“…A possible research method for a closer test of our hypothesis may be to directly measure the synchronization of patient and therapist's emotional flow during psychotherapy sessions; and the relationship between synchronization level and outcome in exposure-based psychotherapy. Emotional fluctuations may be evaluated through different psychophysiological measures such as heart rate or skin conductance responses (for review, see, Marci & Riess, 2009 ) or through vocal measures, such as changes in voice prosody (Moneta, Penna, Loyola, Buchheim, & Kächele, 2008 ) or vocal acoustics (Rochman, Diamond, & Amir, 2008 ).…”