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S V Stager

Publications and source records attributed to S V Stager.

8 recordsLinked to original sources
PubMed2001

Quantification of static and dynamic supraglottic activity.

For estimating supraglottic compression in disordered voice production, categorical rating scales of true vocal fold coverage by supraglottic structures are the current standard. Quantification of change in the position of supraglottic structures compared to no supraglottic activity would be a better method for distinguishing between and within voice-disordered groups. This study developed a method for quantifying static supraglottic activity and extent of false vocal fold (FVF) motion during dynamic supraglottic activity. Twelve control participants and 12 individuals with voice disorders (6 with complaints of vocal fatigue and 6 with vocal fold nodules) were enrolled in the study. These individuals participated in a transnasal fiberoptic laryngeal examination in which various speech tasks were recorded. Single-frame images were selected to represent the positions of minimum and maximum supraglottic compression for each speech task. Two individuals rated these single-frame images using a categorical rating scale. Two other individuals measured the anterior-to-posterior (A-P) distance, vocal fold length, and vocal fold area. A-P and FVF compression were derived from these three measures. Reliability was demonstrated between judges for the ratings and between and within judges for the measures. Significant differences in normalized static supraglottic compression measures corresponded to the rating scale categories. Significant differences in normalized dynamic supraglottic compression measures corresponded to the differences in category ratings between minimum and maximum compression. Using the normalized measures, the voice-disordered groups demonstrated significantly greater static A-P compression (t test, p < .03) than did the control participants. These results suggest that static supraglottic activity may be diagnostic of voice disorder. Normalized dynamic FVF compression ratios were not significantly different between groups. This supports a previous hypothesis that dynamic supraglottic activity serves as an articulatory function at the level of the larynx and is part of the linguistic/phonemic system, rather than evidence of disordered laryngeal function.

Adult↗
PubMed2000

Supraglottic activity: evidence of vocal hyperfunction or laryngeal articulation?

False vocal fold (FVF) adduction and compression of the arytenoid cartilages to the petiole of the epiglottis in an anterior to posterior (A-P) direction have been thought to characterize voice disorders with abnormally increased muscle tension or effort, often termed hyperfunctional voice disorders. To further evaluate the association between hyperfunctional voice disorders and supraglottic activity, we compared the incidence of static and dynamic supraglottic activity in individuals with normal laryngeal mucosa, normal voice quality, and no voice complaints to two populations: subjects with vocal fold nodules and subjects with complaints of dysphonia without visible vocal fold lesions, glottal incompetence, or impairment of arytenoid cartilage motion ("hyperfunctional" group). Thirty-two subjects were assigned to one of these three groups (10 control, 12 nodule, and 10 hyperfunctional). Laryngeal movements were recorded using flexible videoendoscopy while a subject was performing speech tasks such as sustained phonation, syllable repetitions, sentence imitations, and conversation. Samples were randomized by subject and task and rated for presence or absence of A-P and FVF compression. Statistically significant group differences were found for FVF compression across speech tasks (chi-square, p<0.001). The control group had the smallest incidence (45%), nodule patients the next larger incidence (68%), and hyperfunctional patients the largest incidence (80%). Statistically significant group differences were found for A-P compression across speech tasks (chi-square, p<.05). The control group had the smallest incidence (74%), nodule patients the next larger incidence (78%), and hyperfunctional patients the largest incidence (92%). Statistically significant task differences were found for the presence of FVF compression in control subjects (chi-square, p<.005), hyperfunctional patients (chi-square, p<.025), and nodule patients (chi-square, p<.001), but not for A-P compression for any of the groups. A higher incidence of FVF compression was present for the speech tasks that included glottal stops. This context-specific variation in supraglottic activity suggested a dynamic component to FVF compression and also explained the high proportion of FVF compression in the control group. Each video sample was also rated for consistency of FVF or A-P compression to explore the static and dynamic nature of supraglottic activity. For samples on which raters agreed, A-P compression was typically present consistently, suggesting a static component, and FVF compression inconsistently, suggesting a dynamic component, for all three groups (chi-square, p<.001). These findings do not support previous suggestions that supraglottic activity may be a precursor to developing vocal fold nodules, as the nodule patients did not exhibit a higher incidence or consistency of A-P or FVF compression than patients with hyperfunctional voicing patterns in this study. Subjects in the hyperfunctional voice group were found to have static components of FVF and A-P compression. The presence of FVF compression in speech tasks that included glottal stops in the control group suggests an articulatory function at the laryngeal level.

Adolescent↗
PubMed1997

Modifications in aerodynamic variables by persons who stutter under fluency-evoking conditions.

The purposes of this study were to (a) compare the effects of fluency-evoking conditions on aerodynamic variables in 10 persons who stutter with those previously reported for 12 individuals who do not stutter; (b) determine if any changes demonstrated in the amplitude and/or timing of aerodynamic variables were accounted for by changes in speech intensity; and (c) determine if any amplitude or timing changes in flow and intraoral pressure were related to improved fluency. The fluency-evoking conditions were choral reading (CR), metronome-pacing (MET), delayed auditory feedback (DAF), and noise (NOISE). From 8 words beginning with plosive consonants in CVC contexts read aloud in sentences, measures were made of 8 variables, including closure duration, amplitude and time to maximum airflow and intraoral pressure for initial plosives, and the duration and intensity of the following vowel. Speech rate was also computed. Only fluently produced target words from persons who stutter were analyzed. All persons who stutter showed improved fluency under all conditions. Both groups demonstrated significant (p < or = 0.006) condition effects for peak flow, vowel intensity, and pressure rise time. Thus, fluency-evoking conditions affected these variables regardless of speaker type. Both groups changed peak pressure in similar directions from baseline depending on condition, but not significantly for each group in the same conditions. Persons who stutter significantly increased speech rate for CR, DAF, and NOISE; and persons who do not stutter significantly decreased rate under DAF. The reported changes in peak pressure and peak flow could not be accounted for by changes in vowel intensity. Larger improvements in fluency occurred under conditions when peak flow and peak pressure values were decreased from baseline. Thus, variables that were modified by both groups when speaking under conditions were also the variables related to changes in fluency for the persons who stutter.

Adult↗
PubMed1995

Fluency changes in persons who stutter following a double blind trial of clomipramine and desipramine.

This study compared fluency changes in adult developmental stuttering speakers treated with two tricyclic antidepressants, clomipramine and desipramine. Clomipramine is primarily a serotonergic reuptake inhibitor, and desipramine, primarily a noradrenergic reuptake inhibitor. Sixteen subjects who stuttered participated in a single-blind placebo, double-blind active drug crossover study lasting 12 weeks. Speech rate and percent fluency did not significantly improve in placebo compared to baseline. Speech rate significantly increased while repeating, reading or constructing sentences, and during a telephone conversation, but no significant changes in percent fluency were found under clomipramine compared to placebo. Speech rate during a telephone conversation and percent fluency while speaking in front of an audience of four to seven listeners significantly increased under clomipramine compared to desipramine. No significant improvements in percent fluency or speech rate were found for any speaking task under desipramine compared to placebo. Twelve of 16 subjects reported improved fluency compared to baseline using clomipramine, whereas 6 reported improvement using desipramine. Because more evidence of improvement was found under clomipramine compared to desipramine, fluency improvement may be related to clomipramine's greater selectivity for serotonergic reuptake inhibition.

Adolescent↗
PubMed1993

Speech production changes under fluency-evoking conditions in nonstuttering speakers.

Changes in airflow and intraoral pressure between baseline and four fluency-evoking conditions--choral reading (CR), metronome pacing (MET), delayed auditory feedback (DAF), and masking noise (NOISE)--were studied in 12 American English nonstuttering speakers. The duration, amplitude, and velocity of airflow and intraoral pressure development during the initial plosive and the duration and intensity of the following vowel were measured in eight target CVC words. Speech rate was computed for each sentence. Comparisons between baseline and the corresponding production in each condition revealed significant changes in peak flow, pressure rise time, peak instantaneous pressure velocity, speech rate, intensity, and vowel duration. Vowel duration increased under DAF, MET, and NOISE conditions. Peak pressure and pressure velocity decreased during CR and MET and increased during NOISE, but did not change during DAF. Subjects were consistent in the variables they modified across conditions. Changes in the aerodynamic variables were not related to intensity or rate changes. Thus, nonstuttering speakers modify intraoral pressure and flow under fluency-evoking conditions.

Adult↗
PubMed1990

Relationships between selected auditory and phonatory latency measures in normal speakers.

Interaction between auditory and phonatory systems was explored in normal speakers by comparing laryngeal reaction time (LRT) with interpeak intervals from the auditory brainstem response (ABR) obtained using high and low stimulus presentation rates. Thirty-four subjects with no history of neurological or speech-language disorders and normal hearing sensitivity participated. Interpeak intervals were derived from ABR's recorded for each ear at rates of 21.1 and 91.1 clicks/s. LRT responses were obtained by instructing subjects to sustain an /s/ and then phonate an /a/ as fast as possible following visual cues. Two measures of reaction time performance were derived, Mean Laryngeal Reaction Time (MLRT) and Best Laryngeal Reaction Time (BLRT). Linear regression analyses were completed between each measure of reaction time performance and each ABR interpeak interval. Using either LRT measure, two significant (p less than .05) positive linear relationships were found. One involved the interpeak interval between Waves III and V and the other involved the interpeak interval between Waves I and V. Both were recorded at high stimulus presentation rates. These results support the small body of literature from normal speakers, stutterers, and spasmodic dysphonics suggesting interaction between the auditory and phonatory systems at the brainstem level.

Adolescent↗
PubMedDate not supplied

The effects of fluency-evoking conditions on voicing onset types in persons who do and do not stutter.

Voicing onset changes between control conditions and three fluency-evoking conditions (choral reading [CHORAL], delayed auditory feedback [DAF], and noise [NOISE]) were studied in 12 persons who do not stutter and 10 who do stutter. Voicing onsets were distinguished physiologically using airflow prior to voicing, with zero airflow prevoicing categorized as hard and the rest as breathy. Persons who stutter were more fluent under all fluency-evoking conditions than control conditions. Speaking under fluency-evoking conditions did not significantly increase the overall proportion of breathy onsets from control conditions for either group. However, looking only at hard onsets in the control condition, we found that both groups changed significantly more to breathy (p = 0.001) under CHORAL and NOISE. In persons who stutter, onset type was not associated with whether a word was produced fluently or dysfluently in the control condition. Also, no relationship was found between onsets changing to breathy under fluency-evoking conditions and onsets changing to fluent. The results suggest that although fluency-evoking conditions can modify some voicing onset behaviors, these modifications do not relate to improvements in fluency.

Adult↗