Neural network prediction of obstructive sleep apnea from clinical criteria.

STUDY OBJECTIVES: Clinical prediction models for the diagnosis of obstructive sleep apnea (OSA) have lacked the accuracy necessary to confidently replace polysomnography (PSG). Artificial neural networks are computer programs that can be trained to predict outcomes based on experience. This study was conducted to test the hypothesis that a generalized regression neural network (GRNN) could accurately classify patients with OSA from clinical data. STUDY DESIGN: Retrospective review. SETTING: Regional sleep referral center. PATIENTS: Randomly selected records of patients referred for possible OSA. MEASUREMENTS: The neural network was trained using 23 clinical variables from 255 patients, and the predictive performance was evaluated using 150 other patients. RESULTS: The prevalence of OSA in this series of 405 patients (293 men and 112 women) was 69%. The trained GRNN had an accuracy of 91.3% (95% confidence interval [CI], 86.8 to 95.8). The sensitivity was 98.9% for having OSA (95% CI, 96.7 to 100), and the specificity was 80% (95% CI, 70 to 90). The positive predictive value that the patient would have OSA was 88.1% (95% CI, 81.8 to 94.4), whereas the negative predictive value that the patient would not have OSA (if so classified) was 98% (95% CI, 94 to 100). CONCLUSIONS: Appropriately trained GRNN has the ability to accurately rule in OSA from clinical data, and GRNN did not misclassify patients with moderate to severe OSA. In this study, use of the neural network could have reduced the number of PSG studies performed. Prospective validation of the neural network for the diagnosis of OSA is now required.

Laryngeal mask airway in paediatric otolaryngologic surgery.

The laryngeal mask airway (LMA) is a relatively recent development that fills the gap in airway management between endotracheal intubation and the use of a face mask. The device is inserted blindly into the pharynx, forming a low-pressure seal around the laryngeal inlet permitting gentle positive-pressure ventilation. It allows the administration of inhaled anaesthetic agents through a minimally stimulating airway. This factor, combined with its ease of insertion, suggested that the laryngeal mask airway might offer some distinct advantages in otolaryngologic paediatric surgery. Our experience in utilizing the laryngeal mask in tonsillectomy and adenoidectomy, and in myringotomies with insertion of ventilating tubes is described, and its advantages and disadvantages are discussed.

Medial meatal fibrosis: the University of Western Ontario experience.

Medial meatal fibrosis is an uncommon but surgically treatable cause of conductive hearing loss. A review of 10 years experience with this entity at The University of Western Ontario revealed a total of 15 cases involving nine patients. Each of them was treated by one of four otologists. This disease may arise from either recurring or chronic infection or from chronic dermatitis, and it frequently presents with bilateral involvement. It may occur at virtually any age, and to our knowledge, this series includes the first cases of this disease to be described in children. The medical and surgical management of this condition is described in detail and the results are summarized.

Reconstructive Middle Ear Surgery: Techniques to improve hearing.

Conductive hearing loss is a common cause of deafness and disability, particularly in children and young adults. This article presents a brief overview of the various methods currently available for reconstructing the tympanic membrane and middle ear ossicular chain, including some comments as to their indications and limitations. Schematic diagrams showing these techniques illustrate the various types of repair described.

Otolaryngological manpower in Canada in the year 2000.

Otolaryngologic manpower in Canada has been carefully monitored since the mid-1970s. Within that frame of reference it is now possible to make some projections as to what the manpower picture will be into the next century. These projections are based on a computer model of population demographics as developed by Statistics Canada following the 1986 census. For these projections it is assumed that current government policies as regards immigration of physicians into Canada will be maintained over the next decade and that domestic training programs will not see any substantial increase in numbers. On the basis of these projections it would appear that current manpower shortages will continue and likely be exacerbated over the next 10 years and probably well into the 21st century.

Recurrent meningitis secondary to perilymph fistula in young children.

All young children treated for meningitis should have post-treatment evoked potential audiometry. If neurosensory hearing loss is identified, the clinician should be alerted to the possibility of a perilymph fistula as the cause of the meningitis. Radiology of the inner ear and possibly exploratory tympanotomy may be necessary to rule out a perilymph fistula. Two young children with meningitis secondary to perilymph fistula are presented to illustrate the problems of diagnosis and management.

Otitis media with effusion in the adult.

The etiologic factors associated with serous otitis media or otitis media with effusion (OME) are well described in children. Little has been published with regard to OME and its etiology in adults. Thirty-five adult patients who presented with OME in a referral-based otolaryngologic practice over a five-year period were studied by retrospective chart review with a follow-up telephone interview. OME in adults may be related to previous middle ear surgery in the contralateral ear, a history of middle ear disease in childhood, chronic nasal symptoms of obstruction and nasal fullness, cigarette smoking, and a family history of middle ear disease. The onset is often associated with upper respiratory tract infection. Nasopharyngeal carcinoma was uncommon.

Epiglottitis: adult and pediatric comparisons.

All cases of epiglottitis admitted to the three affiliated teaching hospitals of the University of Western Ontario over the ten year period prior to December 1986, were subjected to a retrospective chart review. The findings confirmed the suspicion of the senior authors that adult epiglottitis is almost as frequent an entity as epiglottitis in children. This probably results from an increased awareness of the disease process rather than an actual increase in incidence. Also of note is the bimodal age distribution of 0-8 years in children and 20-40 years in adults. As well, clinical presentation, causative organisms, treatment modalities and complications between adults and pediatric age groups are compared and contrasted.

Conductive hearing loss in the elderly.

With a steadily increasing proportion of the population in the geriatric age group, otolaryngologists are frequently confronted with conductive hearing losses in elderly patients. An evaluation of audiometric data from an out-patient audiology clinic over a six-month period revealed 13.4% of our geriatric patients presented with significant conductive components to their hearing loss. Advances in anesthetic management and medical therapy have broadened the indications for surgery in this age group. Recent evidence suggests that the results of surgery in the elderly patient are identical to those in younger age groups, and careful attention to associated medical problems can keep the complication rate at an acceptable minimum. In the appropriately selected elderly patient, surgical correction of a conductive hearing loss may well be the preferred option.

The changing nature of otological practice in a teaching centre.

The impression that otologic surgical practice is a declining segment of the specialty of otolaryngology is widespread. In an attempt to assess objectively the validity of that assumption, the authors reviewed their own experience over the 12 years 1971-82 inclusive. Five representative years out of the 12 were examined--1971, 1974, 1977, 1979, and 1982. In each of these years, the relative and absolute frequency with which six common otological procedures were performed was determined. The procedures selected for study included myringoplasty, tympanoplasty Type I, II, III and IV, and stapedectomy. In addition the relative frequency of primary vs. revision operations was assessed. The data indicate a change in the pattern of otologic surgical practice over the period, most noticeably in the ratio of primary to revision procedures. These changes have significant implications for the teaching and practice of otology in the future.

Epithelial-myoepithelial carcinoma of the salivary gland.

Epithelial-myoepithelial carcinoma of salivary gland is a rare tumor only recently described in the English language literature. This paper adds four new cases to the 30 which have previously been reported. The clinical presentation of this unusual neoplasm is documented in the accompanying case reports and the appropriate surgical management outlined. Follow-up ranges from six months to 12 years. The histopathological characteristics of this interesting tumor, in particular its classical biphasic cellular appearance, are described in detail both by light and electron microscopy. On the basis of histologic appearance and biological behavior, the authors postulate that epithelial-myoepithelial carcinoma is an uncommon variant of adenoid cystic carcinoma.

Otolaryngological manpower in Canada--1983.

The Committee on Manpower of the Canadian Society of Otolaryngology--Head and Neck Surgery conducted its annual survey of otolaryngological manpower in April 1983. A net decline of 16 otolaryngologists occurred in the past one year. Only one province sustained a net increase. A review of previous manpower surveys indicates that a decline in overall numbers has been present since 1979. If this trend continues we can expect severe manpower shortages within 10 years time.

Otolaryngological manpower in Canada -- a 10 year survey.

Over the past 10 years manpower statistics have come under intensive scrutiny, particularly by government finding agencies. Manpower statistics for the specialty of otolaryngology were analyzed for the 10 year period 1971 to 1981 in an attempt to discern any significant trends. On the basis of the available information, some projections for the next decade are outlined.

Perichondritis of the larynx following radiation.

In a retrospective study of 348 patients receiving radiotherapy as the primary treatment for carcinoma involving the laryngeal region, perichondritis developed in 52--an incidence of 15%. Of these 52 cases of clinically diagnosed perichondritis, 50% had residual or recurrent carcinoma. A controversy exists regarding the value of frequent and multiple biopsies in these patients; disease will be missed if this is not done, but perichondritis and cartilage necrosis may result from infection introduced by repeated laryngeal manipulation. On the basis of this study the authors recommend an aggressive approach with close follow-up and multiple frequent biopsies as the data indicate an incidence of 50% recurrent or residual tumor when perichondritis is present.

A survey of Canadian otolaryngologists on the management of middle ear effusions.

Members of the Canadian Otolaryngological Society were surveyed by way of a questionnaire regarding their treatment of the middle ear effusion. Sixty-seven per cent of the members polled replied. The majority of respondents utilized similar conservative measures, but for varied time periods, before proceeding to surgical management. Surgery generally involved insertion of a ventilating tube plus an additional procedure which was most frequently an adenoidectomy. Other aspects surveyed included the role of allergy, type of tube used, site of tube insertion, and the question of swimming with the tube in place. The survey indicated widespread agreement in both conservative and surgical management of this common problem.

Otolaryngological manpower in Canada--1979.

The present status of otolaryngological manpower in Canada has been surveyed. Although no overall shortage exists, there is considerable regional variation. The present output of Canadian training programs in this specialty would seem to be barely adequate to meet future requirements. However, variabilities in population growth, Canadian immigration policies, and rate of emigration to the U.S. can have a significant impact on future manpower needs.

Osteoradionecrosis of the temporal bone.

Six cases of osteoradionecrosis of the temporal bone are described. Persistent symptoms of otitis externa refractory to local treatment measures should alert the physician to the possibility of underlying osteoradionecrosis. Treatment of superficial parotidectomy and partial temporal bone resection with preservation of the facial nerve is indicated if local aggressive conservative measures fail to control the disease. Benign mixed tumors of the parotid gland should be treated surgically with avoidance of radiotherapy.

The mechanics of benign paroxysmal vertigo.

Benign paroxysmal vertigo (BPV) is a disorder of the vestibular labyrinth. The clinical features can be explained by an abnormality in the posterior semicircular canal. Under the influence of gravity, a density differential between the endolymph and the cupula will cause displacement of the cupula when changes in head position occur. The presence or absence of fatiguability is a useful test as it helps define etiology, prognosis, and therapy. At the risk of adding yet another classification of nystagmus to the literature, we submit that division of BPV into two types (fatiguable and nonfatiguable) will simplify and rationalize the management of this common complaint.