Systems, methods, and devices for detecting the threshold of nerve-muscle response using variable frequency of stimulation

A method for determining a stimulation threshold current level in a group of channels of a neuromonitoring device, wherein each channel of the group of channels is associated with one or more muscles, the method comprising:

• causing, by a stimulation system comprising one or more data processors, stimulation, via one or more electrodes, of tissue within a predetermined range of current levels as a sequence of pulses delivered at a frequency by delivering stimulation signals, the sequence of pulses including:
• a first pulse delivered at a first current level within the predetermined range of current levels;
• and
• a second pulse delivered at a second current level within the predetermined range of current levels, the first pulse being delivered immediately preceding the second pulse, and the second current level being higher than the first current level;
• determining that the second pulse evokes a first muscular response, the first muscular response comprising a first evoked response that is processed by the stimulation system to classify the first evoked response;
• causing, by the stimulation system, stimulation, via the one or more electrodes, the tissue with a third pulse from the sequence of pulses to evoke a second muscular response, the third pulse being delivered at a third current level that is equal to or higher than the second current level;
• determining that the third pulse evokes the second muscular response;
• and
• storing, by the stimulation system, based at least in part on the determination that the second pulse evokes the first muscular response and the determination that the third pulse evokes the second muscular response, the second current level as the stimulation threshold current level.

A stimulation system for detecting and identifying a stimulation threshold to avoid tetany of a patient's muscles, wherein the system comprises:

• at least one processor;
• and
• at least one memory storing instructions which, when executed by the at least one processor, result in operations comprising:
• causing, by the stimulation system, stimulation, via one or more electrodes, of the patient's tissue with a sequence of pulses delivered at a current level and a frequency, the causing including increasing the current level of each sequential pulse in the sequence of pulses;
• determining, by the stimulation system, that a first evocation pulse from the sequence of pulses evokes a first muscular response, the first evocation pulse having a first evocation current level;
• continuing to cause, by the stimulation system, stimulation of the patient's tissue with a second evocation pulse from the sequence of pulses to evoke a second muscular response, the causing comprising:
• maintaining or decreasing the frequency between each pulse in the sequence of pulses;
• and
• maintaining or increasing the current level of each pulse in the sequence of pulses from the immediately preceding pulse by a second current increment;
• determining, by the stimulation system, that the second evocation pulse from the sequence of pulses evokes the second muscular response;
• and
• storing, by the stimulation system, based at least in part on the determination that the first evocation pulse evokes the first muscular response and the determination that the second evocation pulse evokes the second muscular response, the first evocation current level as the stimulation threshold current level.