Date of Defense

6-4-2013

Date of Graduation

4-2015

Department

Psychology

First Advisor

Helen Sharp

Second Advisor

Gregory Flamme

Third Advisor

Stephen Tasko

Abstract

Objective: To evaluate the difference between nasalance measured using overall nasalance for the full set of syllable repetitions in a speech sample contrasted with syllable repetitions selected (trimmed) from the overall sample.

Method: Participants included 24 males and 34 females between 18 and 30 years of age who participated in a normative study of nasalance in Michigan’s lower peninsula. Participants produced 14 syllable stimuli. Each syllable sequence was repeated at least 8 times. Three trials of each repetition were recorded together with other speech stimuli. Overall nasalance was calculated for each syllable repetition sequence (whole) and compared with the mean nasalance across 5 selected (trimmed) syllables. Syllable selection was conducted using MATLAB (Mathworks, 2011) to identify syllable onset and to select syllables 2-6 in the repetition sequence.

Results: Analyses indicate that the mean difference between overall and trimmed nasalance was centered around 0 with a broad variance distribution and a range of EDITEDIT. A multilevel multivariable regression (X2(3, N=2110) = 32.79, p<0.0005) associated with mean differences include consonant manner class (stops, sibilants, nasals) and vowel (/i/ versus /a/) with significant differences observed for oral consonants, but not nasal consonants.

Conclusion: Nasalance measures are statistically different when overall sample is compared with selected syllables. In most cases, differences are small and thus not clinically significant. In a few cases, however, differences were substantial and could yield clinically relevant differences. Further research is needed to define clinical significance and to explore best trimming practices.

Access Setting

Honors Thesis-Open Access

Peebles Honors Thesis Slideshow.pdf (768 kB)
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