Cochlear implant magnet displacement during magnetic resonance imaging.

OBJECTIVE: Magnet displacement is a rare but possible complication in patients with cochlear implants. We report 1 case in a young child that occurred during magnetic resonance imaging scanning, despite precautionary measures taken by the surgeon and the radiographer. STUDY DESIGN: Retrospective case report. SETTING: This case is presented by the ENT Department of Armand Trousseau Paediatrics Hospital, Paris, France. PATIENT: An 8-year-old child, implanted with a Freedom Contour Nucleus cochlear implant, was referred for a 1.5-T cerebral magnetic resonance imaging because of a progressive neurologic disorder. CONCLUSION: This rare complication underlines the importance of risk information and preventive measures required, even in case of compatible devices, for performing a magnetic resonance imaging examination in patients wearing a cochlear implant with removable magnet.

SLC26A4 gene is frequently involved in nonsyndromic hearing impairment with enlarged vestibular aqueduct in Caucasian populations.

Sensorineural hearing loss is the most frequent sensory deficit of childhood and is of genetic origin in up to 75% of cases. It has been shown that mutations of the SLC26A4 (PDS) gene were involved in syndromic deafness characterized by congenital sensorineural hearing impairment and goitre (Pendred's syndrome), as well as in congenital isolated deafness (DFNB4). While the prevalence of SLC26A4 mutations in Pendred's syndrome is clearly established, it remains to be studied in large cohorts of patients with nonsyndromic deafness and detailed clinical informations. In this report, 109 patients from 100 unrelated families, aged from 1 to 32 years (median age: 10 years), with nonsyndromic deafness and enlarged vestibular aqueduct, were genotyped for SLC26A4 using DHPLC molecular screening and sequencing. In all, 91 allelic variants were observed in 100 unrelated families, of which 19 have never been reported. The prevalence of SLC26A4 mutations was 40% (40/100), with biallelic mutation in 24% (24/100), while six families were homozygous. All patients included in this series had documented deafness, associated with EVA and without any evidence of syndromic disease. Among patients with SLC26A4 biallelic mutations, deafness was more severe, fluctuated more than in patients with no mutation. In conclusion, the incidence of SLC26A4 mutations is high in patients with isolated deafness and enlarged vestibular aqueduct and could represent up to 4% of nonsyndromic hearing impairment. SLC26A4 could be the second most frequent gene implicated in nonsyndromic deafness after GJB2, in this Caucasian population.