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Findings from the Vocal Development Landmarks Interview

Mary Pat Moeller, Ph.D. and Sophie Ambrose, Ph.D.

As part of the Outcomes of Children with Hearing Loss project, the research team developed the Vocal Development Landmarks Interview (VDLI). This is a measurement tool that can be used for tracking early stages of vocal development in children ages 6 – 21 months. The VDLI is parent-report scale that includes audio files of authentic infant vocalizations to make the target behaviors clear for families.

The team first reported on findings from using the VDLI tool with infants who were hard of hearing in the Journal of Deaf Studies and Deaf Education in 2016 (full article). Findings indicate that children who were hard of hearing (HH) had delays in their early vocal development when compared to their peers with typical hearing (TH). The figure below shows the differences in the scores of the two groups on the three skill areas that are measured by the tool (precanonical, canonical and word productions) as well as their total score on the measure. The team has since revised the tool and conducted a validation study on 160 infants with typical hearing. A manuscript reporting results from this validation study was recently accepted to the Journal of Speech, Language, and Hearing Research.

In addition, Boys Town National Research Hospital has released an iPad app that can be used to administer the VDLI tool. If you are a professional working with young children and you are interested in using the tool to monitor their vocal development, you can find more information on being a beta tester for the app by contacting Dr. Sophie Ambrose or searching "VDLI" in the Apple App Store.

Moeler and Ambrose graph

The horizontal lines in the middle of each box indicate that half the children in the group scored above that score and half scored below that score. The precanonical scale items focus on sounds infants make before they start regularly using consonants. The canonical scale items look at how children start using consonants when they babble. The word scale items focus on children's use of words and word combinations. The results indicate that the children with typical hearing (TH) outperformed the children who were hard of hearing (HH) on this scale.

Sophie with Baby 

Educational seminars by Dr. Moeller can be found here: