Changes in the extracellular potential power spectra depending on the duration, asymmetry and conduction velocity of the intracellular potentials generated by an excitable fiber: [formula omitted], Z. Lateva and N. Dimitrova (CLBA, Center of Biology, Bulgarian Academy Sci., Sofia 1113, Bulgaria)

Abstract

Simultaneous auditory brainstem responses (ABRs) to click stimuli at 30 and 60 dB nHL were recorded from 16 full term neonates with four electrode arrays: vertical (Cz-Nape of neck), ipsilateral (Cz-Mi), contralateral (Cz-Mc), and horizontal (Mc-Mi). Results indicated that ABR waveforms were morphologically similar to those recorded in adults: Waves I, III, and V were clearly identifiable and of the same polarity in 15 of 16 subjects 60 dB nHL and Wave V was clearly identifiable in 14 of 16 subjects at 30 dB nHL. Although ABR waves were identified in most cases, waveforms expression was variable with different electrode recording montages. It is suggested that if a clinician must choose one montage array for recording neonatal ABRs at high intensity levels for neurodiagnostic evaluations, the ipsilateral recording array is indicated since it displays the highest expression of wave components. For screening applications or threshold searching at lower stimulus levels, however, either the ipsilateral or vertical montage would be justified. Further, caution should be employed when interpreting ABR results in neonates recorded with unconventional montages due to the variable expression of wave components.