Kinematic upper limb analysis outperforms electromyography at grading the severity of dystonia in children with cerebral palsy.

BACKGROUND: Severity of dyskinesia in children with cerebral palsy is often assessed using observation-based clinical tools. Instrumented methods to objectively measure dyskinesia have been proposed to improve assessment accuracy and reliability. Here, we investigated the technique and movement features that were most suitable to objectively measure the severity of dystonia in children with cerebral palsy. METHODS: A prospective observational study was conducted with 12 participants with cerebral palsy with a predominant motor type of dyskinesia, spasticity, or mixed dyskinesia/spasticity who had upper limb involvement (mean age: 12.6 years, range: 6.7-18.2 years). Kinematic and electromyography data were collected bilaterally during three upper limb tasks. Spearman rank correlations of kinematic or electromyography features were calculated against dystonia severity, quantified by the Dyskinesia Impairment Scale. FINDINGS: Kinematic features were more influential compared to electromyography features at grading the severity of dystonia in children with cerebral palsy. Kinematic measures quantifying jerkiness of volitional movement during an upper limb task with a reaching component performed best (|rs| = 0.78-0.9, p < 0.001). INTERPRETATION: This study provides guidance on the types of data, features of movement, and activity protocols that instrumented methods should focus on when objectively measuring the severity of dystonia in children with cerebral palsy.

A model to calculate the progression of the centre of pressure under the foot during gait analysis.

Pedobarography and the centre of pressure (COP) progression is useful to understand foot function. Pedobarography is often unavailable in gait laboratories or completed asynchronously to kinematic and kinetic data collection. This paper presents a model that allows calculation of COP progression synchronously using force plate data. The model is an adjunct to Plug-In-Gait and was applied to 49 typically developing children to create reference COP data. COP progressions were noted to spend 8% of stance behind the ankle joint centre, traverse lateral of the longitudinal axis of the foot through the midfoot for 76% of stance and finishing past the second metatarsal head on the medial side for 16% of stance. It is hoped the model will bridge the information gap for gait laboratories lacking pedobarography during foot assessments and will open up the possibility of retrospective research into COP progression based indices on kinematic data.

Shod wear and foot alignment in clinical gait analysis.

Sagittal plane alignment of the foot presents challenges when the subject wears shoes during gait analysis. Typically, visual alignment is performed by positioning two markers, the heel and toe markers, aligned with the foot within the shoe. Alternatively, software alignment is possible when the sole of the shoe lies parallel to the ground, and the change in the shoe's sole thickness is measured and entered as a parameter. The aim of this technical note was to evaluate the accuracy of visual and software foot alignment during shod gait analysis. We calculated the static standing ankle angles of 8 participants (mean age: 8.7 years, SD: 2.9 years) wearing bilateral solid ankle foot orthoses (BSAFOs) with and without shoes using the visual and software alignment methods. All participants were able to stand with flat feet in both static trials and the ankle angles obtained in BSAFOs without shoes was considered the reference. We showed that the current implementation of software alignment introduces a bias towards more ankle dorsiflexion, mean=3°, SD=3.4°, p=0.006, and proposed an adjusted software alignment method. We found no statistical differences using visual alignment and adjusted software alignment between the shoe and shoeless conditions, p=0.19 for both. Visual alignment or adjusted software alignment are advised to represent foot alignment accurately.