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The purpose of this investigation was to prospectively examine performance on the pure-tone air-conduction threshold, speech-recognition threshold, and suprathreshold word-recognition tests over time in 21 monaurally aided (experimental group) and 28 unaided adults (control group) with asymmetric, sensorineural hearing impairment. The results revealed significant declines on the mean suprathreshold word-recognition scores over time at one and two years post-baseline for the worse ears of the control participants; no declines occurred in the worse ears of the experimental participants or in the better ears of either group. A slight, significant increase in the pure-tone average occurred for the better ears of both groups. The findings are consistent with the presence of an auditory deprivation effect on suprathreshold word-recognition ability in the control group, suggesting that lack of amplification leads to decline in word-recognition performance over time in the worse ears of adults with asymmetric sensorineural hearing impairment. [ABSTRACT FROM AUTHOR]

PURPOSE: To present a case study in order to alert clinicians to the possibility of occurrence of intermodulation distortion during otoacoustic emissions testing that arises from the cavity formed by the external auditory meatus and tympanic membrane rather than from the inner ear, compromising the reliability and validity of otoacoustic emissions testing. RESEARCH DESIGN: Prospective case study. STUDY SAMPLE: A young (26-year-old) female adult with a longstanding, bilateral, essentially moderate to severe sensorineural hearing loss presented with robust distortion product otoacoustic emissions. RESULTS: Repeat otoacoustic emissions testing with another device of the same model revealed essentially absent distortion product otoacoustic emissions and transient otoacoustic emissions. Calibration of both otoacoustic emissions devices using a 1 cc membranous cavity indicated present intermodulation distortion for the device that yielded robust distortion product otoacoustic emissions for the patient but absent intermodulation distortion for the device that revealed absent distortion product otoacoustic emissions and absent transient evoked otoacoustic emissions for the patient. The calibration findings for the device yielding intermodulation distortion in the cavity were confirmed by an engineer of a technical instrumentation company. The device was shipped back to the manufacturer of the device for repair. The manufacturer's engineers diagnosed the problem as an interruption in the relay system. Following repair, calibration revealed the absence of intermodulation distortion in the 1 cc membranous cavity. CONCLUSIONS: The findings have implications for the reliability and validity of otoacoustic emissions. Clinicians should routinely calibrate otoacoustic emissions devices using 1.0 and 0.5 cc membranous cavities to rule out intermodulation distortion that could produce artifactual otoacoustic emissions in patients. [ABSTRACT FROM AUTHOR]

BACKGROUND: Previous research has noted an age effect on the temporal integration of the acoustic reflex for a noise activator. PURPOSE: To determine whether the age effect earlier noted for a noise activator will be noted for a tonal activator. RESEARCH DESIGN: Comparison of ARTs of younger and older groups at activating stimulus durations of 12, 25, 50, 100, 200, 300, 500, and 1000 msec. STUDY SAMPLE: Two groups of adults with normal-hearing sensitivity: one group of 20 young adults (ten males and ten females, ages 18-29 years, with a mean age of 24 years) and one group of 20 older adults (ten males and ten females, ages 59-75 years, with a mean age of 67.5 years). RESULTS: A significant main effect for duration was obtained. That is, as the duration increased, the acoustic reflex threshold for the 1000 Hz tonal activator decreased. The interactions of duration x age group and duration x hearing level were not significant. There was a nonsignificant main effect (p = .889) for the between-subjects factor of age. CONCLUSION: Results contradict the findings for broadband noise. [ABSTRACT FROM AUTHOR]

Objective: To enhance the understanding of tinnitus origin by disseminating two case studies of vestibular schwannoma (VS) involving behavioural auditory adaptation testing (AAT)., Design: Retrospective case study., Study Sample: Two adults who presented with unilateral, non-pulsatile subjective tinnitus and bilateral normal-hearing sensitivity. At the initial evaluation, the otolaryngologic and audiologic findings were unremarkable, bilaterally. Upon retest, years later, VS was identified., Results: At retest, the tinnitus disappeared in one patient and was slightly attenuated in the other patient. In the former, the results of AAT were positive for left retrocochlear pathology; in the latter, the results were negative for the left ear although a moderate degree of auditory adaptation was present despite bilateral normal-hearing sensitivity. Imaging revealed a small VS in both patients, confirmed surgically., Conclusion: Behavioural AAT in patients with tinnitus furnishes a useful tool for exploring tinnitus origin. Decrease or disappearance of tinnitus in patients with auditory adaptation suggests that the tinnitus generator is the cochlea or the cochlear nerve adjacent to the cochlea. Patients with unilateral tinnitus and bilateral, symmetric, normal-hearing thresholds, absent other audiovestibular symptoms, should be routinely monitored through otolaryngologic and audiologic re-evaluations. Tinnitus decrease or disappearance may constitute a red flag for retrocochlear pathology.

This article reports on four retrospective case studies in which parental behavioral management of the implanted child included withholding the cochlear implant or activities associated with it as a disciplinary measure or as a means of preventing device loss or damage. The need for parental counseling by health care and educational professionals as to the importance of a child's connection to the hearing world all day long through the implant for optimal speech, language, academic, and psychosocial development is emphasized.

We describe tympanic membrane displacement (TMD) testing for non-invasive estimation of intracranial pressure (ICP). With the TMD test, displacement of the tympanic membrane of the middle ear is recorded during elicitation of the acoustic middle-ear reflex (AR). Increased intracranial/perilymphatic pressure displaces the resting stapes footplate laterally so that TMD during the acoustic reflex is medial. Decreased intracranial/perilymphatic pressure displaces the baseline stapes footplate position medially (inward) so that TMD during the AR is lateral. The TMD typically is bidirectional when intracranial/perilymphatic pressure is normal. Discrepant findings have been reported for the sensitivity of the TMD test to ICP as the regression of TMD on invasive measurement of the ICP reveals substantial intersubject variability and overlap among patient and control groups. Large-sample research on TMD test performance in healthy persons and patients with various disorders affecting the ICP is needed using direct, invasive measures of the ICP as the gold standard. Research also is needed to examine whether non-invasive TMD testing can be used to investigate the trans-lamina cribrosa pressure difference in glaucoma.

Objectives/hypothesis: The aim was to examine short- and long-term efficacy of the bone-anchored hearing aid (BAHA) on adults with single-sided deafness., Study Design: Prospective investigation., Methods: The outcome measures included the Hearing in Noise Test (HINT), Abbreviated Profile of Hearing Aid Benefit (APHAB), and Single-Sided Deafness Questionnaire (SSD). The BAHA group comprised seven adults with single-sided deafness and the control group comprised 20 adults with essentially normal-hearing sensitivity, bilaterally. The outcome measures were administered in the unaided, directional BAHA, and omnidirectional BAHA conditions after 1 month, 6 months, and 12 months of BAHA use. A repeated measures analysis of variance (ANOVA) model was used to evaluate the data (for the SSD, a nonparametric analog of ANOVA was employed)., Results: None of the factors (time, HINT condition, amplification status) or their interactions were significant predictors of change in signal-to-noise ratio (SNR) from baseline over time on the HINT. The mean SNR (non-baseline-subtracted) was significantly lower in the directional BAHA versus the unaided status and in the omnidirectional BAHA versus the unaided status, but only under the noise in front, speech lateralized to the bad ear HINT condition. Significant short- and long-term BAHA benefit was observed on the APHAB (all subscales except Aversiveness) and SSD (all questionnaire items)., Conclusions: Our results show short- and long-term efficacy for the BAHA in adults with single-sided deafness for recognition of speech in noise (noise in front, speech lateralized to the bad ear) and on subjective measures of benefit.

Although numerous studies have investigated temporal integration of the acoustic-reflex threshold (ART), research is lacking on the effect of age on temporal integration of the ART. Therefore the effect of age on temporal integration of the ART was investigated for a broad-band noise (BBN) activator. Subjects consisted of two groups of adults with normal-hearing sensitivity: one group of 20 young adults (ten males and ten females, ages 18-29 years, with a mean age of 24 years) and one group of 20 older adults (ten males and ten females, ages 59-75 years, with a mean age of 67.5 years). Activating stimulus durations were 12, 25, 50, 100, 200, 300, 500, and 1000 ms. Significant main effects for duration and age were obtained. That is, as the duration increased, the acoustic reflex threshold for BBN decreased. The interactions of duration x age group and duration x hearing level were not significant. The result of pair-wise analysis indicated statistically significant differences between the two age groups at durations of 20 ms and longer. The observed age effect on temporal integration of the ART for the BBN activator is interpreted in relation to senescent changes in the auditory system.

Objective: To objectively evaluate facial function with a computer and video system in a group of normal adults and a group of adults who have been treated for acoustic neuroma., Study Design: A prospective descriptive study was performed in which the experimenter performing the objective facial motion analysis was blinded to the subjective rating of facial function., Patients: The normal subjects comprised 18 women and 16 men. The subjects who had been treated for acoustic neuroma included 12 patients (seven women and five men) who underwent treatment for acoustic neuroma., Methods: Light-reflective markers were placed at selected facial sites. A video and computer-assisted system was used to measure displacement that was unconfounded by head motion at these sites during two expressions. Proximal and remote displacement were measured for the x and y coordinates. Percentage of asymmetry relative to the total displacement was determined., Results: Significant asymmetry in displacement for the y coordinate during the eyes-closed expression occurred in 100% of the subjects who had been treated for acoustic neuroma with apparent facial dysfunction and 0% of the subjects who had been treated for acoustic neuroma with no apparent facial dysfunction. Synkinesis was severe (>0.2 cm) in 17%, moderate (0.1-0.2 cm) in 25%, mild (>95th percentile for normal subjects but <0.1 cm) in 42%, and absent in 16% of the subjects who had been treated for acoustic neuroma., Conclusion: This method of objective assessment of facial function is useful in the evaluation of the asymmetry in facial motion and in the detection and quantification of synkinesis. The findings suggest that those subjective rating systems of facial function that compare the abnormal to the normal side may be confounded by compensatory motion on the presumed normal side.

The preoperative and postoperative bone conduction (BC) thresholds were prospectively investigated in 24 patients with chronic ear disease in the form of cholesteatoma, chronic suppurative otitis media, or adhesive otitis media. All underwent tympanoplasty with mastoidectomy. Ossicular reconstruction was performed in 14, and the remaining 10 were still awaiting second-stage ossicular reconstruction at the time of this investigation. In each group, the postoperative results were compared with the preoperative results by the paired-samples t-test. In the ossicular reconstruction group, the results revealed a significant improvement in the postoperative BC thresholds, as compared with the preoperative BC thresholds, at 250, 1,000, and 2,000 Hz, with the largest mean improvement observed at 2,000 Hz. No significant improvement was observed at any frequency for the group without ossicular reconstruction. Postoperative improvement of at least 10 dB at 2 or more frequencies was observed in 71% of the ossicular reconstruction group, as compared with 0% of the group that did not undergo ossicular reconstruction. The results support the theory that the elevated BC thresholds of patients with chronic ear disease result from the elimination, due to disease, of the middle ear contribution (from the inertial ossicular component and ossicular resonance) to the BC response. The results also suggest that the middle ear contribution to the BC response is restored with ossicular reconstruction.

Objectives/hypothesis: A paucity of research exists on trans-eustachian tube endoscopy to evaluate the status of the eustachian tube. Fuller examination of the role of the eustachian tube in chronic ear disease is needed, particularly because the eustachian tube has been implicated in the chronicity and pathogenesis of chronic ear disease. Therefore the purpose of this study was to evaluate the eustachian tube, based on observations from trans-eustachian tube endoscopy., Study Design: Twenty-two adult patients with chronic ear disease gave informed consent to participate in a prospective, trans-eustachian tube endoscopic investigation., Methods: Flexible, fiberoptic, nonarticulating (outside diameter of 0.5 mm) and articulating (outside diameter of 1.0 mm) endoscopes (coherent fused bundle of 3,000 pixels) were employed. The eustachian tube endoscopy was performed under general endotracheal anesthesia as the initial part of a larger, otological surgical procedure for chronic ear disease. The endoscope was passed from the middle ear (transtympanic approach) to the nasopharynx., Results: The 0.5-mm endoscope passed entirely through the eustachian tube from the tympanic orifice into the pharyngeal orifice in 16% of the cases. Stenotic blockage occurred at the infundibulum in 37%, isthmus in 42%, and fossa of Rosenmuller in 5% of cases. The eustachian tube mucosa was abnormal in 64% of cases. The risk for abnormal eustachian tube mucosa was four times greater for persons with long-standing disease (> or = 20 y) than for persons without long-standing disease (<20 y). The mean therapeutic efficiency of ossicular reconstruction was higher for the subgroup with normal than for the subgroup with abnormal eustachian tube mucosa., Conclusions: The findings of trans-eustachian tube endoscopy provide objective evidence concerning eustachian tube status in persons with chronic ear disease and have implications for the timing of surgical intervention (ossicular reconstruction).

The central auditory test results for three normal-hearing children who were initially diagnosed as having a central auditory processing disorder and learning disability are presented. They were referred to the authors for second-opinion consultations. Central auditory processing retesting was performed by the authors under the condition of no reinforcement and then the condition of reinforcement with the child's favorite food, hobby, or toy. For all three cases, the central auditory test scores improved markedly bilaterally under the condition of reinforcement as compared with the condition of no reinforcement. We hypothesize that the improvement was related to increased motivation associated with the reinforcement and that these children represented false-positive results on the central auditory test battery. Large-sample studies are needed to investigate the effect of reinforcement on test performance in children with reduced central auditory test scores.

Hypothesis: To investigate the feasibility of a video and computer-assisted system for evaluating the temporal and spatial aspects of facial motion during selected facial expressions in a pilot group of six normal adults. Evaluation of the diverse medical and surgical treatments for facial paralysis and paresis cannot occur until objective, reliable, and sensitive measures of the spatial and temporal aspects of facial function at specific facial landmarks are developed., Methods: Facial motion at predetermined facial locations was assessed using a commercially available computer-interactive motion analysis system, which is based on videography principles. The displacement, velocity, and acceleration data were averaged across all trials and subjects. Time plots also were obtained for the left versus right side., Results: The greatest mean maximum displacement (resultant vector) occurred during the eyebrow lift expression, reaching 1.2 cm in magnitude. The mean maximum velocity (resultant vector), which ranged from 4.5 to 8.5 cm/s for the dynamic facial expressions, was greatest for the eyes closed tight expression. The mean maximum acceleration (resultant vector), which ranged from 193 to 465 cm/s/s, was greatest for the eyebrow lift expression. Symmetrical time plots were obtained. The system documented synkinesis by revealing substantial left upper eyelid motion during the nose-wrinkle expression in an illustrative case with slight left facial dysfunction., Conclusion: This approach to facial motion analysis is feasible for the simultaneous, multiregional, spatial-temporal assessment of facial expressions. Because motion at relatively remote regions could be quantified, this approach is potentially useful for the evaluation of synkinesis.

We compared interaural suprathreshold speech recognition scores in 62 adults with sensorineural hearing loss. Subjects were tested at two sites, 25 at the Baylor College of Medicine, Houston, TX and 37 at Brooklyn College, Brooklyn, NY. Ears were categorized according to telephone usage. Results showed, at both sites, a small but significant difference in speech understanding scores between the ear habitually used on the telephone and the opposite, nontelephone ear. The average speech recognition score was approximately 5 percent better on the telephone ear. Results are interpreted in relation to the theories of auditory deprivation and auditory acclimatization.

The basic audiologic tests (audiogram, speech recognition, and acoustic-immittance), special audiologic tests (otoacoustic emissions and auditory-evoked potentials), and screening protocols, including universal hearing screening, are discussed. Hearing and acoustic-immittance screeners are evaluated. This article also reviews advances in hearing and sensory aids and assistive-listening devices.

The purpose of this investigation was to describe, in a longitudinal prospective study, the acoustic-immittance profile during sessions with effusion and during sessions without effusion in children with recurrent middle-ear effusion (MEE). The static-acoustic middle-ear admittance, tympanometric width (TW), tympanometric peak pressure (TPP), and ipsilateral acoustic reflex (IAR) were evaluated in 36 ears of 18 children with recurrent MEE and 24 ears of 12 children without a history of MEE. Recurrent MEE was operationally defined as MEE diagnosed by microtoscopy and/or pneumotoscopy at four or more sessions over the first year of investigation. Subjects in the recurrent MEE group were followed over a time span of 1.1 to 3.0 years with an average intersession interval of 3.0 months. The results revealed that MEE was present at 78.3 percent of the sessions. A pure-tone average (PTA) exceeding 25 dB HL was present at 80 percent of the effusion sessions in the recurrent MEE group. The false-alarm rate for each of the individual acoustic-immittance measures, especially the TPP and IAR, was markedly higher during the otoscopically normal sessions of the recurrent MEE group than in the control group. This suggests that even when MEE is absent at a particular session, recurrent episodes of MEE appear to alter the acoustic-immittance characteristics of the middle ear. Negative findings on all or three of the four acoustic-immittance measures occurred in only 1 percent of the effusion sessions in the total recurrent MEE group as compared with 76 percent of the normal sessions in the control group.(ABSTRACT TRUNCATED AT 250 WORDS)

The purpose of this prospective investigation was to evaluate the sensitivity of pure-tone screening of children with middle-ear effusion (MEE) and to describe the short-term audiometric and otologic follow-up of children with MEE who pass versus fail a pure-tone screen. Eighty-two ears of 54 children with MEE based on pneumotoscopy/microtoscopy were investigated. A complete otolaryngologic evaluation, pure-tone screen, then complete audiologic evaluation were performed at the initial test. Retesting was done at 6-8 weeks post initial test. The sensitivity of the ASHA (1985) pure-tone screen to MEE was 54 percent when 500 Hz was excluded, 85 percent when 500 Hz was included, and 89 percent when 250 Hz was also included. Significant air-bone gaps were present in 100 percent of the MEE group that failed and in 92 percent of the MEE group that passed the screen (excluding 500 Hz). Of the cases with MEE at the initial test that returned for the retest, 53 percent to 54 percent continued to show MEE. The mean speech-recognition threshold (SRT) was in best agreement with the hearing-threshold levels at the low frequencies, regardless of the pure-tone screen outcome. The results suggest that 500 Hz, as well as 1000-4000 Hz, should be used in a pure-tone screen at 20 dB HL for detection of MEE. The results also question the assumption in the ASHA (1985) screening guidelines that passing a pure-tone screen at 1000-4000 Hz puts one at low risk for hearing impairments that "interfere with or have the potential for interfering with communication" (ASHA, 1985).

The purpose of this investigation was to investigate (1) whether auditory deprivation effects are present in the poorer ears of adults with asymmetric sensorineural hearing impairment and (2) whether, if such effects are present, they can be reversed by amplification. Subjects were 16 males with asymmetric sensorineural hearing impairment, 8 of whom had never been aided, 6 of whom were aided monaurally at the initial test, and 2 of whom were unaided at the initial test but aided monaurally later on. Data were obtained from a retrospective review of records. The initial and retest (2-13 years post initial test) suprathreshold speech-recognition scores for 50-word, taped lists of the CID W-22 PB words were analyzed. The results revealed a significant difference between the initial and retest mean suprathreshold speech-recognition scores for the poorer ears of the unaided subjects. The results also revealed no significant change from the initial test to retest in six of the aided ears and significant improvement from the initial test to retest in the two of the aided ears. The findings are discussed with reference to the theory of auditory deprivation and recovery from auditory deprivation by amplification.

The purposes of this investigation were two-fold: 1) to prospectively investigate the effect of prolonged lack of binaural amplification in the unaided ears of adults with bilaterally symmetrical sensorineural hearing impairment (BSSHI) fitted monaurally; and, 2) to prospectively investigate the effects of amplification on speech-recognition performance in the aided ears of monaurally and binaurally fitted subjects. Subjects consisted of 19 monaurally aided adults, 28 binaurally aided adults, and 19 control adults. Both ears of the experimental subjects (binaurally and monaurally aided adults) had BSSHI. The speech measures included the W-22 CID suprathreshold speech-recognition test, nonsense syllable test, and speech-perception-in-noise test. Initial testing was done between 6 and 12 weeks following hearing-aid fitting. Retests were performed approximately 1 year following the initial test. The results revealed that the mean aided minus unaided ear score for the nonsense syllable and W-22 tests increased significantly from the initial test to retest, reflecting a slight improvement in speech performance in the aided ear and a slightly greater decrement in the unaided ear. The findings were interpreted with respect to the theories of auditory deprivation and acclimatization.

Adult-onset auditory deprivation following prolonged lack of amplification in the unaided ears of persons with bilaterally symmetrical sensorineural hearing impairment was first reported in 1984. This article on the phenomenon includes a review of the literature on adult-onset auditory deprivation in relation to etiology, pathophysiology, hearing-loss manifestations, typical audiologic profile, amplification strategies, contraindications or challenges to conventional hearing-aid fitting, and future research. A case study illustrates the phenomenon of auditory deprivation from monaural amplification with recovery following binaural amplification. The results of a complete audiologic and acoustic-immittance evaluation are presented for a bilaterally sensorineural hearing-impaired male with adult-onset auditory deprivation who initially was fit monaurally and later was fit binaurally. A significant decrement in the suprathreshold word-recognition scores occurred only in the unaided ear following monaural amplification, illustrating the phenomenon of adult-onset auditory deprivation. Following binaural amplification, the suprathreshold word-recognition scores for the formerly unaided ear improved significantly, illustrating the phenomenon of recovery from the adult-onset auditory deprivation with binaural amplification.

The purpose of this investigation was to evaluate the sensitivity and specificity of the following acoustic-immittance protocols and their constituent measures for detection of middle-ear effusion in children: (a) tympanometric width; (b) absent ipsilateral acoustic reflex; (c) ASHA guidelines; (d) tympanometric peak pressure; and (e) static-acoustic middle-ear admittance. The middle-ear sample was composed of 82 ears of 54 subjects ranging in age from 3 to 11 years. The control (normal-hearing, normal middle-ear) sample was composed of 53 ears of 53 subjects ranging in age from 3 to 10 years. Each subject was given a complete otolaryngologic evaluation (including pneumotoscopy and/or microtoscopy) and audiologic (including acoustic-immittance) evaluation. In the group of middle ears with normal-hearing sensitivity, the sensitivity and specificity of the ASHA guidelines were 63 percent and 79 percent, respectively. An acoustic-immittance screening protocol, based on all of the individual acoustic-immittance measures, and characterized by high sensitivity and specificity, is proposed.

The suprathreshold word-recognition scores for 2 young, adult males with bilateral, symmetrical sensorineural hearing impairment were evaluated following monaural and then binaural hearing-aid fitting. Subjects were obtained by retrospective review of records. Subject 1 was followed over an approximately 11.5-year time period and Subject 2 was followed over an approximately 6-year period. Results revealed that a significant decrement occurred in the unaided ear following the monaural hearing-aid fitting. Then, significant improvement in the formerly unaided ear occurred following the binaural hearing-aid fitting. The implications with respect to recovery from apparent auditory deprivation after binaural amplification are discussed.

Moxalactam disodium is a new third-generation semisynthetic, broad-spectrum, cephalosporin-like antibiotic for parenteral administration. Topical, subconjunctival, and intravenous administration provide poor concentration in the vitreous. To determine its toxicity in intravitreal administration, we injected comparative doses directly into the vitreous cavity of 21 rabbits. With doses of 1.25 mg or less there was no toxic damage to the retina. With a dose of 2.5 mg, early degeneration of photoreceptors was seen after three months. With higher doses (5 and 10 mg) there were major histopathologic and electroretinographic changes. These results suggest the feasibility of employing moxalactam in the treatment of acute, severe, fulminant bacterial endophthalmitis.

Performance on tests of pure-tone thresholds, speech-recognition thresholds, and speech-recognition scores for the two ears of each subject were evaluated in two groups of adults with bilateral hearing losses. One group was composed of individuals fitted with binaural hearing aids, and the other group included persons with monaural hearing aids. Performance prior to the use of hearing aids was compared to performance after 4-5 years of hearing aid use in order to determine whether the unaided ear would show effects of auditory deprivation. There were no differences over time for pure-tone thresholds or speech-recognition thresholds for both ears of both groups. Nevertheless, the results revealed that the speech-recognition difference scores of the binaurally fitted subjects remained stable over time whereas they increased for the monaurally fitted subjects. The findings reveal an auditory deprivation effect for the unfitted ears of the subjects with monaural hearing aids.

This study investigates the controversy regarding the influence of age on the acoustic reflex threshold for broadband noise, 500-, 1000-, 2000-, and 4000-Hz activators between Jerger et al. [Mono. Contemp. Audiol. 1 (1978)] and Jerger [J. Acoust. Soc. Am. 66 (1979)] on the one hand and Silman [J. Acoust. Soc. Am. 66 (1979)] and others on the other. The acoustic reflex thresholds for broadband noise, 500-, 1000-, 2000-, and 4000-Hz activators were evaluated under two measurement conditions. Seventy-two normal-hearing ears were drawn from 72 subjects ranging in age from 20-69 years. The results revealed that age was correlated with the acoustic reflex threshold for BBN activator but not for any of the tonal activators; the correlation was stronger under the 1-dB than under the 5-dB measurement condition. Also, the mean acoustic reflex thresholds for broadband noise activator were essentially similar to those reported by Jerger et al. (1978) but differed from those obtained in this study under the 1-dB measurement condition.

Butirosin (BTN) (P. W. K. Woo, G. L. Coffey, H. W. Dion, S. A. Fusari, and G. D. Senos, U. S. Patent 3,541,078, 1970) is a new aminoglycoside antibiotic notably active against opportunist bacterial species within Pseudomonas, Klebsiella, Enterobacter, Serratia, and Proteus. Numerous comparative tests were carried out with BTN and gentamicin (GTM) in vitro and in experimental infections in mice. BTN was more active in Mueller-Hinton broth than in agar, but its activity was lessened at acid pH or under anaerobiosis, as has been observed with other aminoglycosides. In standard agar diffusion tests, inhibition zones greater than 12 mm around 30-mug BTN disks generally denoted susceptibility, equivalent to minimal inhibitory concentrations [Formula: see text] 25 mug/ml. Cross-resistance between BTN and GTM occurred in a variable manner, with a number of bacterial strains strongly resistant to GTM being moderately susceptible to BTN. In mice, after a single subcutaneous injection, absorption of both antibiotics was rapid, with peak serum levels occurring in 15 min; this was followed by rapid elimination with estimated serum half-lives of about 20 min for each. After peroral administration of high doses in mice, there was no appreciable absorption of BTN. Several tests were carried out to compare BTN and GTM with respect to minimal inhibitory concentrations in vitro, acute subcutaneous median mouse protective doses, peak serum levels at such doses, and the therapeutic ratios derived from acute median protective and lethal doses. Although GTM usually proved to be more potent antibacterially on a weight basis, observations on BTN indicated a superior effectiveness in terms of therapeutic ratios.

Abnormal acoustic-reflex adaptation monitored in the same ear for both contralaterally and ipsilaterally presented tonal activators is reported in three cases. One case had Bell's palsy, whereas the other two cases had no clinically observable evidence of seventh-nerve involvement. These cases show that the existence of abnormal acoustic-reflex adaptation in the absence of Bell's palsy does not necessarily implicate the presence of eighth-nerve pathology.

The contralateral acoustic-reflex growth functions (ARGFs) for 500-Hz and 1000-Hz tonal activators were obtained pre- and postsurgery in a patient with a right cerebellar tumor. The acoustic-reflex magnitude was quantified as the change in equivalent air volume at the tympanic membrane during acoustic-reflex contraction. The presurgical ARGFs were shallow in the right ear and steep in the left ear at both activator frequencies. The postsurgical ARGFs were steep, bilaterally, reflecting a return to normal in the right ear. The implications with respect to the use of the ARGF measure in differential diagnosis are discussed.

The acoustic-reflex thresholds (ART) for multicomponent tonal complexes of varying bandwidth and spectral density were obtained from 20 normal-hearing (air-conduction thresholds less than or equal to 20 dB HL at 250-8000 Hz) young adults ranging in age from 20-30 years and 20 normal-hearing, old subjects ranging in age from 60-71 years. The results revealed that the ART decreased with spectral density, plateauing after seven components in the young group and after five components in the old group; the decrease in the acoustic-reflex threshold as a result of the increase in spectral density was less in the old than in the young group. The bandwidth effect (when bandwidth was plotted in hertz or octaves) on the acoustic-reflex threshold was present in the young adults, but substantially reduced in the elderly, as evidenced by the statistically significant interaction between subject group and signal bandwidth. The spectral density results are discussed in terms of their theoretic implications for the energy summation capacity and frequency resolution of the auditory system. The bandwidth results are discussed in terms of their theoretic implications for the frequency-resolving power of the auditory system.

The effect of age on accuracy of prediction of hearing impairment with the bivariate-plotting procedure was investigated in 72 normal-hearing subjects aged 20-69 years and in 86 sensorineural hearing-impaired subjects aged 20-83 years. The predictive accuracy with the bivariate-plotting procedure improved markedly when the data from subjects over 44 years of age were excluded from the bivariate plot. The predictive accuracy improved further when the construction of the line segments in the traditional bivariate plot was modified.

Acoustic reflex growth functions for pure tone activators of 500, 1000 and 2000 Hz and a broad-band noise (BBN) were obtained with activator durations of 20, 200 and 1000 msec (10 msec rise/decay) in four young, normal subjects. The lowest reflex thresholds were obtained for the 1000 msec activators, followed by 200 msec and then 20 msec. The reflex growth functions revealed lower reflex magnitudes for the shorter duration activators. When normalized to account for temporal summation at reflex threshold, reflex magnitude growth was similar among the three durations at 500 Hz, slower for 20 msec than for 200 and 1000 msec at 1000 Hz, and became progressively slower with decreasing duration from 1000 to 200 to 20 msec at 2000 Hz. When expressed in SPL, the BBN growth functions reasonably resembled those at 2000 Hz. No particular pattern was revealed for the normalized BBN growth functions.