SINGLE SIDED DEAFNESS ETIOLOGY IN COCHLEAR IMPLANTED CHILDREN. OUR EXPERIENCE.
 Dres ENT: Mª José Lavilla Martín de Valmaseda, Raquel Artal, Ana Mª Gasós, Luis Carmen, Juan Royo
ENT department Hospital Clínico Universitario Lozano Blesa. Zaragoza. Spain.
INTRODUCTION AND OBJECTIVES
This study aims to evaluate the etiology of children with single sided deafness (SSD) who became candidates for unilateral cochlear Implantation (uCI) in our center during the last seven years.
Severe to Profound Unilateral Hearing loss in children has traditionally been underappreciated but we are now beginning to understand the impact of permanent unilateral deafness on children's development. Children with unilateral hearing loss have educational and behavioural problems. Additionally, treatment provided has been highly variable, ranging from no action taken or watchful waiting up to single-sided cochlear implantation. Literature demonstrates that uCI rapidly reverses abnormal cortical function to restore normal hemispheric representation of sound in the brain if provided early. UCI intervention should take place as early as possible before the age of 4 years in the setting of congenital deafness as well as when it appears later. Currently, identifying and understanding the etiology of SSD is important to assess the appropriate treatment including counseling.
MATERIAL AND METHOD
Since January 2016 yo Januaru 2023 yo we have received 68 children with SSD. We have analized the etiology and therapeutic decision in all of them. Two of this 68 have not been included since they had a conversion disorder. 23 were Implanted (Ci 23/68: 37%).
RESULTS
From 66 SSD children, 8 were of unknown origin, 36 were unilateral inner ear malformation (54,55%) 1 Cystic cochlea, 2 incomplete partition type two ,33 unilateral cochlear nerve agenesia (50%), 2 were genetic origin, 1 familiar and 1 waanderburg syndrome, 4 were bilateral enlarged vestibular acqueduct (EVA), 1 unilateral EVA, 7 congenital citomegalovirus infection, 3 meningitis, 3 cochlear fracture, and 2 yactrogenics one during a tympanoplasty cavity aspiration, and the other by chlorexidine.
More Than half of children did not go on to implantation (43/66: 65%). Whit the 2 main reasons: did not meet candidacy criteria due to cochlear nerve aplasia or other inner ear malformations (36/ 66: 54,55%) and parents declined cochlear imlantation.
CONCLUSIONS
This work summarizes causes and treatment of SSD in children in our center, in order to draw attention to the importance of early audiology identification and etiology, so as to assess the treatment options. Ultimately many children with SSD who present for implant candidacy assesment do not receive uCI. The main factors contributing to noncandidacy are cochlear nerve dysplasia and parental decision. Of the proportion of children with SSD who are candidates, some have risk of sudden or progressive deterioration in the better earing ear. It is stressed the importance of performing a uCI above all in these risky etiologies as EVA and CMV.

**SINGLE SIDED DEAFNESS ETIOLOGY IN COCHLEAR IMPLANTED CHILDREN. OUR EXPERIENCE.**
 Dres ENT: Mª José Lavilla Martín de Valmaseda, Raquel Artal, Ana Mª Gasós, Luis Carmen, Juan Royo
ENT department Hospital Clínico Universitario Lozano Blesa. Zaragoza. Spain.
**INTRODUCTION AND OBJECTIVES**
This study aims to evaluate the etiology of children with single sided deafness (SSD) who became candidates for unilateral cochlear Implantation (uCI) in our center during the last seven years.
Severe to Profound Unilateral Hearing loss in children has traditionally been underappreciated but we are now beginning to understand the impact of permanent unilateral deafness on children's development. Children with unilateral hearing loss have educational and behavioural problems. Additionally, treatment provided has been highly variable, ranging from no action taken or watchful waiting up to single-sided cochlear implantation. Literature demonstrates that uCI rapidly reverses abnormal cortical function to restore normal hemispheric representation of sound in the brain if provided early. UCI intervention should take place as early as possible before the age of 4 years in the setting of congenital deafness as well as when it appears later. Currently, identifying and understanding the etiology of SSD is important to assess the appropriate treatment including counseling.
**MATERIAL AND METHOD**
Since January 2016 yo Januaru 2023 yo we have received 68 children with SSD. We have analized the etiology and therapeutic decision in all of them. Two of this 68 have not been included since they had a conversion disorder. 23 were Implanted (Ci 23/68: 37%).
**RESULTS**
From 66 SSD children, 8 were of unknown origin, 36 were unilateral inner ear malformation (54,55%) 1 Cystic cochlea, 2 incomplete partition type two ,33 unilateral cochlear nerve agenesia (50%), 2 were genetic origin, 1 familiar and 1 waanderburg syndrome, 4 were bilateral enlarged vestibular acqueduct (EVA), 1 unilateral EVA, 7 congenital citomegalovirus infection, 3 meningitis, 3 cochlear fracture, and 2 yactrogenics one during a tympanoplasty cavity aspiration, and the other by chlorexidine.
More Than half of children did not go on to implantation (43/66: 65%). Whit the 2 main reasons: did not meet candidacy criteria due to cochlear nerve aplasia or other inner ear malformations (36/ 66: 54,55%) and parents declined cochlear imlantation.
**CONCLUSIONS**
This work summarizes causes and treatment of SSD in children in our center, in order to draw attention to the importance of early audiology identification and etiology, so as to assess the treatment options. Ultimately many children with SSD who present for implant candidacy assesment do not receive uCI. The main factors contributing to noncandidacy are cochlear nerve dysplasia and parental decision. Of the proportion of children with SSD who are candidates, some have risk of sudden or progressive deterioration in the better earing ear. **It is stressed the importance of performing a uCI above all in these risky etiologies as EVA and CMV.**

SINGLE SIDED DEAFNESS ETIOLOGY IN COCHLEAR IMPLANTED CHILDREN. OUR EXPERIENCE

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,