Long-term evolution of the electrical stimulation for cochlear implant adult patients. The role of a progressive adaptation method.

Background: In clinical experience patients who do not frequently check the cochlear implant (CI) maps have poor auditory performance and poor acceptance of map variations over time.Aims: The aim of the present study was to evaluate the effect of CI map optimization on both speech perception and subjective hearing in a group of CI patients with a long-standing map.Material and methods: 14 patients (6 females and 8 males; age range 16-77, mean age 45.86 ± 23.85 years) fitted with a unilateral CI (Cochlear Ltd, Sydney, Australia) and a map unchanged for at least 12 months were evaluated. All CIs were remapped using mapping method with progressive adaptation. The speech discrimination in noise and subjective hearing perception (SSQ questionnaire) were evaluated with old and new map.Results: The differences in electrode level with old and new map were significantly different both for T and C- Levels (p < .001). Speech discrimination in noise was significantly better (22.9%; p < .0001) after map optimization. The SSQ questionnaire showed no statistically significant difference in the overall scores, except the listening effort sub-scale.Conclusions: Longstanding MAPs are associated with poor speech discrimination. Degradation of electrical stimulation is associated with increased mental effort.