How do you recommend ruling out breath support problems as a causal factor in a child who cannot sustain voice? The child who is the source of this question also has Kleinfelter's Syndrome with cognitive problems and has significant oral motor problems a
One way to determine if an individual child or adult has normal lung functioning to produce a normal sustained utterance is by measuring basic static lung function. Determine what the child's vital capacity (VC) is along with expiratory pressure, if possible. Vital capacity will give you the total usable lung volume that the individual has access to when talking and expiratory pressure will give you information on the amount of pressure an individual can generate on expiration, important for speech as we speak on a controlled expiration. Adult women usually have about 3.0-4.0 liters, Adult men 4.0==-6.0 liters. Children vary with age but there are some data available in several articles written by Stathopoulos & Sapienza, 1993 & 1995 (JSHLR). Vital capacity will give you information on the lung capacity but not about how the individual uses that volume. Sometimes testing phonatory airflow (amount of airflow used during speaking) can give you information on how the vocal folds are valving the air used for speech. If there are great losses of air at the larynx this may be a reason the child can't sustain the production for as long as they should. Therefore, the child may have normal lung functioning but have difficulty valving or controlling the airflow at the vocal folds. So determining if the child has enough air to use for sustaining speech (measuring VC, exp. pressure), and determining normal laryngeal valving for speech (measuring airflow) will help determine respiratoy and laryngeal behavior.
Bridget A. Russell is an associate professor at the State University of New York College at Fredonia and received her PhD. for the University at Buffalo in 1998. She has many publications in the Journal of Speech, Hearing and Language Research as well as Speech and Voice Journal. She was an editorial assistant for JSHLR and has written many consumer publications for ASHA. Her main interests include voice disorders as well as a special interest in respiration and ventilation during speech and singing.