Su-hua Wang - US grants

Orofacial clefts (i.e., cleft lip, cleft lip and palate, and isolated cleft palate, as well as the rare median, lateral [transversal], and oblique facial clefts) are among the most common congenital anomalies. Approximately 20 infants are born in the United States with orofacial clefts on an average day, or 7500 every year. With a cleft palate, one is unable to stop airflow through the nose using normal mechanisms; cleft palate speech therefore contains sounds with air leaking out of the nose, referred to as "nasal escape." In the world of trial-and-error that governs speech learning, the child uses the only tool s/he has available to keep air from escaping out of the nose; s/he holds it back at the level of the glottis or larynx. This mechanism is used by the normal voice to make a hard 'g' as in 'go.' The child uses this "glottal stop" as a substitute for a variety of sounds that s/he cannot create normally. Cleft palate speech thus becomes a collection of sounds characterized by glottal stops and inappropriate nasal escape; these anomalous articulation patterns are usually referred to as compensatory articulation disorder (CAD), and they severely affect speech intelligibility. For this reason, corrective surgery is commonly performed around 10-12 months of age, with the goal of providing a more normal anatomical framework by the time the child begins practicing speech. The repaired palate continues, however, to be variably impaired by the less-than-normal muscle bulk typical of cleft palates and by the stiffness of normal post-surgical scar tissue. Over perhaps one year following surgical repair, palatal function spontaneously improves to the point where in the majority of children it is adequate to selectively prevent nasal escape. Speech therapy after surgery to correct CAD begins at the age of two years and often continues for many years. Correcting cleft speech is important for the child's future ability to live independently and to participate fully in society. Despite the documented benefits, it is a challenge for speech pathologists to train children in proper speech production at an early age when the likelihood of success is highest, because young children are typically less cooperative, sometimes do not fully comprehend what they are being asked to do, and are often unwilling to do unrewarding speech homework, typically under the guidance of inexperienced parents who are unable to assess subtle progress (or lack thereof). The PI's goal in this research is to understand the best strategy for helping children with corrected cleft palate produce normalized speech, and to facilitate this process through games that children can use at home with minimal help from parents while allowing data relating to the child's progress to be delivered to speech pathologists in real time. Project outcomes will especially benefit children from underserved populations. A cleft speech corpus will benefit researchers working on speech recognition algorithms for cleft speech detection, and new speech engine algorithms will benefit speech therapy at large. The work will also spur development of a new research focus at UCSC and UCD in human-centered games for health and healthy living.

A major scientific contribution of this project will be a deeper understanding of the determining characteristics of children with cleft palate and how these relate to the phonetic and phonological rule causes of cleft speech. The technological contributions will be the games and speech engines that are procedurally generated to support in-home and independently administered speech therapy for children with corrected cleft palate, and an algorithm that enables longitudinal voice data curation and analysis to be carried out in real time over the intervention history for every participant as well as across participants. Methodological contribution will include a measure of error rates when a speech recognition system is designed to pick up cleft-specific mispronunciations, and a method for conducting participatory design of games for speech therapy involving computer scientists, engineers, developmental psychologists, speech and language pathologists, plastic surgeons, and children with corrected cleft palate and their parents.