Hearing is an essential function which is performed by a human body in response to the various noises and sound around him. Impaired brain structure and functioning may lead to auditory processing deficits or auditory interhemispheric transfer deficits which may lead to hearing difficulties in the end. This disorder usually affects children and almost 7% of children are reported facing this disorder. Auditory processing deficits are usually related to communication, learning and other difficulties. This makes it very difficult to identify and start the necessary treatments. According to a recent study, the auditory interhemispheric transfer deficit happens due to the mutation of the PAX6 gene. These adults tend to have structural abnormalities in the brain as well. Also, this transfer takes place due to the deficits present in the auditory processing area. PAX6 genes are characterized by developmental aniridia and the panocular features present[1]. Children who face the mutations of gene PAX6 also happen to face vision disability. These are due to the effect of auditory interhemispheric deficiency in the body.

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Identifying the Auditory Interhemispheric Transfer Deficits

In order to identify auditory interhemispheric transfer deficits, the patients underwent Brain Magnetic Resonance Imaging (MRI) which included T1- weighted and T2- weighted multisection images. It was done to measure the corpus callosum area of individuals suffering from auditory interhemispheric transfer deficit as compared with random control subjects. Various Standard Baseline Audiometric tests were done in order to confirm the disorder of Auditory interhemispheric transfer deficit. An audiometer was used to carry out Pure-tone Audiometry tests bilaterally using earphones in a sound-treated room. Behavioral Central Auditory tests were also conducted. This included dichotic speech tests, which includes vowels and consonants, digits and fused rhymed words. The second test includes Pattern tests. In this test for Auditory interhemispheric transfer deficit, the frequency varies greatly from one sound tone to another and the patient has to report about the frequency changes.

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Findings and Symptoms of Auditory Interhemispheric Transfer Deficits

The majorly known subgroups of PAX6 gene are haploinsufficiency, a condition which may lead to the absence of PAX6 protein, in-frame deletion due to a splicing error, the mutation causing a predicted C- terminal protein extension, missense mutation and deletion of the entire gene which is a rare case. The brain MRI helped to know about the differences in the corpus callosum. Corpus callosum was found to be comparatively smaller in size in most of the cases. Moreover, some cases reported having a cyst in the splenium of the corpus callosum. The great difficulty in localizing sound and facing difficulty in understanding speech are the symptoms of Auditory interhemispheric transfer deficit.

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Reasons for the Occurrence of Auditory Interhemispheric Transfer Deficits

The PAX6 mutations are known to cause structural abnormalities in the body by creating an absence of anterior commissure which leads to auditory interhemispheric transfer deficit. This structure contains auditory interhemispheric fibers. The functional role of the corpus callosum is to perform the function of listening. The functions of the left ear are severely decreased as compared to the right ear. Usually, parents notice the problem as the child shows signs of hearing issues. Children with Auditory interhemispheric transfer deficit also face the problem of understanding prosody, difficulty in pragmatic aspects of language, and so on.

Conclusion

Auditory interhemispheric transfer deficit is a very rare disorder which is caused due to the mutations in the PAX6 gene. This disease usually affects the auditory function of the human body. The person suffering from auditory interhemispheric transfer deficit finds it very difficult to listen in the surrounding clearly and it becomes very difficult for them to respond in their surroundings as well. Auditory interhemispheric transfer deficit usually affects children. Various surveys have confirmed that auditory interhemispheric transfer deficits, hearing difficulties, and brain magnetic resonance imaging abnormalities in children with congenital aniridia are caused due to PAX6 mutations. Auditory interhemispheric transfer deficit not only affects the hearing ability but also make a person blind or almost difficult to see. The mutations in the PAX6 gene affect the formation of required proteins in the body leading to this condition. It is very difficult to diagnose auditory interhemispheric transfer deficit in the early childhood because only after the parents figure out the hearing difficulties faced by the child that they get to know about the diagnosis of it Various methods such as MRI, Audiometric tests, and so on are used to diagnose the disease and draw conclusions about the severity of the same. Appropriate management can be initiated to start the treatment of the disease in case it is at a minor level.

References:  

  1. Bamiou, D., Free, S., Sisodiya, S., Chong, W., Musiek, F., & Williamson, K. et al. Auditory Interhemispheric Transfer Deficits, Hearing Difficulties, and Brain Magnetic Resonance Imaging Abnormalities in Children With Congenital Aniridia Due to PAX6 Mutations. Archives Of Pediatrics & Adolescent Medicine, (2007). 463. doi: 10.1001/archpedi.161.5.463
Pramod Kerkar

Written, Edited or Reviewed By:

, MD,FFARCSI

Pain Assist Inc.

Last Modified On: July 15, 2019

This article does not provide medical advice. See disclaimer

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