Christopher R. Watts

Pitch Matching Accuracy of Trained Singers, Untrained Subjects with Talented Singing Voices, and Untrained Subjects with Nontalented Singing Voices in Conditions of Varying Feedback

At a physiological level, the act of singing involves control and coordination of several systems involved in the production of sound, including respiration, phonation, resonance, and afferent systems used to monitor production. The ability to produce a melodious singing voice (eg, in tune with accurate pitch) is dependent on control over these motor and sensory systems. To test this position, trained singers and untrained subjects with and without expressed singing talent were asked to match pitches of target pure tones. The ability to match pitch reflected the ability to accurately integrate sensory perception with motor planning and execution. Pitch-matching accuracy was measured at the onset of phonation (prephonatory set) before external feedback could be utilized to adjust the voiced source, during phonation when external auditory feedback could be utilized, and during phonation when external auditory feedback was masked. Results revealed trained singers and untrained subjects with singing talent were no different in their pitch-matching abilities when measured before or after external feedback could be utilized. The untrained subjects with singing talent were also significantly more accurate than the trained singers when external auditory feedback was masked. Both groups were significantly more accurate than the untrained subjects without singing talent.

Measurement of Hyolaryngeal Muscle Activation Using Surface Electromyography for Comparison of Two Rehabilitative Dysphagia Exercises

OBJECTIVE To investigate the effects of a resistance-based chin-to-chest (CtC) exercise on measures of hyolaryngeal muscle activation compared with a head-lift exercise. DESIGN Within-subject, repeated-measures design. SETTING Academic research laboratory. PARTICIPANTS Healthy young women (N=20) without a history of dysphagia, cervical spine conditions, neurologic disease, or head/neck cancer (mean age, 22.5y). INTERVENTIONS All participants performed an isometric jaw-opening exercise against resistance (CtC) and an isometric head-lift exercise, both targeting activation in the hyolaryngeal (suprahyoid) muscles. The CtC exercise required jaw opening into a chin brace secured against the upper torso for a duration of 10 seconds. The isometric head-lift exercise required lifting and holding the head from a supine position for 10 seconds. The degree to which each exercise activated the suprahyoid muscles was measured using surface electromyography (sEMG). MAIN OUTCOME MEASURES Microvolts as measured from sEMG sensors placed on the skin surface above the hyolaryngeal muscles (surface of skin above geniohyoid, mylohyoid, and anterior digastric). Dependent variables included the peak microvolts during 10 seconds of sustained contraction and the difference in microvolts from rest to peak contraction for each exercise. RESULTS Activation in the hyolaryngeal musculature as measured via sEMG was significantly greater when participants performed the CtC exercise compared with the head-lift exercise. Measures of peak microvolts during contraction were significantly greater for CtC (t=10.72, P<.001) compared with the head-lift exercise, and difference measures in microvolts calculated between rest and contraction for each exercise revealed a 2-fold increase in hyolaryngeal muscular activation for CtC (t=8.27, P<.001). CONCLUSIONS The isometric CtC exercise resulted in greater activation of the hyolaryngeal muscles compared with an isometric head-lift exercise. Results support the need for further investigations to determine whether the CtC exercise has a positive effect as a rehabilitative exercise for clinical populations with dysphagia secondary to upper esophageal sphincter dysfunction where hyolaryngeal excursion is a physiological impairment.

A randomized controlled trial of stretch-and-flow voice therapy for muscle tension Dysphonia

To investigate the effect of stretch‐and‐flow voice therapy on vocal function and handicap.

Dialectical Effects on Nasalance: A Multicenter, Cross-Continental Study

PURPOSE This study investigated nasalance in speakers from six different dialectal regions across North America using recent versions of the Nasometer. It was hypothesized that many of the sound changes observed in regional dialects of North American English would have a significant impact on measures of nasalance. METHOD Samples of the Zoo Passage, the Rainbow Passage, and the Nasal Sentences were collected from young adult male and female speakers (N=300) from six North American dialectical regions (Midland/Mid-Atlantic; Inland North Canada; Inland North; North Central; South; and Western dialects). RESULTS Across the three passage types, effect sizes for dialect were moderate in strength and accounted for approximately 7%-9% of the variation in nasalance. Increased differences in nasalance tended to occur between speakers from distinctly different geographical regions, with the highest nasalance across all passages observed for speakers from the Texas South dialect region. CONCLUSION Clinicians and researchers who use perceptual and instrumental measures of speech production should be aware that dialectical and socially acquired speech patterns may influence the acoustic characteristics of speech and may also influence the interpretation of normative expectations and typical versus disordered cutoff scores for instruments such as the Nasometer.

Phonation Quotient in Women: A Measure of Vocal Efficiency Using Three Aerodynamic Instruments

OBJECTIVE The purpose of this study was to examine measures of vital capacity and phonation quotient across three age groups in women using three different aerodynamic instruments representing low-tech and high-tech options. STUDY DESIGN This study has a prospective, repeated measures design. METHODS Fifteen women in each age group of 25-39 years, 40-59 years, and 60-79 years were assessed using maximum phonation time and vital capacity obtained from three aerodynamic instruments: a handheld analog windmill type spirometer, a handheld digital spirometer, and the Phonatory Aerodynamic System (PAS), Model 6600. Phonation quotient was calculated using vital capacity from each instrument. Analyses of variance were performed to test for main effects of the instruments and age on vital capacity and derived phonation quotient. Pearson product moment correlation was performed to assess measurement reliability (parallel forms) between the instruments. Regression equations, scatterplots, and coefficients of determination were also calculated. RESULTS Statistically significant differences were found in vital capacity measures for the digital spirometer compared with the windmill-type spirometer and PAS across age groups. Strong positive correlations were present between all three instruments for both vital capacity and derived phonation quotient measurements. CONCLUSIONS Measurement precision for the digital spirometer was lower than the windmill spirometer compared with the PAS. However, all three instruments had strong measurement reliability. Additionally, age did not have an effect on the measurement across instruments. These results are consistent with previous literature reporting data from male speakers and support the use of low-tech options for measurement of basic aerodynamic variables associated with voice production.

Measurement Reliability of Phonation Quotient Derived From Three Aerodynamic Instruments

OBJECTIVE The purpose of this study was to examine parallel forms reliability between two hand-held spirometers and a pneumotachograph-based system for vital capacity and derived phonation quotient measurements. STUDY DESIGN This is a prospective, repeated measures design. METHODS A total of 20 adult males were tested using three aerodynamic instruments-Baseline windmill-type spirometer, Contec SP10 digital spirometer and the Pentax Medical Phonatory Aerodynamic System (PAS), Model 6600 for measures of vital capacity. Phonation quotient was calculated using vital capacity from each instrument along with maximum phonation time. Repeated measures analyses of covariance (ANCOVAs) were performed to test for main effects of the instruments on vital capacity and phonation quotient, with age as a covariate. Pearson Product Moment correlation was performed to assess measurement reliability between the instruments. RESULTS Statistically significant differences on ANCOVA were seen in vital capacity measures for the digital spirometer compared with the windmill spirometer and PAS. No differences were found between any of the instruments for phonation quotient. Large and positive correlations were present between all three instruments for both vital capacity and phonation quotient measurements. CONCLUSIONS Strong parallel forms reliability in measures of vital capacity and derived phonation quotient was seen among the three instrument systems, although measurement precision was different when comparing the digital spirometer to two other instrument types.

Laryngeal aging and acoustic changes in male rat ultrasonic vocalizations.

This study examined changes in the acoustic and temporal structure of ultrasonic vocalizations as a function of age and correlated acoustic changes with vocal fold microstructure. Ultrasonic vocalizations were recorded in three age groups of male rats: aged (24-26 months), middle-aged (17-18 months), and young (4-5 months). Acoustic and structural changes in vocal fold tissue were evident by 18 months of age. Histological analyses revealed decreased density of elastin and hyaluronic acid and increased collagen density in the middle-aged and aged groups compared to the young rats. Laryngeal microstructure correlated with some of the ultrasonic acoustic features. These results show that male Long Evans rats experience changes in ultrasonic acoustic structure by middle age, and these changes correlate with deterioration in laryngeal microstructure. Ultrasonic vocalizations can be used as a model system for age-related degeneration in vocal fold structure and function.

Evidence for Heterozygous Abnormalities of the Elastin Gene (ELN) Affecting the Quantity of Vocal Fold Elastic Fibers: A Pilot Study

OBJECTIVES To investigate the effects of a heterozygous elastin gene (Eln) abnormality (deletion of one Eln allele) on the structural characteristics of the vocal fold lamina propria using a mouse model of human disease. STUDY DESIGN Cross-sectional between-subjects design. METHODS Five mice, four with heterozygous Eln deletions (Eln +/-) serving as an animal model for the human disease supravalvular aortic stenosis and one normal wild-type control (Eln +/+) were used for this study. Vocal folds were obtained from each animal and stained for the protein elastin using histochemical methods. Descriptive data from qualitative visual inspection and quantitative data from microscopic digital image analysis were collected to determine the staining density of elastic fibers within the vocal fold lamina propria. RESULTS Qualitative visual inspection revealed greater staining density (eg, a greater quantity) for elastic fibers in the Eln +/+ animal. Quantitative measurements using digital pixel analysis of staining density revealed significant differences between mice with the two genotypes, confirming the qualitative findings. CONCLUSIONS Results suggest that Eln requires two functioning alleles for normal structural development of the vocal fold lamina propria. This pilot evidence supports the hypothesis of a structural etiology causing altered vocal function in humans with a similar genotype.

A Comparison of Cepstral Peak Prominence Measures From Two Acoustic Analysis Programs

PURPOSE This study aimed to investigate the relationship and reliability of cepstral peak prominence (CPP) measures from two acoustic software applications, Analysis of Dysphonia in Speech and Voice (ADSV) and Praat. METHODOLOGY Flemish and English recordings of sustained vowels and connected speech samples were analyzed using ADSV and Praat. Correlational analyses and measures of the standard error of the estimate were applied to the vowel and connected speech data obtained from the two programs. RESULTS Analyses revealed very strong relationships (eg, r > 0.88) between CPP measures derived from ADSV and those derived from Praat, regardless of context (vowel or connected speech) or language spoken. Average residual errors ranged from 0.55 to 1.1 dB for the prediction of Praat CPP data from actual observed ADSV CPP data, and average residual errors ranged from 0.57 to 1.58 dB for the prediction of ADSV CPP data from actual observed Praat CPP data. CONCLUSIONS Measurements of CPP derived from ADSV and Praat manifested strong parallel-forms reliability. Although CPP data values obtained via these programs will be different owing to algorithmic processing differences, this study found that estimated CPP values derived using regression equations could be transformed between programs with relatively small predictive error, regardless of language. The strong measurement relationships indicate that CPP values from either program have a high degree of shared variance and may be expected to differentiate across a wide range of voice signal periodicity in a relatively similar fashion. This finding supports the use of either program in clinical use and voice science research.

The Effect of Bolus Consistency and Sex on Electrophysiological Measures of Hyolaryngeal Muscle Activity During Swallowing

The purpose of this study was to investigate the effect of bolus consistency and sex on the activity of the submandibular hyolaryngeal muscles during swallowing. Twenty young, healthy adults (10 males, 10 females) swallowed four types of bolus material (thin liquid, thick liquid, pudding, and cookie) while being measured with surface electromyography. Measurements of peak contraction amplitude and contraction duration were computed from recorded electromyographic signals. Results from statistical analyses revealed a significant effect of bolus consistency on measures of peak contraction amplitude, but not contraction duration. There were no significant effects of sex on either measure. Findings from this study further the body of knowledge in electrophysiological measurements acquired during swallowing and their potential clinical application during assessment and treatment of dysphagia.