Validation of an Intelligibility Assessment Tool in an Indian Language for Perceptual Speech Analysis in Oral Cancer Patients

This study aimed to develop a speech intelligibility tool in Malayalam, an Indian language, based on the perceptual analysis. The tool had components of vowel, consonant, word, passage, and overall intelligibility. After face and content validation, a sample of 30 consecutive oral cancer patients underwent preliminary testing for internal consistency, inter- and intra-rater reliability, concurrent, and known-group validity. Subsequent validation was done in 80 T1–T4 patients from two centers. The scale had a high level of internal consistency; the Cronbach’s alpha was 0.847 and good intra-rater and inter-rater agreement amongst all raters. There was a strong correlation between the Malayalam and the English passage. Pearson correlation coefficient of 0.646 proved concurrent validity. On known-group and subsequent validation, the tool showed expected differences between the treatment groups. The speech tool proved to be reliable and valid for perceptual evaluation of speech intelligibility in oral cancer patients.