ABSTRACT
The present study was designed to investigate whether mellaril and thorazine, when used alone and in combination with other medications by mentally retarded clients, either abolish acoustic reflexes or compromise estimates of hearing sensitivity based on acoustic reflex measures. Acoustic reflex thresholds were determined in 35 normal-hearing institutionalized mentally retarded subjects who were regular users of the medications under investigation. Five sensitivity prediction methods based on acoustic reflex thresholds were applied to the data. The results of the study showed that acoustic reflexes were present in most subjects. However, the accuracy of all the acoustic reflex-based sensitivity prediction methods was quite poor with greatly exaggerated predictions of hearing loss. The methods based solely on noise reflex thresholds provided better accuracy than those based on noise-tone differences. In general, the accuracy of the prediction methods decreased as the number of medications used by the subjects increased. It is argued that the results provide evidence for reticular activating system mediation of acoustic reflex activity.
Subject(s)
Auditory Threshold/drug effects , Chlorpromazine/adverse effects , Institutionalization , Intellectual Disability/physiopathology , Reflex, Acoustic/drug effects , Thioridazine/adverse effects , Adult , Drug Therapy, Combination , Female , Hearing Tests/methods , Humans , Intellectual Disability/drug therapy , Male , Middle Aged , Predictive Value of TestsABSTRACT
Hearing Performance Inventory scores were correlated with sensitivity, discrimination, and sensitivity + discrimination measures for 39 subjects with noise-induced hearing loss. The highest correlation obtained (0.67) was with monosyllabic speech discrimination in noise. However, there were not significant differences in correlations among the three types of audiometric measures. The audiometric variables accounted for less than half of the variance in Hearing Performance Inventory scores; therefore they are inadequate in predicting the amount of self-perceived hearing difficulties. The need for a variety of hearing handicap scales is discussed.
Subject(s)
Audiometry/methods , Hearing Loss, Noise-Induced/diagnosis , Self-Assessment , Speech Discrimination Tests , Adult , Audiometry, Pure-Tone , Audiometry, Speech , Bone Conduction , Hearing Loss, Noise-Induced/psychology , Hearing Loss, Sensorineural/diagnosis , Humans , Loudness Perception , Middle Aged , Surveys and QuestionnairesABSTRACT
The purpose of this study was to describe an acoustic method for measuring temporal characteristics of electroacoustic impedance bridges, and to present data on the temporal responses of three widely used electroacoustic instruments. The potential effects of these instrument parameters on measured characteristics of the acoustic reflex are discussed.
Subject(s)
Acoustic Impedance Tests/instrumentation , Reflex, AcousticABSTRACT
The ability of the sensitivity prediction from acoustic reflex (SPAR) technique to estimate hearing loss in mentally retarded subjects was investigated by comparing measured pure-tone thresholds determined through tangible-reinforcement operant-conditioning audiometry with predicted sensitivity from the SPAR procedure. Measurements were completed on a total of 32 retarded individuals having hearing levels ranging from normal to profound hearing loss. With minor exception, absences of the acoustic reflex were always accompanied by clearly abnormal tympanometry findings in the probe ear; therefore, the problem of unexplained absences of the reflex appeared to be minimal. Hearing loss never was present in those subjects for which SPAR predicted normal hearing, and the SPAR procedure never failed to detect an existing sensorineural hearing loss. On the other hand, there was some tendency for hearing loss to be predicted in normal-hearing subjects and for extent of hearing loss to be overestimated in subjects having a hearing loss.
Subject(s)
Auditory Perception , Intellectual Disability/diagnosis , Reflex , Adolescent , Adult , Audiometry/methods , Hearing Disorders/diagnosis , Humans , Middle AgedABSTRACT
The purpose of the present study was to examine the functional between acoustic reflex (AR) latency and the intensity and frequency of the eliciting stimulus. AR latency was determined at various intensities for 500 Hz and 300 Hz pure tones, and for wide-band noise. The results of the study indicated that AR latency decreased as stimulus intensity increased for all stimuli; the exact nature of the relationship depended on the stimulus, however. Latency differences between the stimuli at a given sound pressure level tended to disappear at higher presentation levels. Of particular interest was the dependency of inter- and intrasubject variability on parameters of the eliciting stimulus. The data do no indicate that AR latency is mediated solely by the loudness of the eliciting stimulus.
Subject(s)
Acoustic Stimulation/methods , Reflex , Synaptic Transmission , Adult , Auditory Threshold , Evoked Potentials , HumansABSTRACT
This study was designed to clarify characteristics of an artifact that has been reported to be a potential source of misleading information when determing acoustic reflex thresholds elicited by low-frequency tones. The study was conducted in two parts. Experiment 1 was concerned with an investigation of acoustic interactions in a sealed cavity between the probe tone from a commercial electroacoustic impedance bridge and interfering tones of various frequencies. Experiment 2 consisted of measurements of sound pressure levels in the sealed external ear canal of the probe ear when the contralateral ear was stimulated by air-conducted pure tones. The results indicated that acoustic reflex thresholds in 250-Hz tones probably cannot be determined for most persons unless special measures are taken to prevent the artifact. The artifact should not occur when the eliciting stimulus is 500 Hz, however.
Subject(s)
Ear, Middle/physiology , Reflex , Acoustic Stimulation , Acoustics/instrumentation , Ear Canal/physiology , Evaluation Studies as Topic , Female , Humans , Male , Methods , Models, Biological , Physiology/instrumentation , Pressure , SoundABSTRACT
An adaptive psychophysical procedure was used to determine the articulation functions for nonretarded and retarded subjects using Kindergarten Phonetically Balanced stimulus words. Merits of this procedure are: (a) it is efficient since stimulus intensity levels are well-placed with respect to the measures being obtained, and (b) estimates of intrasubject variability can be obtained from one test session. The slope of the articulation function based on the pooled data from the nonretarded subject (3.5 percent/dB) was greater than the slope of the function from the retarded subjects (2.1 percent/dB). No significant differences in intrasubject variability between the two groups were discovered. It is not clear whether the reduced slope of the articulation function from the retarded subjects was due to a familiarity factor and/or to a basic difference in auditory processing characteristics. Work is continuing in an attempt to clarify this issue.
