Speech Intelligibility &

Augmentative Communication Laboratory

University of Wisconsin - Madison

Research in Progress

Two groups of studies are currently ongoing in our laboratory.  The first deals with speech, language, and communication development in young children with cerebral palsy. The second deals with the identification variables that impact speech intelligibility in individuals with dysarthria and the translation of those variables into intervention approaches that enhance functional communication abilities.

Communication Development in Children with Cerebral Palsy

Cerebral palsy (CP) is regarded as the most common cause of severe motor disability in children.  Although motor impairment is the primary defining feature of CP, other disabilities such as mental retardation, seizure disorder, and learning disabilities often co-occur.  Research suggests that 60% of children with CP have communication problems; however, the exact nature of these problems has never been comprehensively examined.  As a result, very little is known about the nature of speech, language, and cognitive problems and their co-occurrence with gross motor, and fine motor problems.  Data-based prognoses for communication development are unknown, and many children who have CP do not receive appropriate intervention until they experience significant communication failure. 

Our ongoing longitudinal study of communication development in children with CP seeks to characterize speech and language development beginning in the toddler years and proceeding through elementary school.  We are currently following the longitudinal communication development of 85 children with CP over a period of four years. Data collected from these children are being used to:

• Identify communication subgroups within the population of children with CP
• Establish growth curves for speech and language development in each subgroup
• Determine longitudinal stability of communication subgroups over time
• Identify variables that predict subgroup membership and long term communication outcomes over time.
• Describe the relationship between clinical neuro-imaging findings and communication outcomes.

Results of this research will have important clinical implications, leading to the advancement of interventions that are specifically tailored to different communication subgroups and ultimately to better long-term communication outcomes and quality of life for individuals with CP.  This research will also contribute to the broader theoretical understanding of CP, where classification of speech and language problems has been identified as an important priority. 

Studies in this line are funded by the National Institutes of Health (NIDCD), and the United Cerebral Palsy Research and Education Foundation.

Variables that influence speech intelligibility in speakers dysarthria

The second group of studies focuses on identification and characterization of variables that influence speech intelligibility in children and adults with dysarthria.  Participants in these studies range in age from 3 – 80 years, and most have cerebral palsy or other motor-based disorders that result in compromised intelligibility.  Specifically, studies are seeking to:

• Characterize the impact of different linguistic features of messages (e.g. sentence length, predictability, syntactic complexity, other contextual information) on speech intelligibility at phoneme, word, sentence, and narrative levels.
• Describe the nature of production characteristics (i.e. temporal and spectral acoustic properties) and the interaction between production and listener perception in dysathria
• Determine the influence of supplemental augmentative and alternative communication strategies on intelligibility.
• Identify variables that impact listener attitudes toward speakers with reduced intelligibility and evaluate the effectiveness of different listening strategies for enhancing intelligiblity and improving attitudes. 
• Characteristize the contribution of prosody, particularly fundamental frequency, to speech intelligibility in individuals with cerebral palsy.
• Quantify the effects of medical interventions such as intrathecal baclofen on speech production in individuals with cerebral palsy. 

Collectively, this research will lead to the development of more effective communication interventions, oriented toward functional outcomes, for individuals with dysarthria.  The work will also contribute theoretical information that furthers our understanding of variables associated with intelligibility, forming the basis for a comprehensive model of speech intelligibility in dysarthria.   

Studies in this line are funded by the American Speech, Language and Hearing Foundation, and the National Institutes of Health (NIDCD).

For all of the research in the Speech Intelligibility and Augmentative Communication Lab, we work closely with several clinics at the Waisman Center including:  the Communication Aids and Systems Clinic, the Cerebral Palsy Clinic, the Developmental Disabilities Clinic, and the Spasticity and Movement Disorders Clinic.

Speech Intelligibility and Augmentative Communication Lab

Waisman Center, Room 511

1500 Highland Avenue

Madison, WI 53705