Objectives: to determine the frequency-to-place mismatch in cochlear implant users, and to compare anatomy based fitting (ABF) vs standard fitting in terms of speech tests and subjective outcomes.
Methods: The Synchrony ST Flex28 (MED-EL,Innsbruck/Austria) was used in the eight adults who were enrolled. A postoperative Computed Tomography was performed following surgery. The length of the cochlear duct and the insertion depth for each patient was measured. The tonotopic distribution of each electrode was calculated using the Otoplan software (CAScination AG,Bern/Switzerland). The frequency-to-place mismatch was calculated in octaves through the difference between the ABF distribution and that performed by default in the standard fitting software. Speech tests (disyllables in silence and MATRIX - Oldenburg test with fixed noise at 55dB), the sound quality questionnaire HISQUI19, and the patient preference were used to evaluate the hearing outcomes after nine months with ABF and one month later of the standard fitting.
Results: In 6 out of 8 patients, the cochlear duct length was >35mm, with an insertion angle >600º, while the other two patients had a cochlear duct length between 30 and 35mm, with an insertion depth ≤540º. The mean mismatch for the low frequencies and for the medium frequencies was 0.67 and 0.003 for the wider insertions, and 0.93 and 0.003 for the shallowest insertions, respectively. It was observed that the shallower the depth, the wider the application of bandwidth in the most apical electrodes.
The mean score of disyllables in silence was 73% ±11 vs 72% ±16 with ABF and standard fitting, respectively. The Signal to Noise Ratio to achieve the Speech Recognition Threshold was 4±3 vs 4±5dB with ABF and standard fitting, respectively. Patients considered as moderate their quality of sound with both ways of fitting (77±25 vs 76±24). However, all patients except one preferred ABF when they were asked about their preference between both fitting methods.
Conclusions: Insertion depth is critical in finding the best tonotopic match. In spite of similar hearing outcomes most patients prefer ABF vs standard fitting. More data are necessary to corroborate the benefit of the ABF over standard fitting in speech and subjective tests.

**Objectives**: to determine the frequency-to-place mismatch in cochlear implant users, and to compare anatomy based fitting (ABF) vs standard fitting in terms of speech tests and subjective outcomes.
**Methods:** The Synchrony ST Flex28 (MED-EL,Innsbruck/Austria) was used in the eight adults who were enrolled. A postoperative Computed Tomography was performed following surgery. The length of the cochlear duct and the insertion depth for each patient was measured. The tonotopic distribution of each electrode was calculated using the Otoplan software (CAScination AG,Bern/Switzerland). The frequency-to-place mismatch was calculated in octaves through the difference between the ABF distribution and that performed by default in the standard fitting software. Speech tests (disyllables in silence and MATRIX - Oldenburg test with fixed noise at 55dB), the sound quality questionnaire HISQUI19, and the patient preference were used to evaluate the hearing outcomes after nine months with ABF and one month later of the standard fitting.
**Results:** In 6 out of 8 patients, the cochlear duct length was >35mm, with an insertion angle >600º, while the other two patients had a cochlear duct length between 30 and 35mm, with an insertion depth **≤**540º. The mean mismatch for the low frequencies and for the medium frequencies was 0.67 and 0.003 for the wider insertions, and 0.93 and 0.003 for the shallowest insertions, respectively. It was observed that the shallower the depth, the wider the application of bandwidth in the most apical electrodes.
The mean score of disyllables in silence was 73% ±11 vs 72% ±16 with ABF and standard fitting, respectively. The Signal to Noise Ratio to achieve the Speech Recognition Threshold was 4±3 vs 4±5dB with ABF and standard fitting, respectively. Patients considered as moderate their quality of sound with both ways of fitting (77±25 vs 76±24). However, all patients except one preferred ABF when they were asked about their preference between both fitting methods.
**Conclusions:** Insertion depth is critical in finding the best tonotopic match. In spite of similar hearing outcomes most patients prefer ABF vs standard fitting. More data are necessary to corroborate the benefit of the ABF over standard fitting in speech and subjective tests.

The effect of the Anatomy Based Fitting in postlingually deaf cochlear implant users

It is with great pleasure and enthusiasm, that on behalf of the Cochlear Implant centers of the Radboud UMC in Nijmegen and Erasmus MC Sophia Children’s Hospital in Rotterdam to invite you to attend the 16th European Symposium on Pediatric Cochlear Implantation to Rotterdam, the Netherlands in 2023.

Yours sincerely, on behalf of the CI Centers at Radboud UMC and Erasmus MC,