Test-retest reliability of the Dyskinesia Impairment Scale: measuring dystonia and choreoathetosis in dyskinetic cerebral palsy

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.

Alterations in Serotonin Neurotransmission in Hyperdopaminergic Rats Lacking the Dopamine Transporter

Biogenic amines dopamine (DA) and serotonin (5-HT) are among the most significant monoaminergic neurotransmitters in the central nervous system (CNS). Separately, the physiological roles of DA and 5-HT have been studied in detail, and progress has been made in understanding their roles in normal and various pathological conditions (Parkinson's disease, schizophrenia, addiction, depression, etc.). In this article we showed that knockout of the gene encoding DAT leads not only to a profound dysregulation of dopamine neurotransmission in the striatum but also in the midbrain, prefrontal cortex, hippocampus, medulla oblongata and spinal cord. Furthermore, significant changes were observed in the production of mRNA of enzymes of monoamine metabolism, as well as to a notable alteration in the tissue level of serotonin, most clearly manifested in the cerebellum and the spinal cord. The observed region-specific changes in the tissue levels of serotonin and in the expression of dopamine and serotonergic metabolism enzymes in rats with an excess of dopamine can indicate important consequences for the pharmacotherapy of drugs that modulate the dopaminergic system. The drugs that affect the dopaminergic system could potently affect the serotonergic system, and this fact is important to consider when predicting their possible therapeutic or side effects.

The Dyskinesia Impairment Scale, Second Edition: Development, construct validity, and reliability

AIM

To create a shortened, more user-friendly Second Edition of the Dyskinesia Impairment Scale (DIS-II) to assess dystonia and choreoathetosis, and evaluate its construct validity and reliability.

METHOD

Scale development included an online expert meeting (n = 21) and iterative discussions within the research group (n = 6). A Rasch measurement model analysis on DIS scores from individuals with dyskinetic cerebral palsy or inherited/idiopathic dystonia (n = 123, 74 males, mean age 14 years, SD 5 years) was performed to evaluate the construct validity and reliability of the DIS-II.

RESULTS

The DIS-II evaluates dystonia and choreoathetosis in action and rest in 11 body regions, with action items scored from 0 to 3 and rest items 0 to 2. The number of videos to record are reduced from 26 to 14 and the items to score are reduced from 144 to 88. Rating scale functioning, goodness-of-fit evaluation, principal component analysis, and targeting met the predefined quality criteria of the study and construct validity was therefore considered good. Furthermore, person reliability indicated that the DIS-II can separate individuals into eight distinct ability levels.

INTERPRETATION

The DIS-II provides valid and reliable measures for dystonia and choreoathetosis, and reduces the administration and scoring time compared with the DIS. The DIS-II logit scores (interval level data) enhance comparison over time and between individuals in clinical practice and research.

Clinical Presentation of Spasticity and Passive Range of Motion Deviations in Dyskinetic Cerebral Palsy in Relation to Dystonia, Choreoathetosis, and Functional Classification Systems

Objectives: To map the presence, severity, and distribution of spasticity and passive range of motion (pROM) deviations in dyskinetic cerebral palsy (DCP), and to explore their relation with dystonia, choreoathetosis, and functional abilities.Methods: This cross-sectional study included 53 participants with DCP. Spasticity was assessed with the Modified Ashworth Scale, limited- and increased pROM (hypermobility) with a goniometer, dystonia and choreoathetosis with the Dyskinesia Impairment Scale, gross motor and manual abilities with corresponding functional classification systems.Results: Spasticity and limited pROM were correlated with dystonia of the upper limbs (0.41< r_s<0.47, <0.001 < p < .002) and lower limbs (0.31< r_s<0.41, 0.002 < p < .025), and both functional systems of gross motor (0.32< r_s<0.51, <0.001 < p < .018) and fine manual abilities (0.34< r_s<0.44, 0.001 < p < .014). Hypermobility is correlated only with choreoathetosis of the lower limbs (0.44, p = .001).Conclusions: Coexisting spasticity and pROM deviations in DCP are functionally limiting and should be addressed accordingly. Hypermobility may lead to an increased luxation risk.

Reliability and Validity of the Dyskinesia Impairment Scale in Children and Young Adults with Inherited or Idiopathic Dystonia

Background: The Dyskinesia Impairment Scale (DIS) is a new assessment scale for dystonia and choreoathetosis in children and youth with dyskinetic cerebral palsy. Today, the Burke–Fahn–Marsden Dystonia Rating Scale (BFM) is mostly used to assess dystonia in children with inherited dystonia. The aim of this study was to assess reliability and validity of the DIS in children and youth with inherited or idiopathic dystonia. Methods: Reliability was measured by (1) the intraclass correlation coefficients (ICCs) for inter-rater and test-retest reliability, as well as (2) standard error of measurement (SEM) and minimal detectable difference (MDD). For concurrent validity of the DIS-dystonia subscale, the BFM was administered. Results: In total, 11 males and 9 females (median age 16 years and 7 months, range 6 to 24 years) were included. For inter-rater reliability, the ICCs for the DIS total score and the dystonia and choreoathetosis subscale scores were 0.83, 0.87, and 0.71, respectively. For test-retest reliability, the ICCs for the DIS total score and the dystonia and choreoathetosis subscale scores were 0.95, 0.88, and 0.93, respectively. The SEM and MDD for the total DIS were 3.98% and 11.04%, respectively. The Spearman correlation coefficient between the dystonia subscale and the BFM was 0.88 (p < 0.01). Conclusions: Good to excellent inter-rater, test-retest reliability, and validity were found for the total DIS and the dystonia subscale. The choreoathetosis subscale showed moderate inter-rater reliability and excellent test-retest reliability. The DIS may be a promising tool to assess dystonia and choreoathetosis in children and young adults with inherited or idiopathic dystonia.

Use of the Dyskinesia Impairment Scale in non-ambulatory dyskinetic cerebral palsy

AIM

To assess the responsiveness, concurrent validity, and feasibility of the Dyskinesia Impairment Scale (DIS) in non-ambulatory patients with dyskinetic cerebral palsy (CP).

METHOD

The study is a secondary analysis of data collected in the IDYS trial, a randomized controlled trial on the effects of intrathecal baclofen (ITB). The DIS and Barry-Albright Dystonia Scale (BADS) were conducted at baseline and after 3 months of ITB or placebo treatment. Responsiveness was assessed by comparing the effect sizes and correlation of change after treatment between the DIS and BADS. Concurrent validity was evaluated by assessing the correlations between scales. Feasibility was evaluated for each DIS item by the number of participants who successfully accomplished the item.

RESULTS

Thirty-three non-ambulatory patients (9 females, 24 males) with dyskinetic CP (ITB-treated: n=17, mean [SD] age: 14y 1mo [4y 1mo]; placebo-treated: n=16, mean [SD] age: 14y 7mo [4y]) were included in the study. The effect sizes for BADS and DIS were similar in The ITB-treated group (-0.29 and -0.22 respectively). Changes after treatment on the DIS dystonia subscale correlated with changes on the BADS (r=0.64; p<0.001). The DIS dystonia subscale and BADS correlated at baseline and follow-up (r=0.78; p<0.001 and r=0.79; p<0.001). Not all DIS activity items could be performed in this sample of patients.

INTERPRETATION

For non-ambulatory patients with dyskinetic CP, the responsiveness of the DIS equalled the responsiveness of BADS. Concurrent validity was adequate. Feasibility for activity items was restricted in patients with severe dyskinetic CP.

WHAT THIS PAPER ADDS

The Dyskinesia Impairment Scale (DIS) and Barry-Albright Dystonia Scale showed similar responsiveness in non-ambulatory patients with dyskinetic cerebral palsy (CP). No floor or ceiling effect was observed for DIS in non-ambulatory participants. The concurrent validity of DIS was adequate in non-ambulatory participants. Patients with dyskinetic CP in Gross Motor Function Classification System levels IV and V could not perform all DIS activity items.