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Biomedical subjects

M D Morrison

Publications and source records attributed to M D Morrison.

At least 19 recordsLinked to original sources
PubMed1992

Design and evaluation of a subclassification system for supraglottic laryngeal cancer.

The management of supraglottic laryngeal cancer is predicted upon tumor staging as determined by the American Joint Committee Classification (AJCC). Because of changes in both radiotherapy and surgical treatment, the current AJCC may lack the detail and specificity required for accurate selection of treatment. An expanded classification system should provide predictive information that would aid in clinical decision making. Using the AJCC as a foundation, a subclassification system based upon existing knowledge of laryngeal anatomy, embryology and pattern of tumor spread was developed. This system identifies those cancers that involve subsites deemed to represent regions of increased risk for spread. The validity of this subclassification system and its clinical application was assessed by reviewing 139 cases of supraglottic laryngeal cancer and performing a statistical analysis with respect to treatment outcome. The results of this study support the conclusion that two subpopulations of laryngeal tumors, those with a subsite designation of infrahyoid epiglottis, and those demonstrating fixation of the vocal cord, may benefit from a more aggressive treatment protocol.

British Columbia↗
PubMed1990

A double-blind controlled study of the efficacy of cimetidine in the treatment of the cervical symptoms of gastroesophageal reflux.

Globus pharyngeus and post-nasal drip are common patient complaints encountered in general otolaryngologic practice. Although these complaints have been traditionally ascribed to stress and sinusitis respectively, recently it has been suggested that they are secondary to gastroesophageal reflux, either by a direct effect on the pharynx and posterior larynx or by referred sensation along vagal pathways from the lower esophagus. This reflux could alter the motor tone of the laryngoesophagus and contribute to the pathogenesis of dysphonias. If globus and post-nasal drip are secondary to gastroesophageal reflux, then reduction of stomach pH should reduce the frequency and severity of these complaints. To test these hypotheses in a clinical setting, a large population of patients with vocal disorders was analyzed for the incidence of these complaints. Twenty healthy patients with globus and/or postnasal drip were then entered in a double-blind random placebo-controlled study to assay the efficacy of cimetidine in treating these complaints. No significant difference was found between cimetidine and placebo.

Cimetidine↗
PubMed1989

Technical considerations in computation of spectral harmonics-to-noise ratios for sustained vowels.

This paper explores technical issues affecting computed measures of the relative level of noise in the frequency spectrum of a vowel. This type of measure has been proposed for quantification of hoarseness in pathological speakers. An analysis of synthesized vowels was used to test the influence of vowel type, fundamental frequency, perturbation type, perturbation level and quantization. The algorithms were shown to be highly sensitive to errors in pitch-period demarcation, and a dependency on jitter perturbations, fundamental frequency, and vowel type was demonstrated. Relationships between algorithm performance and methods of spectrum estimation were discussed, and approaches for reducing the dependencies were proposed. Finally, a method for achieving a significant reduction in computation time was described.

Algorithms↗
PubMed1989

Data labeling and sampling effects in harmonics-to-noise ratios.

The harmonics-to-noise ratio (HNR) was proposed for measurement of noise in sustained vowels. A generalized algorithm is described here for removing the dependence on the data offset and for reducing the influence of jitter and shimmer. In addition, a new algorithm is proposed that accommodates periodic perturbations. Formulations are presented that can be computed in a single pass through the data under certain assumptions, thus simplifying the implementation of an efficient analysis program. A mathematical analysis of the effect of small errors in pitch-period demarcation is presented. The analysis indicates that the sensitivity to demarcation errors depends on the preponderance of high-frequency components, and significant underestimation is predicted for /a/ and /i/ data. A method for correcting quantization and demarcation errors in pitch-period markers is described. The method is shown to be effective at reducing demarcation errors for all but the most severely perturbed waveforms. Examples of the use of this method for HNR estimation are provided. Finally, a comparison with recent work by Milenkovic [J. Speech Hear. Res. 30, 529-538 (1987)] is presented.

Algorithms↗
PubMed1988

Is chronic gastroesophageal reflux a causative factor in glottic carcinoma?

Several forms of laryngeal dysfunction and pathology can be attributed to the effects of chronic gastric reflux through direct acid irritation, from a reflex alteration in voluntary muscle tone or referred sensation. It is widely accepted that contact ulcers and granulomata over the arytenoid are associated with gastric reflux, but there have not been well-documented cases of glottic carcinoma that are reflux-related. This article presents six cases of glottic carcinoma, all with T1 lesions of the anterior two-thirds of the vocal cord. All of these patients are lifetime nonsmokers, and all had no other ailments other than moderately severe chronic gastroesophageal reflux. Clinical details from the study of these patients gives strong indication that the reflux may have been a factor in the development of the disease. In addition, review of 21 lifetime nonsmokers with glottic carcinoma presenting over a 10-year period at the Cancer Control Agency of British Columbia revealed that 48% had probably experienced reflux, compared to 16% in a group that had stopped smoking 10 or more years earlier. While this small number of cases cannot be said to prove the etiologic relationship between reflux and glottic carcinoma, it is important for the otolaryngologic community to be aware of the possible clinical relationship.

Adult↗
PubMed1986

Diagnostic criteria in functional dysphonia.

One thousand consecutive patients seen in a multidisciplinary voice clinic are reviewed. The incidence and relative severity of diagnostic features in each of five assessment areas are calculated and compared. The five areas include: 1. history, 2. laryngoscopic examination, 3. perceptual-acoustic assessment, 4. voice related musculoskeletal, and 5. psychological evaluations. Feature prevalence is presented for patients we have classified as having muscular tension dysphonia, which can be primary, or associated with vocal nodules, chronic laryngitis, or polypoidal degeneration; or as having a psychogenic "functional" dysphonia. Following review of the data, we present a suggested list of diagnostic criteria that should be present before using a specific diagnostic label. These criteria have been further broken down into those that will be present to make a diagnosis, and those that may be present.

Adult↗
PubMed1986

Primary tracheo-esophageal puncture voice restoration with laryngectomy.

In 1979 Singer and Blom introduced a technique of tracheo-esophageal puncture for restoration of voice in the post-laryngectomy patient. This procedure is usually done as a staged secondary procedure, six months after the primary laryngectomy. This study compares 13 patients who have had a laryngectomy and primary tracheo-esophageal fistula formation with 13 patients in whom the procedure is performed as a delayed operation. A clinical evaluation of the results of tracheo-esophageal puncture is presented. Acceptable results were obtained in 77% of the primary tracheo-esophageal puncture group whereas only 54% of the delayed group attained acceptable results. The advantages of primary tracheo-esophageal puncture include an improved patient morale and acceptance of the procedure, as well as the ability to feed the patient through the Foley catheter. The disadvantages of performing the procedure primarily include an increased rate of postoperative mucocutaneous fistula. The relationship of the tracheo-esophageal puncture to the increased fistulization rate is discussed. Further experience is required before firm conclusions can be drawn about the role this procedure will take in the management of patients for cancer of the larynx.

Aged↗
PubMed1986

Voice disorders in the elderly.

A review of the literature clearly shows that connective tissue degeneration in the larynx, particularly of elastic and collagen fibers, is more prevalent in males than in females. Reinke's edema or polypoidal degeneration of vocal cords may or may not be more common in females. Whether or not the above statements are true, tissue atrophy causes a problem in males because the voice becomes higher pitched, weak or reedy, less masculine, whereas polypoidal change in the older female larynx results in a lower pitch, husky voice that would be acceptable in a male but makes the female voice more male-like and undesirable. Functional misuses of laryngeal muscles come into play when patients try to compensate for these changes. The etiology of dysphonia in the elderly gets even more confusing when psychological factors such as loneliness and depression add their effects to laryngeal muscle misuse. Laryngeal cancer is still probably the most common cause of hoarseness in older persons. Unfortunately the biopsy to rule out cancer in a person who is hoarse from degenerative or functional causes will often greatly worsen the dysphonia and render voice therapy less effective.

Aged↗
PubMed1984

Paranasal sinus malignancy--a retrospective analysis of treatment methods.

A retrospective analysis has been made of all cancers of paranasal sinuses seen at the Cancer Control Agency in Vancouver during the years 1970 to 1978. The overall crude five year survival for all cases (49) was 46%. A combined treatment using irradiation and surgery in selected cases generated a five year survival rate of 74.4% as compared to 42.1% in cases receiving irradiation alone. The clinical presentation, staging, and the need for the individualization of treatment methods based on a realistic knowledge of the pathological extent of the disease are discussed.

Adenocarcinoma↗
PubMed1983

Acoustic analysis of voice for computerized laryngeal pathology assessment.

The purpose of this paper is to review the techniques of computerized acoustic analysis of voice signals used for laryngeal pathology assessment. Results of using a methodology described by Davis for distinguishing between T1 glottic cancer, noncancerous pathology, and normal speakers are presented. These results indicate that this technique is not sufficiently sensitive for general clinical usefulness. There is an intentional lack of mathematical detail in this paper, as its prime intent is to conceptually outline issues and approaches.

Adolescent↗
PubMed1983

The voice clinic: an interdisciplinary approach.

The University of British Columbia Voice Clinic provides care to patients with various types of voice disorder, and the effectiveness of therapy is enhanced by an interdisciplinary approach. The Voice Clinic team includes an otolaryngologist, speech pathologist, psychiatrist, and singing teacher consultant. This paper particularly highlights the interactions between the speech pathologist and psychiatrist in their therapy programs for voice disordered patients.

British Columbia↗
PubMed1983

Muscular tension dysphonia.

Muscular tension dysphonia (MTD) is a condition commonly seen in young and middle aged females. It is manifest by excess tension in the paralaryngeal and suprahyoid muscles, an open posterior glottic chink, larynx rise, and frequently mucosal changes on the vocal cords. These mucosal changes are usually fleshy vocal nodules. About 8% of vocal nodules are found in patients not exhibiting features of MTD. The two types of vocal nodules require different therapeutic approaches. One hundred patients out of 500 seen consecutively at the Voice Clinic at the University of British Columbia exhibited the features of MTD. These patients are discussed and an etiology hypothesis is presented.

Adolescent↗
PubMed1983

Anatomic correlation for muscle tension dysphonia.

Dysphonia resulting from increased muscular tension in the larynx and neck is associated with 1) palpably increased phonatory muscle tension in the paralaryngeal and suprahyoid muscles, 2) elevation of the larynx in the neck on increasing vocal pitch, 3) an open posterior glottic chink between the arytenoid cartilages on phonation, and 4) variable degrees of mucosal changes such as vocal nodules or chronic laryngitis. Using six cadaver larynges, the glottic features observed during examination of patients with muscular tension dysphonia (MTD) are reproduced. In each larynx the posterior, lateral, and interarytenoid muscles were dissected free and tension applied in the direction of action in various combinations. Glottic changes were observed, recorded on videotape, and compared to similar clinical video recordings.

Cadaver↗
PubMed1982

Prognostic factors in primary tracheal malignancy.

Published literature discussing factors influencing prognosis in primary malignancy of the trachea is reviewed. Twenty-four patients with primary tracheal malignancies presenting during an 11 year period are discussed. Review of their radiological investigations demonstrate that extratracheal extension correlates with poor prognosis whereas vertical length of tumors does not. Overall five year survival in this series is 30%. Patients with extratracheal extension show 18% five year survival while those with only intraluminal disease show 50% survival.

Aged↗
PubMed1979

Teratomas of the nasopharynx.

The case of an infant with a large nasopharyngeal teratoma is presented. The tumor completely obstructed the airway and necessitated immediate intubation. It was excised the day of birth and the child's postoperative course has been satisfactory. A review of the literature reveals dermoid tumors to be relatively common but teratomas occur considerably less frequently. Four previously reported cases with successful surgical excision were found. The etiology of these lesions is unknown. They probably arise from uncontrolled growth of a pleripotential cell originating in the region of the embryonic notochord. Dermoid tumors often present in the adolescent or adult. Teratomas however, generally present in the neonate and are incompatible with life without surgical excision which provides the only chance of survival for these infants.

Airway Obstruction↗
PubMed1978

Early detection of childhood hearing impairment - problems and possible solutions.

The identification of infants with profound hearing loss is a complex task, and one that is beset with problems. This paper discusses some of these problems and points out a few of the ways by which, hopefully, they are coming closer to solution. The first problem results from the nature of the beast, which seems to have so many social, medical, educational, and political implications. There are also some problems with the high risk register and with screening for hearing loss; but probably the most disturbing are the conflicts that arise between professionals when their aims, objectives, and methods don't quite match. Current progress in the linking up of high risk and screening methodologies is discussed, as well as ways in which existing health care systems can be utilized in deafness detection.

Audiology↗
PubMed1978

The effects of indomethacin on inner ear fluids and morphology.

Metabolic disturbances may affect inner ear fluid homeostasis in various ways. The membrane sodium-potassium pump must play a role in this homeostasis, and as this pump derives energy from A.T.P. it may also depend somewhat on the presence of prostaglandins, through their stimulatory effect on the adenylate cyclase system. Salicylates suppress prostaglandins; and Indomethacin is even more potent in this respect. Could the temporary ototoxic effects of salicylates and Indomethacin be due to prostaglandin suppression? Further, could energy system problems involving prostaglandins be related to the development of endolymphatic hydrops? These questions prompted this study. Sublethal doses of Indomethacin were given to 14 guinea pigs in order to maximally suppress prostaglandins. Samples of perilymph and endolymph were analyzed for sodium and potassium concentrations and compared to normal controls. No significant differences were found in either acute (two to 24 hour) or chronic (three week) experiments. Light microscopic examination of serially sectioned cochleae in similarly treated animals showed, in a few cases, somewhat questionable distension of Reissner's membrane. Electron microscopy or the organ of Corti did not demonstrate any abnormalities. The study suggests that Indomethacin does not produce significant inner ear electrolyte shifts or endolymphatic distension, at least over the short term.

Animals↗