Historically, diagnosing and tracking depressive symptoms has been accomplished by assessing subjective diagnostic criteria, either from the DSM, or from standardized rating scales. Though useful for semantic and billing purposes, this approach has limited utility for
Despite recent research efforts, no clinically useful, non-invasive, inexpensive biomarkers for the diagnosis and prognosis of depression have been identified.
Therefore, there is a critical need to identify and discover objective biomarkers for the diagnosis, prognosis, and treatment of depression. Brain imaging and recent findings have led us to hypothesize that depression, especially of the anxious type, might lead to larger right amygdala activation than left in most right-handers, and that this would map to larger electrodermal activity (EDA) on the right than on the left.
Abstract: Electrodermal activity (EDA) recording is a powerful, widely used tool for monitoring psychological or physiological arousal. However, analysis of EDA is hampered by its sensitivity to motion artifacts. We propose a method for removing motion artifacts from EDA, measured as skin conductance (SC), using a stationary wavelet transform (SWT). We modeled the wavelet coefficients as a Gaussian mixture distribution corresponding to the underlying skin conductance level (SCL) and skin conductance responses (SCRs).
Abstract: The growing need for ambulatory measurement of sympathetic nervous system arousal makes it important to find an unobtrusive alternative to the palmar site for long-term measurement of electrodermal activity (EDA), where sensors may need to be worn for a month or longer. Two prior studies have shown that EDA measured on the palmar and forearm sites is highly correlated; consequently, in this work we examine EDA measured simultaneously from the left and right forearm and left and right calf locations on the bodies of healthy adult volunteers (n=32), sites that support long-term wear. Time-synchronized measurements are made while each participant experiences three types of stressors: physical, cognitive, and emotional, preceded and followed by four rest periods. We also examine the lag of EDA response times in the physical task. All multi-site cross-correlations for all tasks and rest periods had median correlation coefficients above 0.5. The bilateral EDA measurements between both calves have the highest correlation coefficients (mean = 0.91, median = 0.96) calculated over the entire experiment, followed by the correlation coefficients between the forearms (mean=0.78, median=0.91). Participants who reported regularly playing sport showed faster EDA responses to the physical task than those who were less active. All participants reported the four locations to be comfortable, while 40% of participants reported the calf to be slightly more comfortable than the forearm. This study suggests that the back of the lower calf is a viable site for long term measurement of EDA.