Substitution voicing index: towards improved speech assessment in patients who have undergone laryngeal oncosurgery

This study aimed to develop a multidimensional model for the evaluation of substitution voicing (SV) after laryngeal oncosurgery. The study group consisted of 121 adult male individuals: 59 patients with SV after laryngeal oncosurgery (endolaryngeal cordectomy, partial laryngectomy, total laryngectomy with tracheoesophageal prosthesis) and 62 healthy controls. A multidimensional protocol for the assessment of SV included, 1) self-reported speech evaluation with a short version of the Speech Handicap Index, 2) auditory-perceptual assessment, and 3) acoustic speech analysis using AMPEX® (Auditory Model Based Pitch Extractor) software. Moderate correlations were observed between parameters from self-reported auditory-perceptual and acoustic speech analysis domains. The multidimensional Substitution Voicing Index (SVI), including markers from these domains, was elaborated by using linear stepwise regression to determine the optimal set of parameters for categorising SV patients. The lowest mean SVI score was revealed in the control subgroup corresponding to the normal speech, followed by cordectomy subgroup and partial laryngectomy subgroup. The highest mean SVI score was revealed in the total laryngectomy subgroup, reflecting the most severely deteriorated quality of SV. One-way analysis of variance identified statistically significant differences between the mean SVI scores in separate subgroups. The results demonstrated the potential benefits of the SVI for a multidimensional evaluation of SV in patients after laryngeal oncosurgery.