Cross-Correlation Function in the Analysis of Auditory Brainstem Response in Spinocerebellar Degeneration

Abstract

Cross-correlation functions were derived from the analysis of auditory-evoked brainstem response (ABR) and compared with measurements of wave latency and computed tomography findings in the assessment of ABR findings in spinocerebellar degeneration (SCD). Gender-specific normative ABR templates were produced from 30 normal males and 30 normal females separately. The cross-correlation indices used were the correlation coefficient at time 0, the maximal correlation coefficient and the latency delay in milliseconds. The technique was applied to 33 patients with SCD. The incidence of abnormal cross-correlation functions (81.8%) was greater than the incidence of abnormal ABR peak latencies assessed according to gender (75.8%) which, in turn, was more common than the abnormal peak latencies assessed conventionally (69.7%). Moreover, the incidence of abnormal cross-correlations and latencies in Meniere's disease was much lower (less than 8%). These results suggest that the evaluation of ABR waveform characteristics with cross-correlation functions using normative ABR templates of the same gender contributes to the precise detection of abnormality in the brainstem auditory pathway.

Key Words:

• Auditory brainstem response
• Cross-correlation function
• Fast Fourier transform
• Spinocerebellar degeneration