1. A method for detecting anomalies in a multi-channel signal, the method comprising: sampling the multi-channel signal over a time window, said multi-channel signal representing physiological signals derived from outputs of a plurality of electrodes positioned to acquire physiological signals from a patient, wherein each channel of the multi-channel signal corresponds to a different one of the plurality of electrodes; computing with a processor an anomaly metric for the multi-channel signal over the time window, wherein said computing an anomaly metric comprises: computing a condition number of the multi-channel signal over the time window; and adiusting the condition number based on a parameter of the multi-channel signal to generate a data condition number (DCN); and identifying the presence of an anomaly based on a magnitude of the anomaly metric, wherein said identifying the presence of an anomaly comprises comparing the magnitude of the DCN to at least one threshold.