CINCINNATI – Dystonia is a frequent complication seen in cerebral palsy, but it often goes undiagnosed. Using a unique video analysis, researchers have identified some movement features that have the potential to simplify diagnosis.
“[We have] previously demonstrated that by the age of 5 years, only 30% of children seen in a clinical setting have had their predominant motor phenotype identified, including dystonia. This helps demonstrate a broad diagnostic gap and the need for novel solutions,” said Laura Gilbert, DO, during her presentation of the results at the 2022 annual meeting of the Child Neurology Society.
Diagnosis of dystonia is challenging because of its clinical variability, and diagnostic tools often require a trained physician, which limits access to diagnoses. Expert clinician consensus therefore remains the gold standard for diagnosis of dystonia.
Another clinical need is that specific features of dystonia have not been well described in the upper extremities, and the research suggests there could be differences in brain injuries contributing to dystonia in the two domains.
The researchers set out to discover expert-identified features of patient videos that could be used to allow nonexperts to make a diagnosis of dystonia.
The researchers analyzed 26 videos with upper extremity exam maneuvers performed on children with periventricular leukomalacia at St. Louis Children’s Hospital Cerebral Palsy Center from 2005 to 2018. Among the study cohort, 65% of patients were male, 77% were White, and 11% were Black; 24% of patients were Gross Motor Function Classification Scale I, 24% were GMFCS II, 24% were GMFCS III, 16% were GMFCS IV, and 12% were GMFCS V. A total of 12% of patients were older than 20, 11% were aged 15-20, 38% were aged 10-15, 31% were aged 5-10, and 8% were age 5 or younger.
Video clues aid diagnosis
Three pediatric movement disorder specialists independently reviewed each video and assessed severity of dystonia. They then met over Zoom to reach a diagnostic consensus for each case.
The research team performed a content analysis of the experts’ discussions and identified specific statement fragments. The frequency of these fragments was then linked to severity of dystonia.
A total of 45% of the statement fragments referenced movement codes, which in turn comprised five content areas: 33% referenced a body part, 24% focused on laterality, 22% described movement features, 18% an action, and 3% described exam maneuvers. Examples included shoulder as a body part, flexion as an action descriptor, brisk as a movement feature, unilateral, and finger-nose-finger for exam maneuver.
With increasing dystonia severity, the shoulder was more often cited and hand was cited less often. Mirror movements, defined as involuntary, contralateral movements that are similar to the voluntary action, occurred more often in patients with no dystonia or only mild dystonia. Variability of movement over time, which is a distinguishing feature found in lower extremities, was not significantly associated with dystonia severity.
Within the category of exam maneuver, hand opening and closing was the most commonly cited, and it was cited more frequently among individuals with mild dystonia (70% vs. about 10% for both no dystonia and moderate to severe dystonia; P < .005).
“So how can we adopt this clinically? First, we can add in a very brief exam maneuver of hand opening and closing that can help assess for mild dystonia. Shoulder involvement may suggest more severe dystonia, and we must recognize the dystonia features seem to differ by body region and the triggering task. Overall, to help improve dystonia diagnosis, we must continue to work towards understanding these salient features to fully grasp the breadth of dystonia manifestations in people with [cerebral palsy],” said Dr. Gilbert, who is a pediatric movements disorder fellow at Washington University in St. Louis.