Sebastian I. Wolf

Motion analysis of the upper extremity in children with unilateral cerebral palsy—An assessment of six daily tasks

Restrictions in range of motion of the upper extremity are common in patients with unilateral cerebral palsy (CP). The purpose of this study was to investigate movement deviations of the upper extremity in children with unilateral CP by means of 3D motion capture as well as by the use of easy to use scores and questionnaires (MACS, MRC, MAS, ABILHAND-Kids). 16 children with a spastic, unilateral CP were included and compared to a group of 17 typically developing adolescents (TD). The movement time and range of motion (ROM) of six uni- and bimanual daily tasks were compared and correlated with the scores and questionnaires. Movement times increased significantly with involvement according to MACS in all tasks. The restrictions in ROM were pronounced in the forearm. As a compensatory mechanism the children of the MACS 2 and 3 groups showed increased trunk movement. Furthermore, there was a positive correlation between the MACS and the ABILHAND-Kids Questionnaire. In contrast to previous studies, which reported a correlation between the restrictions in ROM and the MACS, this study showed no consistent correlation between the restrictions in ROM neither with the MACS nor with the ABILHAND-Kids. While the MACS and the ABILHAND-Kids function as a simple rating tool for clinical use, the detailed analysis of different daily tasks using 3-D-motion capture provides more detailed information about the movement deviations and spatiotemporal parameters.

Factors associated with recurrence after femoral derotation osteotomy in cerebral palsy

Femoral derotation osteotomy (FDO) as gold standard treatment for internal rotation gait in cerebral palsy (CP) leads to satisfying short-term results, whereas rates of recurrence up to 33% are reported in long-term outcome studies. The purpose of this study was therefore to identify factors contributing to recurrence of internal rotation gait in patients with CP who were treated with FDO in childhood. 70 patients (age: 10 (± 3.3) years at surgery) with bilateral CP and internal rotation gait were examined pre-, one year and at least five years (mean 8 ± 2 years) postoperatively after distal or proximal FDO, using standardized clinical examination and 3D gait-analysis. 27 patients had a good hip rotation one year postoperatively (between 5° external and 15° internal for both limbs) and were considered for the analysis of factors contributing to recurrence of internal rotation gait. Regarding all included patients both mean hip rotation and foot progression angle improved significantly (p < 0.001) from pre- to postoperative. A significant deterioration in hip rotation (more involved side) (p < 0.001) from one year postoperatively to the long-term follow-up can be observed. Younger age, reduced hip joint impulse, increased plantar flexion and internal foot progression angle postoperatively could be identified as factors for recurrence. FDO on average leads to a satisfactory correction of internal rotation gait. In order to improve the long-term outcome after FDO the time of multilevel surgery should be indicated as late as possible and the different factors leading to potential recurrence should be considered.

The effects of muscle-tendon surgery on dynamic electromyographic patterns and muscle tone in children with cerebral palsy

During multilevel surgery, muscle-tendon lengthening (MTL) is commonly carried out in children with cerebral palsy. However, it is unclear if MTL also modifies increased muscle tone and if pathologic activation patterns are changed as an indirect effect of the biomechanical changes. Since investigations addressing this issue are limited, this study aimed at evaluating the effects of MTL on muscle tone and activation pattern. Forty-two children with spastic diplegia who were treated by MTL underwent standardized muscle tone testing (modified Ashworth and Tardieu test), dynamic EMG and three-dimensional gait analysis before, one and three years after MTL. For the evaluation of muscle activation patterns the norm-distance of dynamic EMG data was analyzed. Range of motion and joint alignment in clinical examination were found to be significantly improved one year after MTL. However, deterioration of these parameters was noted after three years. Muscle tone was significantly reduced one year postoperatively but showed an increase after three years. Joint kinematics were found significantly closer to reference data of age matched controls initially after surgery, but deteriorated until three years postoperatively. However, the EMG patterns of the muscles which were surgically addressed were found to be unchanged in either follow-up. These findings suggest that despite the influence of MTS on biomechanics and physiology (muscle tone reduction and improvements of joint mobility and gait pattern) MTS does not change abnormal patterns of muscle activation. Recurrence of increased muscle tone and deterioration of kinematic parameters three years after surgery may be attributed to these persistent pathologic activation patterns.

Body sensor network-based spasticity detection

Spasticity is a common disorder of the skeletal muscle with a high incidence in industrialised countries. A quantitative measure of spasticity using body-worn sensors is important in order to assess rehabilitative motor training and to adjust the rehabilitative therapy accordingly. We present a new approach to spasticity detection using the Integrated Posture and Activity Network by Medit Aachen body sensor network (BSN). For this, a new electromyography (EMG) sensor node was developed and employed in human locomotion. Following an analysis of the clinical gait data of patients with unilateral cerebral palsy, a novel algorithm was developed based on the idea to detect coactivation of antagonistic muscle groups as observed in the exaggerated stretch reflex with associated joint rigidity. The algorithm applies a cross-correlation function to the EMG signals of two antagonistically working muscles and subsequent weighting using a Blackman window. The result is a coactivation index which is also weighted by the signal equivalent energy to exclude positive detection of inactive muscles. Our experimental study indicates good performance in the detection of coactive muscles associated with spasticity from clinical data as well as measurements from a BSN in qualitative comparison with the Modified Ashworth Scale as classified by clinical experts. Possible applications of the new algorithm include (but are not limited to) use in robotic sensorimotor therapy to reduce the effect of spasticity.

Long‐term development of gait after multilevel surgery in children with cerebral palsy: a multicentre cohort study

We investigated the long‐term efficacy and safety of multilevel surgery (MLS) in ambulatory children with bilateral spastic cerebral palsy (CP).

Effect of kinesiotaping, non-elastic taping and bracing on segmental foot kinematics during drop landing in healthy subjects and subjects with chronic ankle instability

OBJECTIVE To evaluate the effects of kinesiotape, non-elastic tape, and soft brace on segmental foot kinematics during drop landing in subjects with chronic ankle instability and healthy subjects. DESIGN Controlled study with repeated measurements. SETTING Three-dimensional motion analysis laboratory. PARTICIPANTS Twenty participants with chronic ankle instability and 20 healthy subjects. INTERVENTIONS The subjects performed drop landings with 17 retroreflective markers on the foot and lower leg in four conditions: barefoot, with kinesiotape, with non-elastic tape and with a soft brace. MAIN OUTCOME MEASURES Ranges of motion of foot segments using a foot measurement method. RESULTS In participants with chronic ankle instability, midfoot movement in the frontal plane (inclination of the medial arch) was reduced significantly by non-elastic taping, but kinesiotaping and bracing had no effect. In healthy subjects, both non-elastic taping and bracing reduced that movement. In both groups, non-elastic taping and bracing reduced rearfoot excursion in inversion/eversion significantly, which indicates a stabilisation effect. No such effect was found with kinesiotaping. All three methods reduced maximum plantar flexion significantly. CONCLUSIONS Non-elastic taping stabilised the midfoot best in patients with chronic ankle instability, while kinesiotaping did not influence foot kinematics other than to stabilise the rearfoot in the sagittal plane. CLINICAL TRIAL REGISTRATION NUMBER ClinicalTrials.gov NCT01810471.

Foot kinematics in walking on a level surface and on stairs in patients with hallux rigidus before and after cheilectomy.

BackgroundWalking down stairs is a clinically relevant daily activity for older persons. The aim of this pilot study was to investigate the impact of cheilectomy on walking on level ground and on stairs.Methods3D motion analysis of foot kinematics was performed in eight patients with hallux rigidus and 11 healthy control participants with a 12-camera system, using the Heidelberg foot measurement method before and one year after surgery. The clinical results were documented using the AOFAS Scale.ResultsThe range of motion of the first metatarsophalangeal joint did not improve after the operation under any gait condition. Preoperatively, hallux dorsi-/plantarflexion in level walking was 11.9° lower in patients than in controls (p = 0.006), postoperatively 14.5° lower (p = 0.004). Comparing walking conditions in patients, hallux dorsi-/plantarflexion was significantly higher in level walking than in climbing stairs (difference up stairs – level: -8.1°, p = 0.018).The AOFAS Scale improved significantly from 56.9 ± 19.9 points (mean ± SD), preoperatively, to 75.9 ± 13.9 points, postoperatively (p = 0.027).ConclusionsCheilectomy is appropriate for reducing symptoms of hallux rigidus. However, neither a positive influence on the range of motion in walking on level ground and on stairs nor a functional improvement was observed in this group of patients.Trial registrationNCT01804491

Equinus Correction During Multilevel Surgery in Adults With Cerebral Palsy

Background: Equinus foot deformity constitutes a common gait disorder in ambulatory adults with bilateral spastic cerebral palsy (BSCP). The outcome after intramuscular aponeurotic lengthening in the context of single-event multilevel surgery (SEMLS) in adulthood has not been investigated. Methods: We followed a group of 31 ambulatory adults with BSCP and equinus who underwent SEMLS including gastrocnemius-soleus intramuscular aponeurotic recession or Achilles tendon lengthening. All patients were analyzed preoperatively and at least 1 year (mean follow-up period: 1.6 years) postoperatively by clinical examination and 3-dimensional instrumented gait analysis including the Gait Profile Score (GPS). Results: Clinical examination showed no significant improvement of ankle dorsiflexion (P = .5) and an unchanged plantarflexion (P = .7) with knee extended but a significant postoperative reduction of spasticity in the calf muscle (P = .0001) as measured by clinical examination following the modified Ashworth scale. Significant improvement of mean ankle dorsiflexion in stance and swing (P = .0001) was found. The GPS decreased and improved significantly (15.9 ± 4.6 to 11.4 ± 3.1; P = .0001). Persistence of equinus and calcaneal gait indicating under- and overcorrection at follow-up was found in 1 patient (3%), respectively. Conclusion: Intramuscular gastrocnemius-soleus aponeurotic recession is part of multilevel surgery corrected equinus deformity in adults. The increase in muscle length led to significant improvement of kinetic and kinematic parameters during walking without a loss of muscle strength and push-off capacity. The risk of overcorrection after equinus correction in adults with BSCP was found to be relatively low. Level of Evidence: Level IV, retrospective case series.

Mid‐term development of hamstring tendon length and velocity after distal femoral extension osteotomy in children with bilateral cerebral palsy: a retrospective cohort study

Flexed knee gait can be treated with distal femoral extension osteotomy (DFEO) and additional patellar tendon advancement (PTA) in children with cerebral palsy (CP). This study assesses changes in hamstring muscle tendon length (MTL) and velocity after DFEO (+PTA).

Knee-ankle-foot orthosis with powered knee for support in the elderly

A prototype of a powered knee orthotic device was developed to determine whether fractional external torque and power support to the knee relieves the biomechanical loads and reduces the muscular demand for a subject performing sit-to-stand movements. With this demonstrator, consisting of the subsystems actuation, kinematics, sensors, and control, all relevant sensor data can be acquired and full control is maintained over actuator parameters. A series-elastic actuator based on a direct current motor provides up to 30 Nm torque to the knee via a hinge joint with an additional sliding degree of freedom. For reasons of feasibility under everyday conditions, user intention is monitored by employing a noninvasive, nonsticking muscle activity sensor to replace electromyographic sensors, which require skin preparation. Furthermore, foot plates with force sensors have been developed and included to derive ground reaction forces. The actual knee torque needed to provide the desired support is based on an inverse dynamics model using ground reaction forces signals and leg kinematics. A control algorithm including disturbance feed forward has been implemented. A demonstration experiment with two subjects showed that 23 % of moment support in fact leads to a similar reduction in activation of the main knee extensor muscle.