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E T Stathopoulos

Publications and source records attributed to E T Stathopoulos.

18 recordsLinked to original sources
PubMed1999

Formants of children, women, and men: the effects of vocal intensity variation.

The purpose of this study was to investigate the formant frequencies and amplitudes of a wide age range of children and one group of adults at three sound pressure levels (SPLs). Subjects were ten females and ten males in the following age groups (in years): 4, 6, 8, 10, 12, 14, 16, 18, and adults. A sustained /a/ was produced three times by each subject. Formant frequencies were obtained using linear predictive coding analysis. Formant amplitudes were measured from the highest amplitude harmonic in the area of each formant. In addition to following established trends previously published in other studies, it was hypothesized that the first formant frequency would increase with increasing intensity, that females would have higher formant frequencies than same aged males, and that women and children would have reduced formant amplitudes as compared to men. It was found that first formant frequency increased with intensity and changed as a function of age and sex. Second and third formant frequencies changed with age and sex. Formant amplitudes followed the trends set by the SPL differences and did not change as a function of age and sex. Results are discussed in terms of anatomic differences and SPL.

Adolescent↗
PubMed1998

Approximations of open quotient and speed quotient from glottal airflow and EGG waveforms: effects of measurement criteria and sound pressure level.

Noninvasive measures of vocal fold activity are useful for describing normal and disordered voice production. Measures of open and speed quotient from glottal airflow and electroglottographic (EGG) waveforms have been used to describe timing events associated with vocal fold vibration. To date, there has been little consistency in the measurement criteria used to calculate quotient values. In this study, criteria of 20% and 50% were applied to the AC amplitude of glottal airflow and inverted EGG waveforms for measurement of open quotient. Criteria of 20%, 50%, and 80%, and a midslope criterion that segmented the waveform between 20% and 80% of the waveform amplitude, were used for the calculation of speed quotient. Subjects produced waveforms at sound pressure levels (SPL) of 70, 75, 80 and 85 dB. Results indicated that approximations of open quotient obtained from the glottal airflow waveform significantly decreased using both the 20% and 50% criteria as SPL increased from 80 to 85 dB. No significant changes were found in open quotient from the EGG waveform as a function of SPL. Results of speed quotient measures from the glottal airflow and EGG waveforms showed a generally increasing trend as SPL increased, although the differences were not statistically significant. The data suggest that the signal type, measurement criterion and SPL must be considered in interpreting quotient measures.

Adult↗
PubMed1998

Effects of varied vocal intensity on ventilation and energy expenditure in women and men.

This study was completed to determine how ventilatory responses change by means of speech reading at three different sound pressure levels (SPL) as compared to quiet breathing prior to each task. The energy required to alter SPL was also studied and compared to energy expenditures during a quiet breathing condition. Twenty-four adults (12 women, 12 men) were studied while reading a standard passage at low, comfortable, and high SPLs for 7 minutes with quiet breathing periods between each task to achieve respiratory steady state and serve as a control to which the reading tasks were compared. The last 2 minutes of exhaled air for all speaking and quiet breathing tasks were collected using a Hans Rudolph mouth breathing face mask. A Sensor Medics Vmax 29 series diagnostic instrument system measured all ventilatory responses and energy expenditures. Volume and timing alterations in ventilation were characterized by measuring tidal volume (V[T]), inspiratory time (T[I]), inspiratory flow rate (V[T]/T[I]), and expiratory time (T[E]). Average ventilation, energy expenditure, and adequacy of ventilation were measured using minute ventilation (V[E]), oxygen consumption (VO2), carbon dioxide production (VCO2), and partial pressure of end-tidal carbon dioxide (end-tidal PET[CO2]). Results indicated volume, timing, ventilation, and energy expenditure values remained closest to quiet breathing values for the comfortable SPL. Volume, ventilation, and energy expenditure were significantly greater for the high SPL and lower for the low SPL, compared to the baseline steady state, indicating that the low SPL causes a ventilatory deficit that was found to be paid back at the end of the speech task during the quiet breathing period. These results demonstrate that an individual's comfortable SPL is the least energy-requiring way to speech breathe. As SPL rises above or below comfortable SPL, speech breathing requires more energy.

Adolescent↗
PubMed1998

Effects of a circumferentially vented mask on breathing patterns of women as measured by respiratory kinematic techniques.

Since pneumotachograph masks are commonly used in studies of speech breathing, the purpose of this study was to measure the differences in respiratory volumetric and frequency measures during speech under two conditions: with and without a circumferentially vented pneumotachograph mask coupled to the face. Thus we sought to identify whether changes in breathing patterns occur with the use of a specific face mask, because these patterns are accepted as representative of normal speech breathing. Subjects were 10 normal-speaking women, each of whom produced a syllable train and a connected speech task, both at comfortable intensity levels. Respiratory measures were made using linearized magnetometers during speech production. The measurements included lung volume, rib cage volume, and abdominal volume at utterance initiation and termination, volume excursions during the utterance, and the number of breath groups during the speech task. There were no significant differences between the mask-on and mask-off conditions in volumetric and frequency measures. A significant task difference for abdominal initiation was found. It was concluded that the use of a circumferentially vented pneumotachograph mask does not alter the reliability of respiratory volume and frequency measures for studies of voice.

Adult↗
PubMed1997

Speech breathing during reading in women with vocal nodules.

This study examined speech breathing patterns during reading by women with bilateral vocal fold nodules judged as mildly dysphonic and by women without vocal nodules. Although it might be predictable that the speech breathing patterns of individuals with laryngeal dysfunction will differ from those without laryngeal dysfunction, there is a lack of empirical data to support such assumptions. The results of the current study indicated that glottal airflow was greater during reading for the women with vocal nodules and that a larger volume of air was expended both per syllable and per breath group during reading. The rate of speech did not significantly differ between the two groups of women. There was no significant difference for the average duration of the breath groups and no significant difference for the number of syllables spoken per breath group. Additionally, both groups of women demonstrated a similar pattern of inspiratory pause location during the reading. The results suggest that speech breathing patterns associated with dysphonia be examined independently to distinguish specifically the nature of the interaction between the laryngeal dysfunction and the speech breathing pattern. Certainly, more information on how the severity of a voice disorder influences speech breathing is necessary.

Adolescent↗
PubMed1997

Developmental changes in laryngeal and respiratory function with variations in sound pressure level.

The development of the speech production system was investigated using a cross-sectional design that included children aged 4-14 years and adults. Given that the size and internal structure of the laryngeal and respiratory systems differ between children and adults, it was predicted that children would show functional distinctions from adults during speech. Aerodynamic, acoustic, and respiratory kinematic techniques were used to assess laryngeal and respiratory function while participants varied their sound pressure level. In general, the aerodynamic and acoustic results show that men and 14-year-old boys function differently than women and all other groups of children. For the respiratory function data, children's values are similar to adults' by the time they are 12-14 years of age. These changes correspond closely to developmental laryngeal and respiratory anatomic data. All participants used a combination of laryngeal and respiratory mechanisms to increase sound pressure level, but the combination of mechanisms differed across age groups. These data emphasize that the laryngeal and respiratory behavior of children is not easily predicted from an adult model.

Adolescent↗
PubMed1995

Speech task effects on acoustic and aerodynamic measures of women with vocal nodules.

Vowel prolongation is often used to evaluate disordered voice production. In light of previous findings showing that co-articulation has significant influence on laryngeal function measures, the practice of using prolonged vowels to represent a speech sample is questioned. To test whether disordered and normal voice during vowel production is generalizable to connected speech, three speaking tasks were investigated: sustained vowel prolongation, syllable repetition and reading. Statistical differences were found between these tasks for certain amplitude and time based laryngeal function measures for adult women with disordered and normal voice. However, for the specific measures which were statistically different, the actual numerical and perceptual differences may be quite small. From a clinical assessment standpoint, the choice of the speech task may not make an apparent difference in the objective evaluation of disordered voice.

Adult↗
PubMed1995

Vocal efficiency as a function of vocal intensity: a study of children, women, and men.

The effect of vocal intensity on vocal efficiency (VE) for children as compared to adults is investigated, leading to the conclusion that children have different VE values than adults. Vocal efficiency was measured using a logarithmic form of the ratio of the acoustical power radiated from the lips to the aerodynamic power supplied to the glottis for voice production. Sixty subjects participated in this study, including 20 subjects with 10 males and 10 females in each of the three age groups: 4-year-olds, 8-year-olds, and adults. The speech tasks were produced at soft, comfortable, and loud levels, and the VE measurements were mathematically adjusted to account for the sound-pressure level variations within each intensity level among the subject groups. The VE values were compared for age, intensity, and gender differences. The results indicate that 4-year-olds and 8-year-olds have lower VE values than adults. Vocal efficiency increased with vocal intensity for all the age groups, and no significant differences were found for females as compared to males. Factors influencing VE such as maturation of the vocal ligament, amplitude of vocal fold vibration, fundamental frequency, tracheal pressure, as well as the source spectra are discussed.

Adult↗
PubMed1994

Comparison of maximum flow declination rate: children versus adults.

The measure of maximum flow declination rate (MFDR) and location of MFDR provided information regarding the laryngeal mechanism's response to vocal intensity variation as a function of gender and age. Results indicate (a) increases in MFDR values as vocal intensity increases for both children and adults, and (b) higher MFDR values for men versus women and children; no gender difference was found for the children. Results for location of MFDR indicate (a) the location of MFDR to be highest for the loud-intensity production as compared with soft- and comfortable-intensity productions, and (b) the location of MFDR in women to be higher than in men. No gender difference was found for the children.

Adult↗
PubMed1994

Respiratory and laryngeal measures of children and women with bilateral vocal fold nodules.

Simultaneous assessment of laryngeal and respiratory function was completed on 8 children and 10 women with bilateral vocal fold nodules and compared to that of 8 children and 10 women with normal voice production. Laryngeal function for the individuals with bilateral vocal fold nodules was characterized by significantly higher peak, alternating, and minimum glottal airflow. The presence of the high glottal airflow was accompanied by a significantly larger lung volume excursion. Both the children with nodules and those with normal voice showed laryngeal and respiratory function differences when compared to adults. All subject groups demonstrated appropriate laryngeal and respiratory function when increasing intensity from comfortable to loud speech. Simultaneous measurement of laryngeal and respiratory function using a multidimensional analysis of voice production is advocated in the evaluation of voice disorders because it can provide specific information regarding which of the subsystems of voice production are compromised.

Adolescent↗
PubMed1993

Respiratory and laryngeal function of women and men during vocal intensity variation.

Simultaneous procedures for making aerodynamic and kinematic observations of the laryngeal and chest wall systems were used to investigate variations in vocal intensity in normal women and men. Laryngeal results indicate that significant increases of maximum flow declination rate and laryngeal airway resistance and significant decreases in open quotient occur when higher intensity levels are produced. Respiratory results indicate that tracheal pressure, percent rib cage contribution, lung volume, and rib cage volume initiations are higher, and lung and rib cage volume excursions are larger when higher vocal intensity levels are produced. Laryngeal and respiratory function results indicate that some measures are different for women than for men. Mean data support the notion that increases in tracheal pressure are achieved by inhaling to higher lung and rib cage volumes. Individual subject data provide alternative respiratory and laryngeal patterns for changing the shape of the glottal airflow waveform.

Adult↗
PubMed1993

Respiratory and laryngeal measures of children during vocal intensity variation.

Simultaneous aerodynamic, acoustic, and kinematic measurements from the laryngeal and respiratory systems were made in order to study mechanisms for changing vocal intensity. Aerodynamic and acoustic measures include an approximation of open quotient, maximum flow declination rate, alternating glottal airflow, estimated tracheal pressure, sound pressure level, and fundamental frequency. Respiratory measures included lung volume, rib cage, and abdominal displacements. Adults were used as a comparison group to twenty 4-year-olds and twenty 8-year-olds. Laryngeal and respiratory results indicate that speech production differences between the children and adults are based both on size and function. For example, children's absolute anteroposterior diameters of the rib cage are smaller than adults, but their rib cage movement is larger and encompasses a different range during speech breathing. Since children are functionally different than adults, age specific speech production models need to be developed.

Adult↗
PubMed1991

Respiratory and laryngeal function during whispering.

Established procedures for making chest wall kinematic observations (Hoit & Hixon, 1987) and pressure-flow observations (Smitheran & Hixon, 1981) were used to study respiratory and laryngeal function during whispering and speaking in 10 healthy young adults. Results indicate that whispering involves generally lower lung volumes, lower tracheal pressures, higher translaryngeal flows, lower laryngeal airway resistances, and fewer syllables per breath group when compared to speaking. The use of lower lung volumes during whispering than speaking may reflect a means of achieving different tracheal pressure targets. Reductions in the number of syllables produced per breath group may be an adjustment to the high rate of air expenditure accompanying whispering compared to speaking. Performance of the normal subjects studied in this investigation does not resemble that of individuals with speech and voice disorders characterized by low resistive loads.

Adult↗
PubMed1986

Relationship between intraoral air pressure and vocal intensity in children and adults.

Intraoral air pressure (Po) varies as a function of age. Specifically, children produce significantly higher Po values than adults. The higher Po produced by children has been discussed in relation to age-related volumetric differences of the subglottal and vocal tract, to lung compression differences, and to the fact that children's "comfortable" speaking level might exceed that of adults. The present study was undertaken to evaluate the hypothesis that children (vs. adults) and women (vs. men) produce higher Po values when sound pressure level (SPL) is held constant. Measurements were made of Po generated by children and adults during a connected speech task completed at three intensity levels. The findings of the study indicated that peak Po values increased as vocal intensity increased for all subject groups, peak Po values were higher for voiceless stops than for voiced stops, and peak Po values were not significantly different for adults than for children or for men than for women. These results were interpreted to show that despite physical and physiological differences between male and female, and between adult and child vocal tracts, all groups use the same Po mechanism for achieving a given vocal intensity level.

Adult↗
PubMed1985

Effects of monitoring vocal intensity on oral air flow in children and adults.

The purposes of the present investigation were (a) to determine whether child and adult oral air flow data were parallel across two monitoring methods, (b) to determine whether an instruction to speak at a "comfortable effort level" resulted in greater variability of peak oral air flow (Vo) than visual monitoring of vocal intensity level, and (c) to expose possible sources of variation introduced by visual monitoring. Peak Vo from children and adults was measured for stops and fricatives in connected speech during a "comfortable-effort-level" task and during a visually monitored vocal intensity task. The lack of an age-by-monitoring effect in the analysis of variance (ANOVA) showed that child and adult data were parallel. The nonsignificance of F-Max scores for testing across-subject variability showed that the natural maintenance of a comfortable intensity level did not produce greater Vo variance than visual monitoring. This result was extended by a within-subjects comparison: visual monitoring induced subjects to alter their Vo production for some phonemes. Although the Vo of voiced consonants increased only slightly from comfort-level to visual monitoring, the Vo of voiceless consonants increased more sharply. Thus, visual monitoring does not decrease Vo variability, and does introduce spurious Vo values for some consonants.

Adult↗