a. Field of the Disclosure
The present disclosure relates generally to methods, systems, and apparatus for signal detection. More particularly, the present disclosure relates neural signal detection methods, systems, and apparatus that utilize a circuit to measure and record the amplitude of nerve firings along the spinal cord and peripheral nerves.
b. Background Art
Medical devices and procedures that affect or involve neural signals are known. It is known, for example, that ablation systems are used to perform ablation procedures to treat certain conditions of a patient. A patient experiencing arrhythmia, for example, may benefit from cardiac ablation to prevent irregular heartbeats caused by arrhythmogenic electric signals generated in cardiac tissues. By ablating or altering cardiac tissues that generate such unintended electrical signals, the irregular heartbeats may be stopped. Ablation systems are also known for use in treating hypertension, and in particular drug-resistant hypertension, in patients. In particular, renal ablation systems, also referred to as renal denervation systems, are used to create lesions along the renal sympathetic nerves, which are a network of nerves in the renal arteries that help control and regulate blood pressure. The intentional disruption of the nerve supply has been found to cause blood pressure to decrease. Other medical devices that measure or record neural signals include, spinal cord stimulation (SCS) systems that provide pulsed electrical stimulation to a patient's spinal cord to control chronic pain, and cardiac rhythm management devices (CRMD) used to regulate a patient's heart beat.
Known techniques for detecting high frequency signals in a body, and particularly high frequency neural signals, typically require very sensitive equipment, as nerve signals differ from cardiac signals and are at a higher frequency and much narrower pulse duration. In particular, neural signals are typically collected through surgically positioned microelectrodes or micropipette electrodes. The signals generated by these sensors are generally sampled by controllers at a sampling rate of about four kilohertz. The sensors and controllers required for such techniques are not inexpensive. Moreover, some medical devices and procedures may benefit from limited information about neural signals and do not require the detailed information that is obtained using the known techniques.
There is a need, therefore, for neural signal detection systems that do not require expensive, surgically implanted electrodes, utilize simpler and less expensive controllers with relatively low sampling rates, and provide useful data about detected neural signals in real time. It would also be beneficial if the neural signal detection systems were compact in size so that they could be easily built into or onto an ablation catheter, or into or onto an implantable medical device such as a spinal cord stimulator device or a cardiac rhythm management device.