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Biomedical subjects

T J Hixon

Publications and source records attributed to T J Hixon.

At least 19 recordsLinked to original sources
PubMed2001

Effects of abdominal trussing on breathing and speech in men with cervical spinal cord injury.

Abdominal trussing constitutes an inward fixation of the abdominal wall. In the context of speech habilitation/rehabilitation, it is sometimes used to supplant, in part, the function of a paralyzed or paretic abdominal wall. A paralyzed or paretic abdominal wall may be found in individuals with cervical spinal cord injury or in individuals with other neurologic disorders, such as muscular dystrophy. This research was designed to study the effects of trussing as a dinical treatment. A study was designed to systematically and precisely place the abdominal wall at one position (50% inward) to study the effects of trussing (as compared to an untrussed condition) on lung volume and oral reading in three men with cervical spinal cord injury (C5-C6). Results showed that abdominal trussing increased vital capacity, realized via an increase of inspiratory capacity, presumably by optimization of the function of the diaphragm. With the increase in inspiratory capacity, longer utterance duration for oral reading was observed. With increased utterance duration, more syllables were produced per utterance, and pauses occurred at appropriate linguistic locations. Oral reading samples for trussed and untrussed conditions were submitted to preference judgment by a group of 10 judges. For two of the three men studied, oral reading during trussing was preferred because of longer phrases and pauses taken at suitable linguistic boundaries. The findings from this study support clinical impressions that abdominal trussing may be useful in improving speech in individuals with a paralyzed or paretic abdomen whose breathing function for speech is diminished.

Abdominal Muscles↗
PubMed1997

Vocalization and breathing during the second and third years of life.

Vocalization and breathing were studied in 40 healthy young children, including 5 boys and 5 girls at each, of ages of 18, 24, 30, and 36 months. A variable inductance plethysmograph was used to obtain estimates of volume changes of the rib cage, abdomen, and lung, as well as estimates of selected temporal features of the breathing cycle. Results indicated that breathing behavior was influenced by height and age, but not by vocalization type or sex. Such behavior was found to be highly variable, demonstrating that these young children had multiple degrees of freedom of performance available to accomplish the aeromechanical drive required.

Abdomen↗
PubMed1996

Vocalization and breathing during the first year of life.

Vocalization and breathing were studied in 40 healthy infants, including five boys and five girls each at ages 5 weeks, 2.5 months, 6.5 months, and 12 months. Breathing was monitored through the use of a variable inductance plethysmograph that enabled estimates of the volume changes of the rib cage, abdomen, and lung, as well as estimates of selected temporal features of the breathing cycle. Four vocalization types were studied intensively. These included cries, whimpers, grunts, and syllable utterances. Breathing behavior was highly variable across the four vocalization types, demonstrating the degrees of freedom of performance available to the infant to accomplish the aeromechanical drive required. Such behavior was influenced by body length, body position, and age, but not by vocalization type and sex. The protocol established is a useful tool for observing the natural course of the emergence of vocalization and breathing during the first year of life.

Age Factors↗
PubMed1995

Perspectives on the Edinburgh study of speech breathing.

This article offers critical perspectives on the Edinburgh study of speech breathing reported in this journal (Draper, Ladefoged, & Whitteridge, 1959) and elsewhere (Draper, Ladefoged, & Whitteridge, 1960; Ladefoged, Draper, & Whitteridge, 1958). These perspectives concern: (a) errors in establishing a backdrop of mechanical information; (b) discrepancies between data and statements about them; (c) counterpredictive features between data and other knowledge about breathing; and (d) inadequacies in acquiring, portraying, and interpreting electromyographic information relative to the muscular contributions of different parts of the breathing apparatus.

Air Pressure↗
PubMed1993

Speech breathing in Parkinson's disease.

Breathing was investigated in 14 male subjects with Parkinson's disease and 14 healthy male control subjects. Kinematic, spirometric, acoustic, and pressure data were used to assess function during resting tidal breathing, reading aloud, and monologue production. Data were collected at two times during the drug cycle for subjects with Parkinson's disease. During resting tidal breathing, subjects with Parkinson's disease, on average, had a faster breathing rate, greater minute ventilation, and smaller relative contribution of the rib cage to lung volume change than did healthy control subjects. During speech breathing, rib cage volume was smaller and abdominal volume was larger at initiation of the breath groups for subjects with Parkinson's disease than for healthy control subjects. Subjects with Parkinson's disease produced fewer words and spent less time producing speech per breath group and tended to have a faster interpause speech rate than did healthy control subjects. There was no difference between groups for duration of inspirations between speech breath groups. Oral pressure was lower for subjects with Parkinson's disease but estimated tracheal pressure did not differ between the two subject groups. Few differences were found between the two times in the drug cycle for resting and speech breathing. Results provide indirect evidence for reduced relative compliance of the rib cage to the abdomen for subjects with Parkinson's disease as compared to healthy control subjects. In addition, the results support the possibility of inadequate valving of the air stream for subjects with Parkinson's disease.

Adult↗
PubMed1993

Effect of lung volume on voice onset time (VOT).

This investigation was designed to test the hypothesis that voice onset time (VOT) varies as a function of lung volume. Recordings were made of five men as they repeated a phrase containing stressed /pi/ syllables, beginning at total lung capacity and ending at residual volume. VOT was found to be longer at high lung volumes and shorter at low lung volumes in most cases. This finding points out the need to take lung volume into account when using VOT as an index of laryngeal behavior in both healthy individuals and those with speech disorders.

Adult↗
PubMed1992

Age and laryngeal airway resistance during vowel production in women.

An investigation was conducted to determine if laryngeal valving economy, as reflected in measures of laryngeal airway resistance during vowel production, differs with age in women. Seventy healthy women were studied, 10 each at age 25, 35, 45, 55, 65, 75, and 85 years. Results indicated that laryngeal airway resistance did not differ significantly with age, although it was noted that the 45-year-old women generally had lower laryngeal airway resistance values. This pattern of function differs from that observed in men (Melcon, Hoit, & Hixon, 1989). Discussion of findings includes consideration of factors that might influence laryngeal function during speech production in women. Clinical implications are offered.

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↗
PubMed1990

Speech breathing in children and adolescents.

An investigation was conducted to elucidate the nature of speech breathing in children and adolescents and to determine if sex and age influence performance. Eighty healthy boys and girls representing four age groups (7, 10, 13, and 16 years) were studied using helium dilution to obtain measures of subdivisions of the lung volume and using magnetometers to obtain measures of resting tidal breathing and speech breathing. Results for subdivisions of the lung volume and resting tidal breathing revealed sex- and age-related differences, most of which were attributable to differences in breathing apparatus size. Results for speech breathing indicated that sex was not an important variable, but that age was critical in determining speech breathing performance. The most substantial differences were between the 7-year-old group and older groups. These differences were characterized by larger lung volume, rib cage volume, and abdominal volume initiations and terminations for breath groups, larger lung volume excursions per breath group, fewer numbers of syllables per breath group, and larger lung volume expenditures per syllable for the 7-year-old group compared to older groups. In most respects, speech breathing appeared adultlike by the end of the first decade of life. Clinical implications regarding these findings are offered.

Adolescent↗
PubMed1989

Age and laryngeal airway resistance during vowel production.

An investigation was conducted to determine if laryngeal valving economy, as reflected in measures of laryngeal airway resistance during vowel production, varies across adulthood. Sixty healthy men were studied, 10 from each of six age groups--25, 35, 45, 55, 65, and 75 years (+/- 2 years). Results indicated that there are age-related differences in laryngeal airway resistance during vowel production and that these differences are characterized by a lower mean resistance in 75-year-old men than in younger men of the ages studied. This finding provides insight into the impact of age on laryngeal function and has important implications for the evaluation and management of men with voice disorders.

Adult↗
PubMed1989

Speech breathing in women.

Thirty healthy women representing three age groups (25, 50, and 75 years) were studied with respect to general respiratory function and speech breathing. Certain subdivisions of the lung volume differed with age: vital capacity, expiratory reserve volume, and residual volume. Speech breathing also differed with age and was characterized by differences in lung volume excursion, rib cage volume excursion, lung volume initiation, rib cage volume initiation, and lung volume expended per syllable. Age-related differences in general respiratory function and speech breathing are discussed in relation to possible underlying mechanisms. In addition, patterns of function observed in women are compared to those observed in men in an earlier investigation (Hoit & Hixon, 1987). Clinical implications are drawn regarding the evaluation and management of speech breathing disorders.

Adult↗
PubMed1988

Abdominal muscle activity during speech production.

Abdominal muscle activity was investigated during resting tidal breathing and speech production in upright and supine body positions in five male and five female young adult subjects. Results showed that patterns of abdominal electromyographic (EMG) activity were highly dependent on body position. Data for resting tidal breathing resembled those of previous investigations and revealed one sex-related finding. Data for speech production indicated that the lateral region of the abdomen was highly active in the upright position and occasionally active in the supine position. In the upright position, lateral EMG levels during speech production were characterized by generally higher levels in the lower than upper lateral sites and were almost always higher than during resting tidal breathing. In the supine position, EMG levels during speech production occasionally exceeded those associated with resting tidal breathing but were substantially lower than those associated with upright speech production. Abdominal EMG activity was most prevalent during loud speech production and during speech produced at low lung volumes. Findings are discussed in relation to current knowledge of respiratory mechanics and neural control.

Abdomen↗
PubMed1987

Age and speech breathing.

Thirty healthy men representing three widely different age groups (25, 50, and 75 years) were studied with respect to general respiratory function and speech breathing. Subdivisions of the lung volume were found to differ with age and most markedly so for measures of vital capacity and residual volume. Speech breathing also was found to differ with age and was characterized by differences in lung volume excursion, rib cage volume initiation, number of syllables per breath group, and lung volume expended per syllable. Age-related differences in general respiratory function and speech breathing are discussed in relation to possible underlying mechanisms. In addition, implications are drawn regarding the evaluation and management of individuals with speech breathing disorders.

Adult↗
PubMed1986

Body type and speech breathing.

Diameter changes of the rib cage and abdomen were recorded during tidal breathing and speech production in 12 adult male subjects grouped on the basis of prominence on three body type components: relative fatness, relative musculoskeletal development, and relative linearity. Data were charted to solve for lung volume, volume displacements of the rib cage and abdomen, and muscular mechanism. Tidal breathing differed across subject groups with regard to depth, rate, and chest wall configuration. Subjects rated high in relative fatness breathed deeper, slower, and with a greater chest wall deformation from relaxation than did other subjects. Speech breathing differed across subject groups with regard to relative volume contributions of the rib cage and abdomen, abdomen excursions, rib cage paradoxing, and chest wall configuration. Subjects rated high in relative fatness demonstrated substantial abdomen contributions to lung volume change, large abdomen excursions, frequent rib cage paradoxing, and marked chest wall deformations from relaxation. By contrast, subjects rated high in relative linearity demonstrated large rib cage contributions to lung volume change, small abdomen excursions, and slight chest wall deformations from relaxation. Subjects rated high in relative musculoskeletal development generally represented a mixture of characteristics of the other two subject groups in their speech breathing performance. Functional differences are discussed in relation to possible underlying mechanism and inferences are drawn concerning evaluation and management of individuals with speech breathing disorders.

Adolescent↗
PubMed1985

Respiratory kinematics in classical (opera) singers.

Anteroposterior diameter changes of the rib cage and abdomen were recorded during respiratory, speaking, and singing activities in six adult male subjects, all baritones with extensive classical singing training and performance experience. Data were charted to solve for lung volume, volume displacements of the rib cage and abdomen, and inferred muscular mechanisms. Separate major roles were inferred for different parts of the respiratory apparatus in the singing process. The abdomen served as a posturing element that mechanically tuned the diaphragm and rib cage to optimal configurations for performance. The rib cage operated as a pressure-flow generating element that regulated expiratory drive. And, the diaphragm functioned as an inspiratory element devoted to reinflating the lungs. Subjects' descriptions of how they thought they breathed during singing bore little correspondence to how they actually breathed. Implications for the training of singers are offered.

Abdominal Muscles↗
PubMed1983

Speech production with flaccid paralysis of the rib cage, diaphragm, and abdomen.

Anteroposterior diameter changes of the rib cage and abdomen were measured during breathing maneuvers and utterance activities in an adult subject with flaccid paralysis of the rib cage, diaphragm, and abdomen. Data were charted to solve for lung volume, volumes of the rib cage and abdomen, chest wall configuration, and inferred neck muscle actions. Free breathing was accomplished through an alternate waxing and waning of neck muscle drive or through step-wise glossopharyngeal pumping. Connected speech was performed in breath groups begun by neck gestures that "cocked" the breathing apparatus and stored recoil energy in it for use during ensuing expirations. Some breath groups were also extended through intermittent glossopharyngeal pumping. Connected speech was characterized by frugal control of the air supply through compensatory adjustments in the larynx and upper airway. Compensations involved in the breathing maneuvers and utterance activities are described, and consideration is given to two understandings--the human potential for functional restoration and the clinical evaluation and management of individuals with neuromuscular impairment.

Abdomen↗