Introduction
Hearing impairment is one of the most prevalent health-related issues worldwide. According to the World Health Organization (WHO), in 2023 more than 5% of world population (more than 466 million people) were suffered from disabling hearing impairment. Prevalence of neonatal hearing impairment in Iran may be more than global level. The genetic causes of hearing loss has been reported to be more prevalent in Iran. Cochlear implantation is a medical procedure for patients with severe hearing loss who cannot restore functional hearing with their hearing aids. By implementing this intervention at the right time, a cochlear implant (CI) can prevent language deficit, cognitive problems, and social and communication impairments. It has been the most successful medical device intended for restoring a sensory function in humans. There is no available information about the precise number of CI users in Iran. There are 16 CI centers throughout the country.  In this study, we aimed to investigate the demographic and audiologic characteristics of CI users in Guilan, north of Iran.

Methods
There were three centers to search for CI users including the Guilan cochlear implant center (GCIC), the Welfare Organization, and Exceptional Education Organization. The data such as gender and ethnicity of patients, age at diagnosis of hearing loss, age at implantation, place of residence, educational level of parents, family history of deafness, history of using hearing aids, type of used prosthesis , type of surgery (in terms of using government services), and the implantation side were extracted. The relationship of parents’ educational level, place of residence, and economic status with the age at diagnosis of hearing loss and the age of implantation in children under 7 years was investigated using Spearman’s correlation test. Pre-school children (age <6 years) were divided into two groups based on the presence or absence of a deaf member in the family and were compared according to the age at diagnosis of hearing loss and the age at implantation using the Mann-Whitney U test. 

Results
In this study, the information of 153 CI users were examined, who included 79 females (51.6%) and 74 males (48.4%). Their mean age was 15.23±18.88 years, ranging from 7 months to 67 years. Most of them had Gilak ethnicity (64.7%) and 18 were non-Gilak. Diagnosis of severe to profound hearing loss and cochlear implantation had occurred in 84 patients before the age of 7. Most of the children were implanted in the age range of 1-2 years.
In children under 7 years of age, there was a significant positive correlation between the age at diagnosis of hearing loss and the age at cochlear implantation (r=0.43, P<0.01). There were 84 children in pre-school age, of whom 18 had at least one deaf person in the family (parents or siblings) and 66 had healthy parents or siblings. In comparing these two groups (groups with and without a deaf person in the family), no significant difference was observed in the age at diagnosis of hearing loss (P=0.15) and the age at cochlear implantation (P=0.71). The age at diagnosis of hearing loss and the age at implantation in children under 7 years of age had no significant relationship with the educational level of parents, place of residence, and economic status of the family (P>0.05).

Conclusion
The high governmental services for cochlear implantation in Guilan province,  low age at diagnosis of hearing loss in nearly 70% of CI patients (before one year old), and the variety of CI prostheses used in the GCIC are among the strengths of cochlear implantation process at the provincial level in Iran. However, there was a significant delay between the age at diagnosis of hearing loss and the age at cochlear implantation in CI patients, which requires investigating the reasons and planning to shorten this delay time.

Ethical Considerations

Compliance with ethical guidelines
This research was approved by the Ethics Committee of Guilan University of Medical Sciencess, Rasht, Iran (Code: IR.GUMS.REC.1402.052).

Funding
This study was funded by Guilan University of Medical Sciences (Grant No: 3795-4772).

Authors contributions
Conceptualization and study design: Shadman Nemati Noghlbari and Rasool Panahi; Data collection, data interpretation, and initial draft preparation: Mojtaba Gholami Jaliseh, Maedeh Jabbari, and Rasool Panahi; Statistical analysis: Maedeh Jabbari and Rasool Panahi; Editing & review: Shadman Nemati Noghlbari.

Conflicts of interest
The authors declared no conflict of interest

Acknowledgments
The authors would like to thank the experts at the Otorhinolaryngology Research Center and the Vice-Chancellor for Research and Technology of Guilan University of Medical Sciences and the Guilan Cochlear Implant Center (GCIC) for their support and assistance.



 

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