Current Practices in the Evaluation of Global Developmental Delay/Intellectual Disability: A Nationwide Survey of Child Neurologists.

BACKGROUND AND OBJECTIVES

Global developmental delay/intellectual disability (GDD/ID) are among the most common neurologic conditions evaluated by child neurologists in the United States. No recent neurology-specific guidelines for GDD/ID diagnostic evaluation exist, which could lead to practice variability. We assessed current practices in GDD/ID diagnostic evaluation among US child neurologists, including drivers of exome sequencing (ES).

METHODS

A 19-item online anonymous survey was distributed between April 2021 and September 2021 to 953 eligible child neurologists by email and/or online platforms through the American Academy of Neurology and Child Neurology Society. Multinomial logistic regression was used to determine the predictors of sending ES as a part of GDD/ID diagnostic evaluation.

RESULTS

Of 172 unique respondents, 69.2% reported almost always obtaining a chromosomal microarray while 10.5% reported almost always pursuing ES. However, 65.1% identified ES as a first-tier diagnostic test for GDD/ID. Clinical practice demographics independently associated with a higher likelihood of pursuit of ES were more years of experience ( = 0.002) and more people with GDD/ID in one's practice ( < 0.001). Inclusion of brain MRI, EEG, and metabolic laboratory values as part of GDD/ID diagnostic evaluation varied widely. Modalities to screen for treatable disorders (ES or metabolic laboratory values) were reported to be consistently used by only 24.8% of respondents. Respondents identified key barriers to the pursuit of ES including the need for genetics referral/genetic counseling and insurance coverage/out-of-pocket cost.

DISCUSSION

Among US child neurologists, there is marked practice variability in GDD/ID diagnostic evaluation across multiple types of testing, raising concern for disparities in care. There is a widespread lack of screening for treatable causes of ID, which may lead to missed diagnoses and avoidable morbidity. Despite most respondents' support for ES as a first-tier diagnostic test for GDD/ID, only a small minority routinely pursue ES as a part of their evaluation. Provider-level factors (years of experience, percent of patients with GDD/ID) and system-level barriers (access to genetics expertise, lack of insurance coverage) were determinants of the frequency of use of ES. These findings suggest the need for updated consensus guidelines and advocacy/education to improve child neurologists' ability to pursue ES for GDD/ID.