Methods and systems are disclosed for determining physiological information about a patients autonomic nervous system based on at least one physiological signal measured from the patient and at least one known characteristic of a patients respiration. Respiration protocol may be provided to guide characteristics of the patients respiration. The physiological signal measured from the patient may be transformed using a wavelet transform to create a transformed signal, and a scalogram may be generated based at least in part on the transformed signal. A metric that may indicate information about the patients autonomic nervous system may be determined from the scalogram and the known characteristic of the patients respiration.
