Frequency and electrode discrimination in children with cochlear implants

• Published in: Hearing research 2010-09, Vol.268 (1), p.105-113
• Main Authors: Kopelovich, Jonathan C., Eisen, Marc D., Franck, Kevin H.
• Format: Article
• Language: English
• Subjects: Acoustic Stimulation; Adolescent; Adolescent Development; Age Factors; Aging; Biological and medical sciences; Case-Control Studies; Child; Child Development; Child, Preschool; Cochlear Implants; Correction of Hearing Impairment; Ear and associated structures. Auditory pathways and centers. Hearing. Vocal organ. Phonation. Sound production. Echolocation; Ear, auditive nerve, cochleovestibular tract, facial nerve: diseases, semeiology; Electric Stimulation; Fundamental and applied biological sciences. Psychology; Humans; Medical sciences; Non tumoral diseases; Otorhinolaryngology. Stomatology; Persons With Hearing Impairments - rehabilitation; Pitch Discrimination; Pitch Perception; Prosthesis Design; Psychoacoustics; Reproducibility of Results; Signal Detection, Psychological; Vertebrates: nervous system and sense organs; Video Games
• ISSN: 0378-5955; 1878-5891
• DOI: 10.1016/j.heares.2010.05.006

The objective of this study was to develop reliable pediatric psychophysical methodologies in order to address the limits of frequency and electrode discrimination in children with cochlear implants. Discrimination was measured with a two-alternative, adaptive, forced choice design using a video game graphical user interface. Implanted children were compared to normal-hearing children in the same age ranges. Twenty-nine implanted children and 68 children with normal-hearing performed frequency discrimination studies at varying frequencies. Electrode discrimination was assessed in thirty-four implanted children at varying electrode locations and stimulation intensities. Older children had better frequency discrimination than younger children, both for implanted and hearing subjects. Implanted children had worse frequency discrimination overall and exhibited learning effects at older ages than hearing children. Frequency discrimination Weber fractions were smallest in low frequencies. Electrode discrimination improved with stimulus intensity level for older but not younger children at all electrode locations. These results support the premise that developmental changes in signal processing contribute to discrimination of simple acoustic stimuli. For implanted children, auditory discrimination improved at lower frequencies and with electrodes at higher intensity. These findings imply that spatial separation may not be the key determinant in creating discriminable electrical stimuli for this population.