System and method for testing contact quality of electrical-biosignal electrodes

Abstract

One variation of a method for testing contact quality of electrical-biosignal electrodes includes: outputting a drive signal—including an alternating-current component oscillating at a reference frequency and a direct-current component—through a driven electrode; determining that a reference electrode is in improper contact with a user's skin if a reference signal read from the reference electrode excludes a first signal component oscillating at the reference frequency and a second signal component oscillating at an ambient frequency; determining that a sense electrode is in improper contact with the user's skin if the reference signal includes the first signal component and if a sense signal read from the sense electrode excludes a third signal component oscillating at the reference frequency; and generating an electrode adjustment prompt if one of the reference and sense electrodes is determined to be in improper contact with the user's skin.

I claim: 
     
         1 . A method for testing electrode contact quality of an electroencephalography headset comprising a driven electrode and a set of sense electrodes, the method comprising:
 outputting a drive signal through the driven electrode, the drive signal comprising an alternating-current component oscillating at a reference frequency and a direct-current component;   reading a set of sense signals from the set of sense electrodes, the set of sense signals comprising a first sense signal detected by a first sense electrode in the set of sense electrodes;   calculating a linear combination of the set of sense signals;   in response to the linear combination excluding a first signal component oscillating at the reference frequency and comprising a second signal component oscillating at an ambient frequency, determining that the driven electrode is in improper contact with a user's skin;   in response to the linear combination comprising the first signal component oscillating at the reference frequency and in response to the first sense signal excluding a third signal component oscillating at the reference frequency, determining that the first sense electrode is in improper contact with the user's skin; and   in response to determination of improper contact between the user's skin and one of the driven electrode and the first sense electrode, generating an electrode adjustment prompt.   
     
     
         2 . The method of claim Error! Reference source not found, wherein generating the electrode adjustment prompt comprises:
 tracking a duration of a contiguous period of time during which the first sense electrode is determined to be in improper contact with the user's skin; and   in response to the duration of the contiguous period of time exceeding a threshold duration, transmitting an electronic notification to an external computing device accessible by an electroencephalography test administrator, the electronic notification comprising a prompt to adjust the first sense electrode.   
     
     
         3 . The method of claim Error! Reference source not found, further comprising in response to the linear combination comprising the first signal component oscillating at the reference frequency and in response to a second sense signal, detected by a second sense electrode in the set of sense electrodes, comprising a fourth signal component oscillating at the reference frequency, determining that the second sense electrode is in proper contact with the user's skin. 
     
     
         4 . The method of claim Error! Reference source not found, wherein reading the set of sense signals from the set of sense electrodes comprises scanning the set of electrodes integrated into an electroencephalography headset worn by the user 
     
     
         5 . The method of claim Error! Reference source not found, further comprising, in response to determining that the first sense electrode is in improper contact with the user's skin, removing the first sense signal from the linear combination.