title: Response threshold determination of the brain stem auditory evoked response: a comparison of the phase versus magnitude derived from the fast Fourier transform.
abstract: An ensemble of 10 groups of brain stem evoked responses (BAERs), each consisting of 200 sweeps, was collected for different intensity levels and for a no-stimulus condition. A fast Fourier transform was calculated for the separate groups, which permitted a phase variance to be derived. The phase variance was compared to the magnitude value for selected frequency components making up the BAER. It was found that the phase variance was a better predictor of signal than magnitude. The superiority of prediction by phase results from intersubject variation being smaller for phase compared to magnitude.
mesh_terms: D000161:Acoustic Stimulation; D001309:Auditory Threshold; D001933:Brain Stem / Q000502:physiology; D005072:Evoked Potentials, Auditory; D005583:Fourier Analysis; D006801:Humans