26 research outputs found
Independent component analysis for cochlear implant artifacts attenuation from electrically evoked auditory steady-state response measurements
Programming characteristics of cochlear implants in children: effects of aetiology and age at implantation
Evaluation of focused multipolar stimulation for cochlear implants in acutely deafened cats
A comparison of adaptive psychometric procedures based on the theory of optimal experiments and Bayesian techniques: Implications for cochlear implant testing
Effects of Elicitation Task Variables on Speech Production by Children With Cochlear Implants
Mansoura University habilitation outcome of prelingual cochlear-implanted children: 5 years of experience
A Model of Incomplete Adaptation to a Severely Shifted Frequency-to-Electrode Mapping by Cochlear Implant Users
In the present study, a computational model of phoneme identification was applied to data from a previous study, wherein cochlear implant (CI) users’ adaption to a severely shifted frequency allocation map was assessed regularly over 3 months of continual use. This map provided more input filters below 1 kHz, but at the expense of introducing a downwards frequency shift of up to one octave in relation to the CI subjects’ clinical maps. At the end of the 3-month study period, it was unclear whether subjects’ asymptotic speech recognition performance represented a complete or partial adaptation. To clarify the matter, the computational model was applied to the CI subjects’ vowel identification data in order to estimate the degree of adaptation, and to predict performance levels with complete adaptation to the frequency shift. Two model parameters were used to quantify this adaptation; one representing the listener’s ability to shift their internal representation of how vowels should sound, and the other representing the listener’s uncertainty in consistently recalling these representations. Two of the three CI users could shift their internal representations towards the new stimulation pattern within 1 week, whereas one could not do so completely even after 3 months. Subjects’ uncertainty for recalling these representations increased substantially with the frequency-shifted map. Although this uncertainty decreased after 3 months, it remained much larger than subjects’ uncertainty with their clinically assigned maps. This result suggests that subjects could not completely remap their phoneme labels, stored in long-term memory, towards the frequency-shifted vowels. The model also predicted that even with complete adaptation, the frequency-shifted map would not have resulted in improved speech understanding. Hence, the model presented here can be used to assess adaptation, and the anticipated gains in speech perception expected from changing a given CI device parameter