Implantable sensory system

1 . A sensory system ( 100 ) for use in restoring sensation to a hand of a patient, comprising:

at least one force sensor ( 102 ) for being implanted subcutaneously within a hand of a patient; and

a separate base unit ( 104 ) for powering said at least one sensor ( 102 ) and for receiving data from said at least one sensor ( 102 );

wherein said at least one force sensor ( 102 ) is configured to transmit wireless communication signals to said base unit ( 104 ) in response to forces sensed by said at least one sensor ( 102 ), is configured to transmit the wireless communication signals to said base unit ( 104 ) by magnetic human body communication (mHBC), and is configured to sense normal and shear components of forces and to transmit data concerning the forces to said base unit ( 104 );

wherein said at least one force sensor ( 102 ) is for being implanted within a finger or palm of a hand of the patient and said base unit ( 104 ) is for being worn externally around a wrist of the patient; and

wherein the at least one sensor ( 102 ) includes at least four separate sensor capacitors (Cx 1 , Cx 2 , Cy 1 , Cy 2 ) and four oscillators ( 1 , 2 , 3 , 4 ), wherein an oscillation frequency band of each of the four oscillators ( 1 , 2 , 3 , 4 ) does not overlap with the other of the four oscillators ( 1 , 2 , 3 , 4 ), and wherein the oscillation frequencies of two of the four oscillators ( 1 , 2 , 3 , 4 ) are on one side of a frequency of a powering signal generated by the base unit ( 104 ), and the oscillation frequencies of the other two of the four oscillators ( 1 , 2 , 3 , 4 ) are on an opposite side of the frequency of the powering signal.

2 . The sensory system ( 100 ) according to claim 1 , wherein said at least one force sensor ( 102 ) is a battery-less capacitive pressure sensor ( 110 ), wherein the data provides information with respect to changes in capacitance sensed by the at least one force sensor ( 102 ), and wherein said battery-less capacitive pressure sensor ( 110 ) is microfabricated within a biocompatible, hermetically sealed fused silica package ( 24 ), containing an application-specific integrated circuit ( 116 ).

3 . The sensory system ( 100 ) according to claim 2 , wherein said at least one sensor ( 102 ) includes a coil ( 118 , 128 ) via which the wireless signals are transmitted to said base unit ( 104 ) and via which signals are received to power said at least one sensor ( 102 ).

4 . The sensory system ( 100 ) according to claim 1 , wherein the base unit ( 104 ) is configured to transmit data concerning forces sensed by said at least one sensor ( 102 ) to neural implants ( 106 ) for use in driving muscle stimulators ( 108 ).

5 . The sensory system ( 100 ) according to claim 1 , wherein the four separate sensor capacitors (Cx 1 , Cx 2 , Cy 1 , Cy 2 ) are aligned such that when a normal force is applied to each of the four separate sensor capacitors (Cx 1 , Cx 2 , Cy 1 , Cy 2 ), a frequency shift will occur for each of the four oscillators ( 1 , 2 , 3 , 4 ) in a same direction, and when a shear force is applied in a particular direction, a frequency shift will occur in an opposite direction for at least one of the sensor capacitors (Cx 1 , Cx 2 , Cy 1 , Cy 2 ).

6 . The sensory system ( 100 ) according to claim 1 , wherein the base unit ( 104 ) includes an oscillator ( 140 ) for generating a power signal for the at least one sensor ( 102 ) and a driver ( 144 ) for transferring the power signal to an inductor ( 142 ) which transmits the power signal.

7 . The sensory system ( 100 ) according to claim 6 , wherein the inductor ( 142 ) is an antenna for receiving the communication signals transmitted by the at least one sensor ( 102 ), and wherein the base unit ( 104 ) further includes a filter ( 146 ), counter ( 148 ), and micro-controller ( 150 ) for detection and processing of the communication signals.

8 . A sensory system ( 10 ) for use in restoring sensation to a foot of a patient, comprising:

at least one force sensor ( 12 ) for being implanted subcutaneously within a foot of a patient; and

a separate base unit ( 18 ) for powering said at least one sensor ( 12 ) and for receiving data from said at least one sensor ( 12 );

wherein said at least one force sensor ( 12 ) is configured to transmit wireless communication signals to said base unit ( 18 ) in response to forces sensed by said at least one sensor ( 12 ), is configured to transmit the wireless communication signals to said base unit ( 18 ) by magnetic human body communication (mHBC), and is configured to sense normal and shear components of forces and to transmit data concerning the forces to said base unit ( 18 ); and

wherein said at least one force sensor ( 12 ) is for being implanted subcutaneously on a plantar surface of a foot of a patient, wherein said base unit ( 18 ) is for being implanted subcutaneously in a leg of the patient and has a nerve cuff ( 20 ) for applying peripheral nerve stimulation to a tibial nerve of the patient, and wherein said base unit ( 18 ) is configured to apply peripheral nerve stimulation to the tibial nerve based on the wireless communication signals received from said at least one force sensor ( 12 );

wherein said at least one force sensor ( 12 ) and said base unit ( 18 ) are configured to provide a closed-loop system transmitting tactile sensations from the plantar surface of the foot via said at least one force sensor ( 12 ) to the tibial nerve via the peripheral nerve stimulation applied by said base unit ( 18 );

wherein said at least one force sensor ( 12 ) is configured to sense normal and shear components of ground reaction forces experienced during standing and walking and to transmit data concerning the forces to said base unit ( 18 );

wherein said base unit ( 18 ) includes an application-specific integrated circuit ( 46 ) for communicating with said at least one sensor ( 12 ); and

wherein said application-specific integrated circuit ( 46 ) of said base unit ( 18 ) is configured to transmit a carrier signal via a base unit coil ( 54 ) to said at least one sensor ( 12 ) and receive said communication signals from said at least one sensor ( 12 ) as backscattered signals corresponding to a measured force vector from said at least one sensor ( 12 ).

9 . The sensory system ( 10 ) according to claim 8 , wherein said base unit ( 18 ) is configured for being implanted subcutaneously adjacent a knee of the patient.

10 . The sensory system ( 10 ) according to claim 8 , wherein said base unit ( 18 ) includes a microcontroller ( 44 ) for determining characteristics of the peripheral nerve stimulation to be applied to the tibial nerve based on the communication signals received from said at least one sensor ( 12 ).

11 . The sensory system ( 10 ) according to claim 8 , wherein said at least one sensor ( 12 ) includes a plurality of separate sensors ( 22 a , 22 b , 22 c ) each for being separately implanted subcutaneously within the foot, and wherein said application-specific integrated circuit ( 46 ) of said base unit ( 18 ) communicates with each of said sensors ( 22 a , 22 b , 22 c ) through different frequency channels.

12 . The sensory system ( 10 ) according to claim 8 , wherein said application-specific integrated circuit ( 46 ) of said base unit ( 18 ) is configured to drive said nerve cuff ( 20 ) to stimulate the tibial nerve.

13 . The sensory system ( 10 ) according to claim 8 , wherein said base unit ( 18 ) is battery powered and includes at least one battery ( 62 ), and wherein said base unit ( 18 ) includes an accelerometer ( 48 ).

14 . The sensory system ( 10 ) according to claim 9 , further comprising an external unit ( 58 ) that communicates with said base unit ( 18 ) via wireless communication signals and that controls operation of said base unit ( 18 ) and monitors information passed between said at least one sensor ( 12 ) and said base unit ( 18 ).