The importance of pre-analysis windowing on auditory brainstem response fast Fourier transform analysis

Analysis of auditory brainstem response (ABR) frequency content using fast Fourier transform (FFT) analysis has been used to improve ABR sensitivity and specificity as a diagnostic/site of lesion assessment tool, to improve our understanding of ABR components, and to guide ABR stimulus and recording parameter settings. Threatening this success, however, is the literature's poor control of pre-FFT windowing of the ABR prior to ABR FFT analysis. This study examined the significance of using no (NW), vs Blackman (BW), vs modified Blackman (MBW) pre-FFT windows on the FFT analysis of ABRs recorded from normal subjects. Pre-FFT windowing was shown to significantly reduce (p < 0.00005) ABR FFT magnitudes, but not frequencies, with BW causing greater reductions than MBW. The high significance of these results shows that choice of pre-FFT window is critical in any ABR FFT analysis.