• Speech Sciences
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• v.11 no.3
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• pp.201-211
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• 2004

This paper introduces a development of an electrical stimulator for auditory stimulation. The electrical stimulator is useful in neurotological diagnosis, audiological evaluation, candidate selection for cochlear implantation, optimal device selection and decision making of MAP strategy for severe-to-profound hearing impaired persons. The development was based on sound parameters of auditory brainstem responses and auditory electrophysiological characteristic such as effective firing of auditory nerve and recording evoked potentials during refractory period of neuron. Besides pulse parameter could adjustable by programming for more varied electrical stimulation evoked response audiometry. Using the electrical stimulator, electrical square pulse was applied to promontory, and electrically evoked auditory brainstem response and electrically middle latency response were successfully recorded in cats.

• Journal of Veterinary Clinics
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• v.40 no.4
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• pp.260-267
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• 2023

Specialized hearing tests for pets are currently in demand. A brainstem auditory evoked response (BAER) test is an objective, non-invasive, and practical electrophysiological method that records electric signals from the peripheral auditory system to the brainstem when an auditory stimulation is provided. In veterinary medicine, sedation or anesthesia is essential for a successful examination. In human medicine, research has established the indications for various sedatives, anesthetics, and drugs according to the depth of anesthesia required. However, in veterinary medicine, there are very few comparative studies on propofol or isoflurane, which are the most common anesthetics used. Therefore, the present study aimed to analyze the difference in BAER test results between sedation with medetomidine, anesthesia using propofol, and inhalation anesthesia with isoflurane after propofol administration. The test was conducted on four healthy adult dogs. There was no statistically significant difference in latency, interpeak latency, or amplitude between the various drugs. The results suggest that a sedative or anesthetic for the administration of a BAER test can be selected according to the patient's needs.

• Korean Journal of Audiology
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• v.24 no.1
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• pp.48-52
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• 2020

Lateralization for central auditory processing (CAP) with dichotic digits recognition (DDR) test is believed expression of hemispheric dominance. Multiple sclerosis (MS) is considered an inflammatory and autoimmune alteration of central nervous system (CNS). Hearing alterations in MS and their role in CAP has not been well studied. A patient with MS and new kind of alteration in lateralization of CAP with DDR test is presented. A 53 year of age female with MS of 16 years of evolution, nine of them remained asymptomatic. She has a persistent advantage of the right ear for DDR test; but other monaural tests showed predominance of the left afferent pathway. Brainstem auditory evoked potentials (BAEPs) and long latency auditory evoked potentials (LLAEPs) showed adequate right response with deficits in organization of left response in BAEP, and N2 wave. In the contrary direction of previous publication, we disclosed advantage for DDR test, BAEP, and LLAEP in the right ear. We observed no left ear suppression; with predominance of correct left percentages in monaural psychoacoustics tests. We must keep on searching to find pathophysiological meaning of predominant of right or left auditory laterality as a CAP disorder in patients with MS.

• Journal of Audiology & Otology
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• v.24 no.1
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• pp.48-52
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• 2020

Lateralization for central auditory processing (CAP) with dichotic digits recognition (DDR) test is believed expression of hemispheric dominance. Multiple sclerosis (MS) is considered an inflammatory and autoimmune alteration of central nervous system (CNS). Hearing alterations in MS and their role in CAP has not been well studied. A patient with MS and new kind of alteration in lateralization of CAP with DDR test is presented. A 53 year of age female with MS of 16 years of evolution, nine of them remained asymptomatic. She has a persistent advantage of the right ear for DDR test; but other monaural tests showed predominance of the left afferent pathway. Brainstem auditory evoked potentials (BAEPs) and long latency auditory evoked potentials (LLAEPs) showed adequate right response with deficits in organization of left response in BAEP, and N2 wave. In the contrary direction of previous publication, we disclosed advantage for DDR test, BAEP, and LLAEP in the right ear. We observed no left ear suppression; with predominance of correct left percentages in monaural psychoacoustics tests. We must keep on searching to find pathophysiological meaning of predominant of right or left auditory laterality as a CAP disorder in patients with MS.

• Journal of Veterinary Clinics
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• v.40 no.6
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• pp.414-422
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• 2023

Hearing assessment is critical in dogs and cats. Hearing loss in dogs and cats may be congenital or secondary to a central nervous system disorder or ear disease. The brainstem auditory-evoked response (BAER) test has been developed as an electrophysiological test for auditory function assessment. Modern BAER equipment is based on a computerized system. Thus, auditory function assessment can be performed using this objective, safe, and noninvasive method. No study has yet investigated the interspecies differences between BAER test results of dogs and cats. Therefore, the present study aimed to analyze the differences in BAER test results between dogs and cats. The test was conducted on four healthy adult dogs and four healthy adult cats. Regarding latency, lower values were obtained for all waveforms above 50 dB in cats compared to dogs. Regarding amplitude, cats showed higher values than dogs at intensities above 50 dB. Through a comparative analysis in this study, it was concluded that the two species had statistically significant differences. The BAER data of dogs cannot be applied to cats, and vice versa.

• Journal of Veterinary Clinics
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• v.25 no.6
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• pp.506-509
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• 2008

A 2-month-old, intact female white Bull Terrier presented because of suspected deafness. The coat color was predominantly white and the iris color, of both eyes, was brown. The dog did not respond to the owner's voice when the sound stimuli were presented outside of the visual field; however, the dog responded to visual gestures. The other physical, neurological, otoscopic, radiographic, and blood examinations were unremarkable. To assess the apparent deafness, brainstem auditory evoked responses (BAER) were recorded and analyzed in the dog with suspected deafness as well as a normal littermate. The response in the normal littermate consisted of a series of five wave peaks (I-V) with decreased amplitude and prolonged latency as the stimulus intensity decreased. The BAER from the dog suspected of deafness appeared as a flat line and did not reveal identifiable peaks that corresponded to those found in the normal littermate. Thus, congenital, sensorineural and bilateral deafness was confirmed by the BAER.

• Korean Journal of Audiology
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• v.24 no.2
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• pp.71-78
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• 2020

Background and Objectives: Currently limited information is available on speech stimuli processing at the subcortical level in the recipients of cochlear implant (CI). Speech processing in the brainstem level is measured using speech-auditory brainstem response (S-ABR). The purpose of the present study was to measure the S-ABR components in the sound-field presentation in CI recipients, and compare with normal hearing (NH) children. Subjects and Methods: In this descriptive-analytical study, participants were divided in two groups: patients with CIs; and NH group. The CI group consisted of 20 prelingual hearing impairment children (mean age=8.90±0.79 years), with ipsilateral CIs (right side). The control group consisted of 20 healthy NH children, with comparable age and sex distribution. The S-ABR was evoked by the 40-ms synthesized /da/ syllable stimulus that was indicated in the sound-field presentation. Results: Sound-field S-ABR measured in the CI recipients indicated statistically significant delayed latencies, than in the NH group. In addition, these results demonstrated that the frequency following response peak amplitude was significantly higher in CI recipients, than in the NH counterparts (p<0.05). Finally, the neural phase locking were significantly lower in CI recipients (p<0.05). Conclusions: The findings of sound-field S-ABR demonstrated that CI recipients have neural encoding deficits in temporal and spectral domains at the brainstem level; therefore, the sound-field S-ABR can be considered an efficient clinical procedure to assess the speech process in CI recipients.

• Journal of Audiology & Otology
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• v.24 no.2
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• pp.71-78
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• 2020

Background and Objectives: Currently limited information is available on speech stimuli processing at the subcortical level in the recipients of cochlear implant (CI). Speech processing in the brainstem level is measured using speech-auditory brainstem response (S-ABR). The purpose of the present study was to measure the S-ABR components in the sound-field presentation in CI recipients, and compare with normal hearing (NH) children. Subjects and Methods: In this descriptive-analytical study, participants were divided in two groups: patients with CIs; and NH group. The CI group consisted of 20 prelingual hearing impairment children (mean age=8.90±0.79 years), with ipsilateral CIs (right side). The control group consisted of 20 healthy NH children, with comparable age and sex distribution. The S-ABR was evoked by the 40-ms synthesized /da/ syllable stimulus that was indicated in the sound-field presentation. Results: Sound-field S-ABR measured in the CI recipients indicated statistically significant delayed latencies, than in the NH group. In addition, these results demonstrated that the frequency following response peak amplitude was significantly higher in CI recipients, than in the NH counterparts (p<0.05). Finally, the neural phase locking were significantly lower in CI recipients (p<0.05). Conclusions: The findings of sound-field S-ABR demonstrated that CI recipients have neural encoding deficits in temporal and spectral domains at the brainstem level; therefore, the sound-field S-ABR can be considered an efficient clinical procedure to assess the speech process in CI recipients.

• Journal of Veterinary Clinics
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• v.35 no.3
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• pp.103-106
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• 2018

A 12-year-old castrated male Shih Tzu presented with suspected hearing loss. The patient had no history of head trauma or exposure to ototoxic drugs. The results of neurologic and physical examinations were normal. An otoscopic examination showed that both the tympanic membranes and the external ear canals had a normal appearance. However, the results of brainstem auditory evoked response tests confirmed sensorineural deafness in the right ear and indicated conduction disturbances and brainstem abnormalities in the left ear. Magnetic resonance imaging was performed to confirm the causes of the conduction disturbances and brainstem abnormalities. Inflammatory changes in the left middle ear were highly suspected to be responsible for the findings in the left ear. The results of these examinations confirmed complete hearing loss in the right ear and indicated otitis media in the left ear, which could have been the cause of the conduction disturbances.

• Journal of Veterinary Clinics
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• v.37 no.3
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• pp.123-129
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• 2020

We aimed to investigate the differences in the efficacy of insert and circumaural earphones when performing the brainstem auditory evoked response (BAER) test with dogs. Hearing loss may occur congenitally or secondarily in dogs. The BAER test, unlike the classical ethological method, is the most reliable diagnostic tool to assess canine auditory function. Furthermore, there are certain advantages of using insert earphones rather than the standard, circumaural earphones. We subjected eight dogs to the BAER test with insert earphones and circumaural earphones. The result revealed that the latency of waves was delayed with an insert earphone. The inter-peak latency did not show any significant differences between the two transducers, and the threshold was higher when using an insert earphone. Moreover, the circumaural headphones produced a greater degree of crossover effect than the insert earphones, and this cross-over effect could affect the outcomes of the BAER test. Considering these results, we concluded that insert earphones may be more appropriate when performing the canine BAER test.