Latency change estimation for evoked potentials via frequency selective adaptive phase spectrum analyzer.

This paper addresses the problem of detecting and estimating latency changes in evoked potentials (EP's). EP's have been widely used to quantify neurological system properties. Transient and time-varying changes in latency may indicate impending neurological injury. Traditional time averaging and correlation methods for EP latency estimation are inefficient under low signal-to-noise ratio (SNR) and/or strong periodic interference conditions. This paper proposes an adaptive phase spectral time delay estimation method to detect and estimate the time-varying latency changes when both the SNR and the signal-to-interference ratio (SIR) are low. A theoretical analysis and computer simulation demonstrate that the proposed method can track the time-varying latency changes effectively and accurately when both the SNR and the SIR are as low as -5 dB. The method is also suitable for real time detection and estimation of the latency changes.