Neuropsychological function in children with primary complex motor stereotypies
E Mark Mahone1, Matthew Ryan, Lisa Ferenc
1Department of Neuropsychology, Kennedy Krieger Institute, Baltimore, MD, USA.
Insights
Children with primary complex motor stereotypies (CMS) show largely intact cognitive skills but may have motor difficulties. Stereotypy severity correlates with inattention and executive dysfunction.
Area of Science:
- Neuroscience
- Developmental Psychology
- Pediatric Neurology
Background:
- Complex motor stereotypies (CMS) are involuntary, repetitive movements.
- Primary CMS occurs without other developmental issues, unlike secondary CMS.
- Neuropsychological function in primary CMS is understudied.
Purpose of the Study:
- To investigate neurobehavioral deficits in children with primary CMS.
- To compare neuropsychological profiles of children with primary CMS to controls.
Main Methods:
- A case-control study involving 57 children with primary CMS and 57 controls.
- Participants aged 4-12 years underwent neuropsychological assessments.
- Parental ratings assessed stereotypy severity, inattention, and executive function.
Main Results:
- Children with primary CMS performed worse on motor skills and IQ tests (average range).
- One-third of the CMS group exhibited motor coordination difficulties.
- Higher stereotypy severity correlated with increased inattention and executive dysfunction.
Conclusions:
- Primary CMS is associated with largely intact neuropsychological profiles.
- Stereotypy severity is linked to executive dysfunction.
- Observed motor difficulties were not correlated with stereotypy severity.
Aim:
Complex motor stereotypies (CMS) are patterned, repetitive, rhythmic, and involuntary movements that persist over time. They are divided into two subgroups dependent on the presence of other developmental problems: 'primary' (development is otherwise typical) or 'secondary' (associated with autism, intellectual disability, or sensory deficits). There are no currently published studies that examine neuropsychological function in children with primary CMS. This case-control study examines whether children with primary CMS manifest neurobehavioral deficits.
Method:
Fifty-seven children with primary CMS (32 males, 25 females; mean age 6y 8mo, SD 2y 4mo, range 4-12y) with negative screens for autism and 57 comparison participants (32 males, 25 females; mean age 6y 6mo, SD 2y 1mo) completed neuropsychological assessments of IQ, reading ability, attention, language, and motor and executive functions. Parents completed ratings of their child's repetitive movement severity.
Results:
The CMS group performed significantly less well than comparison participants on motor skills and IQ tests (both p<0.01), although IQ was consistently in the average range. One-third of the CMS group showed signs of developmental motor coordination difficulties. Parent report of stereotypy severity was significantly associated with parent report of inattention and executive dysfunction.
Interpretation:
Children with primary CMS were found to have largely intact neuropsychological profiles. Stereotypy severity appears to be associated with executive dysfunction. Although motor difficulties were observed in children with CMS, these were not correlated with parent report of symptom severity.
