With this protocol we want to investigate the degree to which the use of Meludia training (the online self-paced music training application) can improve music perception, music enjoyment, and speech understanding in pediatric and postlingually deafened adult CI users. The study also aims to assess the participants' changes in cognitive skills (attention and memory) and quality of life.

Participant recruitment Group A: New CI users All postlingually deafened patients older than 6 years who undergo cochlear implantation at the La Paz Hospital in Madrid (Spain) between September 2024 and September 2027 will be invited to participate in the study.

Group B: Experienced CI users CI users older than 6 years old with at least 12 months of stable fitting will be recruited from the CI program at the La Paz Hospital between September 2024 and September 2027. Within this group this group, it will be required that pediatric CI have been implanted before the age of 3 years.

Both in the Group A and in the Group B, participants at the time of enrolment will be randomly divided 1:1 into two groups, with subjects being instructed to practice with Meludia music training application (intervention group: MT group) and participants in the non-MT group non receiving music training (NMT group).

We will establish 20 minute sessions three times per week over a period of 4 weeks for participants in the MT group. After this period, all the participants will be evaluated (session 1). An additional training period of 12 weeks, also with 20-min sessions three times per week, will then be conducted in the MT group, followed by another evaluation (session 2).

The ongoing protocol for music training cannot replace conventional tools in the rehabilitation of CI users. However, after scientific-based improvement of music practice protocols (easily implementable, low-priced, and with little probability of adverse effects) as an auditory practice rehabilitation along with the conventional methods, music training may provide an important tool for the aural rehabilitation plan

Inclusion Criteria:

• Group A: New CI users All postlingually deafened patients older than 6 years who undergo cochlear implantation at the La Paz Hospital in Madrid (Spain) between September 2024 and September 2027 will be invited to participate in the study.

Group B: Experienced CI users CI users older than 6 years old with at least 12 months of stable fitting will be recruited from the CI program at the La Paz Hospital between September 2024 and September 2027. Within this group this group, it will be required that pediatric CI have been implanted before the age of 3 years.

All participants in both groups will have been implanted either unilaterally or bilaterally with CI devices from the manufacturer MED-EL (Innsbruck, Austria).

Exclusion Criteria:

• Participants will be excluded from the study if they have visual or motor impairments that prevent them from seeing the computer screen and pressing the correct keys, or if there is evidence of cognitive decline. Participants who have previously used Meludia software will also be excluded.