Phase spectral analysis of auditory brainstem response in cats.

In order to apply the phase spectral analysis of auditory brainstem response (ABR) to the clinical diagnostic test, the phase spectra of ABRs were investigated under adequate stimulus intensity in normal cats and after the destruction of acoustic nerve and brainstem auditory pathways in cats. The results were as follows; i) In normal ABRs, the phase spectra were mainly composed of three frequency components at 0-300 Hz (component A), 300-900 Hz (component B) and 900-1500 Hz (component C). ii) A greater decrease of the component synchrony measure (CSM) occurred if ipsilateral destruction was performed in a peripheral lesion. Lesions of the auditory pathway were followed by a decrease of the CSM of component C in response to contralateral stimulation. These results suggest that the phase spectral analysis of ABRs has significant clinical value in the detection of brainstem lesions.