Table of Contents
Introduction
Hearing impairment in childhood can severely impact language, social, and emotional development, as well as academic achievement. However, early identification of hearing loss and prompt intervention to enhance hearing and promote language development can mitigate these risks. Children with hearing loss show significant variation in causes and functional abilities. The success of many children, even those with profound hearing loss, demonstrates the potential for neuronal plasticity and their resilience.
Mondini dysplasia is a congenital inner ear malformation where individuals have one and a half cochlear coils instead of the usual two. This condition can affect one ear (unilateral) or both ears (bilateral) and leads to varying degrees of sensorineural hearing loss, with most individuals experiencing profound hearing loss. It also increases the risk of recurrent meningitis. Mondini dysplasia is caused by a disruption in the inner ear's embryonic development during the seventh week of gestation. It may appear alone or alongside other ear malformations or syndromes. Treatment options include surgical repair to prevent recurrent meningitis, amplification aids for residual hearing, and cochlear implantation.
What Is Mondini Dysplasia?
It is also called familial non-syndromal Mondini dysplasia. Mondini dysplasia is a congenital cause of hearing loss that can affect one or both ears. It often occurs in people with Pendred syndrome. Some syndromes accompanying Mondini dysplasia include DiGeorge syndrome, CHARGE syndrome, Klippel-Feil syndrome, and autosomal dominant and recessive inheritance patterns. Mondini dysplasia frequently appears with another inner ear malformation called enlarged vestibular aqueduct (EVA), where a fluid-filled tube in the inner ear is abnormally wide. Children with Mondini dysplasia may also have other inner ear malformations that impact the vestibular (balance) system, so a vestibular audiologist or physical therapist can help manage balance issues.
How Is Mondini Dysplasia Diagnosed?
Imaging techniques diagnose Mondini dysplasia. Computed tomography scans (CT scans) and magnetic resonance imaging (MRI) can diagnose Mondini dysplasia.
- CT Scan - The CT scan of the ear reveals a widening of the basal turn of the cochlea, vestibule, and the anterior limb of the lateral semicircular canal. It also shows a short internal auditory canal and a wide opening between the internal auditory canal and cochlea.
- MRI - The MRI of the temporal bones indicates a fluid-filled right middle ear cavity and fluid in the cochlea, apparently connected at the oval window, along with a well-demonstrated saccular deformity of the basal turn of the cochlea. The left inner ear appears normal. These radiological findings are consistent with a diagnosis of Mondini dysplasia with incomplete expression.
How Is Mondini Dysplasia Treated?
Mondini dysplasia is treated according to its severity.
- Hearing Aids - Depending on the extent of the hearing loss, hearing aids or cochlear implants can improve hearing. This improvement will aid in developing speech and understanding others.
- Physical Therapy - If someone experiences balance issues, a healthcare provider may recommend physical therapy. This type of physical therapy involves exercises designed to alleviate dizziness and balance problems caused by inner ear disorders.
- Behavior Management - Comprehensive service management for a child with hearing impairment requires a commitment to advocacy and support. Health professionals play a crucial role in medical management and as educators for the family and the community about these children's special needs.
- Emotional Support - Families of children with hearing impairments need support, guidance, and training during many difficult adjustment periods. Coordinating these services and information is best achieved in the primary care medical home and with consultants like developmental-behavioral pediatricians. Over 90 percent of children who are deaf are born to hearing parents, leading to significant changes in the family dynamic.
The diagnostic process is often delayed and traumatic for parents, who might have previously received false reassurances. With various specialists involved, such as audiologists, otolaryngologists, pediatricians, or family practitioners, parents often receive the fragmented diagnosis, hoping another specialist might offer a cure.
What Are Cochlear Implants?
Cochlear implants can offer helpful hearing aids to many children with profound hearing loss. This treatment has garnered much attention and sparked considerable debate recently, and its frequency of use is increasing. The device includes an internal component that is surgically implanted and an external component that the child wears. An external microphone receives, processes, and encodes sounds into radiofrequency signals.
These signals are transmitted across the skin to a magnetic receiver near the mastoid. From there, an electric signal passes through the round window to a multichannel electrode implanted in the cochlea.
This electrode directly stimulates the spiral ganglion cells of the cochlear nerve, with higher-frequency sounds stimulating the basal turn and lower frequencies activating the apical turn. Candidates for cochlear implantation should be carefully selected from children with bilateral profound sensorineural hearing loss who have shown little or no benefit from hearing aids. Cognitive or behavioral problems must be considered, and a family must be committed to the intensive training and habilitation program essential to the process.
Follow-up studies have shown promising results, including better appreciation of environmental sounds, significant long-term gains in speech perception and intelligibility, and improvements in expressive language abilities. Cochlear implants have revolutionized the treatment of childhood hearing impairment, and new technology has broadened communication opportunities for individuals with hearing impairment. Physicians must remain alert to early signs of hearing problems and ensure that children with these issues have access to all the advances in management that will enable them to succeed.
Conclusion
Profound hearing loss is rare, but milder degrees of hearing impairment are more common. All clinicians who treat children will encounter patients with hearing loss. More than 50 percent of childhood hearing impairment stems from genetic factors, while over 20 percent is due to prenatal, perinatal, or postnatal environmental influences. The outlook for children with hearing impairment has improved dramatically in recent decades.
Increased knowledge of the genetic basis of hearing loss has facilitated more accurate diagnosis and genetic counseling. Primary prevention efforts, such as immunizations against infectious agents responsible for meningitis and counseling about the negative effects of loud sound exposure, can further reduce the incidence of acquired deafness. Hearing impairment significantly challenges language development, social-emotional adjustment, and academic achievement. However, early identification and intervention for children with hearing loss lead to positive outcomes.
