Community values for environmental protection in a cane farming catchment in northern Australia: a choice modelling study.

Choice modelling is an emerging approach to estimating the non-use values of environmental services with multiple attributes. In this paper, results are reported of a choice modelling study conducted in the Herbert River District of North Queensland to estimate the value placed on the protection of natural vegetation in areas suitable for cane production by the local community. Resource use options that vary in the level of environmental protection and the level of agricultural production were presented as a series of choice sets and respondents were asked to choose among a set of three discrete alternatives in a given choice set. The alternatives in each choice set were described by four attributes, pertaining to the area of teatree woodlands, the area of vegetation along rivers and in wetlands, regional income from cane production, and an environmental levy. The responses were analysed together with socio-economic data using a nested-logit discrete-choice model to estimate the community willingness-to-pay for the protection of natural vegetation. The results indicate that the environmental values of wetlands are comparable to returns from commercial production of sugar cane and that the values of teatree woodlands are comparable to returns from extensive grazing. It is argued that land allocation policies should recognise these values in tandem with commercial benefits of production to ensure that resources are used more efficiently.

Botulinum toxin treatment of essential palatal myoclonus tinnitus.

OBJECTIVE: The purpose of this study was to review the use of botulinum toxin in the treatment of essential palatal myoclonus tinnitus. DESIGN: Two case series. METHOD: Four to 10 units of botulium toxin are injected into the tensor veli palatini muscle. The dose and interval between doses is titrated according to patient symptoms. With bilateral symptoms, injection is alternated between sides at sequential visits. OUTCOME MEASURES: Relief of tinnitus with cessation of palatal contractions. RESULTS: Both patients had relief of tinnitus. One patient required ventilation tube placement to relieve aural fullness. CONCLUSIONS: Tensor veli palatini botulinium toxin injection is an effective treatment for essential palatal myoclonus tinnitus.

Esophagolaryngeal reflex in a porcine animal model.

OBJECTIVE: The purpose of this study was to determine the effect of stimulation of the distal esophagus upon tension in the thyroarytenoid muscles. METHOD: Stimulation of the distal esophagus of six anaesthetized female pigs by means of balloon dilatation and acid infusion was performed. Response was measured with electromyography of the thyroarytenoid muscles. RESULTS: Acid infusion into the distal esophagus showed a statistically significant response in the thyroaytenoid muscles. Response to balloon dilatation was marked but not statistically significant. CONCLUSION: Stimulation of the distal esophagus during episodes of gastroesophageal reflux may play a causative role in producing some of the symptoms that otolaryngologists treat on a daily basis.

Complete DNA sequence of canine adenovirus type 1.

The complete DNA sequence of a field strain of canine adenovirus type 1 was determined by sequencing random fragments of viral DNA cloned into pBluescript. The virus has a genome of 30536 bp flanked by two identical 161 bp inverted terminal repeats. Thirty ORFs have been identified, based on genomic location or sequence identity with published adenoviruses. These are arranged into similar discrete regions found in the human adenoviruses. ORFs in the late region show greatest identity with published human adenovirus sequences, whereas the E3 and E4 ORFs show little or none.

A comparison of the efficacy of unilateral versus bilateral botulinum toxin injections in the treatment of adductor spasmodic dysphonia.

The current treatment of choice of adductor spasmodic dysphonia due to focal dystonia is thyroarytenoid-vocalis injection of botulinum toxin type A (Botox). Botox exerts its effect by presynaptic motor endplate blockade, preventing the release of acetylcholine and causing muscle paresis. Botox treatment protocols vary. Some centres perform unilateral injections, whereas others treat both cords. Our hypothesis is that unilateral injections may reduce the severity of whisper voice and aspiration side effects in the early two to three weeks after treatment. The purpose of this study, therefore, is to compare the efficacy of unilateral versus bilateral Botox injections in the treatment of adductor spasmodic dysphonia in terms of duration of effect versus the side effects of breathing and swallowing difficulties. This study presents data from a retrospective chart review and a prospective telephone interview of all patients receiving bilateral and unilateral Botox injections.

Benign mucous membrane pemphigoid: treatment of esophageal stricture.

The authors describe a 35-year-old man who has had benign mucous membrane pemphigoid from the age of 12 years. Upper esophageal stricture, a rare complication of the syndrome, developed when he was 24 years old. This recurrent condition has been followed for 11 years. It was treated initially, for 6 years, with esophagoscopy and bougie dilatation. Balloon dilatation under fluoroscopic guidance was then substituted for bougienage; this procedure has been performed successfully 10 times over the last 5 years and remains the patient's preferred treatment. The mean period for recurrence of symptoms has been 5 months. Several previous reports of this condition describe treatment with esophagoscopy and bougie dilatation, but there has been no previous report of interventional radiology with balloon dilatation.

Effects of okadaic acid on expression of phosphoenolpyruvate carboxykinase in cultured rat hepatocytes.

In normal rat hepatocytes in primary culture the level of mRNA encoding the key gluconeogenic enzyme phospho enol pyruvate carboxykinase (PEPCK) is increased by the cyclic AMP analogue, chlorophenylthio cyclic AMP (cpt cAMP), and this response is reversed by insulin. The protein-phosphatase inhibitor okadaic acid diminished the stimulatory effects of cpt cAMP on PEPCK mRNA. Protein kinase A remained fully active in the presence of okadaic acid, therefore, the insulin-mimetic actions of okadaic acid were localised to a site subsequent to initial protein kinase A activation. Insulin produced a decrease in PEPCK mRNA expression which was similar to that of okadaic acid both in extent and mechanism (i.e., lack of change in protein kinase A activation). The effects of okadaic acid on PEPCK mRNA amount were not additive with those of insulin and the effects of insulin were not abolished by okadaic acid. These data suggest that okadaic acid and insulin may interact with the cAMP regulation of the PEPCK gene expression at a common site. The mechanisms by which this may be attained are discussed in relation to what is known about the control of specific protein kinases and protein phosphatases by insulin and okadaic acid and of the importance of protein phosphorylation state to regulation of gene-transcriptional processes.

Interdisciplinary approach to functional voice disorders: the psychiatrist's role.

A review is given of the experience obtained over 6 years of having a psychiatric consultant available as part of the staff of the Voice Clinic, to which more than a thousand patients have been referred. The presenting features in a case that should alert the otolaryngologist to the need for psychiatric consultation and possible treatment are noted. Suggestions are made as to how to prepare the patient for the referral to a psychiatrist with the appropriate interests and willingness to collaborate closely with the otolaryngologist and the speech pathologist.

Muscle misuse voice disorders: description and classification.

It is apparent that voice disorders frequently labelled "functional" are associated with laryngeal muscle misuse. This use of the word "functional" is, however, intrinsically ambiguous, and so we propose an alternative term based on descriptive features of dysfunction: "muscle misuse voice disorders". Persistent phonation with an abnormal laryngeal posture can lead to organic changes such as nodules or polyps, particularly in females with posterior glottic chink. We hypothesized that the chink was related to an overall increase in laryngeal muscle tension, and more directly due to inadequate relaxation of the posterior crico-arytenoid muscle during phonation. We employed the term "muscular tension dysphonia" (MTD) to note this condition, but it may be that the term "laryngeal isometric" is superior since there are other misuses of the larynx that obviously are manifestations of abnormalities of muscular tension. With this in mind we have evolved a new classification based on the laryngeal isometric, glottic and supraglottic lateral contraction states, antero-posterior contraction states, conversion aphonia, psychogenic bowing, and adolescent transitional dysphonia.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.