Introduction: Multidimensional voice evaluation is considered as gold standard in voice medicine. In this respect, the European Laryngological Society recommended a protocol for standardized evaluation (ELS-Protocol). However, there are only rare data analyzing changes during therapeutical follow-up.

Material and methods: Using this protocol, 276 patients (136 after phonosurgery, 81 after voice therapy and as a control group 59 patients without voice impairment) were evaluated with regard to their vocal capacity before and after voice therapy or phonosurgery, respectively.

Results: The parameters of the ELS-protocol showed significant improvement under therapy with respect to DSI, VHI, and RBH-scale. It has been confirmed, that these measurements are suitable for the assessment of dysphonic patients with organic as well as functional voice disorders. However, detailed analysis of all the obtained parameters showed only weak or no correlation between all regarding parameters, which should be expected to provide comparable information, such as perturbation parameters or such parameters, that are derived from the acoustical spectrum.

Discussion: Multidimensional evaluation of the voice as recommended by the ELS protocol is independent from the therapeutical approach able to document therapeutical success. The lack of sufficient correlations of values which should provide comparable information shows that an optimization or standardization of measuring instruments, computer hardware and software is necessary.