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Biomedical subjects

C I Berlin

Publications and source records attributed to C I Berlin.

At least 37 records · Page 2Linked to original sources
PubMed1994

Cortical deafness: a longitudinal study.

We have studied a patient with MRI-confirmed bilateral absence of considerable portions of her temporal lobes resulting in cortical deafness. Although physiologic measures demonstrate normal peripheral hearing sensitivity, this patient's speech has the inflection and prosodic characteristics associated with profound peripheral hearing loss, and she is unable to understand spoken communication. Behaviorally obtained pure-tone thresholds taken over nearly 20 years range from normal to moderate hearing loss with normal middle ear muscle reflexes and normal ABRs; however, we consistently found abnormal middle latency and cortical evoked potentials. Because of her total inability to communicate auditorily, this patient was ultimately taught American Sign Language and educated at the Louisiana School for the Deaf. This rare case highlights the importance of using multiple audiologic measures sensitive to abnormalities at various levels of the auditory system.

Adult↗
PubMed1993

Contralateral suppression of non-linear click-evoked otoacoustic emissions.

Click-evoked otoacoustic emissions from nominal 80 dB pSP (peak sound pressure) 80-microseconds pulses presented at 50 pulses per second were collected from the right ears of eleven normal hearing subjects using an ILO88 Otodynamic Analyzer in the non-linear mode. Clicks, pure tones, and narrow bands of noise were then presented to their left ears through insert earphones. The 80-microseconds contralateral clicks ranged in intensity from 80 dB pSP in 5 dB steps down to 60 dB pSP but data on only 10 of the subjects were collected successfully. The pure tones and narrow bands of noise centered at 250, 500, 1000, 2000, and 4000 Hz were also presented through insert phones at 20, 40, 60 and 80 dB HL (Hearing Level) to all 11 subjects. The mean overall 'echo amplitude' without contralateral stimuli was 11 dB SPL and underwent more than 3 dB of overall suppression in response to the noises which were the most effective of the contralateral suppressors. When we analyzed the echo suppression to noise in 2-ms segments, we found consistent contralateral suppression of 3-4 dB concentrated in the time zones after 8 ms. Time shifts of more than 200 microseconds between the control and experimental traces were also observed in the same zones. The clicks were the next most effective suppressors, but showed their amplitude and time effects in somewhat earlier time zones. The tones were the least effective suppressors suggesting that efferent effects we measured in the human system are not strongly tonotopic. Because 'non-linear' mode high intensity clicks were deliberately selected as stimuli to evoke the TEOAE's, the emissions and their suppression can represent neither the 'true' TEOAE nor all of the efferent system's suppression abilities.

Acoustic Stimulation↗
PubMed1993

Does type I afferent neuron dysfunction reveal itself through lack of efferent suppression?

We present here two patients and three control subjects to demonstrate the clinical utility of studying evoked otoacoustic emissions and their contralateral suppression, as an aid to the delineation of afferent neuron dysfunction and possible lack of efferent suppression. The key patients here who fail to show contralateral suppression of their very robust otoacoustic emissions, concomitantly show paradoxically absent auditory brainstem responses (ABRs) and absence of middle ear muscle reflexes despite normal audiograms in the 2 kHz region and normal tympanograms. One of these patients has nearly normal pure tone sensitivity up to 3 kHz. The other has normal sensitivity in the 2 kHz region, but poor sensitivity on either side of that frequency. In addition, the two patients of interest show absent masking level differences and inordinately poor speech discrimination. Three 'foils' are presented: one patient with poor hearing on either side of 2 kHz, one with Bell's Palsy, and the third with bilateral temporal lobe disease. These patients show respectively that (1) isolated normal hearing at 2 kHz, (2) absence of middle ear muscle reflexes and (3) conscious cortical awareness of sound do not contribute directly to this intriguing clinical state. We propose that these patients with absent ABRs suffer from an auditory nervous system dysfunction which disrupts access to the efferent system. This condition also disables whatever systems contribute to the neural synchrony inherent in recording compound far-field action potentials such as the ABR. There are a number of hypotheses to be considered here. One suggests that the key patients are deficient in synchronous activation of Type I afferent fibers to the degree that they cannot activate efferent feedback, or they may be able to use only so-called Type II afferent neurons to support their normal zones of pure tone sensitivity. A less likely consideration focuses on the notion that discharge of primary neurons might be in some way synchronized by an efferent system which in these patients is the primary source of deficit.

Acoustic Impedance Tests↗
PubMed1991

Derived guinea pig compound VIIIth nerve action potentials to continuous pure tones.

A technique is described which verifies neural activity to a very faint continuous sine wave through subtraction of two different far-field whole nerve action potentials from one another. A brief transient is presented to an animal in order to elicit a supra-threshold action potential. The technique is then repeated, but on the second trial a near-threshold sine wave is mixed with the transient and another action potential is collected. The resultant evoked is then subtracted from the evoked potential generated by the transient alone and a small but persistent difference potential is acquired that presumably represents the unit activity occupied by the continuous sine wave. Four experiments are presented to show the validity of this technique, along with a surprising stability of the derived-response latency despite a 30 dB range of the probes. The technique may have promise in predicting behavioral responses to sinusoids acquired from individual animals.

Acoustic Stimulation↗
PubMed1991

Guinea pigs show post-natal stability in frequency mapping at the basal turn.

Others have shown that in animals born with immature cochleae the basal turn undergoes changes in function during the early days of postnatal life. We examined whether similar changes could be detected in the guinea pig, an animal born with a functionally mature cochlea. Our results indicate that no changes occur in the function of the basal turn of the guinea pig cochlea immediately after birth.

Acoustic Stimulation↗
PubMed1991

Objective auditory threshold estimation using sine-wave derived responses.

A derived response method of acquiring frequency specific auditory evoked potentials that utilizes a pure tone in combination with a toneburst is applied to the measurement of hearing sensitivity in guinea pigs, chinchillas and pocket gophers. Two experiments which demonstrate that thresholds acquired via tone-derived responses are 10 to 15 dB more sensitive than thresholds to solitary tonebursts are described. The derived potentials approximate behaviorally acquired thresholds at frequencies of 0.5 kHz and above. This technique may provide a more rapid means of assessing hearing sensitivity in laboratory animals than by behavioral means.

Acoustic Stimulation↗
PubMed1991

Animal research.

Explore the source record for details and available documents.

Animal Welfare↗
PubMed1991

Measurement of sound.

The measurement of sound involves the analysis of frequency, intensity, and temporal dimensions of acoustic signals. Each dimension of sound can be related directly to clinically observed phenomena. Frequency information, measured in Hz, can be extracted from pure-tone and complex stimuli. Intensity represents the physical energy of a signal and is described by using the decibel scale--a logarithmic scale of ratios. Temporal characteristics of sound include duration, phase, and repetition rate. In the analysis of human hearing sensitivity, the middle ear system and its impedance characteristics also must be considered. In this article, we have reviewed some major principles of sound and have presented a series of practical clinical applications. Such principles as these help to predict and explain frequency of laryngeal tones, middle ear mechanics, ear canal resonance, real-ear measurements of hearing aids, the Articulation Index, hearing loss, understanding of speech in quiet and in noise, and the relation between hearing and speech.

Acoustic Stimulation↗
PubMed1990

Auditory evoked potentials differ at 50 milliseconds in right- and left-handed listeners.

Left-handed individuals show a 4 ms later Wave Pb in the 45-60 ms latency range of the auditory middle latency response (MLR) than right-handed individuals. Examination of auditory evoked potentials in fifteen right-handed and fifteen left-handed normal hearing adults showed that this difference was not evident in time periods earlier or later than 45-60 ms. The isolation of this latency difference to a specific time period suggests that the source or sources of Wave Pb may be an independent physiological index which correlates with hand preference.

Acoustic Stimulation↗
PubMed1988

Hemispheric processing of affective and linguistic intonation contours in normal subjects.

In a previous study of the comprehension of linguistic prosody in brain-damaged subjects, S. R. Grant and W. O. Dingwall (1984. The role of the right hemisphere in processing linguistic prosody, presentation at the Academy of Aphasia, 1984) demonstrated that the right hemisphere (RH) of nonaphasic patients plays a prominent role in the processing of stress and intonation. The present study examines laterality for affective and linguistic prosody using the dichotic listening paradigm. Both types of prosody elicited a significant left ear advantage. This advantage was more pronounced for affective than for linguistic prosody. These findings strongly support previously documented evidence of RH involvement in the processing of affective prosody (R. G. Ley & M. P. Bryden, 1982. A dissociation of right and left hemispheric effects for recognizing emotional tone and verbal content, Brain and Cognition, 1, 3-9). They also provide support for the previously mentioned demonstration of RH involvement in the processing of linguistic intonation (S. Blumstein & W. E. Cooper, 1974. Hemispheric processing of intonation contours, Cortex, 10, 146-158; Grant & Dingwall, 1984).

Adult↗
PubMed1981

Binaural interaction components. Their possible origins in guinea pig auditory brainstem response.

A two-step ablation technique under visual control was used to clarify the possible sites of origin of the binaural interaction component (BIC) of the auditory brainstem-evoked response (ABR). The BIC is obtained by summing ABRs elicited by monaural clicks to each ear and subtracting this sum from the ABR elicited by binaural clicks. Among the results were the following: first, the ABR and the BIC remained virtually unchanged after collicular aspiration; second, after midsagittal section of the brainstem, both wave III in the ABR and the BIC were abolished. These results suggest that although the inferior colliculus is a powerful integrative center for the processing of binaural signals, the neural structures in the guinea pig necessary for the primary generation of the BIC must be located caudal to the colliculus, yet rostral to the medial nucleus of the trapezoid body.

Animals↗
PubMed1981

Electrophysiological simulation of tinnitus.

The auditory brainstem response to clicks of 60 dB sensation level was recorded with superimposed pure tones at six frequencies and four sensation levels in an attempt to simulate the effects of tinnitus on the auditory brainstem response. Changes in responses were assessed by subtracting the auditory brainstem response obtained to the click-plus-tone from the auditory brainstem response obtained to the immediately preceding click alone. The dyssynchrony created by exogenously produced pure tones was considerable and probably reflected adaptation of individual single units; however, the auditory brainstem response to clicks alone changed markedly from the beginning to the end of the experiment and confounded a simple interpretation of the results.

Adolescent↗
PubMed1981

Auditory signal processing in a hearing-impaired subject with residual ultra-audiometric hearing.

A number of hearing-impaired individuals with near-normal thresholds for frequencies above 8,000 Hz who are characterized by good speech articulation have recently been identified. It is unclear whether this unusually good articulation is linked to the ability of such persons to process speech signals containing energy that falls within the range of their residual, high-frequency hearing (for example, certain consonants). This paper reports a detailed study of the signal-processing capabilities of one patient with a long-standing, severe to profound hearing loss in the standard audiometric range, and normal left-ear thresholds in the region of 13,000 Hz. Measures obtained include difference limens for frequency and intensity, gap detection, rate matching, temporal integration, and tone-on-tone masking profiles (psychoacoustical tuning curves). In addition, measures of speech production and perception were made when the patient was using an experimental hearing aid designed to transpose speech range frequencies into the region of her residual high-frequency hearing. Results indicate the patient can efficiently process signals which fall within the band of her best hearing, and suggest her ultra-audiometric hearing may be useful in speech communication.

Adult↗
PubMed1980

Amplification in sudden deafness: a case study.

This report describes a case of traumatic sudden deafness in an adult and the unanticipated clinical problems in providing appropriate amplification and aural rehabilitation. The effect of acoustic distortion on central visual perceptual processes and previously ingrained aural language patterns is presented as a viable explanation. Implications regarding the necessity of evaluating the interaction between the auditory and visual channels are discussed.

Adult↗
PubMed1980

Central deafness: fact or fiction?

Although there has been some skepticism about the existence of central hearing loss because of the absence of an acceptable tool for its evaluation, techniques are now available for its measurement. There are some excellent behavioral methods available [1]. However, with judicious use of ABR, electrocochleography, and transcranially and ipsilaterally elicited middle-ear muscle reflexes, certain forms of central dysfunction can be studied physiologically.

Adult↗
PubMed1979

Binaural interaction in brainstem-evoked responses.

Binaural interaction (BI) in brainstem-auditory-evoked responses (BSERs) was defined as any deviation from the predictions of a model that assumes two independent monaural BSER generators whose outputs are additive. Brainstem-auditory-evoked responses were recorded in response to right (R) monaural, left (L) monaural, and binaural click stimuli. The monaural BSERs were added to give the model's prediction (P) of binaurally evoked BSER (P = L + R), and this trace was then subtracted from the actual binaurally evoked response (B). The resultant difference trace (d = b - p) represents the derived BI. In each of ten guinea pigs, a strong BI was present in the peak IV region (latency = 3.5 to 4.0 ms). This interaction is probably present with interaural intensity differences of up to 40 dB and interaural time differences of up to 3 ms. Preliminary studies suggest the presence of a similar phenomenon in human BSERs.

Acoustic Stimulation↗