Using Ultrasound Tongue Imaging to Support the Phonetic Transcription of Childhood Speech Sound Disorders
Purpose: This study aims to determine whether adding an additional modality (ultrasound tongue imaging) improves the inter-rater reliability of phonetic transcription in childhood speech sound disorders (SSDs) and whether it enables the identification of different or additional errors in children’s speech.Method: Twenty-three English speaking children aged 5–13 years with SSDs of unknown origin were recorded producing repetitions of /aCa/ for all places of articulation with simultaneous audio recording and probe-stabilized ultrasound. Two types of transcriptions were undertaken off-line: (1) ultrasound-aided transcription by two ultrasound-trained speech-language pathologists (SLPs) and (2) traditional phonetic transcription from audio recordings, completed by the same two SLPs and additionally by two different SSD specialist SLPs. We classified transcriptions and errors into ten different subcategories and compared: the number of consonants identified as in error by each transcriber; the inter-rater reliability; and the relative frequencies of error types identified by the different types of transcriber.Results: Error-detection rates were significantly different across the transcription types, with the ultrasound-aided transcribers identifying more errors (χ2(2) = 9.388, p = 0.009). Analysis revealed that these additional errors were identified on the dynamic ultrasound image despite being phonetically transcribed as correct, suggestive of subtle motor errors being present. Interrater reliability for classifying the type of error was substantial (κ = 0.72) for the ultrasound-aided transcribers and ranged from fair to moderate for the audio-only transcribers (κ = 0.38 to 0.52). Ultrasound-aided transcribers were more likely to identify covert errors such as increased variability and abnormal timing than the audio-only transcribers.Conclusions: This study provides preliminary evidence that using ultrasound tongue imaging in the assessment phase of the clinical management of childhood SSDs is useful for improving transcription reliability and detecting subtle covert errors.