“…Thirty-four used only one method to estimate SI frequency: three used objective instrumental assessments [4,33,34], seven water and saliva test [22-24, 37, 39, 43], seventeen a screening instrument [18-20, 25, 29, 30, 36, 40, 41, 45-47, 49-51, 54], and seven self-perception [3,16,21,26,38,42,48]. Seven studies presented the estimated frequency of SI by more than one assessment method: one presented by all subtypes [17], two by objective assessment, water test, and a screening instrument [28,37], and four presented by water test and a screening instrument [27,32,44,53]. The lowest estimated frequency of SI was found by Zhang H. et al 2020 [44], 5.5% assessed by Eating Assessment Tool (EAT-10), followed by Mulheren et al 2018 [28], 6.4%, assessed by videofluoroscopy and Penetration/Aspiration Scale in the USA.…”