Abstract
Purpose
The advent of cochlear implantation has been followed by an explosion in surgical and technological advances with subsequent alterations in the treatment of sensorineural hearing loss management. Many individuals with rare genetic abnormalities who once may have not been considered candidates for cochlear implantation are now benefiting from cochlear implantation. One of these unusual syndromes is the 13q deletion syndrome. The clinical features of 13q deletion syndrome, a rare chromosomal abnormality, were originally described in the early 1960s, though the literature currently lacks defined phenotypic abnormalities. Patients with 13q deletion syndrome present with varying degrees of cognitive and growth delay, craniofacial dysmorphisms, and congenital malformations. The etiology of the sensorineural hearing loss has not been elucidated, and genes associated with other syndromes which include sensorineural hearing loss have been proposed as the causative agents. We describe the unique clinical and surgical considerations for 13q deletion syndrome and review the considerations when deliberating on cochlear implantation in syndromic hearing loss.
Materials and Methods
Case report.
Results
Successful cochlear implantation in a patient with 13q deletion syndrome.
Conclusion
Many patients with 13q deletion syndrome suffer from sensorineural hearing loss, and when appropriately selected may likely benefit from cochlear implantation. Many other syndromic patients following careful selection may also benefit from cochlear implantation and should not be excluded from consideration until appropriately evaluated.
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Introduction
An explosion of surgical and technological advances has followed the advent of cochlear implantation, including an evolution in the therapeutic approach toward severe to profound sensorineural hearing loss. There has been a rapid increase in volume of cochlear implant cases , which may be explained by a movement toward performing this intervention at greater extremes of age with a concurrent expansion of the originally acceptable recipient patient criteria.
A rare genetic disease which only occasionally features sensorineural hearing loss is 13q deletion syndrome. Though the syndrome was first described in the 1960s , there remains a lack of reliable phenotypic features that can be identified in the medical literature. Patterns in disease severity and organ involvement do become evident when the size of the deleted segment is considered, along with its specific location on the long arm of the chromosome . Generally patients with 13q deletions present on a spectrum that features varying degrees of cognitive and growth delay, craniofacial dysmorphisms, and congenital malformations variously involving the central nervous, cardiac, genitourinary, gastrointestinal, and musculoskeletal systems . No reproducible structural or functional deficits have been cited which may be directly related to the hearing loss that occurs in a small portion of 13q deletion syndrome patients. The following genes, however, have been suggested to play a role: DFNB1, which codes for the gap junction protein connexin-26 expressed in various parts of the inner ear and responsible for non-syndromic autosomal recessive deafness and EDNRB, the endothelin-B receptor gene, a G protein-coupled receptor expressed in various tissues and responsible for Waardenburg syndrome and Hirschsprung disease . Gross anatomical abnormalities involving inner structures ear may also be involved.
This case report describes the presentation and management of a deaf 13q deletion syndrome patient with suggestions for appropriate surgical considerations in preparation for cochlear implantation in any patient with 13q deletion syndrome. As this case report involved four or fewer cases, Georgia Regents University Institutional Review Board has determined review was not required for this type of activity. The Georgia Regents University Institutional Review Board has determined that this type of case report does not produce generalizable knowledge, nor is it an investigation of a product regulated by the Food and Drug Administration (FDA).
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Case presentation
A three year old male with a 13q-46 deletion and ring chromosome formation presented to the otolaryngology clinic with progressive receptive and expressive language impairment. His other pathologic features included mental retardation, agenesis of the corpus collosum, seizure disorder, coloboma, a flattened occiput, joint abnormalities, and a previously corrected ventricular septal defect. The child had failed his neonatal hearing screen and subsequently underwent sedated auditory brainstem response (ABR) testing at an outside facility, revealing what was believed to be a mild bilateral sensorineural hearing loss. Repeat ABR testing was recommended, and two years later the patient was referred to our clinic with his repeat ABR test showing that he had a profound bilateral sensorineural hearing loss.
At that time he was referred to a speech therapist and fitted with hearing aids, but there was no improvement in his speech development during the three month trial. The decision was then made to proceed with bilateral cochlear implantation. Preoperative computed tomography (CT) scanning of his temporal bones revealed an atretic cartilaginous external ear canal bilaterally with normal internal auditory canals and no otic capsule anomalies. CT scanning of the head revealed brachycephaly with an abnormal prominence at the right inter-hemispheric fissure projecting into the frontal lobe, suspicious for an arachnoid cyst. Preoperative magnetic resonance imaging (MRI) revealed abnormal appearance of the apical turn of the cochlea bilaterally, with the left dysplasia worse than right, findings that was not appreciated on temporal bone CT scan. Normal internal auditory canals were seen. Left cerebellopontine and posterior fossa arachnoid cysts were identified, along with known agenesis of the corpus collosum. After imaging the patient was scheduled for sequential cochlear implantation; his right side was implanted first, and the left was implanted one month later.
During his first postoperative clinical appointment following activation of the right processor, the patient’s mother reported that he was able to repeat the word “red” to the speech pathologist. Three months post implantation he was able to localize low and high pitch sounds bilaterally in addition to becoming attentive to unseen sounds. Six months after implantation his age equivalent speech auditory comprehension scores increased from two to eight months, age equivalent expressive communication scores increased from six to eight months, and overall language comprehension age equivalent scores increased from four to six months. In the time since he has made further receptive and expressive progress, he states “mama” when he addresses his mother, “hey” to individuals when they arrive at his house, and “no” when he was in disagreement with someone. Nine months post implantation, at his most recent visit, he was following 75% of commands such as “get the ball”.
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