Analytic study of the Tadoma method: discrimination ability of untrained observers.

This study reports the ability of two observers with normal-hearing and sight to discriminate pairs of speech elements through the Tadoma method of speechreading. The observers were blindfolded and exposed to masking noise to eliminate visual and auditory cues. They placed their right hand over the speaker's face and neck so that the thumb rested lightly on the lips and the fingers fanned out over the cheek and neck. The discrimination tests were conducted using an ABX procedure. Average discrimination scores for the five types of test materials used in the ABX tests were 87% on W-22 words, 83% on Modified Rhyme Test words, 70% on vowels, 77% on CV and VC nonsense syllables, and 71% on consonant clusters. In all of the ABX tests, the inexperienced observers performed at least as well as the experienced Tadoma user studied by Norton, et al (1977). This finding indicates that the basic tactile sensitivity of inexperienced observers is comparable to that of an experienced deaf-blind Tadoma user.