Date of Award


Degree Type


Degree Name

Master of Science in Human Development and Family Studies


Human Development and Family Studies

First Advisor

Karen McCurdy


The current study researches the impact of voice output communication aids (VOCA) on the language acquisition of toddlers and school-aged children with developmental disabilities. There are a wide variety of augmentative and alternative communication (AAC) devices available to nonverbal individuals, making the decision of parents, teachers, and speech pathologists of which to use and implement a substantial task, one that needs the guidance of research based evidence. SPSS software was used to conduct a series of analyses with secondary data from Nancy Brady’s study Language Development of Non-verbal Children Age 3 Years through 7 Years, 2007 to 2012, looking specifically at the increase in total words rate of children using various AAC interventions over a year’s time. Total words rate scores were determined using the number of different words each child spoke, signed, or selected during observations and assessments completed by researchers. A multitude of T-tests and a multiple regression equation were run, comparing the outcomes of participants based on their use of a VOCA and presence of an autism diagnosis. Results found participants using other forms of augmentative communication to have a higher total words rate at time 2 than those using VOCA, though these findings were not significant. Gender and autism were not found to be significant predictors of language acquisition, though being male was positively correlated with total words rate scores. Analyses also concluded that participants with an autism diagnosis using VOCA had a slightly higher total words rate at time 2 than those with other developmental disabilities using VOCA, though these findings were also not significant. Future research should consider looking at a randomly selected sample with a wider quantitative range of expressive vocabulary, as well as obtaining the identification of the type and severity of a child’s diagnosis to further clarify the evidence-based benefits of VOCA with specific populations.



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