument. Explanatory variables considered were pre-treatment levels of each outcome, treatment group, prior treatment, age, and dynamic motor control computed from surface electromyography using synergy analysis. Effect sizes were estimated from the adjusted response.

RESULTS

Pre-treatment levels had effect sizes 2 to 13 times larger than the next largest variable. Individuals with milder pre-treatment involvement had smaller gains or actual declines. Dynamic motor control was significant in all domains except energy cost. The effect size of dynamic motor control was second only to pre-treatment level, and was substantially larger than the effect size of treatment group for outcomes where both were significant (gait pattern 2:1, gait speed 4:1). The effect of dynamic motor control was independent of treatment group.

INTERPRETATION

Dynamic motor control is an important factor in treatment outcomes. Better dynamic motor control is associated with better outcomes, regardless of treatment.

Selective Control of the Upper Extremity Scale: validation of a clinical assessment tool for children with hemiplegic cerebral palsy

AIM

The ability to determine the relationship between selective motor control and upper extremity function in children with unilateral cerebral palsy (CP), and to measure the functional outcome and efficacy of interventions designed to improve selective motor control, has been limited by the lack of an objective, validated tool. The primary objective of this study is to describe the development of a clinical tool entitled Selective Control of the Upper Extremity Scale (SCUES), and present evidence of its validity and reliability.

METHOD

Content validity was established through an expert panel (eight clinicians, mean and median of 17y of clinical experience, range 2-30y). Intra- and interrater reliability was determined by six occupational therapists who scored 10 participant studies. Construct validity of the SCUES was established by comparison to the spontaneous functional analysis section of the Shriners Hospitals Upper Extremity Evaluation, the Manual Ability Classification System, and the Box and Block test for 25 children with unilateral CP.

RESULTS

The content validity ratio values were greater than 0 (indicating >50% agreement) for 33 of the 34 items (97%), and equal or greater than 0.5 (indicating ≥75% agreement) for 26 of the 34 items (76%). Intrarater reliability was excellent (intraclass correlation coefficient [ICC] >0.75) for all segments and joints of the affected extremity. Interrater reliability was excellent for all segments and joints of the affected extremity except the shoulder (ICC=0.72). The SCUES was strongly correlated with the SHUEE (Spearman's rho=0.69, p=0.003). The SCUES was not correlated with the Manual Ability Classification System (rho=-0.24, p=0.369) or the Box and Block test (rho=0.47, p=0.066).

INTERPRETATION

Psychometric analysis of the SCUES revealed comparable validity to other accepted video-based clinical assessment tools for the upper extremity in children with CP.

Construct validity and reliability of the Selective Control Assessment of the Lower Extremity in children with cerebral palsy

AIM

Assessing impaired selective voluntary movement control in children with cerebral palsy (CP) has gained increasing interest. We investigated construct validity and intra- and interrater reliability of the Selective Control Assessment of the Lower Extremity (SCALE).

METHOD

Thirty-nine children (21 males, 18 females) with spastic CP, mean age 12 years 6 months [range 6y 11mo-19y 9mo], Gross Motor Function Classification System (GMFCS) levels I to IV, participated. Differences in SCALE scores were determined on joint levels and between patients categorized according to their limb distribution and GMFCS levels. SCALE scores were correlated with the Fugl-Meyer Assessment, Manual Muscle Test, and Modified Ashworth Scale. To determine reliability, the SCALE was applied once and recorded on video.

RESULTS

SCALE scores differed significantly between the less and more affected leg (p<0.001) and between most leg joints. Total SCALE scores differed significantly between GMFCS levels I and II. Correlations with Fugl-Meyer Assessment, Manual Muscle Test, and Modified Ashworth Scale were 0.88, 0.88, and -0.55 respectively. Intraclass correlation coefficients were all above 0.9, with the minimal detectable change below 2 points.

INTERPRETATION

The SCALE appears to be a valid and reliable tool to assess selective voluntary movement control of the legs in children with spastic CP.

Reported outcomes of lower limb orthopaedic surgery in children and adolescents with cerebral palsy: a mapping review

AIM

Lower limb surgery is often performed in ambulatory children with cerebral palsy (CP) to improve walking ability. This mapping review reports on outcome measures used in the published literature to assess surgical results, determine range and frequency of use, and map each measure to the International Classification of Functioning, Disability and Health.

METHOD

A mapped review of literature published between 1990 and 2011 was carried out to identify papers reporting the outcomes of lower limb orthopaedic surgery in ambulatory children with CP, aged 0 to 20 years.

RESULTS

A total of 229 published papers met the inclusion criteria. Thirty-two outcome measures with known psychometric properties were reported in the 229 papers. Twenty measures assess impairments in body structure and function and were used in 91% of studies. Ten measures assess restrictions in activity and participation and were used in 9% of papers. Two measures assessed quality of life. Since 1997, 29% of papers have used the Gross Motor Function Classification System to describe participants.

INTERPRETATION

The body of literature evaluating outcomes of lower limb orthopaedic surgery in CP is small but increasing. There is a need to develop a suite of outcome measures that better reflect outcomes across the International Classification of Functioning, Disability and Health, including activity and participation.

Structural equation modeling of motor impairment, gross motor function, and the functional outcome in children with cerebral palsy

Physical therapy intervention for children with cerebral palsy (CP) is focused on reducing neurological impairments, improving strength, and preventing the development of secondary impairments in order to improve functional outcomes. However, relationship between motor impairments and functional outcome has not been proved definitely. This study confirmed the construct of motor impairment and performed structural equation modeling (SEM) between motor impairment, gross motor function, and functional outcomes of regarding activities of daily living in children with CP. 98 children (59 boys, 39 girls) with CP participated in this cross-sectional study. Mean age was 11 y 5 mo (SD 1 y 9 mo). The Manual Muscle Test (MMT), the Modified Ashworth Scale (MAS), range of motion (ROM) measurement, and the selective motor control (SMC) scale were used to assess motor impairments. Gross motor function and functional outcomes were measured using the Gross Motor Function Measure (GMFM) and the Functional Skills domain of the Pediatric Evaluation of Disability Inventory (PEDI) respectively. Measurement of motor impairment was consisted of strength, spasticity, ROM, and SMC. The construct of motor impairment was confirmed though an examination of a measurement model. The proposed SEM model showed good fit indices. Motor impairment effected gross motor function (β=-.0869). Gross motor function and motor impairment affected functional outcomes directly (β=0.890) and indirectly (β=-0.773) respectively. We confirmed that the construct of motor impairment consist of strength, spasticity, ROM, and SMC and it was identified through measurement model analysis. Functional outcomes are best predicted by gross motor function and motor impairments have indirect effects on functional outcomes.