The effect of task variables on speech during oral anesthesia

A normal, adult female performed a variety of speech tasks before and after a series of nerve-block injections that anesthetized the oral cavity. The tasks included diadokokinesis, imitation of unfamiliar Swedish phonemes, production of one-, two-, three-, and four-syllable words, and of two prose passages. Four experienced judges scored misarticulations. Intelligibility was determined in a series of listening studies involving college students. The highest percentage of misarticulations occurred on the single-syllable word list and the most complex prose passage. There were virtually no misarticulations on the two- or three-syllable words. Intelligibility tended to covary with articulation, but the specific nature of the relationship depended on the particular speech task. A misarticulation was especially likely to result in unintelligibility on the most difficult passage, although not all unintelligible words on that passage were attributable to phonemic errors.