Systems and methods for determining physiological state based on surface biopotentials

A system for assessing a physiological state of a user based at least in part on biopotentials detected at an external surface of a skin portion of the user, the system comprising:

• a wearable device configured to be worn by the user, the wearable device comprising:
• one or more electrodes configured to be disposed adjacent to an external surface of the skin portion, wherein the skin portion is disposed at a body portion comprising peripheral nerve tissue that is biologically coupled to a central nervous system of the user;
• and
• one or more processors;
• wherein the system is configured to:
• obtain, using the one or more electrodes, biopotential signals generated at least in part by the peripheral nerve tissue;
• determine a first timestamp, the first timestamp indicating a first time at which a stimulus is presented to the user;
• determine a second timestamp, the second timestamp indicating a second time at which the biopotential signals indicate an intention by the user to perform a responsive action in response to the stimulus;
• based at least on the first timestamp and the second timestamp, determine a subject response time for the user;
• and
• compare the subject response time for the user, or one or more values based thereon, to at least a baseline response time determined based at least in part on (i) one or more prior reaction time tests for the user or (ii) one or more reaction times for a representative population, and, based on this comparison, generate an assessment of a physiological state of the user.