Method and apparatus for determining the proximity of a tms coil to a subject's head

Abstract

A proximity sensor for a transcranial magnetic stimulation (TMS) system detects the proximity of a TMS coil assembly to a position at which the coil is to receive pulses during TMS treatment and provides feedback to the operator so that the operator may adjust the TMS coil assembly to maintain optimal positioning during treatment. A flexible substrate containing a sensor or sensor array is disposed between the TMS coil assembly and the position such that the coupling of the TMS coil assembly to the position may be detected by the sensor(s). Sensor outputs are processed by signal processing circuitry to provide an indication of whether the TMS coil assembly is properly disposed with respect to the position during TMS treatment. A display provides an indication of how to adjust the TMS coil assembly to improve the positioning of the TMS coil assembly.

What is claimed: 
     
         1 . A transcranial magnetic stimulation (TMS) system comprising:
 a TMS coil assembly comprising a magnetic stimulation element configured to generate a pulsing magnetic field;   an optical sensor configured to provide an optical output signal; and   signal processing electronics configured to receive the optical output signal and determine whether the TMS coil assembly is properly disposed with respect to a patient during a TMS treatment based on the optical output signal.   
     
     
         2 . The TMS system of  claim 1 , wherein the signal processing electronics are configured to identify a position on the patient's anatomy as a contact area or as a non-contact area based on the optical output signal. 
     
     
         3 . The TMS system of  claim 1 , wherein the signal processing electronics is configured to send feedback to a display device of the TMS system to indicate whether the TMS coil assembly is properly disposed with respect to the patient during the TMS treatment based on the optical output signal. 
     
     
         4 . The TMS system of  claim 3 , wherein the display device is configured to indicate to an operator of the TMS system whether the TMS coil assembly is properly disposed and, in the event that the TMS coil assembly is not properly disposed with respect to the patient during the TMS treatment, display a direction to move the TMS coil assembly. 
     
     
         5 . The TMS system of  claim 1 , wherein the TMS coil assembly comprises a plurality of contact areas where the TMS coil assembly is in contact with a patient's anatomy and a plurality of non-contact areas where the TMS coil assembly is not in contact with the patient's anatomy; and
 wherein the signal processing electronics is configured to identify a position on the patient's anatomy as a contact area or as a non-contact area based on the optical output signal.   
     
     
         6 . The TMS system of  claim 1 , wherein the signal processing electronics is configured to provide an audible feedback to an operator of the TMS system to indicate whether the TMS coil assembly is properly disposed. 
     
     
         7 . The TMS system of  claim 1 , further comprising:
 an articulating arm configured to support the TMS coil assembly and allow an operator to adjust the TMS coil assembly with respect to a patient's head.   
     
     
         8 . The TMS system of  claim 1 , wherein the optical sensor comprises an optical fiber. 
     
     
         9 . The TMS system of  claim 1 , wherein the optical sensor comprises:
 an optical fiber;   a fiber Bragg grating; and   a light source configured to provide at least a first wavelength of light to the fiber Bragg grating via the optical fiber;   wherein the fiber Bragg grating is configured to reflect at least a portion of the light at the first wavelength.   
     
     
         10 . The TMS system of  claim 1 , wherein the sensor comprises:
 a light source;   an opaque sliding arm; and   an actuator arm;   wherein, when the actuator arm is depressed, the actuator arm is configured to move the opaque sliding arm such that the opaque sliding arm is positioned between the light source and the optical detector, and wherein the optical detector is configured to identify the position on the patient's anatomy as a contact area based on a determination that the optical detector is not receiving light from the light source.   
     
     
         11 . A magnetic stimulation system comprising:
 a transcranial magnetic stimulation (TMS) coil assembly that comprises a plurality of contact areas where the TMS coil assembly is in contact with a patient's anatomy and a plurality of non-contact areas where the TMS coil assembly is not in contact with the patient's anatomy;   an optical sensor; and   an optical detector configured to:
 receive an output signal from the optical sensor; and 
 identify a position on the patient's anatomy as a contact area or as a non-contact area based on the output signal. 
   
     
     
         12 . The magnetic stimulation system of  claim 11 , wherein the optical detector comprises signal processing electronics configured to process the output signal received from the optical sensor. 
     
     
         13 . The magnetic stimulation system of  claim 11 , wherein the optical sensor comprises:
 an optical fiber;   a fiber Bragg grating; and   a light source configured to provide at least a first wavelength of light to the fiber Bragg grating via the optical fiber;   wherein the fiber Bragg grating is configured to reflect at least a portion of the light at the first wavelength.   
     
     
         14 . The magnetic stimulation system of  claim 13 , wherein the portion of the light at the first wavelength reflected by the fiber Bragg grating decreases when the fiber Bragg grating is depressed, and wherein the optical detector is configured to identify the position on the patient's anatomy as a contact area or a non-contact area based on the portion of the light at the first wavelength reflected by the fiber Bragg grating. 
     
     
         15 . The magnetic stimulation system of  claim 13 , wherein the light source is further configured to provide a second wavelength of light to the fiber Bragg grating, and wherein a peak reflectance wavelength of the fiber Bragg grating changes when the fiber Bragg grating is depressed. 
     
     
         16 . The magnetic stimulation system of  claim 15 , wherein the optical detector is configured to identify the position on the patient's anatomy as a contact area or a non-contact area based on the peak reflectance wavelength of the fiber Bragg grating. 
     
     
         17 . The magnetic stimulation system of  claim 11 , wherein the optical sensor comprises:
 a light source;   an opaque sliding arm; and   an actuator arm;   
       wherein, when the actuator arm is depressed, the actuator arm is configured to move the opaque sliding arm such that the opaque sliding arm is positioned between the light source and the optical detector, and wherein the optical detector is configured to identify the position on the patient's anatomy as a contact area based on a determination that the optical detector is not receiving light from the light source. 
     
     
         18 . The magnetic stimulation system of  claim 11 , wherein the optical sensor comprises:
 a light source;   an opaque sliding arm; and   an actuator arm;   wherein, when the actuator arm is depressed, the actuator arm is configured to move the opaque sliding arm such that the opaque sliding arm is not positioned between the light source and the optical detector, and wherein the optical detector is configured to identify the position on the patient's anatomy as a contact area based on a determination that the optical detector is receiving light from the light source.   
     
     
         19 . The magnetic stimulation system of  claim 11 , wherein the optical sensor is disposed between the TMS coil assembly and the position on the patient's anatomy.