Characteristics And Training Strategies Of Pitch Matching Accuracy In Cochlear Implant Children

OBJECTIVE:Pitch processing is thought to be limited in cochlear implant children. The lacking in studies on pitch matching accuracy of CI children may hinder the training of pitch disorders for CI children. This study aims to obtain the characteristics of pitch matching accuracy of single pitch, interval and melody of cochlear implant children and normal-hearing children aging3to6years old, and to develop effective training strategies of pitch matching accuracy for CI children.METHODS:The first part of the research shed light on characteristics of pitch matching accuracy of CI children. Altogether24CI children and33NH children aging3-6attended the study. C4, D4, E4, F4and G4were combined into different form to test stimuli in single pitch matching, interval matching and melody matching test. Seven indicators were selected to reflect the ability of pitch matching:(1) the original notes sung by subjects,(2) compression ratio,(3) pitch contour,(4) note error,(5) mean note deviation,(6) interval error,(7)mean interval error. Additionally, the relationship between pitch matching accuracy and voice fundamental frequency range, pitch discrimination, chronological age, age of implant, duration of implant were examined. The second part of the research is on training strategies of pitch matching.19CI children aging4-6attended the training section. Based on the results of characteristics of CI and NH children, training plan and this section required the subjects to attend a pre-test, a training section and a post-test. The original notes sung by subjects, compression ratio, pitch contour, mean note deviation and mean interval error were examined by comparison between pre-test and post-test. RESULTS:In the first part of characteristics study, results show:(1) the increasing complexity of the test form results in the expansion of pitch range up to6semitones, but a decreasing in pitch contour correctness in CI children.(2)In all three test forms, with the rising of target pitch height increased the original notes sung by CI subjects, the proportion of CI subjects who sung lower than the target pitch, and the mean note deviation. With the rising of target interval size, increased the proportion of CI subjects who sung smaller interval than the target interval size, and the mean interval deviation. Such tendency was also found in NH children, whose performance was increasingly better than that of CI children in more complex tasks.(3) The direction of interval affects the pitch matching accuracy of CI children. Pitch matching was more accurate in descending interval than in ascending interval or two flat notes.(4) Pitch matching accuracy was related to the voice FO range, maximum voice FO and duration of implant, but not with other factors. In the second part of study, effective training plan and strategies were developed in that most chosen indicators were found to be significantly improved after training.CONCLUSIONS: This study accomplished in access to (1) characteristics of pitch matching accuracy of CI children aging3to6,(2) factors affecting pitch matching,(3) factors related to pitch matching, and (4) the pitch matching patterns of NH children aging3-6. In addition, effective training plan and strategies were developed for pitch matching of CI children aging4-6. The enlargement in subject recruitment and more CI-children-specified training strategies were to explore in the near future.