An ambulatory medical device, comprising: a stimulation generation circuit configured to generate stimulations for stimulating a target site; a signal analyzer circuit configured to receive one or more physiologic signals and generate two or more signal metrics from the one or more physiologic signals; a device parameter adjustment circuit configured to determine a desired device parameter value for a device parameter, a controller circuit configured to be included with or coupled to the signal analyzer circuit, the device parameter adjustment circuit, and the stimulation generation circuit, the controller circuit configured to program or schedule delivery of the stimulations using the desired device parameter value, characterised in that the the device parameter adjustment circuit comprises: a sensitivity calculator circuit configured to determine for at least two of the two or more signal metrics a respective sensitivity to a perturbation to the device parameter in response to the stimulations, the sensitivity determined using a comparison of values of the same signal metric during stimulations having different values of the device parameter; a variability calculator circuit configured to determine for at least two of the two or more signal metrics a respective variability in response to the stimulations; a covariability calculator circuit configured to determine a covariability between at least two of the two or more signal metrics in response to the stimulations; and an information fusion circuit configured to determine the desired device parameter value using at least one of the sensitivity for the at least two signal metrics, the variability for the at least two signal metrics, or the covariability between the at least two signal metrics. a stimulation generation circuit configured to generate stimulations for stimulating a target site; a signal analyzer circuit configured to receive one or more physiologic signals and generate two or more signal metrics from the one or more physiologic signals; a device parameter adjustment circuit configured to determine a desired device parameter value for a device parameter, a controller circuit configured to be included with or coupled to the signal analyzer circuit, the device parameter adjustment circuit, and the stimulation generation circuit, the controller circuit configured to program or schedule delivery of the stimulations using the desired device parameter value, characterised in that the the device parameter adjustment circuit comprises: a sensitivity calculator circuit configured to determine for at least two of the two or more signal metrics a respective sensitivity to a perturbation to the device parameter in response to the stimulations, the sensitivity determined using a comparison of values of the same signal metric during stimulations having different values of the device parameter; a variability calculator circuit configured to determine for at least two of the two or more signal metrics a respective variability in response to the stimulations; a covariability calculator circuit configured to determine a covariability between at least two of the two or more signal metrics in response to the stimulations; and an information fusion circuit configured to determine the desired device parameter value using at least one of the sensitivity for the at least two signal metrics, the variability for the at least two signal metrics, or the covariability between the at least two signal metrics. a sensitivity calculator circuit configured to determine for at least two of the two or more signal metrics a respective sensitivity to a perturbation to the device parameter in response to the stimulations, the sensitivity determined using a comparison of values of the same signal metric during stimulations having different values of the device parameter; a variability calculator circuit configured to determine for at least two of the two or more signal metrics a respective variability in response to the stimulations; a covariability calculator circuit configured to determine a covariability between at least two of the two or more signal metrics in response to the stimulations; and an information fusion circuit configured to determine the desired device parameter value using at least one of the sensitivity for the at least two signal metrics, the variability for the at least two signal metrics, or the covariability between the at least two signal metrics.