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Biomedical subjects

M N Kotby

Publications and source records attributed to M N Kotby.

At least 19 recordsLinked to original sources
PubMed1996

Multidimensional analysis of speech of hearing impaired children.

The character of speech of hearing impaired children was evaluated via multidimensional protocol in order to provide sensitive and quantitative measures of assessment. 20 children (9 males and 11 females) with moderate to severe hearing impairment, were studied. The protocol of assessment included auditory perceptual assessment (APA) (documented by high fidelity audiorecording), audiological assessment, formal testings, aerodynamic assessment and acoustic analysis. APA showed addected vowels (90%), affected suprasegmental phonology; rate (60%), stress (80%), tonality (85%); decreased resonance (15%); affected voice (45%) and affected intelligibility (85%). Aerodynamic results showed highly significant increase in the subglottic pressure, highly significant decrease in glottal resistance and glottal efficiency, indicating a possible breakdown in respiratory, phonatory and articulatory coordination. Spectrographic results showed significant increase in the syllable duration; vowel duration and sentence duration. Visi-Pitch results showed highly significant increase in the intensity, significant decrease in the maximum fundamental frequency (Fo) and highly significant decrease in the percent pause. The accoustic findings may represent a quantitative correlate to some of the subjective observations of APA.

Audiometry↗
PubMed1995

Mechanism of glottic closure in a model of unilateral vocal fold palsy.

The effect of extrinsic laryngeal muscles on the position of the paralyzed vocal fold (VF) was analyzed in 13 adult human larynges. Fresh specimens were suspended within a specially constructed frame designed to reproduce the three-dimensional position of the VF, and to allow for simulation of laryngeal muscle action, in five successive experiments resembling: 1) complete vagal paralysis and contralateral adduction, 2) laryngeal elevation added, 3) vocal fold stretching added, 4) contralateral laryngeal tilting added, and 5) ipsilateral cricothyroid muscle activation added. We observed an incremental narrowing of the middle and posterior glottic gaps from 3.9 mm and 6.8 mm respectively in experiment 1 to 1.1 mm and 1.9 mm in experiment 5. Glottic closure in the final experiment was associated with rotation of the glottis to the "paralyzed" side in the axial plane, and contralateral laryngeal tilting in the coronal plane. We show that extrinsic laryngeal muscles can help to close a paralytic gap; crossing of the contralateral VF past the midline was not observed in any of the experiments.

Adult↗
PubMed1993

The accent method of voice therapy: effect of accentuations on FO, SPL, and airflow.

The effect of the increased flow rate (delta U) in response to the Accent Method exercises on fundamental frequency (FO) and sound pressure level (SPL) was studied in three subjects (professionally trained, trained, and untrained in this method). In all the subjects, the rhythmic accentuated exercises produced a variable degree of increase in FO (delta FO) and SPL (delta SPL). The professionally trained subject showed greater delta FO and delta SPL in response to the delta U in the fastest tempo, which requires higher skills. Both trained subjects showed a greater correlation between delta U and both delta SPL and delta FO, as well as between delta FO and delta SPL, as compared to the untrained subject. The effects of the accentuated exercises on FO and SPL in response to the increased airflow rate (delta U) thus appear to demonstrate the treating effectiveness of the Accent Method.

Adult↗
PubMed1993

Fundamental frequency stability in functional dysphonia.

Functional dysphonia is a term applied to voice disorders for which there is an absence of apparent structural change in the larynx. The aim of this work was to investigate how functional dysphonia may differ acoustically from other types of dysphonia. Fundamental frequency profiles for steady vowels were generated using a software program called GLIMPES (Glottal Imaging by Processing External Signals). The fundamental frequency variations were found to be unimodal in normal individuals. In contrast, the variations for dysphonic patients were sometimes bi-modal or multi-modal due to the presence of subharmonics or low-frequency modulations. The appearance of these patterns was generally related to the severity of the dysphonia rather than to its etiology.

Adolescent↗
PubMed1992

Pattern of gross displacement of the vocal fold in adduction and abduction movements.

The pattern of gross displacement of the vocal fold during adduction and abduction was studied in 4 adult fresh human larynges (2 males and 2 females). Markers were placed on specific sites along the edge of the vocal fold. Preliminary observations showed upward and lateral movement of the free edge during abduction. The vocal fold as a whole glides into and fills the cavity of the laryngeal ventricle. To quantify this observation 14 larynges (8 males and 6 females) were studied, using a technique designed to measure vertical and horizontal displacement of the vocal fold. An average of a 1.34 mm elevation and 4.43 mm lateral excursion were observed at midvocal fold level. A model for studying the pattern of vocal fold abduction is suggested and discussed.

Adult↗
PubMed1991

Histo-anatomical structure of the human laryngeal ventricle.

A study of the microstructure of the human laryngeal ventricle and ventricular band was carried out on 20 human larynges in an attempt to up-date and elucidate the function of these structures. Celloidin and paraffin whole organ coronal serial sections were studied to clarify the epithelial, glandular as well as muscular structures of the ventricle and ventricular band. The present study showed that the superior thyro-arytenoid muscle was bilaterally present in 80% of cases. On the other hand, the ventricularis muscle was bilaterally present in 95% of cases. These ventricular muscular elements have been reported differently in the literature. The functional significance of these variations are discussed. The opening of the saccule into the ventricle is guarded anteriorly by the ventriculo-saccular fold. This fold was present in 19 out of 20 larynges. Neither the percentage of its presence, nor its orientation to the saccular opening has been reported in the literature. The function of this structure is discussed in the light of the present data.

Adolescent↗
PubMedDate not supplied

Ultrastructural features of vocal fold nodules and polyps.

Earlier investigation did not show any clear distinctive pathological features that differentiate vocal polyps from vocal nodules. The light microscopic distinctive features between the two lesions point in the direction of a more pronounced epithelial reaction and a more fibrous stromal change in vocal nodules. In the present study, 19 vocal polyps and 11 vocal nodules were subjected to ultrastructural examination aiming at finding distinctive features that may be pathognomic for each of these clinically distinct entities. The study was carried out by EM Philips 400 T. The results demonstrate that nodules showed epithelial changes in the form of gaping of the intercellular junctions and absence of the basal lamina in parts. These changes are less apparent in polyps, whereas the stromal changes are more pronounced and varied. The significance of these results and their interpretation are discussed.

Adult↗