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Biomedical subjects

E Vilkman

Publications and source records attributed to E Vilkman.

30 records · Page 2Linked to original sources
PubMed1995

Phonation into a tube as a voice training method: acoustic and physiologic observations.

Phonation into narrow glass tubes has been used as a voice training method. The present study examined phonatory and voice quality during and after tube phonation. The methods used were (a) electromyography with surface electrodes, (b) a dual-channel electroglottography from which the vertical larynx position was derived and (c) inverse filtering of the acoustic signal of vowel samples produced before and immediately after the exercise. Phonation into a tube seemed to cause a tendency to heighten the vertical laryngeal position. For female subjects (n = 3) the tube exercise tended to lead to increased vocal effort in vowel production after the exercise and, in contrast, to a tendency for a more relaxed voice production for the males (n = 2).

Adult↗
PubMed1988

Fragile X speech phonology in Finnish.

Fragile X syndrome is a recently discovered relatively common syndrome linked with an anomaly of the X chromosome and causing handicaps of cognitive development especially in males. In the present phonological analysis we will discuss the sound patterns of two Finnish fragile X speakers, a five (borderline intelligence)- and an eight (mildly mentally retarded)-year-old boy. The fragile X syndrome is not necessarily linked with any anomalies of speech organs. The subjects could produce all Finnish speech sounds in isolated test words. However, in the present samples of connected speech they exhibited general dysphonology. What is noteworthy is that their phonological error patterns resembled each other to a great extent. Among the common features were the tendencies to substitute and omit phonemes. As for vowels, our results showed about one-half of the errors to be omissions. Labiality and quantity oppositions were quite resistant to substitution. Most substitution errors of place of consonants occurred in dentals. As for the feature of manner, /r/ and /s/ were the phonemes most prone for substitution. A tendency toward spirantization or /h/ sation was common for both patients. The number of additions was clearly lower than has been reported for English-speaking developmentally dyspraxic children and also for Finnish Broca's aphasics. The speech problems of our patients seemed to indicate higher level motor encoding problems of linguistic information rather than peripheral articulatory deficits.

Articulation Disorders↗
PubMedDate not supplied

Voice problems at work: A challenge for occupational safety and health arrangement.

In modern societies about one third of the labor force are working in professions in which voice is the primary tool. Voice problems are common in general, but they are even more common in professions in which there is heavy vocal loading, i.e. professions that do not only require prolonged voice use, but also involve extra loading factors such as background noise, long speaking distance, poor room acoustics, lack of adequate equipment like voice amplifiers etc. School and kindergarten teachers can be considered to represent professions with heavy vocal loading. The occupational safety and health arrangements of voice and speech professionals are poorly developed as compared to many other professions. However, the existing legislation could be used to support efforts to improve the working conditions of this large but heterogeneous group.

Humans↗
PubMedDate not supplied

Evidence of the significance of secondary excitations of the vocal tract for vocal intensity.

In the production of voiced speech the main excitation of the vocal tract occurs during the glottal closing phase when the rate of change of the flow reaches its absolute maximum. The level of this maximum, the negative peak amplitude of the differentiated glottal flow, correlates strongly with sound pressure level. This study presents a straightforward method that yields a numerical value to characterize the effect of the main excitation on vocal intensity. The method, energy ratio by modified excitation (ERME), utilizes the glottal flow and the vocal tract transfer function estimated by inverse filtering and it synthesizes two signals based on the linear source-filter theory. The first sound is produced using the glottal flow given by inverse filtering per se. The second signal is synthesized by removing the main excitation from the differentiated flow. ERME is defined as the ratio between the energy of the first synthesized signal and the energy of the second one. It is shown that when the loudness of speech increases, the value of ERME first rises but in the case of very loud voices it starts to decrease. Hence, ERME shows that effects of secondary excitations of the vocal tract that occur during glottal opening become important in the production of very loud voices.

Adult↗
PubMedDate not supplied

The effects of post-loading rest on acoustic parameters with special reference to gender and ergonomic factors.

It is a common experience that vocal quality changes during a break in vocal loading. The purpose of the present study was (1) to analyse the effects of a short post-loading vocal rest in terms of changes in a large variety of voice parameters and (2) to assess the possible effects of gender and exposure factors on these changes. The voices of a randomly chosen group of 40 female and 40 male young students were loaded by having them read aloud a novel. Two sets of voice samples were recorded: a post-loading sample after three times 45-min vocal loading during the morning and a post-resting sample after a 45-min lunch break. The material recorded consisted of /pa:ppa/ words produced normally, as softly and as loudly as possible in this order. The long /a/ vowel of the test word was inverse-filtered to obtain the glottal flow waveform. Time-domain parameters of the glottal flow [open quotient, closing quotient (ClQ), speed quotient (SQ), fundamental frequency (F(0))], amplitude-domain parameters of the glottal flow [glottal flow, minimum of the first derivative of glottal flow, amplitude quotient (AQ)], intraoral pressure and sound pressure level (SPL) values of the phonations were analysed. Voice range profiles and the singer's formant (g/G, a/A, c(mid R:)/c, e(mid R:)/e, g(mid R:)/g for females/males) of the loud phonations were also measured. The subjects were divided into eight exposure groups (5 females and 5 males per cell) according to different combinations of the following exposure factors: (1) low (25 +/- 5%) or high (65 +/- 5%) relative humidity of ambient air, (2) low [<65 dB(A)] or high [>65 dB(A)] speech output level during vocal loading and (3) sitting or standing posture during vocal loading. Statistically significant differences between the post-loading and post-resting samples could be observed in many parameters (the values of intraoral pressure in the soft phonations decreased, the values of SPL and SQ in the normal phonations decreased and the values of AQ, F(0) and ClQ in the normal phonations increased). Most of the differences reflected a shift towards softer phonation. Gender and exposure factors also had significant effects.

Adolescent↗
PubMedDate not supplied

Vertical hyoid bone displacement and fundamental frequency of phonation.

Vertical displacement of the hyoid bone as well as its effects on F0 were studied using five excised human larynges. Cranial force introduced to the hyoid bone caused a widening of the vestibule of the larynx, enlargement of the laryngeal ventricles, abduction of the ventricular folds, heightening of the epiglottis and slight abduction of the vocal folds. The displacement (X +/- SD) of the anterior part (corpus) of the bone was 8.0 +/- 5.2 mm and of the posterior part, 22.2 +/- 6.1 mm with a 10 N force. The difference was statistically significant and was found to depend mainly on the tight middle hyothyroid ligament. The cranial force displacing the hyoid bone invariably showed a positive relationship with F0. The F0 changes were statistically significant but relatively small (X +/- SD): 8 +/- 8.4 Hz (about 10%) with an intact hyothyroid ligament. When the subglottal pressure was low, a change in the vibratory pattern of the vocal folds was found in several specimens. The F0 changes found in the present study are too small to explain alone the differences in the so-called intrinsic F0 of vowels. However, they are believed to contribute to this phenomenon.

Cadaver↗