M N Kotby

Ain Shams University, Cairo, Muhafazat al Qahirah, Egypt

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Publications (21)18.78 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. · 1.29 Impact Factor
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    ABSTRACT: Although recognized as a valuable diagnostic tool for more than 60 years, many laryngologists do not routinely use laryngeal electromyography (LEMG). This may be due to a persisting lack of agreement on methodology, interpretation, validity, and clinical application of LEMG. To achieve consensus in these fields, a laryngeal electromyography working group of European neurolaryngologic experts was formed in order to (1) evaluate guidelines for LEMG performance and (2) identify issues requiring further clarification. To obtain an overview of existing knowledge and research, English-language literature about LEMG was identified using Medline. Additionally, cited works not detected in the initial search were screened. Evidence-based recommendations for the performance and interpretation of LEMG and also for electrostimulation for functional evaluation were considered, as well as published reports based on expert opinion and single-institution retrospective case series. To assess the data obtained by this literature evaluation, the working group met five times and performed LEMG together on more than 20 patients. Subsequently, the results were presented and discussed at the 8th Congress of the European Laryngological Society in Vienna, Austria, September 1-4, 2010, and consensus was achieved in the following areas: (1) minimum requirements for the technical equipment required to perform and record LEMG; (2) best practical implementation of LEMG; (3) criteria for interpreting LEMG. Based on this consensus, prospective trials are planned to improve the quality of evidence guiding the proceedings of practitioners.
    Archives of Oto-Rhino-Laryngology 05/2012; 269(10):2227-45. · 1.29 Impact Factor
  • M Nasser Kotby, Hassan Wahba, Amr Mabrouk
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    ABSTRACT: Muwaffaq-al-Deen abu-al-Abbas Ahmad ibn Abi Ussaibea (1203-1270) was born in Damascus. He started his brilliant career in his birth place then moved to Cairo where he worked and excelled for the rest of his life. His learning was intensified by the scholarly contacts of the intellectual leaders of the day. In this study we review The Index of Physicians-Oyoun al-Anbaa Fi Tabaqat al-Attiba--(Sources of Information in the Classes of Physicians) of ibn Abi Ussaibea.The biographies in this book do not just cover physicians only but also the learned people of his day whose knowledge and expertise covered medicine, astronomy, mathematics, philosophy, and botany. For this reason the book of ibn Abi Ussaibea represents an indispensable source of the scientific and philosophical achievements of the Arabic/Islamic civilization.
    Vesalius : acta internationales historiae medicinae. 12/2010; Suppl:6-9.
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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. · 1.08 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. · 1.11 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. · 1.11 Impact Factor
  • M Nasser Kotby
    Archives of Oto-Rhino-Laryngology 02/2010; · 1.29 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. · 1.29 Impact Factor
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    Eur Arch Otorhinolaryngol (2010) 267:171–179. 01/2010; 267:171-179.
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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. · 1.08 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. · 1.08 Impact Factor
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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 A 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. · 1.11 Impact Factor
  • M N Kotby, O Shiromoto, M Hirano
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    ABSTRACT: 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.
    Journal of Voice 01/1994; 7(4):319-25. · 1.55 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. · 1.11 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. · 1.11 Impact Factor
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    ABSTRACT: Laryngeal electromyography (EMG) is an important tool in the study of laryngeal disorders. This review considers the current state of the art. The general principles of EMG and of the laryngeal neuromotor control system are reviewed. Important criteria for interpreting EMG characteristics, including the motor unit action potential and spontaneous activity, are considered in the context of several pathologic conditions. Technical and clinical difficulties are reviewed.
    Journal of Voice - J VOICE. 01/1992; 6(2):159-187.
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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. · 1.11 Impact Factor
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    ABSTRACT: The aim of this work was to study the function of the left and right cerebral hemispheres concerning linguistic, musical and cognitive abilities, through the evaluation of the deterioration of these domains following lesions of either hemisphere. The study was carried out on 80 subjects (60 males, 20 females) with a mean age of 48 years. Subjects were categorized into four groups, 20 in each. Group I had left brain lesion with dysphasia; group II, left brain lesion without dysphasia; group III, right brain lesion without dysphasia; group IV, control. Patient's evaluation included a dysphasia test, psychometric battery, tests for musical abilities, brain CT scanning and EEG. Group I showed deterioration in the linguistic abilities, while groups II and III had intact abilities. Deterioration in musical abilities was noticed in group III, with normal scores in groups I and II. There was deterioration of the intellectual abilities in all patients' groups, to varying degrees. The significance of the results is discussed.
    Acta Oto-Laryngologica 01/1989; 107(5-6):479-84. · 1.11 Impact Factor