On Electrodermal Activity:
The E3 samples EDA at 4 Hz in order to support analysis and summarization of phasic changes in the signal. Phasic skin conductance measurements are peaks in the signal that are typically associated with short-term events and occur in the presence of discrete environmental stimuli (sight, sound, smell, cognitive processes that precede an event such as anticipation, decision making, etc). These peaks are generally referred to as Skin Conductance Responses (SCRs) and are of interest to researchers in a number of fields. Consumer-oriented devices are typically limited to 1/60Hz sampling of skin conductance which prevents SCRs from being retrieved. Many products that claim to offer EDA or Galvanic Skin Response (GSR) do not provide continuous data and just sample periodically to improve activity classification.
Study 1 - Jan 2015
We compared the performance of Empatica E3 EDA sensor with respect to the Thought Technology EDA sensor SA9309M, acquired with a Procomp Infinity unit.
Since the Thought Technology EDA sensor could be used only on the fingers, we decided to apply external cables to the Empatica EDA sensor in order use it also on the finger and thus eliminate any site differences.
In this study, we acquired 10 subjects that were recorded for 3 to 5 minutes while watching an exciting video. EDA data from the E3 was highly correlated to data from the Thought Tech system in 9 out of ten sessions (0.96). Including all ten sessions both systems performed similarly:
|Number of peak events||r=0.95||p<0.0001|
|Phasic-band power (0.05-1 Hz)||r=1.0||P<1E-10|
The comparison is documented in the following presentation: Thought Technology Procomp vs E3 EDA sensor