Validation of the FASD-Tree as a screening tool for fetal alcohol spectrum disorders

Abstract

Background: As many as 80% of individuals with fetal alcohol spectrum disorders (FASD) are misdiagnosed or not diagnosed. This study tests the accuracy and validity of a web-based screening tool (the FASD-Tree) for identifying children and adolescents with FASD.

Methods: Children with histories of prenatal alcohol exposure (PAE) and controls (N = 302, including 224 with PAE and 78 controls) were examined for physical signs of fetal alcohol syndrome (FAS), and parents completed behavioral questionnaires. Data were entered into the FASD-Tree, a web-based decision tree application. The FASD-Tree provided two outcomes: a dichotomous indicator (yes/no) and a numeric risk score (0 to 5), which have been shown separately to identify children with PAE and neurobehavioral impairment and to correlate with neurobehavioral outcomes. Overall accuracy (ACC), sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) were calculated for the decision tree, risk score, and their combination. Misclassified cases were examined for systematic bias.

Results: The FASD-Tree was successful in accurately identifying youth with histories of PAE and the subgroup of individuals with FASD, indicating its validity as an FASD screening tool. Overall accuracy rates for FASD-Tree components ranged from 75.0% to 84.1%, and both the decision tree outcome and risk score, and their combination, resulted in fair to good discrimination (area under the curve = 0.722 to 0.862) of youth with histories of PAE or FASD. While most participants were correctly classified, those who were misclassified differed in IQ and attention. Race, ethnicity, and sex did not affect the results.

Conclusion: The FASD-Tree is not a biomarker of PAE and does not provide definitive evidence of prenatal alcohol exposure. Rather it is an accurate and valid screening tool for FASD and can be used by clinicians who suspect that a patient has a history of PAE, even if the exposure is unknown.

Keywords: behavior; diagnosis; fetal alcohol spectrum disorders; prenatal alcohol exposure; screening.