Binaural Loudness Balance Research Articles

Special hearing tests in otoneurologic diagnosis.

IN the past decade or so, a relatively large number of special audiological tests has been devised in efforts to increase the precision with which the clinician is able to predict the site of lesion within the auditory system of a given patient. The concept of a "battery of tests" has emerged, particularly with respect to the differentiation among lesions at the three primary sites in the peripheral mechanism; (1) conductive, (2) sensory, (3) neural. The purpose of this presentation is to consider the usefulness of such a test battery, with attention on the precision which it allows in differentiating between peripheral lesions of the cochlear and retrocochlear varieties. The individual tests to be considered are: (1) speech discrimination; (2) short increment sensitivity index (SISI); (3) alternate binaural loudness balance; (4) Bekesy audiometry using both continuous and interrupted stimuli; and (5) threshold tone decay. <h3>Patient Samples Studied</h3> Two patient groups,

Sensory interaction: perception of loudness during visual stimulation.

Eight subjects engaged in an alternate binaural loudness balance (ABLB) task utilizing the method of adjustment to explore the perception of loudness of a 300-msec-duration 1-kHz auditory stimulus at 20 dB and 50 dB SL's. Conditions utilized were no visual stimulation during ABLB, visual stimulation in synchrony with the standard auditory stimulus during ABLB, and visual stimulation in sychrony with the comparison auditory stimulus during ABLB. The visual stimulus was a short-duration stroboscopic light flash. The data indicated that sensory interaction in terms of visual facilitation of auditory loudness does occur and is more apparent at higher rather than lower SL's. The comparison stimulus was adjusted to a higher SL when the visual stimulus was associated with the standard auditory stimulus than when the visual stimulus was associated with the comparison auditory stimulus. The magnitude of this statistically significant difference was approximately 7 dB and implies that information presented to the visual sensory modality can affect the perception of the magnitude of information presented to the auditory sensory modality.

Perception of Loudness at Suprathreshold Levels during Visual Stimulation

Six observers engaged in an alternate binaural loudness balance (ABLB) task utilizing the method of adjustment to explore the perception of loudness of a 300-msec-duration 1-kHz auditory stimulus at 20 and 50 dB SL's. Conditions utilized were no visual stimulation during ABLB, visual stimulation in synchrony with the standard auditory stimulus during ABLB, and visual stimulation in synchrony with the comparison auditory stimulus during ABLB. The visual stimulus was a short-duration stroboscopic light flash. The data indicated that sensory interaction in terms of visual facilitation of auditory loudness does occur and is more apparent at higher rather than lower SL's. Observers adjusted the comparison stimulus to a higher SL when the visual stimulus was associated with the standard stimulus than they did when the visual stimulus was associated with the comparison stimulus. The magnitude of this statistically significant difference was 7 dB and it implies that information presented to the visual sensory modality can affect the perception of the magnitude of information presented to the auditory sensory modality. [Work supported by University of Wisconsin Graduate School.]

Intensities of aural difference tones.

An aural difference tone attributed to nonlinearity of the ear was produced by the use of four pairs of pure tones, 750 and 1000, 1750 and 2000, 3750 and 4000, and 7750 and 8000 Hz. A binaural loudness balance, which demonstrated the difference tone produced by 750 and 1000 Hz at 100 dB, had a frequency equal to the numerical difference between the paired tones, and had an intensity of approximately 90 dB. Instrumentation difference tones were maintained at a level of at least 70 dB below that of the primary tones. The aural difference tone used as a monaural masking stimulus for a pure tone of 250 Hz produced more threshold shift when the pairs of tones were presented simultaneously than when each of the tones was presented individually. The masking effect of the aural difference tone is a function of the frequency and intensity of the primary tones. The spread of masking over a 2-oct range, 125–500 Hz, using 750 and 1000 Hz simultaneously as the masking stimulus, was similar to that of a 250-Hz pure-tone masking stimulus.

Time-Intensity Trade and the Lateralized Location

Twenty-six male listeners completed the time—intensity trade and judged the lateralized location of interaural intensity differences from reference conditions of binaural loudness balance and binaural intensity balance. These signals of 150, 300, 600, and 1200 Hz were interrupted and had burst durations of 27, 20, 13, and 11 msec, respectively. The mean trading ratio increased as the frequency decreased and as the interaural intensity-difference increased. At lower frequencies, the mean ratio was larger when the trade was completed in a right-lateralized position. The mean judgments of lateralized location were 3.5 and 9.4 for right and left attenuation of 15 dB, respectively. The latter mean had a greater absolute difference from the midline number of 6.0. This indicated more displacement toward the right ear.

Tolerable limit of loudness: its clinical and physiological significance.

In the normal-hearing subject, a sensation of unpleasant loudness is invariably associated with intensities of the order of 100 dB within the frequency range 500–4000 cps. This is referred to as the loudness-discomfort level (LDL). The intensity distribution of LDL has been established in a large group of subjects with unilateral end-organ deafness, in all of whom the presence of loudness recruitment had been verified by means of the alternate binaural loudness balancing procedure. In these, the distribution was similar to that of a normal-hearing group. By contrast, the LDL's of subjects with conductive or nerve-fibre deafness exceeded the maximum available audiometer intensity of 120 db. The test, therefore, is of particular value in establishing the presence or absence of loudness recruitment in bilateral deafness. These findings suggest a physiological limit of loudness perception, the theoretical implications of which are discussed.

Clinical implications of loudness balancing.

THE ABNORMAL growth in loudness of a test tone has come to hold a special and frequently stereotyped significance, applicable only to and diagnostic of certain kinds of end-organ-related hearing losses. Valid as this stereotype may be, most of the time, it is not inviolate and does not always lead the otologist to a proper diagnosis. In fact, considerable valuable diagnostic information is lost by failure to view the Alternate Binaural Loudness Balance (ABLB) test with a broader perspective than it now enjoys. Investigators and clinicians have tried to point this out many times before, including Fowler himself, but their writings seem mainly ignored in everyday application.^1-3In this paper, we join their ranks and explore some test results which we doubt can be ignored. We also offer an operational explanation. Specifically, it will be demonstrated that,<i>it is almost a waste of time to test only for the</i>

THE SISI TEST AND RECRUITMENT OF LOUDNESS BY ALTERNATE BINAURAL LOUDNESS BALANCE.

THE SISI TEST AND RECRUITMENT OF LOUDNESS BY ALTERNATE BINAURAL LOUDNESS BALANCE.

"HYPERACUSIS"ACCOMPANIED BY FACIAL PALSY

We know from experience that the patients suffering from facial palsy complain frequently of hearing disorder, hyperacusis, especially in its early stage, which is regarded as a significa- nt symptom in focal diagnosis of the disease. That is to say, the in these cases has been considered to be due to paralysis of the stapedial muscle innervated by a branch of the facial nerve. However, the literature concerning it is very scanty from the otological point of view. The authors made some clinical observations on 32 patients with accompanied by facial palsy who visited the Oto-Rhino-Laryngological Clinic of University of Tokyo The results obtained were as follows: 1) There was no marked difference between both sexes in number of the cases. 2) The distribution of the patients in age covered from 20 to 39 years of age in the greatest proportion while none being observed under 10 years of age. 3) Etiology of the disease was undetermined in the vast majority of patients, except some cases caused by common cold, herpes zoster oticus or trauma. 4) The chief complaint as prodromal symptom was headache in most cases. 5) As to accompanied symptoms, tinnitus was frequently complained, disorder of the taste in 5 cases, that of the salivary secretion in 3 cases being observed at the same time. 6) In hearing examination, 19 cases revealed normal hearing threshold, increased in 13 cases decreased in none of the cases. 7) Based upon the audiograms, the patients were divided into four types as follows. (1) Type of normal hearing. (2) Type of abrupt high tone loss. (3) Type of gradual high tone loss. (4) Type of c5-dip. 8) In 28 cases examined by means of Fowler's binaural loudness balance test, 15 cases dis- played positive recruitment phenomenon including 8 cases of the normal hearing type, while 13 cases showed negative. 9) It was generally observed that the disappearance of was not paralled by the recovery of facial palsy. In some cases with permanent facial palsy, disappeared in early stage of the disease. 10) According to our observation, was complained even in a case whose facial nerve was injured at the region external to the stylomastoid foramen, peripheral to the bran- ching of the stapedial nerve. Conclusion; We gathered from these observations that the in facial palsy was partly due to the positive recruitment phenomenon, partly due to diplacusis. The term hyperacusis comp- lained in facial palsy is considered as an inadequate word to express its actual state as there was no one showed the increased hearing acuity among these cases complained of hyperacusis. For this reason, we offered the proposal to accept the term Dysacusis stapedica as more reasonable expression to elucidate this particular state of hearing.

Difference limen and recruitment.

THE NEED for the measurement of recruitment is apparent in the speed with which "recruitment tests" have been provided by manufacturers of audiometers and are incorporated in clinical routines, even before sufficient validating work has been done. This need presumably arises in connection with diagnosis. No one doubts by now that the presence of recruitment is indicative of a nonconductive hearing loss. Furthermore, if the thesis of Dix, Hallpike, and Hood¹is substantiated, even finer diagnoses can distinguish between cochlear and retrocochlear pathologies. Recruitment is defined primarily as a more-rapid-than-normal increase in subjective loudness for a given increase in physical intensity. It is most readily explored, according to this definition, by the binaural loudness balance, described originally by Fowler.²In this technique one measures the intensities of two tones (one presented to the left, the other to the right ear) when the listener reports that they sound equally

Some Recent Work on Auditory Adaptation and its Relationship to the Loudness Recruitment Phenomenon

In the course of previous investigations, Dix, Hallpike, and Hood have concluded that the phenomenon of loudness recruitment is attributable to disordered function resulting from injury or disease of the hair cells of Corti's organ. In the present paper, an account is given of an experimental study of certain loudness changes caused by adaptation of the hair cell responses to pure tone stimulation. Two outstanding characteristics of the adapted state are defined: “on-effect normality” and “relapse.” Both resemble very closely those described by Matthews in the case of adaptation occurring the muscle stretch receptors of the frog. Further studies in a number of human subjects show that both of these characteristics are exhibited regularly by the unadapted hair cell responses of individuals suffering from degenerative changes of the hair cells. These studies appear to establish a very close similarity between “on-effect normality” occurring in the case of the adapted normal sense organ and the phenomenon of loudness recruitment, as demonstrated by the alternate binaural loudness balance procedure of Fowler in the case of the unadapted but diseased sense organ. The experimental findings are considered to favor the view that loudness recruitment is one element of a complex disturbance of cochlear function due to disease or injury of specific elements of the cochlear sensory apparatus, namely the hair cells of Corti's organ.