Children's Perception of Temporally Distorted Sentential Approximations of Varying Length

The purpose of this study was to investigate the abilities of second-grade and fourth-grade children to auditorially process three orders of three- and five-word sentential approximations, which had normal interstimulus intervals (ISI) and ISIs of 200 and 400 ms. Results showed that percent correct scores decreased as a function of increasing sentence length and ISI, and decreasing order of sentential approximation and grade level. The results are discussed relative to theoretical notions of short-term memory and auditory perceptual processing as well as potential clinical applications     

Brief-Tone Audiometry in Persons Treated with Salicylate

The ability to integrate acoustic energy over a period of time has been measured by brief-tone audiometry on 14 young persons treated with salicylate and after the salicylate has been excreted. The investigation showed that the temporal integration can be reversible reduced by salicylate treatment, and a relation was demonstrated between the change in temporal integration and the salicylate concentration in the blood. As the test persons had had general anaesthesia, a control test was performed on seven persons. It was shown that anaesthesia does not influence temporal integration. Experimental investigations have shown that the hearing loss produced by salicylate is due to an inhibition of enzymatic systems in the cochlea

Taking into consideration the results of brief-tone audiometry and the cochlear effect of the salicylates, one must conclude that reduced cochlear function caused reduced temporal integration     

Adaptive Speech Audiometry and Speech Discrimination Space in Hearing-Impaired Subjects

Phonemic discrimination difficulties in a small group of patients with sensorineural hearing loss have been mapped using a new form of speech audiometry which is an automated, adaptive, audio-visual system, using a binary forced-choice response mode. Phonemic confusion patterns have been displayed in directed graph form and the cases presented here have been chosen to illustrate the potentialities of the test method for obtaining detailed information on the fine structure of speech reception in these patients.     

Diagnostic Significance of the Electrocochleogram in Clinical Audiometry

In order to understand fully the diagnostic significance of electorcochleography (E. Co. G.) in clinical audiology, the present study was designed to cover 3 problems concerning (1) objective threshold audiometry by E. Co. G., (2) objective bone-conduction audiometry by E. Co. G., and (3) objective differential audiometry of sensory-neural hearing loss by E. Co. G.

The compound action potential (AP) of the cochlear nerve was used as an indicator for this purpose. It was recorded simultaneously from both ears of the same subject with a promontory electrode or a meatal skin electrode by means of an average response computer.

Acoustic signals such as clicks or 3 different tone-pips with center frequencies of 2 000, 4 000, and 8 000 Hz, were given to the subject by both air-conduction and bone-conduction.

Five different electric indices were determined from the AP measurements as measures of neurophysiological activity of the cochlea, i. e., (1) the threshold of the AP, (2) the input-output function of N₁, (3) the increments of the N₁ amplitude, (4) the intensity-latency relation of N₁, and (5) the wave form of the AP. These results lead to the following conclusions

(1) The promontory-recorded AP thresholds were in an excellent agreement statistically not only with the subjective thresholds for the same stimuli but also with the clinical hearing thresholds shown on the audiogram.

(2) The promontory-recorded AP provided significantly more precise and reliable data on E. Co. G. as compared with the meatal skin surface-recorded AP. The difference between the AP thresholds and the subjective thresholds, on the average, was + 0.2 dB, subjective more sensitive, for the promontory recording, and + 17.8 dB, subjective more sensitive, for the meatal skin surface recording. But the choice of electrodes must be according to what is required of the E. Co. G.

(3) The bone-conduction AP measurements could be carried out with the promontory electrode. There was a relatively good agreement between the bone-conduction AP thresholds and the bone-conduction subjective thresholds, but the agreement was worse than that for the air-conduction AP measurements.

(4) An air-bone gap was determined objectively from the input-output and intensity-latency relations of the bone-conduction AP compared to those of the air-conduction AP. The promontory-recorded AP measurements by bone-conduction should be very helpful in estimating objectively the degree of an air-bone gap.

(5) There were some interesting correlations between the changes in the electric indices of the AP measurements and the patterns of subtractive loss. Some patterns of subtractive loss seemed to be specified by various combinations of the threshold elevation of the AP, the 'H curve' type of input-output relation, the reduction in the maximum amplitude of N₁, and the distortion of the AP wave form.

(6) A distinctive pattern of the distorted AP wave form appeared in Ménière's disease. The depression and recovery of the AP was closely correlated with the course of audiological and vestibular symptoms of this disease.

(7) On the basis of observations on the AP measurements for sensorineural hearing loss, 3 conceptual populations of sensory units are hypothesized, i.e., (a) the more sensitive population of sensory units capable of discharging well-synchronized impulses with lower thresholds, (b) the less sensitive population of sensory units capable of discharging well-synchronized impulses with higher thresholds, and (c) the more sensitive population of sensory units capable of discharging less well-synchronized or dispersed impulses with lower thresholds.

Finally, some serious problems confronting the routing clinical use of E. Co. G. are discussed, and the current status of E. Co. G. is described. It seems reasonable to speculate that E. Co. G., combined with electric response audiometry, will serve as the most practical method of objective differential audiometry as well as of objective threshold audiometry.     

Early Components of the Averaged Electroencephalic Response to Monaural and Binaural Stimulation

Early components of the averaged electroencephalic response were recorded in 11 subjects from C_z-A₁, C_z-A₂, C₃-A₁, and C₄-A₂. The early components were examined in response to stimulation of either the left, right, or both ears with 40 dB SL clicks at a rate of 4/sec in awake subjects. Peak latency and peak-to-peak amplitude measures failed to discriminate between stimulus conditions. Left minus right difference scores obtained for each subject showed no consistent relationship to the ear stimulated     

Inter-relationships between objective and subjective measures of the residential environment among urban African American women

PurposeThe inter-relationships between objective (census based) and subjective (resident reported) measures of the residential environment is understudied in African American (AA) populations.MethodsUsing data from the Life Influences on Fetal Environments Study (2009–2011; n = 1387) of AA women, we quantified the area-level variation in subjective reports of residential healthy food availability, walkability, safety, and disorder that can be accounted for with an objective neighborhood disadvantage index (NDI). Two-level generalized linear models estimated associations between objective and subjective measures of the residential environment, accounting for individual-level covariates.ResultsIn unconditional models, intraclass correlation coefficients for block-group variance in subjective reports ranged from 11% (healthy food availability) to 30% (safety). Models accounting for the NDI (vs. both NDI and individual-level covariates) accounted for more variance in healthy food availability (23% vs. 8%) and social disorder (40% vs. 38%). The NDI and individual-level variables accounted for 39% and 51% of the area-level variation in walkability and safety, respectively. Associations between subjective and objective measures of the residential environment were significant and in the expected direction.ConclusionsFuture studies on neighborhood effects on health, especially among AAs, should include a wide range of residential environment measures, including subjective, objective, and spatial contextual variables.     

Evoked Response Thresholds for Long and Short Duration Tones

Evoked response thresholds for 45 and 200 msec tones were compared to behavioral thresholds obtained with Békésy audiometry for signals of like duration is seven normal hearing listeners. The purpose of the study was to determine how closely the summed evoked response threshold approximates behavioral threshold at low and high frequencies, and determine if the temporal integration phenomenon can be demonstrated by the evoked response procedure. The results suggest that the behavioral threshold is the more sensitive of the two, but that, in normal listeners, evoked response thresholds approximate behavioral thresholds within 5 dB. This relationship was not frequency dependent being observed at both 500 and 4 000 Hz. Of the evoked response measurements threshold sensitivity was greatest with a stimulus duration of 200 msec. Mean differences of 3 to 6 dB were found when duration was increased from 45 to 200 msec suggesting the occurrence of temporal integration similar to that observed with psychophysical testing procedures.     

N1 Latencies of the Slow Auditory Evoked Potential

Several studies have been published concerning the relation between stimulus level and amplitude of the slow auditory evoked response. Little attention has, however, been given to the relation between level and latency of the N₁ component (100-200 ms). A mathematical model of such a relation is proposed based on the assumption of an exponential relationship. The model has been tested on normally hearing subjects as well as on patients with sensorineural lesions, cochlear as well as retrocochlear. The results indicate that the proposed method of evaluating the slow evoked responses offers a way of threshold extrapolation with rather good accuracy. It also appears to be useful in determining the type of hearing loss     

Binaural Speech Discrimination

The phenomenon of binaural summation in which the addition of signals presented to the two ears simultaneously takes place at a central level, has been known for many years. It is reasonable to assume that the pattern of summation differs between subjects with central lesions and those with lesions in the peripheral auditory tracts. Various tests have been proposed to aid in locating the site of the lesion which compare the monaural and binaural speech discrimination scores

In the present work, two of these tests have been examined. Thee group of subjects have been used: (1) a normally hearing group; (2) a group with hearing impairment resulting from cochlea pathology, and (3) a group with hearing impairment resulting from lesions at the level of the cochlear nuclei. The results showed that neither test differentiate between peripheral and cochlear nuclei lesions