“…9,15,[24][25][26] The moderate correlation between these two types of instruments means they should not be substituted for each other. The variables driving this nonsubstitutable character may include respondents' age, treatment type (eg, radiation vs chemotherapy), 15 types of vocal dysfunctions, 25 socioeconomic status and social support, 23 cross-cultural differences and individual cultural backgrounds, 34 and speech modes. In terms of the latter, it should be noted that prior studies by Kasper et al, 24 Portone et al, 25 and Dehqan et al, 26 all of whose participants were laryngeal, reported strong correlations between scores on the VHI and V-RQOL.…”