Babbling in children with neurodevelopmental disability and validity of a simplified way of measuring canonical babbling ratio

Abstract

Babbling is an important precursor to speech, but has not yet been thoroughly investigated in children with neurodevelopmental disabilities. Canonical babbling ratio (CBR) is a commonly used but time-consuming measure for quantifying babbling. The aim of this study was twofold: to validate a simplified version of the CBR (CBR^UTTER), and to use this measure to determine if early precursors to speech and language development could be detected in children with different neurodevelopmental disabilities. Two different data sets were used. In Part I, CBR^UTTER was compared to two other CBR measures using previously obtained phonetic transcriptions of 3571 utterances from 38 audio recordings of 12-18 month old children with and without cleft palate. In CBR^UTTER, number of canonical utterances was divided by total number of utterances. In CBR^syl, number of canonical syllables was divided by total number of syllables. In CBR^utt, number of canonical syllables was divided by total number of utterances. High agreement was seen between CBR^UTTER and CBR^syl, suggesting CBR^UTTER as an alternative. In Part II, babbling in children with neurodevelopmental disability was examined. Eighteen children aged 12-22 months with Down syndrome, cerebral palsy or developmental delay were audio-video recorded during interaction with a parent. Recordings were analysed by observation of babbling, consonant production, calculation of CBR^UTTER, and compared to data from controls. The study group showed significantly lower occurrence of all variables, except for of plosives. The long-term relevance of the findings for the speech and language development of the children needs to be investigated.

Keywords: Canonical babbling; Down syndrome; cerebral palsy; developmental delay; early consonant sounds; precursor.