In this paper, we present two different double-talk detection schemes for Acoustic Echo Cancellation (AEC). First, we present a novel normalized detection statistic based on the cross-correlation coefficient between the microphone signal and the cancellation error. The decision statistic is designed in such a way that it meets the needs of an optimal double-talk detector. We also show that the proposed detection statistic converges to the recently proposed normalized crosscorrelation based double-talk detector , the best known crosscorrelation based detector. Next, we present a new hybrid doubletalk detection scheme based on a cross-correlation coefficient and two signal detectors. The hybrid algorithm not only detects doubletalk but also detects and tracks any echo-path variations efficiently. We compare our results with other cross-correlation based doubletalk detectors to show their effectiveness.