Biomedical subjects

J A Baran

Publications and source records attributed to J A Baran.

14 recordsLinked to original sources

PubMed1999

Selected management approaches to central auditory processing disorders.

This is a commentary on three key aspects of the management of central auditory processing disorders in children. It is an update on some selected approaches for the management of auditory processing problems. Auditory training techniques that are theoretically based and for which empirical data are emerging are addressed. The second part of our commentary deals with methods of enhancing acoustic speech signals. Discussions on clear speech, acoustic modifications of the listening environment, and the utilization of assistive listening devices are presented. The final part of the article reviews linguistic and cognitive interventions for people with auditory processing problems. Topics in this section include approaches to facilitate phonological awareness, vocabulary building, prosodic feature recognition, and use of metacognitive abilities.

Auditory Diseases, Central↗

PubMed1997

Distortion product otoacoustic emissions: hit and false-positive rates in normal-hearing and hearing-impaired subjects.

OBJECTIVE: This study aimed to establish hit and false-positive rates for distortion product otoacoustic emissions (DPOAEs) using a commercial instrument. STUDY DESIGN: This was a prospective study. The examiners performing the DPOAEs were blinded to pure-tone audiometric results. A decision matrix analysis was used to determine hit and false-positive rates for absolute amplitude, three amplitude-to-noise ratios, and three conditions that combined these two parameters. SETTING: The study was performed at a tertiary care, outpatient clinical laboratory facility. PATIENTS: Subjects with normal hearing and those with sensorineural hearing loss participated in the study. MAIN OUTCOME MEASURES: Main outcome measures were hit and false-positive rates for various DPOAE measures. RESULTS: Hit and false-positive rates were better for high than low frequencies. As absolute amplitude and amplitude-to-noise ratios increased hit and false-positive rates improved. Optimal hit rates generally exceeded 80%; false-positive rates were approximately 20% in the high-frequency range. Although the absolute amplitude measures seemed more useful than various ratio measures, there were advantages to using both parameters clinically. CONCLUSIONS: DPOAEs have acceptable hit and false-positive rates for high frequencies but not for lower frequencies. DPOAE amplitude-to-noise ratios of +3 and even +6 dB may not be clinically feasible based on the current data. The overall findings obtained on the commercial instrument in this study compare favorably with previous studies of a similar nature.

Acoustic Impedance Tests↗

PubMed1996

Audiologic evaluation and management of adults with auditory processing disorders.

Over the past decade there has been an increase in the number of adults with persistent hearing complaints coincident with normal audiometric findings who are seeking audiologic follow-up in an effort to determine the basis of their hearing difficulties. Although in some cases the etiology of the hearing difficulties is clearly not related to compromise of the auditory system, in many cases the basis of the difficulties can be linked to auditory system compromise. This article reviews the various etiological bases for these hearing difficulties and the symptoms most commonly reported by adults who fit into this category of patients. The application of peripheral and central auditory tests in the assessment of these patients is described and implications of test findings for management of the individual with these deficits are discussed.

Adaptation, Psychological↗

PubMed1996

Comparison of standard and abbreviated distortion product otoacoustic emissions procedures.

Standard and abbreviated distortion product otoacoustic emissions (DPOAEs) procedures derived using the Grason Stadler Model 60 instrument were compared. The standard and abbreviated procedures were compared at frequencies of 1000, 1250, 1593, 2000, 2531, and 3187 Hz for 48 ears from 28 subjects. The subject pool included individuals with normal hearing and those with sensorineural hearing loss. The abbreviated procedure correlated well with the standard procedure for DPOAE amplitude cross all frequencies tested. The two procedures were also highly similar in categorizing the subjects in regard to normal or abnormal hearing sensitivity. It appears that the shorter analysis time for the abbreviated procedure had little effect on its accuracy. Although the abbreviated procedure has an obvious frequency limitation, it may have some clinical advantages for hearing screening.

Acoustic Stimulation↗

PubMed1995

"Negative" ABR findings in an individual with a large brainstem tumor: hit or miss?

This case illustrates the importance of determining the precise locus and extent of a lesion when attempting to correlate lesion site with auditory brainstem response (ABR) findings. The failure to document significant ABR findings in an individual with a large mass involving the low brain stem may initially appear to constitute a threat to the sensitivity of the ABR; however, careful review of the radiologic evidence in this case suggests that sensitivity did not suffer, but rather that the specificity of the procedure was upheld. Moreover, the value of electronystagmography (ENG) in the assessment of an individual with a lesion in the region of the low brain stem and severe vestibular symptoms is demonstrated.

Adolescent↗

PubMed1992

P300 results in patients with lesions of the auditory areas of the cerebrum.

Auditory P300 event-related potentials were obtained at C3 and C4 recording sites from 20 patients with cerebral lesions that affected auditory areas of the brain. The patient group was matched for age and hearing sensitivity to a control group of 20 subjects. There were significant differences between the two groups for both latency and amplitude of the P300. Eight patients demonstrated an absent P300 for at least one recording condition while all subjects in the control group had readable P300s in all recording conditions. A subset of patients with lesions limited to one hemisphere showed no laterality effects for amplitude or latency of the P300 for the ear or electrode that was either ipsilateral or contralateral to the lesion. In comparison to the P2 evoked potential, the P3 was more sensitive to neurologic lesions.

Adolescent↗

PubMed1990

Canal electrode electrocochleography in patients with absent wave I ABRs.

Fifteen patients (23 ears) who demonstrated no recordable wave I at the time of clinical auditory brainstem response testing were subsequently retested under three auditory brainstem response-electrocochleography conditions. One condition was the traditional auditory brainstem response, another was the auditory brainstem response with electrocochleography filtering, and the third was an electrocochleographic condition using a canal electrode (Tiptrode). The electrocochleographic recording condition provided more readable wave I responses than the other conditions. In addition, the electrocochleographic condition provided wave I amplitudes that were greater than those of the traditional auditory brainstem response. The later waves of the auditory brainstem response (III and V) were similar in wave presence amplitudes and latencies for all three test conditions.

Adult↗

PubMed1990

Duration pattern recognition in normal subjects and patients with cerebral and cochlear lesions.

Three groups of subjects were tested on a duration pattern recognition task. The groups included normal subjects, subjects with cochlear hearing loss, and subjects with lesions involving but not limited to the auditory areas of the cerebrum. Results indicated no significant difference in pattern recognition between the normal subjects and subjects with cochlear hearing loss. However, the subjects with cerebral lesions performed significantly more poorly than either the normal subjects or those with cochlear hearing loss. In comparing pattern recognition performance for the ears ipsilateral and contralateral to the lesioned hemispheres no differences were noted. Rather, when a central lesion was present, both ears generally yielded abnormal scores.

Adult↗

PubMed1989

The dichotic rhyme task: results in split-brain patients.

Monosyllabic rhyme words were dichotically presented to normal and complete split-brain subjects. In the normal adult population, only one of the words in the dichotic condition was identified. Hence, normal performance was about 50%, with a small but significant right-ear advantage. The split-brain patients yielded the expected marked left deficit, as seen on other dichotic speech tests, and demonstrated a right-ear enhancement, producing a large interear difference. This right-ear enhancement on the dichotic rhyme task (DRT) may suggest a release from central auditory competition in the left hemisphere. The dichotic rhyme task's normative data results and sensitivity to lack of callosal transmission make it worthy of further clinical and basic research.

Adolescent↗

PubMed1988

Topographic mapping of brain electrical activity in the assessment of central auditory nervous system pathology.

Topographic mapping of brain electrical activity is a method of converting electrical measurements of brain activity (evoked potential and EEG) into quantitative data that then can be displayed as colored visual maps. In this article, we review the basic principles underlying the procedures involved and then discuss their use in the assessment of central auditory nervous system (CANS) pathology. Finally, we highlight some of the limitations of the procedures as presently used.

Adult↗

PubMed1987

Central auditory assessment: thirty years of challenge and change.

In this paper we discuss some of the major developments that have occurred in the field of central auditory assessment over the past 30 years. We discuss both the psychophysical and the electrophysiological procedures that have been used for either research and/or clinical purposes. Case illustrations from our own clinical experience are also provided. Finally, we conclude by suggesting directions for future research.

Auditory Diseases, Central↗

PubMed1986

Neuroanatomy, neurophysiology, and central auditory assessment. Part I: Brain stem.

This paper is the first in a series of three that address neuroanatomical and neurophysiological aspects of central auditory assessment. The focus of this article is the "auditory" brain stem. Pictures of the auditory structures in the human brain stem in normal and pathological states are shown. Physiological evidence of neural coding of acoustic stimuli is discussed. Relationships between brain stem anatomy/physiology and clinical test results and their interpretation are highlighted.

Auditory Pathways↗

PubMed1986

Central auditory function following anterior sectioning of the corpus callosum.

This paper describes auditory findings for eight patients with anterior sections of the corpus callosum. Peripheral (pure tone and speech recognition) and five central auditory tests were administered to each of the eight patients prior to surgery and then again approximately 2 weeks after surgery. The central tests administered included a low-pass filtered speech test, the frequency patterns perception test, and three dichotic speech tests. Mean scores for the peripheral tests fell grossly within the normal range preoperatively and showed little change postoperatively. Similarly, scores on the central tests, though somewhat more variable, did not show any obvious differences upon pre- and postsurgical comparison. A comparison of these results with those reported previously for patients with complete commissurotomies (Musiek, Kibbe, and Baran. Semin Hear 1984;5:219-29) revealed that as a group, patients with anterior sections of the corpus callosum showed fewer postsurgery deficits than did the subjects with complete commissurotomies. The lack of an apparent auditory effect in the anterior group is believed to have an anatomical basis.

Adult↗

PubMed1985

Release from central auditory competition in the split-brain patient.

We used dichotic digits (DD), staggered spondaic words (SSW), and frequency patterns (PATT) to study central auditory function before and after two-stage callosotomy. Preoperatively, the patient demonstrated reduced scores bilaterally on all these tests, consistent with documented bilateral hemisphere lesions. After the first operation (sectioning the posterior half of the corpus callosum), the dichotic tests (DD and SSW) revealed the expected decrease in left-ear scores, but there was improvement on the right, perhaps because there was release from central auditory competition. Our findings also suggest that the "auditory" portion of the corpus callosum may be in the posterior half of this structure.

Adult↗