Apparatus and methods for feedback-based nerve modulation

1. A sleep apnea treatment device, comprising:

a housing configured for location external to a body of a subject; and

at least one processor associated with the housing and further configured to:

communicate with a circuit implanted in the subject within proximity to a tongue of the subject, wherein the circuit is in electrical communication with at least one electrode;

receive a physiological signal from the subject via the circuit and

send a control signal to the circuit in response to the physiological signal, wherein the control signal is predetermined to activate neuromuscular tissue within the tongue.

2. The sleep apnea treatment device of claim 1 , wherein the control signal is sent within a response time chosen from among the group comprising 1 second, 500 milliseconds, 200 milliseconds, 100 milliseconds, 50 milliseconds, 20 milliseconds, 5 milliseconds, and 1 millisecond.

3. The sleep apnea treatment device of claim 1 , further comprising an antenna configured to transmit the control signal from a location outside of the subject's body to an antenna associated with the circuit.

4. The sleep apnea treatment device of claim 1 , wherein the physiological signal includes at least one aspect indicative of a movement of the tongue.

5. The sleep apnea treatment device of claim 4 , wherein the movement of the tongue is detected as a relative motion between an antenna associated with the at least one processor and an antenna associated with the circuit implanted in the subject.

6. The sleep apnea treatment device of claim 1 , wherein the at least one processor is configured to determine, based on the physiological signal, a quantity of energy to be sent via the control signal to the circuit implanted in the subject.

7. The sleep apnea treatment device of claim 1 , wherein the at least one processor is further configured to:

detect a sleep disordered breathing event based on the physiological signal; and

send the control signal in response to the sleep disordered breathing event.

8. The sleep apnea treatment device of claim 7 , wherein the at least one processor is further configured to determine a severity of the sleep disordered breathing event based on the physiological signal and vary a power level associated with the control signal based on the severity of the sleep disordered breathing event.

9. The sleep apnea treatment device of claim 7 , wherein the at least one processor is further configured to determine a severity of the sleep disordered breathing event based on the physiological signal and vary a duration of the control signal based on the severity of the sleep disordered breathing event.

10. The sleep apnea treatment device of claim 7 , wherein the sleep disordered breathing event is a precursor of sleep apnea.

11. The device of claim 1 , wherein the control signal is configured to cause the subject's tongue to move in a direction away from posterior pharyngeal wall of the subject.

12. The device of claim 7 , wherein the physiological signal is indicative of an efficiency of energy transfer to the circuit, and the at least one processor is further configured to vary a power level associated with the control signal based on the efficiency of energy transfer and an upper threshold associated with the circuit.

13. The device of claim 7 , wherein the physiological signal is indicative of an efficiency of energy transfer to the circuit, and the at least one processor is further configured to vary a power level associated with the control signal based on the efficiency of energy transfer and an efficacy threshold associated with the circuit.