| Developmental Changes of Auditory Brainstem Responses in Infancy. |
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Soo Kon Chai, Yeong Ho Ra, Sa Joon Chung, Chang Il Ahn |
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Dept, of Pediatrics, College of Medicine， Kyung Hee University |
| 要兒期 聽性腦幹反應의 發達的 變化에 關한 硏究 |
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蔡洙坤, 羅榮鎬, 鄭思曉, 安昌一 |
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慶熙大學校 醫科大學 小兒科學敎室 |
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| Abstract |
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Auditory Brainstem Response (ABR) has been found to be useful evaluating objective assessment of hearing thresholds, maturation of the brainstem and neurological disorders in the brainstem. Therefore it is essential to define normal ranges and accurate changes in the wave form of the ABR. This study was undertaken with the analysis of 137 ABR in premature infants in a newborn nursery and healthy infants up to the age of 12 months
old who visited well-baby clinic of Dept, of Pediatrics in Kyung Hee University Medical Center.
Evoked potentials were recorded from reference electrodes at both ear lobe and active electrode at vertex.
The ground electrode was placed in the middle of the forehead at the hairline. The auditory stimuli and frequencies were an intensity of 90 dB above the hearing threshold at a rate of 10/sec. 2,048 brainstem
evoked responses were summated on line with a Neuropack II(Nihon Kohden Co.) and analyzed the recorded materials with a recorder. The results were as follows：
1) Waves I,III and V can be clearly recognized in all age groups. Wave II begins to differentiate as clear
peak at age of 2 months and the dominance of the amplitude of wave V becomes apparent at 6 to 9 months of age. 2) Among the normal developmental changes in each wave peak latencies, mean peak I wave latencies were 1.89±0.38 msec in the neonate group, 1.59±0.33 msec in 1 month old group and 1.50±0.15 msec in 12 months old group. There was significant shortening of latencies in 2 months old group. Mean peak III wave latencies were 4.89±0.59 msec in the neonate group, 4.38±0.36 msec in 2 months old group and
4.00±0.53 msec in 12 months old group. There was significant difference in the age group of 2 months. Mean peak V wave latencies were 7.18土0.72 msec in the neonate group, 5.95±0.64 msec in the 12 months old
group. Significant shortening were noted between neonate group and latter group. 3) Mean I-III IPLs were 3.00±0.54 msec in the neonate group, 2.64±0.06 msec in the 3 months old group, 2.50±0.62 msec in the 12 months old group and significant shortening was in the age group of 3 months old. Mean I-V IPLs were 5.29±0.71 msec in the age group of neonate, 4.75±0.28 msec in the 3 months old group, 4.45±0.14 msec in the 12
months old group and significant differencies were noted in each age groups. 4) In the amplitude of peak I wave, there were no significant differences throughout all examined groups. The mean amplitude of wave V in the prematurity group and the neonate group were 0.76±0.18分V and 0.96±0.20#V respectively, of which
were very significant. There was also an increased amplitude of 1.61±0.64^V in the group of 12 months old.
The ratio of amplitude of peak I to the amplitude of peak V was over 1.0 in all age groups.
5) The peak V wave latencies and I-V IPLs of males were significantly longer than those of females only in the age group of 12 months. But the rest of other results such as latencies of each waves, IPLs and amplitude were not significantly different in all age groups.
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| Key Words:
Auditory brainstem response, Developmental changes. |
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