Apparatus and method using near infrared reflectometry to reduce the effect of positional changes during spinal cord stimulation

A stimulator system comprising:

• a controller;
• an optical emitter operatively connected to the controller;
• an incident light beam generated by the optical emitter;
• an optical detector operatively connected to the controller;
• a photocurrent generated by the optical detector;
• a first optical element, coupled to the optical emitter by a first optical fiber;
• a second optical element, coupled to the optical detector by a second optical fiber;
• a set of electrodes operatively connected to the controller;
• wherein the incident light beam is directed by the first optical fiber to the first optical element and emitted from the first optical element to interact with an external surface;
• a reflected light beam produced from the interaction of the incident light beam with the external surface;
• wherein the reflected light beam is collected by the second optical element, directed by the second optical fiber to the optical detector and received by the optical detector to generate the photocurrent;
• and,
• wherein the controller directs a set of currents to the set of electrodes based on the photocurrent.

A method for stimulating a nerve location in the spinal cord comprising the steps of:

• directing an incident light beam toward the spinal cord;
• detecting a reflected light beam from the spinal cord;
• emitting an electric field having an field strength;
• and,
• changing the field strength based on the reflected light beam.