Perception of Specific Musical Attributes in Dependence of the Insertion Depth of Cochlear Implant Electrodes Using the Montreal Battery of Evaluation of Amusia

Hypothesis The insertion angle of the electrode array has an influence on the perception of different musical features. Background A deeper insertion of the electrodes is associated with a greater coverage of the cochlea with possible stimulus locations. This could lead to an improved or extended perception of pitches and pitch changes as well as to a better perception of contours in musical pieces. Methods A Montreal Battery of Evaluation of Amusia test battery was conducted with a collective of 19 cochlear implant (CI) users and 9 normal-hearing subjects. For the CI users, the insertion angles of the intracochlear electrode arrays were calculated using Otoplan software. Results Compared with normal-hearing users, CI users performed worse in the detection of melodic features of music. CI users performed better with temporal features than with melodic features. An influence of the insertion depth of the electrodes on the results of the Montreal Battery of Evaluation of Amusia could be proven neither for Cochlear nor for MED-EL CI users. Conclusion Deeper insertion of electrode arrays may only better approximate the spatial-frequency map. Alone, it does not have an effect on better detection and identification of pitch and tonality and, consequently, better perception of musical attributes. Anatomy-based calculation of electrode locations and matching to characteristic frequencies will be sought in subsequent studies.