Prevalence and phenotype of childhood apraxia of speech in youth with galactosemia

Purpose: In this article, the authors address the hypothesis that the severe and persistent speech disorder reported in persons with galactosemia meets contemporary diagnostic criteria for Childhood Apraxia of Speech (CAS). A positive finding for CAS in this rare metabolic disorder has the potential to impact treatment of persons with galactosemia and inform explanatory perspectives on CAS in neurological, neurodevelopmental, and idiopathic contexts. Method: Thirty-three youth with galactosemia and significant prior or persistent speech sound disorder were assessed in their homes in 17 states. Participants completed a protocol yielding information on their cognitive, structural, sensorimotor, language, speech, prosody, and voice status and function. Results: Eight of the 33 participants (24%) met contemporary diagnostic criteria for CAS. Two participants, 1 of whom was among the 8 with CAS, met criteria for ataxic or hyperkinetic dysarthria. Groupwise findings for the remaining 24 participants are consistent with a classification category termed Motor Speech Disorder-Not Otherwise Specified (Shriberg, Fourakis et al., 2010a). Conclusion: The authors estimate the prevalence of CAS in galactosemia at 18 per hundred-180 times the estimated risk for idiopathic CAS. Findings support the need to study risk factors for the high occurrence of motor speech disorders in galactosemia despite early compliant dietary management.