Electromyography response detection systems and methods

1. A system comprising:

at least one physical computing device configured to

direct an implantable stimulator to sequentially present a plurality of substantially identical stimulation events to a patient;

record a plurality of electromyography (“EMG”) signals generated by a muscle in the patient and each corresponding to a presentation of a particular stimulation event included in the plurality of substantially identical stimulation events;

determine an asynchronous component of each of the recorded EMG signals, the asynchronous components of the recorded EMG signals each being unsynchronized with the sequential presentation of the stimulation events;

determine an amount of energy contained within each of a plurality of phases of each of the asynchronous components;

analyze the amounts of energy contained within each of the plurality of phases of each of the asynchronous components; and

determine, based on the analysis of the amounts of energy, whether an EMG response is evoked by the stimulation events.

2. The system of claim 1 , wherein the at least one physical computing device is configured to determine the asynchronous component of each of the recorded EMG signals by:

determining a synchronous component of each of the recorded EMG signals, the synchronous components of the recorded EMG signals being synchronized with the sequential presentation of the stimulation events and each representing a synchronous component common to all of the recorded EMG signals; and

removing the synchronous components from each of the recorded EMG signals to leave only the asynchronous component of each of the recorded EMG signals.

3. The system of claim 2 , wherein the at least one physical computing device is configured to:

determine the synchronous components of the recorded EMG signals by averaging each of the recorded EMG signals together, the averaging resulting in an averaged EMG signal representative of the synchronous component common to all of the recorded EMG signals; and

remove the synchronous components from each of the recorded EMG signals by subtracting the averaged EMG signal from each of the recorded EMG signals.

4. The system of claim 1 , wherein the at least one physical computing device is configured to direct the implantable stimulator to sequentially present the plurality of substantially identical stimulation events to the patient by directing the implantable stimulator to sequentially present a plurality of substantially identical electrical stimulation pulse trains temporally spaced one from another by a predetermined time period.

5. The system of claim 1 , wherein the at least one physical computing device is configured to direct the implantable stimulator to sequentially present the plurality of substantially identical stimulation events to the patient by directing a cochlear implant to sequentially apply the substantially identical stimulation events to one or more stimulation sites within a cochlea of the patient by way of one or more electrodes disposed within the cochlea.

6. The system of claim 5 , wherein the muscle is a stapedius muscle within the patient and wherein the EMG response is a stapedius reflex.

7. The system of claim 5 , wherein the at least one physical computing device is configured to record the plurality of EMG signals using an electrode that is in physical communication with the muscle.

8. The system of claim 1 , wherein the plurality of phases included within each of the asynchronous components includes a baseline phase corresponding to a time period during which an occurrence of the EMG response in response to the stimulation events is not possible and a response phase corresponding to a time period during which an occurrence of the EMG response in response to the stimulation events is possible.

9. The system of claim 8 , wherein the time period corresponding to the baseline phase of an asynchronous component of a particular EMG signal comprises at least one of a time period prior to the presentation of the stimulation event and a time period that begins a predetermined amount of time subsequent to the presentation of the stimulation event.

10. The system of claim 8 , wherein the time period corresponding to the response phase of an asynchronous component of a particular EMG signal comprises a time period during which the stimulation event is presented.

11. The system of claim 8 , wherein the at least one physical computing device is configured to:

determine the amount of energy contained within each of the plurality of phases of each of the asynchronous components by:

determining an amount of energy contained within the response phase of the asynchronous component of each EMG signal included in the plurality of EMG signals, and

determining an amount of energy contained within the baseline phase of the asynchronous component of each EMG signal included in the plurality of EMG signals; and

determine whether the EMG response is evoked by the stimulation events based on the analysis of the amounts of energy by comparing the amount of energy contained within the response phases to the amount of energy contained within the baseline phases.

12. The system of claim 11 , wherein, if the comparison determines that the amount of energy contained within the response phases is greater than the amount of energy contained within the baseline phases by more than a predetermined threshold amount, the at least one physical computing device is configured to determine that the EMG response is evoked by the stimulation events.

13. The system of claim 12 , wherein, if the comparison determines that the amount of energy contained within the response phases is not greater than the amount of energy contained within the baseline phases by more than the predetermined threshold amount, the at least one physical computing device is configured to determine that the EMG response is not evoked by the stimulation events.

14. The system of claim 1 , wherein the at least one physical computing device is configured to:

determine the amount of energy contained within each of the plurality of phases of each of the asynchronous components by determining an amount of energy contained in each of a plurality of discrete time-based phases of each of the asynchronous components; and

determine whether the EMG response is evoked by the stimulation events based on the analysis of the amounts of energy by:

identifying a time-based trend with respect to the amount of energy contained within each of the discrete phases; and

determining, based on the time-based trend, whether the EMG response is evoked by the stimulation events.

15. The system of claim 1 , wherein the at least one physical computing device is further configured to filter out noise contained in each of the recorded EMG signals prior to determining the asynchronous components of each of the recorded EMG signals.

16. A method comprising:

directing, by an electromyography (“EMG”) response detection system, an implantable stimulator to sequentially present a plurality of substantially identical stimulation events to a patient;

recording, by the EMG response detection system, a plurality of EMG signals generated by a muscle in the patient and each corresponding to a distinct stimulation event included in the plurality of substantially identical stimulation events;

determining, by the EMG response detection system, an asynchronous component of each of the recorded EMG signals, the asynchronous components of the recorded EMG signals each being unsynchronized with the sequential presentation of the stimulation events;

determining, by the EMG response detection system, an amount of energy contained within each of a plurality of phases of each of the asynchronous components;

analyzing, by the EMG response detection system, the amounts of energy contained within each of the plurality of phases of each of the asynchronous components; and

determining, by the EMG response detection system based on the analysis of the amounts of energy, whether an EMG response is evoked by the stimulation events.

17. The method of claim 16 , wherein the plurality of phases included within each of the asynchronous components includes a baseline phase corresponding to a time period during which an occurrence of the EMG response in response to the stimulation events is not possible and a response phase corresponding to a time period during which an occurrence of the EMG response in response to the stimulation events is possible.

18. The method of claim 17 , wherein:

the determining of the amount of energy contained within each of the plurality of phases of each of the asynchronous components includes:

determining an amount of energy contained within the response phase of the asynchronous component of each EMG signal included in the plurality of EMG signals, and

determining an amount of energy contained within the baseline phase of the asynchronous component of each EMG signal included in the plurality of EMG signals; and

the determining of whether the EMG response is evoked by the stimulation events based on the analysis of the amounts of energy includes comparing the amount of energy contained within the response phases to the amount of energy contained within the baseline phases.

19. The method of claim 18 , wherein:

if the comparison determines that the amount of energy contained within the response phases is greater than the amount of energy contained within the baseline phases by more than a predetermined threshold amount, the EMG response is determined to be evoked by the stimulation events; and

if the comparison determines that the amount of energy contained within the response phases is not greater than the amount of energy contained within the baseline phases by more than the predetermined threshold amount, the EMG response is determined to not be evoked by the stimulation events.

20. The method of claim 16 , wherein:

the determining of the amount of energy contained within each of the plurality of phases of each of the asynchronous components includes determining an amount of energy contained in each of a plurality of discrete time-based phases of each of the asynchronous components; and

the determining of whether the EMG response is evoked by the stimulation events based on the analysis of the amounts of energy includes

identifying a time-based trend with respect to the amount of energy contained within each of the discrete phases, and

determining, based on the time-based trend, whether the EMG response is evoked by the stimulation events.