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Acoustical explantation of the weber test
Otolaryngology Head and Neck Surgery Volume 117 Number 2
135
Acoustical Explantation of the Weber Test BRIAN W. BLAKLEY, MD, and SHOAB SIDDIQUE, MD, Detroit, Mich. Tuning fork tests are c o m m o n l y used by otolaryngologists, yet their physical basis has been debated for years. Interaural attenuation, phase lead, masking, and other considerations have been applied to explain the phenomenon with varying degrees of credibility. We propose a physical (acoustical) basis for the lateralization of sound to the side of a conductive hearing loss. The proposal involves two concepts. First, we equate a conductive hearing loss with loss of the middle ear impedance matching function. Second, we show how this results in reflection of internally generated sound back into the cochlea. This reflected sound is perceived as louder in the affected ear. We present engineering acoustical data that support our hypothesis. Our theory also explains the Rinne and other tuning fork tests. 136
Osteoradionecrosis of the Ossicular Chain BENJAMIN M. McGREW, MD, and HASSANH. RAMADAN, MD, Morgantown, W.V. Osteoradionecrosis of the ossicular chain has been reported at least three times previously. Presentation may be as an isolated finding noted because of conductive hearing loss from ossicular discontinuity or in association with more extensive osteoradionecrosis of the temporal bone. Characteristically, this complication occurs 5 to 10 years after completion of radiation therapy and ossicular discontinuity occurs with erosion of the lenticular process of the incus where the blood supply to the ossicular chain is poorest. Presented here is a 7-year-old boy noted to have isolated osteoradionecrosis with ossicular discontinuity after developing a large conductive hearing loss 4 years after completion of radiation therapy for undifferentiated soft tissue sarcoma involving the left neck, brain, and meninges. This presentation will include audiologic and surgical findings, pathology, and a review of literature. 137
Sensorineural Hearing Loss, Early Greying, and Essential Tremor: A New Hereditary Syndrome COLLINS. KARMODY, MD, FRCSE,NIKOLAS H. BLEVINS,MD, and ANIL K. LALWANI, MD, Boston, Mass., and San Francisco, Calif.
Objective: To present three individuals with a triad of progressive sensorineural hearing loss, early greying of scalp hair, and adult onset essential tremor. Each had immediate family members with varying combinations of similar symp-
Scientific Posters
P203
toms. We propose that this triad might represent a previously unreported syndrome. Material: Our patients are a 65-year-old man and two women aged 38 and 36 years. Two noted hearing loss in adulthood and one at age 9 years. All three noted greyness in their early twenties that is now total. Essential tremor presented in their early twenties in the women and at age 50 years in the man. All have blue eyes without heterochromia. Neurologic, radiologic, and serologic evaluations and renal and cardiac functions were normal. There are parents with hearing loss and early greyness, sisters with hearing loss and early greyness, and one brother with greyness and early tremor. A paternal grandmother was hard of hearing and a paternal aunt had severe tremor, Conclusion: These patients present with similar constellations that seemed to be hereditary. They are being presented in the context of other syndromes involving disorders of audition, pigmentation, and movement. This triad might be a variant of a described syndrome, for example, Waardenburg's, but we are yet to make a definitive connection. We will present our attempts to characterize the genetics of this syndrome. 138
Effects of Conductive Deafness on Auditory Brain Stem Response BONING SHI, MD, and HONG ZHANG, MD, Ningbo Zhejiang, P.R. CHINA
Objectives: Using a click to evoke auditory brain stem response (ABR) in both conductive deafness ears and normal ears, we studied whether conductive deafness causes solely a reduction in the intensity of sound. Methods: Sixty-eight conductive deafness ears and 57 normal ears were studied, of which 33 ears (group A) were A-B gap o f pure tone average >20 dB HL, 35 ears (group B) were A-B gap <20 dB HL, and 57 ears (group C) were A-B gap <10 dB HL. The clicks of 60 dB level were used as stimuli, ABRs were recorded. The latencies (absolute and interwave) were compared using Student t test. Results: Waves I, III, and V could be recorded in all ears tested. The latency of each wave was always that: Group A > B > C (p < 0.05 or p < 0.01). However, there were no significant differences among these groups in regard to interwave latencies. Conclusions: These data show that delay of ABR in conductive deafness occurs prior to Wave I. It is more prolonged with the increased severity of hearing loss, and it cannot be corrected by intensity compensation of stimulus. Our data suggest that conductive deafness not only causes the loss of sound intensity in the conductive system but also has a delay in compliance, or possibly changes instantaneous characteristic of click.
135
Acoustical Explantation of the Weber Test BRIAN W. BLAKLEY, MD, and SHOAB SIDDIQUE, MD, Detroit, Mich. Tuning fork tests are c o m m o n l y used by otolaryngologists, yet their physical basis has been debated for years. Interaural attenuation, phase lead, masking, and other considerations have been applied to explain the phenomenon with varying degrees of credibility. We propose a physical (acoustical) basis for the lateralization of sound to the side of a conductive hearing loss. The proposal involves two concepts. First, we equate a conductive hearing loss with loss of the middle ear impedance matching function. Second, we show how this results in reflection of internally generated sound back into the cochlea. This reflected sound is perceived as louder in the affected ear. We present engineering acoustical data that support our hypothesis. Our theory also explains the Rinne and other tuning fork tests. 136
Osteoradionecrosis of the Ossicular Chain BENJAMIN M. McGREW, MD, and HASSANH. RAMADAN, MD, Morgantown, W.V. Osteoradionecrosis of the ossicular chain has been reported at least three times previously. Presentation may be as an isolated finding noted because of conductive hearing loss from ossicular discontinuity or in association with more extensive osteoradionecrosis of the temporal bone. Characteristically, this complication occurs 5 to 10 years after completion of radiation therapy and ossicular discontinuity occurs with erosion of the lenticular process of the incus where the blood supply to the ossicular chain is poorest. Presented here is a 7-year-old boy noted to have isolated osteoradionecrosis with ossicular discontinuity after developing a large conductive hearing loss 4 years after completion of radiation therapy for undifferentiated soft tissue sarcoma involving the left neck, brain, and meninges. This presentation will include audiologic and surgical findings, pathology, and a review of literature. 137
Sensorineural Hearing Loss, Early Greying, and Essential Tremor: A New Hereditary Syndrome COLLINS. KARMODY, MD, FRCSE,NIKOLAS H. BLEVINS,MD, and ANIL K. LALWANI, MD, Boston, Mass., and San Francisco, Calif.
Objective: To present three individuals with a triad of progressive sensorineural hearing loss, early greying of scalp hair, and adult onset essential tremor. Each had immediate family members with varying combinations of similar symp-
Scientific Posters
P203
toms. We propose that this triad might represent a previously unreported syndrome. Material: Our patients are a 65-year-old man and two women aged 38 and 36 years. Two noted hearing loss in adulthood and one at age 9 years. All three noted greyness in their early twenties that is now total. Essential tremor presented in their early twenties in the women and at age 50 years in the man. All have blue eyes without heterochromia. Neurologic, radiologic, and serologic evaluations and renal and cardiac functions were normal. There are parents with hearing loss and early greyness, sisters with hearing loss and early greyness, and one brother with greyness and early tremor. A paternal grandmother was hard of hearing and a paternal aunt had severe tremor, Conclusion: These patients present with similar constellations that seemed to be hereditary. They are being presented in the context of other syndromes involving disorders of audition, pigmentation, and movement. This triad might be a variant of a described syndrome, for example, Waardenburg's, but we are yet to make a definitive connection. We will present our attempts to characterize the genetics of this syndrome. 138
Effects of Conductive Deafness on Auditory Brain Stem Response BONING SHI, MD, and HONG ZHANG, MD, Ningbo Zhejiang, P.R. CHINA
Objectives: Using a click to evoke auditory brain stem response (ABR) in both conductive deafness ears and normal ears, we studied whether conductive deafness causes solely a reduction in the intensity of sound. Methods: Sixty-eight conductive deafness ears and 57 normal ears were studied, of which 33 ears (group A) were A-B gap o f pure tone average >20 dB HL, 35 ears (group B) were A-B gap <20 dB HL, and 57 ears (group C) were A-B gap <10 dB HL. The clicks of 60 dB level were used as stimuli, ABRs were recorded. The latencies (absolute and interwave) were compared using Student t test. Results: Waves I, III, and V could be recorded in all ears tested. The latency of each wave was always that: Group A > B > C (p < 0.05 or p < 0.01). However, there were no significant differences among these groups in regard to interwave latencies. Conclusions: These data show that delay of ABR in conductive deafness occurs prior to Wave I. It is more prolonged with the increased severity of hearing loss, and it cannot be corrected by intensity compensation of stimulus. Our data suggest that conductive deafness not only causes the loss of sound intensity in the conductive system but also has a delay in compliance, or possibly changes instantaneous characteristic of click.