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Biomedical subjects

J Pesák

Publications and source records attributed to J Pesák.

At least 19 recordsLinked to original sources
PubMed2000

Decreased copper level in the blood serum of male stutterers and the occurrence of the vibratio brevis phenomenon.

The blood serum copper level and the phonation start were investigated in sixteen male subjects with developmental stuttering (mean age = 25.8 years). A statistically significant decrease in blood serum copper level was revealed in the stutterers under study. The differences between their mode and mean values and that of the control group were 4.6 mumol/l and 3.1 mumol/l, respectively. The negative linear regression between the copper level in serum and the vibratio brevis phenomenon was registered in the stutterers under study. A decreased copper level can be involved in the biochemical abnormalities of male developmental stutterers and it can be included among the factors participating in pathophysiology of an uncertain phonation start.

Adolescent↗
PubMed1998

[The voice and speech].

Biophysics is the science comprising the sum of biophysical disciplines describing living systems. It also includes the biophysics of voice and speech. The latter deals with physiological acoustics, phonetics, phoniatry as well as logopaedics. In connection with the problems of voice and speech, including also their teaching problems, a common language is often being sought for appropriate to all the interested scientific branches. As a result of our efforts aimed at removing the existing barriers we have tried to set up a University Society for the Study of Voice and Speech. One of its first activities was also, besides other events, the realization of a videofilm On voice and speech.

Acoustics↗
PubMed1998

[An unknown role of the ligament layer of the conus elasticus during phonation?].

The investigation of the intoning vocal folds with the help of Cermák's mirror in as early as the 19th century and also their ensuring records by means of a stroboscopic film have discovered the fact that the front vibrating part of the vocal folds becomes shortened in high frequencies. This information has been ignored since about the 60ies of the 20th century. The aim of the present paper is to verify the shortening of the front vibrating part of the vocal folds and to recall this fact. Approximately in two octaves we have measured the virtual images of a video stroboscopic record. Our results are comparable with similar measurement resulting from stroboscopic investigation and confirm the hypothetic role of the ligament layer conus elasticus.

Adult↗
PubMed1994

Vocal breaks from the modal to falsetto register.

The study offers measurements of the vocal breaks occurring from the modal to the falsetto register in an untrained barytone. The breaks were achieved by increasing the expired airflow. An analogy with a labial pipe served as a help. The voice phenomena were divided into three regions. In the region of low modal frequencies (A-e) a simultaneous sounding of both the modal and falsetto registers was investigated. This was registered perceptually as vocal roughness. Under special conditions a subharmonic tone was produced. In the medium frequency region (e-g1) the vocal breaks occurred. The break intervals occupied the mean value of about a quint on the modal tone e. With increasing modal frequency, the break intervals decreased. In the high-tone region (g1-e2) only the falsetto register could be produced.

Humans↗
PubMed1994

A historical perspective of some occupationally related diseases of women.

The study of occupational diseases among women has been minimal, and when observations of adverse health effects have been made, they often have been obscured, ignored, or mismanaged. Occupational exposures of women to beryllium, benzene, and vinyl chloride serve as past examples of indifference to the plight of women in the workplace. The lack of regulation for waste anesthetic gases and antineoplastic drugs to protect health care workers and veterinarians indicates that this indifference continues today.

Anesthetics↗
PubMed1993

Incoordination of the phonation start in individuals with balbuties.

We studied the effect occurring in close proximity before the phonation start and give an account of the microdramas taking place upon the glottis immediately before the phonation start in a group of individuals suffering from balbuties (60 children and adolescents from 9 to 14 years of age) and an equally large control group suffering from no such speech defect. In the group of children and adolescents with balbuties only less than 4% of the cases showed undisturbed regular phonation starts, whereas in the control group it was almost as much as 90%.

Adolescent↗
PubMed1993

Intralaryngeal pressure conditions and a membranophonic interpretation of voice production.

The article gives one of the possible explanations of the complex event which may be registered when recording the vibrations from the thyroid cartilage in ventral-dorsal direction during phonation and approximately in two octaves of the modal voice. The alternating displacement of the vibrating thyroid cartilage is caused apparently by the alternating increase and decrease in the resulting pressure force acting upon the vocal folds. For the time being the adduced hypothesis does not take into consideration specific reflex activity, in spite of the fact that it can probably be expected with lesions of the nervous system on the basis of the typically changed manifestations.

Air Pressure↗
PubMed1993

Kinematics of the prominentia laryngea at phonation onset.

The present paper deals with the problem of the temporal relations between the beginning of the glottal opening at phonation onset and the thyroid cartilage kinematics at the prominentia laryngea. Furthermore, some differences in comparison with a stationary phonation event are discussed here.

Humans↗
PubMed1991

Tetanic syndrome questionnaire in stutterers.

Clinical symptoms of 32 stutterers--schoolchildren of 14-year average age were evaluated according to the questionnaire containing 45 complaints of tetanic syndrome. We found headache, fatigue, anxiety, paresthesias and hypothermia of limbs in 30 per cent of this group. More than 80 per cent of the patients had positive Chvostek sign and 60 per cent had positive ischemic and hyperventilation tests.

Adolescent↗
PubMed1990

Special structure of the skeletal muscle musculus vocalis.

Histopathological examination of 12 vocal muscles reveals special structure of this muscle which the vocal folds are based upon. The bundles of the muscle fibres passing in two planes perpendicular to each other alternate with stripes of the interstitium, seromucinous glandules and connective tissue septa with elastic fibres separating the groups of cross-striated muscle fibres of various diameters. It represents a physiological variety of the skeletal muscle structure conditioned by its function.

Adult↗
PubMed1990

[Voice production is the result of a reflex process].

In phonation and partly also in intonation the vibration proper of vocal cords is accompanied by the active participation of a neuromuscular reflex. A vocal fold as an oscillator is connected with the thyroid, i.e. the resonator, by a firm mechanical bond. Increased demands upon the tightness of this bond occur during speech. Thus the defective mechanism of the radiation of energy is offered as a contribution to the explanation of the etiology of stuttering.

Humans↗