The effect of speech timing on velopharyngeal function Student Investigator: Megan Griggs Faculty Supervisor: David Jones, PhD

Speech Respiration (Breathing) Phonation (Vocal cord vibration) Articulation (Movement of oral and pharyngeal structures)

Velopharyngeal Mechanism

Previous Research: Speech Rate When speech rate is increased, articulatory movements demonstrate one of two strategies: Decrease in duration of articulatory movements (moving faster) (Kent et al, 1974 ; Gay, 1978) Articulators move a reduced distance (decreased displacement to-and-from target) (Lindblom, 1963)

Previous Research (cont.) Kuehn (1976) Studied velar movement as a function of increased speaking rate Velum either moved faster or shorter distances

Previous Research (cont.) Limitation of Kuehn study Only soft palate movement was measured, not the opening and closing of the velopharyngeal port The velopharyngeal mechanism moves in a sphincteric fashion Lateral View Superior View of Velopharyngeal Port

Purpose To study the effect of speech timing on the opening and closing of the velopharyngeal port in individuals with normal anatomy and normal speech.

Hypothesis As speech rate is increased, speakers will either: a) close the velopharyngeal port faster, or reduce the range of velopharyngeal port opening The findings may have implications for speakers with abnormal palatal structures

Subjects Five males and five females Mean Age: 22 years American English speakers No history of speech disorders Perceived as exhibiting normal speech

Instrumentation Nasal airflow Nasal pressure Oral pressure Microphone All signals digitized at 1000Hz

Speech Sample Phrase “we were a pamper away” 2 Speech Conditions Conversational speech rate “Fast” speaking rate Target word: “pamper” Rate conditions randomized Generalization

Procedure Speech phrases were modeled ~15 repetitions produced Corrections during data collection 10 tokens were measured at each rate

P ER P M A

Key Data Calculations Velopharyngel Port Area Maximum Flow Declination Rate (MFDR) Velocity of velopharyngeal closure

Velopharyngeal Port Area p a m p er Velopharyngeal Port Area Warren & DuBois (1964) Open less with increased rate?

Declination Rate (MFDR) p a m p er VP Port Closing Max Flow Declination Rate (MFDR) . . MFDR = (dV/dt)peak/Vpeak ** * Dotevall (2000) Closed faster with increased rate?

Results

Hypothesis As speech rate is increased, speakers will either: a) close the velopharyngeal port faster, or reduce the range of velopharyngeal port opening

Speakers 1, 3, 4, 5, 6, 9, 10 (7/10) increased velopharyngeal port closing velocity with increased speaking rate

Speakers 3, 4, 5, 9 (4/10) decreased velopharyngeal displacement with increased speaking rate

Discussion The majority of the speakers (7/10) closed the velopharyngeal port with increased velocity as rate increased 4/10 speakers opened their velopharyngeal ports to a lesser extent (decreased displacement) These 4 speakers also moved faster None of the speakers decreased velopharyngeal displacement exclusively

Discussion Speakers 2, 7, and 8: Speech timing for “pamper” did not change significantly from Conversational Rate to Fast Rate These speakers decreased speech timing in other aspects of the utterance

Conclusion Some speakers may use both strategies to accommodate faster speech rate Move the velopharyngeal structures faster Move the velopharyngeal structures a reduced distance Some speakers simply move faster Do speakers reduce displacement of velopharyngeal structures exclusively?

Bilateral Cleft Lip and Palate Implications Nasal Septum Nasal Cavity Bilateral Cleft Lip and Palate

Post Palate Repair Structural Limitations Palatal Scar Tissue Reduced Palatal Length Inadequate Palatal Muscle Bulk

Velopharyngeal Insufficiency Normal Velopharyngeal Closure

Velopharyngeal Mechanism in Speakers with Cleft Palate Normal velopharyngeal function (75%) Velopharyngeal insufficiency Hypernasal speech – More surgery “Borderline” velopharyngeal function Mild, inconsistent nasalization

“Borderline” velopharyngeal function: looking forward How does “borderline” velopharyngeal function change as a result of speech timing? Are there therapy approaches that would help address negative affects of speech timing?

References Gay, T. (1978). Effect of speaking rate on vowel formant movements. The Journal of the Acoustical Society of America, 63(1), 223. doi:10.1121/1.381717 Lindblom, B. (1963). Spectrographic Study of Vowel Reduction. The Journal of the Acoustical Society of America, 35(11), 1773-1781. doi:10.1121/1.1918816 Kent, R. D., & Moll, K. L. (1972). Cinefluorographic Analyses of Selected Lingual Consonants. Journal of Speech Language and Hearing Research, 15(3), 453. doi:10.1044/jshr.1503.453 Kuehn, D. P. (1976). A cineradiographic investigation of velar movement variables in two normals. 88-103. Warren, D. W., & DuBois, A. B. (19964). A pressure-flow technique for measuring velopharyngeal orifice area during continuous speech. 52-71.

Questions?

Speakers 1, 2, 3, 5, 6, 8, 9, 10 opened velop port for shorter duration with increased speaking rate