Distortion product otoacoustic emission and auditory brain stem response measures of pediatric sensorineural hearing loss with islands of normal sensitivity.

OBJECTIVE: To assess the accuracy of: 1) distortion product otoacoustic emission (DPOAE) measures for the identification of frequencies at which auditory sensitivity is normal or near normal; and 2) click and nonmasked tone burst-evoked auditory brain stem response (ABR) thresholds for behavioral threshold estimation for children with sensorineural hearing loss characterized by islands of normal sensitivity. DESIGN: DPOAEs and ABRs were recorded from five hearing-impaired and eight normal-hearing pediatric ears. The accuracy with which DPOAEs permitted identification of frequencies at which elevated hearing thresholds were present was examined. ABR and pure-tone threshold differences for the impaired ears were calculated. RESULTS: For three of the five hearing-impaired ears, significant impairments would have been missed based on click-evoked ABR thresholds. One of those hearing-impaired ears provided an essentially normal 500 Hz tone burst-evoked ABR threshold as well. Four of the hearing-impaired ears provided a 500 Hz tone burst-evoked ABR threshold within 10 dB of the respective pure-tone threshold. However, click-evoked ABR and 500 Hz tone burst-evoked ABR threshold data did not adequately delineate the hearing loss configuration for hearing aid frequency response selection. DPOAEs were present at three out of four frequencies from 1000 to 4000 Hz at which sensitivity was normal or near normal (< or =25 dB HL) and absent at 10 out of 11 frequencies at which sensitivity was impaired. The use of DPOAEs to identify frequencies at which sensitivity was normal and the use of tone burst ABR thresholds at frequencies where DPOAEs were absent provided a better estimate of these pure-tone audiograms than was provided by click-evoked and 500 Hz tone burst-evoked ABR thresholds.

Tuberculosis in the West Midlands, 1990-1991.

In the late 1980s, notifications of tuberculosis stopped their former steady decline. There has been speculation as to why this should be so, with much interest centred on a possible association with the HIV epidemic. Notification rates are higher in persons of Indian subcontinent ethnic origin compared with the indigenous white population. Changes in the size and structure of the former population subgroup may have contributed to the recent increase in notifications in some areas. The absence of data on ethnic group in routinely collected data has led to the recommendation that special surveys should be conducted to clarify the contribution of ethnic minorities to the occurrence of tuberculosis in the UK. One such survey has been carried out in the West Midlands, where notifications increased by 27% between 1987 and 1989. Notification rates were found to vary widely by age, sex, district of residence and ethnic group; the highest notification rates occurring in older females of Indian subcontinent origin. These differences help to explain the increase in the absolute number of notifications and suggest that certain population subgroups warrant special attention.

Aided masked thresholds: case of deception.

A case of contaminated functional gain measures from internal hearing aid noise is presented and clinical implications addressed. The contaminated functional gain measures underestimated real ear insertion gain. Recognition of this source of functional gain measurement error is essential for accurate hearing aid fitting.

A comparison of sound quality judgments for monaural and binaural hearing aid processed stimuli.

Fifteen adults with bilaterally symmetrical mild and/or moderate sensorineural hearing loss completed a paired-comparison task designed to elicit sound quality preference judgments for monaural/binaural hearing aid processed signals. Three stimuli (speech-in-quiet, speech-in-noise, and music) were recorded separately in three listening environments (audiometric test booth, living room, and a music/lecture hall) through hearing aids placed on a Knowles Electronics Manikin for Acoustics Research. Judgments were made on eight separate sound quality dimensions (brightness, clarity, fullness, loudness, nearness, overall impression, smoothness, and spaciousness) for each of the three stimuli in three listening environments. Results revealed a distinct binaural preference for all eight sound quality dimensions independent of listening environment. Binaural preferences were strongest for overall impression, fullness, and spaciousness. Stimulus type effect was significant only for fullness and spaciousness, where binaural preferences were strongest for speech-in-quiet. After binaural preference data were obtained, subjects ranked each sound quality dimension with respect to its importance for binaural listening relative to monaural. Clarity was ranked highest in importance and brightness was ranked least important. The key to demonstration of improved binaural hearing aid sound quality may be the use of a paired-comparison format.

Acquired epileptic aphasia. Diagnostic aspects of progressive language loss in preschool children.

A case of acquired epileptic aphasia presenting as language delay and hyperactivity is presented and clinical aspects reviewed. Acquired epileptic aphasia is a diffuse neurologic process of unknown etiology that presents in preschool children. Although progressive language loss and seizures are the major manifestations, deficits in attention and socialization may be noted. The electroencephalogram is usually diagnostic. While almost all (80%) children develop seizures, approximately half present as language delay without seizures. Recognition of the progressive and global nature of the language dysfunction may permit earlier diagnosis and intervention.