Comorbidity Burden Is Greater Among Children With Tics vs Stereotypies

Erik Greb

October 22, 2020

Children with stereotypies consult neurologists less often than do those with tics, according to an analysis presented at the 2020 CNS-ICNA Conjoint Meeting, held virtually this year. The former also are younger at their first visit than are the latter. Compared with children with tics, children with stereotypies also have fewer comorbidities and receive fewer recommendations for interventions.

Dr Shannon Dean

This difference between groups may not merely reflect the younger age at presentation of children with stereotypies (e.g., at an age before a comorbidity is manifest). "At least in our population, it does seem to reflect an overall lower burden of comorbidities," said Shannon Dean, MD, PhD, assistant professor of neurology at the Kennedy Krieger Institute of Johns Hopkins University in Baltimore.

Common Pediatric Movement Disorders

Tics (i.e., short-lasting, sudden, repetitive movements) and stereotypies (i.e., rhythmic, fixed, deliberate, but purposeless movements) are common pediatric movement disorders with favorable prognoses. The disorders share several comorbidities, the most common of which are ADHD, anxiety, and obsessive-compulsive disorder (OCD). Dean and colleagues examined differences in comorbidity burden, resource use, and need for intervention between children with tics and those with stereotypies.

The investigators performed a retrospective chart review and identified 63 children diagnosed with stereotypies. They matched each of these children, by age when possible, with a child first diagnosed with a chronic or provisional tic disorder during the same year. All patients presented to the University of Rochester (N.Y.) Child Neurology Clinic between 2003 and 2016. Dean and colleagues excluded children with diagnoses for which stereotypies are considered a secondary feature (e.g., autism, intellectual disability, and blindness). They also excluded children who had tics and stereotypies.

The researchers examined the groups' total number of visits, comorbidities, and recommended interventions. They also analyzed data from a follow-up survey that were available for 20 of the 63 patients with stereotypies. They tested continuous or discrete variables for normal distribution and used T tests or Mann–Whitney U as appropriate. To analyze categorical data, they used chi squared or Fisher's exact test for groups smaller than five.

Differing Rates of Intervention

Children with stereotypies were younger at first visit (mean age, 5.6 years vs. 7.1 years) and at last visit (mean age, 6.5 years vs. 9.8 years) and had fewer total visits (1.8 vs. 4.5), compared with children with tics.

The three most common comorbidities in the population were more prevalent among patients with tics than among patients with stereotypies. The prevalence of ADHD was 27% among patients with stereotypies and 48% among patients with tics. The prevalence of OCD was 8% among children with stereotypies and 41% among children with tics. The prevalence of anxiety was 21% among children with stereotypies and 63% among children with tics. Children with stereotypies also had fewer neuropsychiatric comorbidities overall than did children with tics (0.7 per patient versus 1.9 per patient).

The clinicians had recommended at least one medication for tics in 22% of the children with tics. No medication is available for children with stereotypies. The clinicians recommended behavioral therapy for 13% of the children with tics, but for none of the children with stereotypies, "because none of them had functional impairment that would warrant intervention," said Dean. The clinicians also made more recommendations for pharmaceutical and behavioral treatments for comorbidities in patients with tics than in patients with stereotypies.

When the investigators examined the follow-up survey data, they found that patients with stereotypies were older at last contact than patients with tics. Last contact was defined as the time of the survey for patients with stereotypies and the time of the last clinic visit for patients with tics. When Dean and colleagues examined the three most common comorbidities, however, they again found that the burden was greater among patients with tics (1.5 per patient) than among patients with stereotypies (0.8 per patient).

The study was funded by the T32 Experimental Therapeutics Training Grant from the University of Rochester, N.Y. Dean did not report any disclosures.

SOURCE: Dean S et al. CNS-ICNA 2020. Abstract PL52.

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