Measuring the inch stones for progress: Gross motor function in the developmental and epileptic encephalopathies

  • Author Footnotes
    1 ORCID: 0000-0002-0298-5523.
    Anne T. Berg
    Corresponding author at: Department of Neurology, Northwestern Feinberg School of Medicine, 710 N. Lake Shore Drive, Abbott Hall, 11th Floor, Chicago, IL 60611, United States.
    1 ORCID: 0000-0002-0298-5523.
    COMBINEDBrain, Nashville, TN, United States

    Northwestern Feinberg School of Medicine, Department of Neurology, Chicago, IL, United States
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  • Author Footnotes
    2 ORCID: 0000-0001-8147-1899.
    Aaron J. Kaat
    2 ORCID: 0000-0001-8147-1899.
    Department of Medical Social Sciences, Northwestern University Feinberg School of Medicine, Chicago, IL, United States
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  • Author Footnotes
    3 ORCID: 0000-0001-6827-4241.
    Deborah Gaebler-Spira
    3 ORCID: 0000-0001-6827-4241.
    Shirley Ryan Ability Lab, Chicago, IL, United States

    Department of Physical Medicine and Rehabilitation, Northwestern Feinberg School of Medicine, Chicago, IL, United States

    Department of Pediatrics, Northwestern Feinberg School of Medicine, Chicago, IL, USA
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  • Author Footnotes
    1 ORCID: 0000-0002-0298-5523.
    2 ORCID: 0000-0001-8147-1899.
    3 ORCID: 0000-0001-6827-4241.
Published:November 08, 2022DOI:


      • Mobility is often impaired in people with developmental and epileptic encephalopathies (DEE).
      • Clinical trials may target motor skills in patients with DEE as a primary outcome.
      • Severe gross motor and mobility impairments require nonstandard assessment approaches.
      • Alternative scoring and early child assessments perform well in older patients.
      • Adapting existing measures could accelerate clinical trial readiness.



      Developmental and epileptic encephalopathies (DEE) entail moderate to profound impairments in gross motor skills and mobility, which are poorly quantified with clinical outcomes assessments (COA) used in neuro-typical populations. We studied the motor domain of the Adaptive Behavior Assessment System-3 for ages 0–5 years (ABAS) used outside of its intended age range with a focus on raw scores.


      In a cross-sectional survey, 117 parents of children with a variety of DEEs (ages 1–35 years, median = 9) completed the motor domain section of the ABAS. Floor and ceiling effects and associations with epilepsy-related factors were assessed with appropriate parametric and nonparametric statistical techniques. The sensitivity of the ABAS and additional measures of mobility borrowed from the cerebral palsy literature (Functional Activities Questionnaire (FAQ-22) walking level (FAQ-WL)) to different levels of the Functional Mobility Scale was determined.


      ABAS motor scores corresponded to a median age equivalent of 20.5 months (Inter-Quartile Range (IQR) 8–34). Most raw scores corresponded to standardized scores > 2 standard deviations below the ABAS standardization sample mean. ABAS raw scores demonstrated minimal floor and ceiling effects (<5%). In linear regression models, scores increased with age under 6 years (p < 0.0001) but flattened out thereafter. Scores varied substantially by DEE group (p < 0.001) and decreased with higher convulsive seizure frequency (<0.0001) and number of seizure medications (p < 0.001). ABAS and other motor scores were sensitive to important differences in mobility as represented by the FMS at 5 yards. Further, they correlated with declines in mobility function from 5 to 500 yards.


      An out-of-range COA with raw scores may provide a measure of motor ability and mobility sensitive within the range of moderate to profound impairment seen in patients with DEE. This approach could shorten the time to appropriate COA development and ensure timely clinical trial readiness for novel therapies for rare DEEs.


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