Perception of "elliptical speech" following cochlear implantation: Use of broad phonetic categories in speech perception

This study investigated the perception of elliptical speech (Miller & Nicely, 1955) in an adult cochlear implant patient. A group of 20 adult listeners with normal hearing were used for comparison. Two experiments were conducted using sets of meaningful and anomalous English sentences. Two versions of each set of sentences were constructed: One set contained correct place of articulation cues; the other was transformed into elliptical speech using a procedure in which different places of articulation were all converted to alveolar place of articulation. The patient, "Mr. S," completed a same-different discrimination task and a sentence transcription task. The listeners with normal hearing completed both tasks under masking noise and low-pass filtering. In the same-different task, under both conditions of signal degradation, listeners with normal hearing labeled a sentence with intact place of articulation cues and its elliptical version as the same. Mr. S also showed the same pattern. These findings support the claim by Miller and Nicely (1955) that under conditions of signal degradation, ellipsis can no longer be detected. In the sentence transcription task, however, subjects with normal hearing showed better transcription performance for sentences with intact place of articulation cues than for elliptical speech sentences, which was unexpected given the findings from the sentence discrimination experiment. Mr. S also showed the same pattern of performance. These new findings on the perception of elliptical speech suggest that cochlear implant users perceive speech and recognize spoken words using broad phonetic categories.