TECHNICAL FIELD

The disclosure relates to phase detection, and more particularly, to phase detection for use in controlling medical therapy.

BACKGROUND

Medical devices, such as electrical stimulators or therapeutic agent delivery devices, may be used in different therapeutic applications, such as deep brain stimulation (DBS), spinal cord stimulation (SCS), pelvic stimulation, gastric stimulation, peripheral nerve stimulation, functional electrical stimulation or delivery of pharmaceutical agent, insulin, pain relieving agent or anti-inflammatory agent to a target tissue site within a patient. A medical device may be configured to deliver therapy to a patient to treat a variety of symptoms or patient conditions such as chronic pain, tremor, Parkinson's disease, other types of movement disorders, seizure disorders (e.g., epilepsy), urinary or fecal incontinence, sexual dysfunction, obesity, mood disorders, gastroparesis or diabetes. In some therapy systems, an electrical stimulator delivers electrical therapy to a target tissue site within a patient with the aid of one or more electrodes, which may be deployed by medical leads, on a housing of the electrical stimulator, or both. In addition to or instead of electrical stimulation therapy, a medical device may deliver a therapeutic agent to a target tissue site within a patient with the aid of one or more fluid delivery elements, such as a catheter or a therapeutic agent eluting patch.

Some medical devices are configured to sense a patient parameter, such as a bioelectrical brain signal. A sensed patient parameter may be used for various purposes, such as to control therapy delivery by a medical device.

SUMMARY

The disclosure describes example techniques for determining a phase of a frequency band of a signal, such as a bioelectrical brain signal. A frequency band phase detector may include one or more frequency component phase detectors, where each frequency component refers to a frequency within the frequency band. Each of the frequency component phase detectors may be configured to determine a phase of the frequency component by weighting more recent samples of the signal more heavily than later samples of the signal, as part of a correlation of the signal with the frequency component. The frequency band phase detector may average, and in some examples, generate a weighted average of, the determined phases by each of the one or more frequency component phase detectors to determine the phase of the frequency band of the signal.

In one example, the disclosure describes a method comprising receiving, with a processor of a medical device, a first signal generated from a second signal, correlating, with the processor of the medical device, the first signal with a frequency component of a frequency band of the second signal, wherein correlating includes predominantly decreasing weighting of past portions of the first signal, and wherein predominantly decreasing weighting of past portions of the first signal comprises predominantly weighting present and more recent portions of the first signal more heavily than earlier portions of the first signal, and wherein the frequency band includes one or more frequency components, determining, with the processor of the medical device, a phase of the frequency component based on a filtered signal outputted from the correlation, determining, with the processor of the medical device, a phase of the frequency band based on the determined phase of the frequency component, and instructing, with the processor of the medical device, a therapy module to deliver therapy based on the determined phase of the frequency band.

In one example, the disclosure describes a medical device comprising frequency band phase detector comprising a frequency component phase detector configured to receive a first signal generated from a second signal, correlate the first signal with a frequency component of a frequency band of the second signal, wherein to correlate, the frequency component phase detector is configured to predominantly decrease weighting of past portions of the first signal, wherein predominantly decreasing weighting of past portions of the first signal comprises predominantly weighting present and more recent portions of the first signal more heavily than earlier portions of the first signal, and wherein the frequency band includes one or more frequency components, and determine a phase of the frequency component based on a filtered signal outputted from the correlation, and an averager configured to determine a phase of the frequency band based on the determined phase of the frequency component, and a therapy module configured to deliver therapy based on the determined phase of the frequency band.

In one example, the disclosure describes a medical device comprising means for receiving a first signal generated from a second signal, means for correlating the first signal with a frequency component of a frequency band of the second signal, wherein correlating includes predominantly decreasing weighting of past portions of the first signal, and wherein predominantly decreasing weighting of past portions of the first signal comprises predominantly weighting present and more recent portions of the first signal more heavily than earlier portions of the first signal, and wherein the frequency band includes one or more frequency components, means for determining a phase of the frequency component based on a filtered signal outputted from the correlation, means for determining a phase of the frequency band based on the determined phase of the frequency component, and means for delivering therapy based on the determined phase of the frequency band.

In one example, the disclosure describes a computer-readable storage medium comprising instructions that when executed cause one or more processors of a medical device to receive a first signal generated from a second signal, correlate the first signal with a frequency component of a frequency band of the second signal, wherein correlating includes predominantly decreasing weighting of past portions of the first signal, and wherein predominantly decreasing weighting of past portions of the first signal comprises predominantly weighting present and more recent portions of the first signal more heavily than earlier portions of the first signal, and wherein the frequency band includes one or more frequency components, determine a phase of the frequency component based on a filtered signal outputted from the correlation, determine a phase of the frequency band based on the determined phase of the frequency component, and instruct a therapy module to deliver therapy based on the determined phase of the frequency band.

The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.

