Articulation in schoolchildren and adults with neurofibromatosis type 1

Several authors mentioned the occurrence of articulation problems in the neurofibromatosis type 1 (NF1) population. However, few studies have undertaken a detailed analysis of the articulation skills of NF1 patients, especially in schoolchildren and adults. Therefore, the aim of the present study was to examine in depth the articulation skills of NF1 schoolchildren and adults, both phonetically and phonologically. Speech samples were collected from 43 Flemish NF1 patients (14 children and 29 adults), ranging in age between 7 and 53 years, using a standardized speech test in which all Flemish single speech sounds and most clusters occur in all their permissible syllable positions. Analyses concentrated on consonants only and included a phonetic inventory, a phonetic, and a phonological analysis. It was shown that phonetic inventories were incomplete in 16.28% (7/43) of participants, in which totally correct realizations of the sibilants /ʃ/ and/or /ʒ/ were missing. Phonetic analysis revealed that distortions were the predominant phonetic error type. Sigmatismus stridens, multiple ad- or interdentality, and, in children, rhotacismus non vibrans were frequently observed. From a phonological perspective, the most common error types were substitution and syllable structure errors. Particularly, devoicing, cluster simplification, and, in children, deletion of the final consonant of words were perceived. Further, it was demonstrated that significantly more men than women presented with an incomplete phonetic inventory, and that girls tended to display more articulation errors than boys. Additionally, children exhibited significantly more articulation errors than adults, suggesting that although the articulation skills of NF1 patients evolve positively with age, articulation problems do not resolve completely from childhood to adulthood. As such, the articulation errors made by NF1 adults may be regarded as residual articulation disorders. It can be concluded that the speech of NF1 patients is characterized by mild articulation disorders at an age where this is no longer expected.

Readers will be able to describe neurofibromatosis type 1 (NF1) and explain the articulation errors displayed by schoolchildren and adults with this genetic syndrome.