Visual vs. Tactile Reaction Testing Demonstrates Problems with Online Cognitive Testing

Reaction time is one of the most commonly used measures in online cognitive assessments.  However, there are significant technical problems with the methods that are commonly deployed for obtaining this measure.  Most online cognitive toolkits obtain reaction time measures with a visual cue and some type of mechanical response (keyboard, mouse or touchscreen).  Both the hardware and software involved in the computer systems that these online cognitive tests depend on introduce significant delays and more significantly, variation in these delays.  The variability that is introduced by these systems leads to inaccurate results that health care professionals have come to rely on.  In this report, a comparison is made between the reaction time data collected with a tactile based device that is accurately calibrated to sub-millisecond accuracy (the Brain Gauge) to a visual reaction time test that relies on consumer grade computer systems in a manner that parallels the methods commonly used in online cognitive testing.  Forty healthy controls took both the tactile based and visually based reaction time test, and the results demonstrated a significant difference in both reaction time and reaction time variability.  Most significant was the difference in reaction time variability, which was 16 msec for the tactile test and 81 msec for the visual test.  While the differences could be partially accounted for by tactile vs. visual biological pathways, the variability of the results from the visual task are in the range predicted by error measured from previous reports that performed robotic testing to derive differences between the two modalities of testing.