Peter W. Alberti

Speech intelligibility in noise: Effects of fluency and hearing protector type

This research investigated the effect of car protectors on the intelligibility of speech in noise. Listeners with normal hearing, high-frequency, and flat loss were tested. Half the subjects in each group were fluent in English and half-poorly conversant. Taped lists of 25 words were presented free field under conditions defined by the speech-to-noise ratio, spectrum of noise background, and presence of ear protection. The results showed that intelligibility decreased with speech-to-noise ratio and was poorer in crowd noise than in white noise. The protector had no effect for the normal listener, but caused a substantial decrement in those with impairment. In all groups nonfluency contributed an additional loss of 10% to 20%. Significant differences in performance were noted for different muff and plug types.

Auditory Evoked Potentials in Audiometric Assessment of Compensation and Medicolegal Patients

The clinical utility of auditory evoked potentials for validation of the pure tone audiogram in adult compensation claimants and medicolegal patients is examined. Large sample comparisons of evoked potential and conventional pure tone thresholds showed that the slow vertex response can estimate true hearing levels within 10 dB in almost all patients. Given adequate tester skills, it is the tool of choice, and it merits more widespread implementation. Properly used, it can improve and abbreviate the assessment battery for detection and quantification of nonorganic hearing loss. The 40-Hz middle latency response is useful as a secondary tool, but at present, cochlear nerve and brain stem potentials have limited audiometric value in this population.

Hearing loss in early infancy: Incidence, detection and assessment†‡

Auditory evoked potential techniques have revitalized programs for early detection, quantification, and management of hearing loss. Some issues underlying the need for such programs, and their structure, are reviewed with reference to recently‐published guidelines. The prevalence of hearing loss in infancy is poorly understood; estimates depend on the type and degree of loss, the tests used, and their timing. Evidence that significant hearing loss can escape early detection continues to accumulate; delays are attributable to many factors, including insufficient awareness and deficiencies in conventional tests. High‐risk registers are valuable but imperfect tools, and should not be the sole avenue of early detection. Electrophysiologic tests, especially the auditory brain stem response, have a major role in early assessment. Attention to many technical and patient‐related factors is required, and frequencyspecific testing is feasible and informative.

Pediatric ear, nose and throat services’ demands and resources: a global perspective ☆

Abstract Global population trends, health care economics and disease patterns are reviewed. The world’s population has doubled twice in the twentieth century, and will grow by at least a further 2 billion before stabilizing in the middle of the next century. There is gross maldistribution of wealth and health care expenditures: 20% of the population control 80% of the gross domestic product, the same 20% of the population spend 87% of the total global health care funds. Extreme poverty facilitates all manner of diseases. Globally, infections remain the most important causes of disease. Of these, upper respiratory infections are an important cause of hearing loss and learning handicap in children world-wide. Epidemic meningitis in Africa and parts of Asia is a preventable major cause of death and deafness. There are about 80 000 otolaryngologists in the world and they too are maldistributed, with most in Europe and the Americas. This is exacerbated when looked at from the standpoint of children, most children live where there are fewest otolaryngologists: the differences are greater than two orders of magnitude. This greatly affects the role and scope of paediatric otolaryngology. The discipline is small and rapidly evolving. Suggestions are made for sharing training.

Audiometric Estimation Error with the ABR in High Risk Infants

Click ABR wave V thresholds in the first year were compared with follow-up behavioural pure-tone audiometry under earphones at age 3 to 6 years in 713 infants (yielding 1,367 ears) at risk for hearing loss. The observed accuracy of the ABR depends strongly on the precise definitions of the target disorder and the test abnormality criteria. For sensorineural hearing loss of more than 20 dB averaged at 2 kHz and 4 kHz, the click ABR provides an accurate test, with both false positive and false negative rates of less than 10%, using an ABR threshold criterion of 30 dB nHL. The false positive error rate can be at least halved by using a simple rule for wave V latency that discriminates conductive and sensorineural ABR threshold abnormalities. False negative errors may be explicable in terms of the lack of frequency specificity of the click stimulus.

Accessibility for the hearing impaired.

The social anthropology of mild hearing loss is gradually being accepted, as it affects both children and adults. With this comes the understanding that effective aural communication requires adequate sound sources and a good transmission medium as well as good hearing. If the first two conditions are met, much hearing disability might be avoided without resorting to a hearing aid. A plea is made for better accessibility for the hearing impaired by improving environmental conditions for acoustic signals, especially speech.

Clinical Review : Pediatric and Otologic Aspects of Clinical Research in Cleft Palate

In 1971, the American Speech and Hearing Associa tion, under contract with the National Institute of Dental Reseach, assembled an interdisciplinary commit tee to review the present status of clinical research on cleft lip and palate, and to discuss possible approaches and recommend priorities with respect to filling the gaps in existing knowledge. Between August, 1971 and July, 1972, state-of-the-art workshops were conducted by six subcommittees—concerned, respectively, with etiology and pathogenesis, anatomy and physiology, pediatric and otologic aspects, surgery and physical management, orofacial growth and dentistry, and speech and psy chosocial management. Presented here is the report of the subcommittee concerned with pediatric and otologic aspects. Addi tional information concerning the entire review, includ ing a list of the subcommittees and their chairmen, appears at the end of the article.

Complex acoustic impedance of the human ear

Instrumentation capable of measuring and displaying the swept‐frequency, complex acoustic impedance of the human ear, in the range 200 Hz to 2 kHz, has been built, tested, and shown to provide accurate results (3% to 5%). The mean complex acoustic impedance loci measured in a sample population of 20 normal (screened) subjects is presented. Impedance magnitudes showed a variation of 20% to 40% of the mean. Mean resonant frequencies of 641 and 1140 Hz were observed with mean damping factors of 0.33 and 0.26, respectively. To evaluate repeatability, a population of five normals, evaluated five times, established a variation of 5% to 10% of the mean. Five otosclerotic subjects, having received unilateral stapedectomy were tested, indicating that the operation causes a return to normal resistance levels at the expense of increased resonant responses. [Work supported by Natural Sciences and Engineering Research Council of Canada Grant ♯A4316.]

Speech intelligibility in noise with ear protectors

Speech perception was tested in high level noise under controlled laboratory conditions in noise-exposed workmen and normal subjects, with and without a hearing protector. The group was further divided by age and English fluency, the latter group being included because of the high proportion of non-fluent English speakers in the Canadian workforce. In normal-hearing subjects the highest discrimination scores were found without background noise, they were lower with white noise as a masker, and even lower with crowd noise as a masker; wearing of a protector had no effect on intelligibility. The results for non-fluent English speakers were parallel with these results, but the scores were lower in all test conditions. In the presence of a high frequency hearing loss speech discrimination was lower than in the normals in quiet and in noise. The addition of a hearing protector dropped their discrimination score even further. In a flat hearing loss, wearing of a protector also worsened the speech discrimination score. The results are discussed.