Intensity effect on amplitude of auditory brainstem responses in human.
Click intensity effect (90 to 0 dB HL) on amplitude of the auditory brainstem responses (ABAR) was studied in 152 normal children from birth to 6 years and 16 adults. All age groups showed similar amplitude-intensity functions for waves I and V. Wave I amplitude exhibited a 'transitional' response at 60 dB HL intensity, whereas wave V exhibited a more gradual change. As the clicks were decreased from 90 to 60 dB HL, amplitude reduction was much more dramatic for wave I (mean 57%) than for wave V (mean 30%), and the V/I amplitude ratio more than doubled (mean 70%). At moderate intensity range, the reduction in amplitude with the decrease in intensity is only slightly more for wave I than for wave V, and the V/I ratio continued to increase, but more slowly. Wave V amplitude changed linearly with click intensity at the rate of 0.024-0.042 microV/dB for different age groups. The older the children, the larger the decrement of wave V amplitude with decreasing intensity, which was accompanied by an age-related difference in the absolute amplitude at equal click intensities. The V/I amplitude ratio increased with decreasing intensity at a rate of about 0.01/dB, showing no apparent age-related difference.
Jiang
Z D
ZD
Department of Child Health, Children's Hospital, Shanghai Medical University, P.R.C.
D000161:Acoustic Stimulation; D000328:Adult; D002648:Child; D002675:Child, Preschool; D016057:Evoked Potentials, Auditory, Brain Stem / Q000502:physiology*; D005260:Female; D006309:Hearing / Q000502:physiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D012890:Sleep