Medical devices, systems, and methods that adjust physiological signal thresholds to control stimulation therapy

A method of controlling stimulation therapy, the method comprising:

• producing a stimulation signal having a stimulation characteristic at a stimulation generator of the implantable medical device;
• controlling, by processing circuitry, the stimulation generator to deliver the stimulation signal based on a first threshold;
• obtaining, by the processing circuitry, a measurement of a physiological signal sensed via electrodes;
• computing, by the processing circuitry, a first average level of the physiological signal for a first time period;
• adjusting, by the processing circuitry, a first threshold to a second threshold based on the first average level of the physiological signal;
• and
• controlling, by the processing circuitry, the stimulation generator for a next time period by comparing the level of the physiological signal over a current time period immediately preceding the next time period to the second threshold;
• wherein controlling the stimulation generator for the next period comprises, in response to the level of the physiological signal exceeding the second threshold during the current time period, adjusting, by the processing circuitry, the stimulation characteristic of the stimulation signal for the next time period to a level that causes the physiological signal to no longer exceed the second threshold, wherein the physiological signal comprises local field potentials (LFPs) within neurological tissue and the stimulation characteristic is amplitude.

A medical device comprising:

• a stimulation generator configured to produce a stimulation signal having a stimulation characteristic;
• and
• processing circuitry configured to:
• control the stimulation generator to deliver the stimulation signal based on a first threshold;
• obtain a measurement of a physiological signal sensed via electrodes,
• compute an all day average level of the physiological signal for a first time period,
• compute a daytime average level of the physiological signal for the first time period;
• and
• adjust the first threshold to a second threshold based on the all day average level of the physiological signal and the daytime average level of the physiological signal,
• control the stimulation generator for a next time period by comparing the level of the physiological signal over a current time period immediately preceding the next time period to the second threshold,
• wherein to control the stimulation generator for the next time period, the processing circuitry is configured to, in response to the level of the physiological signal exceeding the second threshold during the current time period, adjust the stimulation characteristic of the stimulation signal for the next time period to a level that causes the physiological signal to no longer exceed the second threshold.