1. A system for patient signal analysis, comprising: a patient monitor configured to acquire a patient signal data from a patient; and a computer system communicatively coupled to the patient monitor, wherein the computer system includes a non-transitory memory device, a processor device in communication with the memory device, and a signal analysis unit stored in the memory device and operative with the processor device to perform steps including generating a signature cycle matrix corresponding to a single cycle of the patient signal data by segmenting the patient signal data into multiple portions, segmenting the signature cycle matrix into sub-matrices corresponding to different levels, determining properties of the sub-matrices, determining a sequential energy index based on the properties of the sub-matrices, wherein the sequential energy index comprises a sum of squared magnitudes corresponding to the sub-matrices, and characterizing an abnormality based on the properties and the sequential energy index.