“…In addition, Sanchez and Rocha (2011) mention that ST often changes its loudness, pitch, or localization during stimulation in the head or neck region. Others ( Biesinger, Groth, Hoing, & Holzl, 2015 ; Ward, Vella, Hoare, & Hall, 2015 ) state that the presence of this somatic modulation, through voluntary movements or specific resistance tests, is very important, if not the most important criterion, in diagnosing ST. These differences in diagnostic criteria might, at least partially, explain the large differences in prevalence of ST, which vary from 16% to 83% in different studies ( Abel & Levine, 2004 ; Levine, Abel, & Cheng, 2003 ; Michiels, De Hertogh, Truijen, & Van de Heyning, 2015 ; Ralli et al., 2017 ; Simmons, Dambra, Lobarinas, Stocking, & Salvi, 2008 ; Ward et al., 2015 ; Won et al., 2013 ).…”