The Dyskinetic Cerebral Palsy Functional Impact Scale: development and validation of a new tool

Caregiver descriptions of dystonia in cerebral palsy

OBJECTIVE

To determine how caregivers describe dystonia in people with cerebral palsy (CP).

METHODS

In this prospective cohort study, paper surveys were administered to caregivers between September 7, 2021 and October 28, 2021 during CP Center visits at a large tertiary care center. Caregivers were asked to describe involuntary movements triggered by voluntary movement or triggered by tactile stimulation in the people with CP they cared for. Their CP Center medical provider separately assessed people with CP for dystonia. Movement features described exclusively by caregivers of people with CP and dystonia were determined using conventional content analysis.

RESULTS

113 caregivers responded on behalf of 56 people with and 57 people without dystonia. If caregivers noted that both voluntary movement and tactile stimulation triggered involuntary movements, that had a 92% positive predictive value for a dystonia diagnosis. Movement features exclusively described in people with CP and dystonia included: (1) stiffening, tensing, or tightening (15% of respondents); (2) involvement of the head (10%), torso (5%), or feet (5%); and (3) triggers of stretching (12.5%), excitement (5%), or transfers (5%).

INTERPRETATION

In addition to a thorough exam, asking caregivers of people with CP to describe involuntary movements triggered by voluntary movement or tactile stimulation may inform clinical dystonia diagnosis.

Upper Extremity Dystonia Features in People With Spastic Cerebral Palsy

Background and Objectives

Dystonia in cerebral palsy (CP) is debilitating and common, but underdiagnosed, especially when coexistent with spasticity. With dedicated research-based assessment, dystonia is found in most people with spastic CP but is only clinically diagnosed in the minority. To begin addressing the high rates of dystonia underdiagnosis in this population, we determined the key feature experts use to assess upper extremity dystonia in people with spastic CP.

Methods

In this prospective cohort study, 3 pediatric movement disorder specialists assessed upper extremity dystonia in neurologic examination videos of people with spastic CP and isolated periventricular leukomalacia (PVL) on brain MRI (i.e., those with a brain injury pattern typical for spastic CP). Dystonia severity was rated using the 10-point Global Dystonia Severity Rating Scale, first by each expert independently and then again after consensus-building discussion. Conventional content analysis of these discussions revealed salient features ("codes") that experts used to assess upper extremity dystonia. Code frequency distributions were compared between dystonia severity categories using χ2 tests.

Results

We identified 96 people with spastic CP with isolated PVL on brain MRI seen in the St. Louis Children's Hospital CP Center between 2005 and 2018. Of them, 26 people were able and willing to be recorded while doing a standardized set of upper extremity examination maneuvers (age 4-25 years; 28% nonambulatory, 77% White). When assessing their videos, experts cited the "hand" less often and "shoulder" more often with increasing dystonia severity (p < 0.005, χ2 test). "Mirror movements" and the "hand open/close" examination maneuver were cited significantly more frequently in videos when experts were attempting to distinguish between no dystonia and mild dystonia (p < 0.005).

Discussion

Expert clinicians use distinct movement features to assess upper extremity dystonia in people with spastic CP and PVL. Attention to involuntary shoulder (vs hand) movements can help gauge dystonia severity. Differentiation between mirror movements and dystonia, particularly during the hand open/close examination maneuver, may help identify mild dystonia. These results can help guide upper extremity dystonia assessment in people with spastic CP, thus potentially helping mitigate dystonia underdiagnosis.

Determinants of gait dystonia severity in cerebral palsy

AIM

To determine the movement features governing expert assessment of gait dystonia severity in individuals with cerebral palsy (CP).

METHOD

In this prospective cohort study, three movement disorder neurologists graded lower extremity dystonia severity in gait videos of individuals with CP using a 10-point Likert-like scale. Using conventional content analysis, we determined the features experts cited when grading dystonia severity. Then, using open-source pose estimation techniques, we determined gait variable analogs of these expert-cited features correlating with their assessments of dystonia severity.

RESULTS

Experts assessed videos from 116 participants (46 with dystonia aged 15 years [SD 3] and 70 without dystonia aged 15 years [SD 2], both groups ranging 10-20 years old and 50% male). Variable limb adduction was most commonly cited by experts when identifying dystonia, comprising 60% of expert statements. Effect on gait (regularity, stability, trajectory, speed) and dystonia amplitude were common features experts used to determine dystonia severity, comprising 19% and 13% of statements respectively. Gait variables assessing adduction variability and amplitude (inter-ankle distance variance and foot adduction amplitude) were significantly correlated with expert assessment of dystonia severity (multiple linear regression, p < 0.001).

INTERPRETATION

Adduction variability and amplitude are quantifiable gait features that correlate with expert-determined gait dystonia severity in individuals with CP. Consideration of these features could help optimize and standardize the clinical assessment of gait dystonia severity in individuals with CP.

Under-recognition of leg dystonia in people with cerebral palsy

Objective

To determine the rates of clinical under-documentation of leg dystonia in people with cerebral palsy (CP).

Methods

In this prospective cohort study, we identified independently ambulatory people age 10-20yo with CP-associated spasticity seen in a tertiary care CP center between 1/1/20 to 11/4/21. Three pediatric movement disorders specialists assessed gait videos from these visits for leg dystonia using the Global Dystonia Rating Scale. We compared the gold standard expert consensus assessment for each patient with the clinical documentation of dystonia during a contemporaneous CP Center clinic visit and also with dystonia documentation longitudinally in their medical record.

Results

Of 116 people with CP-associated spasticity assessed in this study, 70 were found to have leg dystonia in their gait videos. Only 13% of these 70 individuals (n=9/70) had leg dystonia documented in their contemporaneous CP Center clinic visit, even though they were assessed during this visit by clinicians well-trained in CP and dystonia assessment. Even with repeated assessment, only 54% (n=38/70) of these individuals had leg dystonia documented in their medical record.

Conclusions

Leg dystonia is clinically under-documented in people with CP-associated spasticity, even when these people are evaluated by well-trained clinicians. Longitudinal evaluation and vigilance for leg dystonia is critical to address this diagnostic gap.

Top 10 Research Themes for Dystonia in Cerebral Palsy: A Community-Driven Research Agenda

Dystonia in cerebral palsy (DCP) is a common, debilitating, but understudied condition. The CP community (people with CP and caregivers) is uniquely equipped to help determine the research questions that best address their needs. We developed a community-driven DCP research agenda using the well-established James Lind Alliance methodology. CP community members, researchers, and clinicians were recruited through multiple advocacy, research, and professional organizations. To ensure shared baseline knowledge, participants watched webinars outlining our current knowledge on DCP prepared by a Steering Group of field experts (cprn.org/research-cp-dystonia-edition). Participants next submitted their remaining uncertainties about DCP. These were vetted by the Steering Group and consolidated to eliminate redundancy to generate a list of unique uncertainties, which were then prioritized by the participants. The top-prioritized uncertainties were aggregated into themes through iterative consensus-building discussions within the Steering Group. 166 webinar viewers generated 67 unique uncertainties. 29 uncertainties (17 generated by community members) were prioritized higher than their randomly matched pairs. These were coalesced into the following top 10 DCP research themes: (1) develop new treatments; (2) assess rehabilitation, psychological, and environmental management approaches; (3) compare effectiveness of current treatments; (4) improve diagnosis and severity assessments; (5) assess the effect of mixed tone (spasticity and dystonia) in outcomes and approaches; (6) assess predictors of treatment responsiveness; (7) identify pathophysiologic mechanisms; (8) characterize the natural history; (9) determine the best treatments for pain; and (10) increase family awareness. This community-driven research agenda reflects the concerns most important to the community, both in perception and in practice. We therefore encourage future DCP research to center around these themes. Furthermore, noting that community members (not clinicians or researchers) generated the majority of top-prioritized uncertainties, our results highlight the important contributions community members can make to research agendas, even beyond DCP.

Using both electromyography and movement disorder assessment improved the classification of children with dyskinetic cerebral palsy

AIM

Children with dyskinetic cerebral palsy (CP) are often severely affected and effective treatment is difficult, due to different underlying disease mechanisms. Comprehensive systematic movement disorder evaluations were carried out on patients with this disorder.

METHODS

Patients born from 1995 to 2007 were identified from the Danish Cerebral Palsy Register and referrals to the neuropaediatric centre, Rigshospitalet, Copenhagen. They were classified by gross motor function, manual functional ability, communication ability, dystonia and spasticity. Electromyography was carried out on the upper and lower limbs. Magnetic resonance imaging scans were revised, and aetiological searches for underlying genetic disorders were performed.

RESULTS

We investigated 25 patients with dyskinetic CP at a mean age of 11.7 years. Dystonia, spasticity and rigidity were found in the upper limbs of 21, four and six children, respectively, and in the lower limbs of 18, 18 and three children. The mean total Burke-Fahn-Marsden score for dystonia was 45.02, and the mean Disability Impairment Scale level was 38% for dystonia and 13% for choreoathetosis. Sustained electromyography activity was observed in 20/25 children. Stretching increased electromyography activity more in children with spasticity. There were 10 re-classifications.

CONCLUSION

The children had heterogenic characteristics, and 40% were reclassified after systematic movement disorder evaluation.