Connection quality assessment for eeg electrode arrays

Abstract

Systems, devices, and methods are provided to assess connection quality between the electrodes of a bioelectrical signal measurement and/or electrical stimulation device and the tissue, typically skin, of the subject. A test signal is provided to a first electrode, voltage differences between the first electrode and additional electrodes are determined, an impedance of the first electrode is determined based on the voltages differences, and the determined impedance indicates connection quality. This process is typically repeated for all of the electrodes to determine connection quality. The user or subject can be alerted if the connection quality is poor, and the bioelectrical signal that is recorded can be provided with data points indicating connection quality during the signal recording.

What is claimed is: 
     
         1 . A method of assessing quality of a connection between an electrical sensor or stimulator and tissue of a subject, the method comprising:
 (a) providing an electrical sensor or stimulator comprising a plurality of electrodes;   (b) contacting the plurality of electrodes to tissue of a subject;   (c) providing a test signal to the tissue of the subject through a first electrode of the plurality of electrodes;   (d) determining, with a processor coupled to the plurality of electrodes, a voltage difference between the first electrode and only one other electrode of the plurality of electrodes in response to the test signal, wherein the voltage difference is determined with neither the first electrode nor the only one other electrode being a common ground or a common reference electrode;   (e) determining, with a processor coupled to the plurality of electrodes, an impedance of the first electrode in response to the determined voltage difference between the first electrode and the only one other electrode of the plurality of electrodes;   (f) repeating steps (d) and (e) for the first electrode and other electrodes of the plurality of electrodes; and   (g) notifying, with an output device coupled to the processor, one or more of the subject or a user that connection quality of the first electrode is poor if the determined impedance of the first electrode is above a predetermined impedance threshold.