M N Kotby

Ain Shams University, Al Qāhirah, Al Qāhirah, Egypt

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Publications (22)13.73 Total impact

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    ABSTRACT: Despite the presence of a number of good publications during the past two decades, the posterior glottis (PG) is still not clearly appreciated in clinical laryngological practice. This study focuses on searching the literature to find out the present day awareness of the PG, as well as highlighting some of its clinical features. The investigation proceeds with two main sections: (1) critical analysis of the literature on the PG during the last 50 years (2) describing the clinical appearance and behavior of the PG in 100 normal subjects. Results of section 1 illustrate the limited awareness in the literature of the existence of PG as a distinct part of the human larynx. Results of section 2 illustrate some misconcepts related to the PG as inter-arytenoid pachydermia, change of voice with lesions in the PG. Discussion elaborates on the significance of the findings and attempts to clarify certain misconcepts about the PG, its structure, function, and clinical features. In the light of the data collected from the literature regarding the dimensions of the PG, a set of recommendations were proposed regarding the optimal sizes of the endotracheal tubes in both sexes.
    Archives of Oto-Rhino-Laryngology 05/2012; 269(11):2373-9. DOI:10.1007/s00405-012-2053-0 · 1.61 Impact Factor
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    ABSTRACT: Animal models for training of surgical skills were widely used for a long time in the education of medical practitioners. It is recognized, however, that endolaryngeal microsurgery requires highly refined skills to handle the delicate structures of the vocal folds under the microscope. The availability of fresh human laryngeal specimens is markedly restricted by legal and hygienic issues. The aim of this work was to report on the design of a feasible and effective model to provide the much needed skills in an animal laryngeal model that is as close as possible to the human vocal fold structure. In the initial phase of the research, three animal larynges were studied: porcine/pig, bovine/calf, and ovine/sheep larynges. The pig/porcine larynx was chosen for this experimental training model because it closely resembled the human laryngeal/glottal configurations. A study was carried out on 10 porcine/pig larynges to assess the dimensions of the glottis and study the histology of the layered structure of the vocal fold. The study was pursued to confirm the resemblance of this animal specimen to the human vocal fold. A wooden box with a black finished interior was prepared with an acrylic bed at its floor. This bed allows placement of the porcine/pig larynx. The design of the box allows the endoscopic exposure of the porcine/pig larynx through a rubber diaphragm. The darkness and confinement of the box, apart from the light of the endoscope, approximates the situation in live endoscopy. The operating microscope is then used to expose the glottis. Routine fine microlaryngeal instruments were used for training in the prescribed skills.
    Journal of voice: official journal of the Voice Foundation 01/2012; 26(3):351-7. DOI:10.1016/j.jvoice.2011.04.002 · 0.94 Impact Factor
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    ABSTRACT: Most scholars, old and modern, agree that the vowel system of the Arabic language is composed of 3 vowels only, namely /i/, /ε/ and /u/. The spoken Cairo dialect suggests that there are 6 identifiable vowels, with a short and long variant for each. The aim of this study is to test the validity of the notion that there are 6 × 2 distinct vowels, with a more central one. Spectral analysis was used to measure F(1) and F(2) for the vowels of 14 real words. Data was collected from 60 healthy adult informants, 30 males and 30 females. They were native Egyptians speaking the colloquial Cairene dialect. The values of the 6 long and short vowels plus the central one are presented. A significant difference was found between each of them. The long and short vowels differed only in the duration but did not differ in their formant values. The study illustrates the distinctive features of the vowels of the Arabic language. Each of the 7 vowels represents a distinct entity. This will have important implications in assessment and management of language, speech and voice disorders in children and adults.
    Folia Phoniatrica et Logopaedica 10/2010; 63(4):171-7. DOI:10.1159/000316323 · 0.55 Impact Factor
  • M N Kotby, L K Haugen
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    ABSTRACT: Muscle and nerve stimulation experiments have been carried out on a series of 12 human larynges with malignant disease of essentially unilateral involvement. In the course of total laryngectomy tests were applied to several internal and external laryngeal muscles as well as the recurrent and superior laryngeal nerves on both sides. Muscle stimulation experiments were carried out also on the recently excised larynx. The effects were studied on the relatively unaffected side, where vocal fold mobility was apparently free. Stimulation of the sternothyroid muscle constantly led to dilatation of the laryngeal inlet and widening of the glottis. Abduction of the vocal fold occurred only in 50% of the cases (3 out of 6) on stimulation of the posterior crico-arytenoid muscle. Various explanations of these phenomena are discussed. Stimulation of the recurrent laryngeal nerve produced adduction of the vocal fold to the paramedian plane. In two experiments out of seven, however, stimulation of the recurrent laryngeal nerve led to abduction of the vocal fold. In no instance could repeated stimulation of this nerve produce two different responses, abduction and adduction, in the same experiment. Evidence is presented of the existence of both sensory and motor bundles in the recurrent laryngeal nerve. Adduction of the vocal fold to an intermediate position was noticed on stimulation of the superior laryngeal nerve. This was shown to be mediated through its external branch, the effector muscle being the crico-thyroid.
    Acta Oto-Laryngologica 02/2010; 70(5):419-27. DOI:10.3109/00016487009181906 · 0.99 Impact Factor
  • M N Kotby, L K Haugen
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    ABSTRACT: Some salient problems concerning the diagnosis and prognosis of vocal fold mobility disturbances are briefly outlined. The application of laryngeal electromyography in such cases is recommended. A brief review of EMG findings in the normal and diseased neuro-muscular system is given. In the present study electromyographic investigations of the laryngeal muscles were made of 13 patients (5 males and 8 females) with ages ranging from 22 to 70 years. Their clinical diagnoses included a variety of etiological factors. The posterior crico-arytenoid, thyro-arytenoid and crico-thyroid muscles were routinely examined. A method for the performance of these tests, in the form of an initial sitting and repeated follow-up control studies, is given. The clinical versus EMG findings are analysed. The criteria of neuropathic changes in laryngeal electromyograms are described and their significance is discussed.
    Acta Oto-Laryngologica 02/2010; 70(5):428-37. DOI:10.3109/00016487009181907 · 0.99 Impact Factor
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    ABSTRACT: Despite the wealth of publications on the topic of gastroesophageal reflux and its variants, there are still many unsettled questions before one accepts the prevalent cult of "reflux disease". This study is summarizing the results of the critical analysis of the literature, 436 articles,during the last 30 years. The golden test to identify the patient group suffering from this rather common phenomenon is still lacking. The claimed extra-esophageal manifestations especially in the larynx are non-specific and may be caused by other factors well-known within the domain of vocology. The response to therapeutic intervention still lacks serious well-controlled studies to allow drawing reasonable conclusions. An outstanding feature of the publications is that most of them fall in the category of "review". It seems that there is a tendency to perpetuate the concept without objective criticism. Following the analysis, a recommendation for anew plan of original well-controlled multi-center studies is highlighted.
    Archives of Oto-Rhino-Laryngology 02/2010; 267(2):171-9. DOI:10.1007/s00405-009-1176-4 · 1.61 Impact Factor
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    ABSTRACT: The aim of this work is to study the hitherto unclear aerodynamic parameters of the pseudo-glottis following total laryngectomy. These parameters include airflow rate, sub-pseudo-glottic pressure (SubPsG), efficiency and resistance, as well as sound pressure level (SPL). Eighteen male patients who have undergone total laryngectomy, with an age range from 54 to 72 years, were investigated in this study. All tested patients were fluent esophageal 'voice' speakers utilizing tracheo-esophageal prosthesis. The airflow rate, SubPsG and SPL were measured. The results showed that the mean value of the airflow rate was 53 ml/s, the SubPsG pressure was 13 cm H(2)O, while the SPL was 66 dB. The normative data obtained from the true glottis in healthy age-matched subjects are 89 ml/s, 7.9 cm H(2)O and 70 dB, respectively. Other aerodynamic indices were calculated and compared to the data obtained from the true glottis. Such a comparison of the pseudo-glottic aerodynamic data to the data of the true glottis gives an insight into the mechanism of action of the pseudo-glottis. The data obtained suggests possible clinical applications in pseudo-voice training.
    Folia Phoniatrica et Logopaedica 02/2009; 61(1):24-8. DOI:10.1159/000188660 · 0.55 Impact Factor
  • M N Kotby, S Tawfik, A Aziz, H Taha
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    ABSTRACT: This presentation of the public health impact of hearing impairment highlights the important elements of interaction between the disability and community. OBJECTIVES: Retrospective study to identify the size of the problem of hearing loss, illustrating not only the magnitude but also the serious effect of the lack of reliable data concerning this matter. It highlights the challenges met within a mid-economy community regarding the handling of the impact of the disability. The Egyptian data is given as an example of the situation in a mid-economy community. STUDY DESIGN: A brief introduction of some epidemiological factors of hearing impairment is presented including the size of the problem in Egypt. Data of the neonatal hearing screening program of the Audiology Unit, Ain Shams University, is presented. The impact of the disability is then discussed in relation to the age of onset and the degree and type of hearing loss. This is followed by the description of the nature and effect of the disability in the different age groups. A discussion of the various factors that may modify the capability of the community to deal with such disability follows. This includes various economic indices with their possible limitations on the part of the community. Such a briefing illustrates the challenges met in the rehabilitation of the deaf and the hearing-impaired in a developing mid-economy country. The broad lines of the management of the problem both at the prophylactic as well as the rehabilitative levels are discussed. A final remark on recommendations and possible future development in a developing country is presented.
    Folia Phoniatrica et Logopaedica 02/2008; 60(2):58-63. DOI:10.1159/000114646 · 0.55 Impact Factor
  • M. N Kotby, A El-Makhzangy
    International Congress Series 10/2003; 1240:1383-1387. DOI:10.1016/S0531-5131(03)01139-7
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    ABSTRACT: Stuttering is one of the controversy diseases. Thus, therapy for stuttering varies according to the therapists' belief. This study was conducted on four groups of stutterers; 30 stutterers each, with age range 15–35 years. Three groups received therapy sessions using the three different behavioral readjustment programs mainly: Coarticulation program of Stromsta, Smith Accent Method, and Van Riper's Non-Avoidance program. All patients attended individual therapy sessions, twice a week. The fourth group was a control one. All patients were assessed at the interview, after 8 weeks, and after 16 weeks.A multidimensional assessment protocol was used for assessment of all patients. It included elementary diagnostic procedures, clinical diagnostic aids, and additional instrumental diagnostic assessment.The results obtained from this study showed that there were significant improvements of the stuttering severity for most of the measurable parameters for all therapeutic groups. Although there was significant difference between all therapeutic groups and control group, there was no significant difference between the results of all therapeutic groups.
    International Congress Series 10/2003; 1240:1243-1249. DOI:10.1016/S0531-5131(03)00690-3
  • M.N Kotby, N.A Labib, A.A Aziz
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    ABSTRACT: This study demonstrates the various socioeconomic indices in Egypt, as a developing country. The implications of such economic indices on planning and developing health services in the field of phoniatrics and communicative disorders are given and discussed. The study refers to the total resources allocated to health, followed by resources allocated to rehabilitative services to reach the final human and financial resources allocated to communicative disorders.
    International Congress Series 10/2003; DOI:10.1016/S0531-5131(03)00860-4
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    ABSTRACT: Psychogenic background of non-organic dysphonia has been suspected for some time. The purpose of this study is to assess cases of non-organic voice disorders in order to elucidate the role of psychogenic stress in the pathogenesis of this clinical entity. To reach our goal, 100 non-organic voice disorder patients were subjected to both voice and psychiatric protocols of assessment and the results obtained were compared with the results of 50 normal individuals whom subjected to the same protocols of assessment. The results showed that there was a highly significant difference between both groups as regards the scales of psychiatric tests. Conclusion: there is evident psychogenic background for some types of non-organic voice disorders, namely, incomplete mutation, phonasthenia and non-organic aphonia. This may necessitate a combined therapy program of behavior readjustment voice therapy as well as psychiatric management for these cases to get best results and avoid relapse.
    International Congress Series 10/2003; DOI:10.1016/S0531-5131(03)00858-6
  • M.N. Kotby, S.R. El Sady
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    ABSTRACT: Background: Care of the professional voice in developing countries like Egypt is not that widely prevalent, so it is expected to have a big size of the problem among the different categories. Methods: In an attempt to demonstrate the type and nature of the breakdown of the singing voice, how to evaluate and to treat this, 22 singers with variable vocal breakdown were subjected to a comprehensive protocol of voice assessment which was carried out in the Phoniatric unit, Ain Shams University. The diagnostic protocol encompassed elementary diagnostic procedures including interviews with the patients APA, clinical diagnostic aids (laryngostroboscopy and high-fidelity voice recording) and additional instrumental measures including aerodynamic and acoustic measures. Results: The presenting problem was change of voice, phonasthenia or potential resonance problem. There was minimal initial pathological profile ranging from hyperfunctional dysphonia or phonasthenic manifestations with suitable stroboscopic aerodynamic and acoustic changes to minimal vocal fold lesions as polyps nodules, early Reinke's oedema or dysplasia. A wide variety of singers were represented in this study (artistic singers “operatic, pop, ballad and oriental” and specialized singers: “Quraan reciters and priests”). Treatment modalities were mainly behavior readjustment voice therapy. Phonosurgery was resorted to some cases with an adjuvant voice therapy. Vocal breakdown improved both subjectively and objectively. Conclusion: Egypt represents a unique multicultural society with a wide variety of singers. Accent Method (AM) proved to be effective either per se or in conjunction with phonosurgery in readjusting some mechanisms of the breakdown of the vocal technique.
    International Congress Series 10/2003; DOI:10.1016/S0531-5131(03)00859-8
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    ABSTRACT: 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.
    Scandinavian audiology. Supplementum 02/1996; 42:27-33.
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    M. Amin Riad, M N Kotby
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    ABSTRACT: 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.
    Acta Oto-Laryngologica 04/1995; 115(2):311-3. DOI:10.3109/00016489509139317 · 0.99 Impact Factor
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    ABSTRACT: 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.
    Acta Oto-Laryngologica 06/1993; 113(3):439-44. DOI:10.3109/00016489309135841 · 0.99 Impact Factor
  • 2nd European Congress of Oto-Rhino-Laryngology and Cervico-Facial Surgery (E.U.F.O.S.), Sorrento, italy; 06/1992
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    ABSTRACT: 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.
    Acta Oto-Laryngologica 02/1992; 112(2):349-52. · 0.99 Impact Factor
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    ABSTRACT: 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.
    Acta Oto-Laryngologica 02/1991; 111(2):396-402. DOI:10.3109/00016489109137409 · 0.99 Impact Factor