Speech Intelligibility and Sentence Duration as a Function of Mode of Communication in Cochlear Implanted Children Nicole L. Wiessner 1, Kristi A. Buckley 1, Emily A. Tobey 1,2 and Ann E. Geers 2 1 Callier Advanced Hearing Research Center, 2 UT Southwestern Medical Center, Dallas, Texas DISCUSSION PARTICIPANT DATA NMinimumMaximumMean Std. Deviation Mode of Communication: Oral 68 Total Communication 67 Gender: Male 63 Female 73 Duration of Deafness (months) Age at Testing (years) Age at Implant (years) Duration of Implant Use (years) Number of Active Electrodes Profound hearing loss is accompanied by diminished speech intelligibility. McGarr (1983) examined speech intelligibility in year old deaf children who used powerful conventional hearing aids. She found deaf children were more intelligible when speaking words in highly predictable than less predictable sentences. She also found deaf speakers were more intelligible in longer utterances than shorter utterances. Unintelligible speech in deaf speakers has been associated with longer durations, inappropriate pausing, poor segmental control, breathiness, and nasality. However, little is known regarding how durational control is influenced by the presence of predictable words within a sentence. Likewise, little is know of the relationship between duration of speech and speech intelligibility. Mode of Communication Parents completed communication rating scales probing the level of emphasis on speech in their child’s educational environment. Auditory-oral refers to environments emphasizing a reliance on spoken speech communication, including cued speech, auditory-oral and auditory-verbal programs. Total communication reflected educational environments emphasizing a reliance on manual forms of communication, including the simultaneous use of speech and sign programs and programs emphasizing signing. Parents rated the communication environment at 5 time periods (pre-implant, the first 3 years post implantation, and the environment at the time of participating in the study). The average rating across time periods served as the child’s mode of communication. Duration and Speech Intelligibility The test materials were 36 sentences varying in length (3, 5, or 7 syllables) and containing keywords embedded in either a high or low context (McGarr, 1983). Subjects were prompted in the child’s communication modality of preference to read aloud the sentences. Productions were recorded directly into a DAT recorder using a microphone positioned 12 inches in front of the child. The recorded sentences were computer segmented and stored individually as.wav sound files. Sentence durations were calculated from the digitized waveforms by locating the first and last zero crossing associated with each sentence. Durations were examined according to syllable length, low versus high context sentences as a function of the child’s communication modality. To assess speech intelligibility, normal hearing adult subjects served as judges, writing down as much of the sentences as they could understand. Each sentence was examined by three judges. Each judge was allowed to hear a given child and a given sentence one time to ensure they did not become familiar with testing materials. Intelligibility scores (percentages) for each child were calculated as the mean number of correct words for the 36 sentences divided by the number of total possible correct. METHODS RESULTS Future studies will examine the impact of important implant variables (age at implantation, duration of implant use, duration of Spectra use, number of active electrodes, nonverbal IQ) on sentence duration and speech intelligibility in children who are profoundly deaf cochlear and receive cochlear implants. FUTURE DIRECTIONS McGarr, N. S. (1983). "The intelligibility of deaf speech to experienced and inexperienced listeners." Journal of Speech, Language, and Hearing Research, 26(3): REFERENCES We thank Andrea Warner-Czyz for providing helpful comments on earlier versions of the poster. This work was supported in part by the NIH-NIDCD. ACKNOWLEDGEMENTS INTRODUCTION Figure 3. Means and standard deviations of sentence duration as a function of mode of communication, syllable length and contextual keywords are shown. Sentence duration significantly increased with greater lengths (p < 0.01). Children relying on sign communication produced longer durations than children relying on spoken communication (p < 0.01). Significant differences in sentence duration were also observed across speakers with different modes of communication as a function of contextual keywords contained within sentences varying in length across speakers with different modes of communication (p < 0.05). Figure 4. The mean and standard deviations of speech intelligibility as a function of mode of communication, syllable length and contextual keywords are shown. No significant differences in sentence intelligibility were observed as a function of contextual keywords contained within sentences varying in length across speakers with different modes of communication. Figure 1. Median duration is indicated by the horizontal line located in the boxes. 25th and 75th percentiles of the durations are the lower and upper boundaries of the boxes, respectively. The whiskers represent the longest and shortest durations that are less than 1.5 box lengths. Outliers in duration (operationally defined as durations greater than the whisker 1.5 box lengths) are indicated by individual data points. Children relying on sign produced significantly longer sentences than children relying on oral communication (p < 0.01). Figure 2. Median intelligibility is indicated by the horizontal line located in the boxes. 25th and 75th percentiles of percent correct are represented as the lower and upper boundaries of the boxes, respectively. The whiskers represent the largest and smallest percentages that are less than 1.5 box lengths. Outliers in intelligibility (operationally defined as greater than the whisker 1.5 box lengths) are indicated by individual data points. Children relying on sign produced significantly less understandable sentences than children relying on oral communication (p < 0.01). Figure 5. The relationship between speech intelligibility and sentence duration for children relying on oral communication is shown. The scatter plot displays an inverse relationship between intelligibility and duration; that is, higher intelligibility scores were related to overall shorter sentence durations p < 0.01). Figure 6. The relationship between speech intelligibility and sentence duration for children relying on sign communication is shown. The scatter plot displays an inverse relationship between intelligibility and duration; that is, higher intelligibility scores were related to overall shorter sentence durations (p< 0.01). Sentence duration and speech intelligibility were examined as a function of syllable length, the incorporation of low versus high context key words, and the communication modality used by children with profound hearing impairment using cochlear implants. Significantly shorter sentence durations were found for cochlear implant users communicating with an oral emphasis than cochlear implant users communicating using manual sign systems. Systematic increases in sentence duration occurred with increased syllables, regardless of mode of communication. In addition, the inclusion of keywords designed to be influenced by sentential context resulted in significantly different temporal strategies as a function of mode of communication and syllable length of sentences. Specifically, an increase in contextual information present significantly resulted in shorter sentence durations at each syllable length for total communication children; however, duration for oral children remained stable regardless of context. Children with cochlear implants using an oral mode of communication produced significantly more intelligible sentences than children relying on manual sign. This difference in intelligibility was further accompanied by great variability in the productions of the group utilizing total communication. Across modes of communication, neither the amount of context nor sentence length had an effect upon speech intelligibility. When intelligibility and the temporal characteristic of speech were examined together, a significant inverse relationship emerged. For children using cochlear implants, higher speech intelligibility was associated with shorter durations. These data demonstrate that durational control of sentences may be a key contributor to overall speech intelligibility in children with profound hearing impairment using cochlear implants. Moreover, an emphasis on spoken communication in children using cochlear implants appears to positively impact both production and perception of speech. Mean Sentence Duration by Context and Mode: Three, Five and Seven Syllables Sentence Length (syllables) Duration (msec) Oral High Context Oral Low Context TC High Context TC Low Context Mean Speech Intelligibility by Context and Mode: Three, Five and Seven Syllables Sentence Length (syllables) Speech Intelligibility (% Correct) Oral High Context Oral Low Context TC High Context TC Low Context