Background

Auditory Neuropathy often called the Auditory neuropathy spectrum disorder is a type of hearing disorder that disallows sound information transferred normally from the inner ear to the brain. Different from typical hearing loss that comes with an overall difficulty in hearing and ANSD usually negatively affects the way sounds are reached within the ear. It may be described as having no hearing loss but it can be hard to understand speech and especially in noisy circumstances.  

Epidemiology

In auditory neuropathy the auditory nerve or pathways are primarily involved whereas in other hearing losses the problem lies with the hair like cells in the inner ear (called stereocilia). Statistics of prevalence fluctuate greatly where one estimates almost 0.5 -15% of the people with hearing impairment depending on population studied and diagnostic standard. 

Anatomy

Pathophysiology

Many of the mechanisms that are implicated in AN/AD pathophysiology such as abnormal spiral ganglion cells and auditory nerve and auditory pathway nuclei can be seen in the lower parts of the body. This is consisted of following reasons such as: traumatic or apoptotic changes within synaptic junction and dendrites or cell body of the spiral neurons and injury to auditory nerves or even axonal damage to nerve fibers. Ion comprehensive risk factors including perinatal problems and genetic disadvantages are involved which are associated with AN/AD. The disease may appear to be a neurological one including diseases like Friedrich’s ataxia and Stevens-Johnson syndrome. Research shows that the brain of people with AN/AD can reorganize to respond to language sounds thus previously unseen changes in their behaviour become apparent.  

Etiology

This condition is found because of processing the harm in not only within the cochlea but also in the auditory nerve as well as in the central pathways. The sophisticated transformation occurs with the hair cells that corresponds to the mechanical stimuli which in turn releases glutamate and then trigger the neural impulses. At different levels the disruption can be IHCs and synapses and neural fibers or cochlear nuclei which can come as a result. 

Genetics

Prognostic Factors

The prognosis may be affected by Age of onset, Hearing loss degree, Neurological involvement and underlying cause. 

Clinical History

Age group: 
Auditory neuropathy can affect people of any age, from young children to elderly persons. Individuals who suffered trauma some medical hearing conditions and exposure to certain drugs are more susceptible to this condition. 

Physical Examination

General Health Assessment 

Vision assessment 

Reflex assessment 

Otoscopic Examination 

Middle Ear Muscle Reflex  

Neurological Examination 

Cranial Nerve Examination 

General Health Assessment 

Age group

Associated comorbidity

Associated activity

Acuity of presentation

Hearing Loss: Sound delays in the brain occur from the interruption of the course of sound signals from the inner ear to the brain hence different degrees of impairment. 
Speech Perception: An auditory neuropathy can often cause a person to have difficulty understanding speech despite their physiological hearing thresholds being normal because of the timing problems with transmitted neural information. 
Sound Quality: People with this type of hearing loss might hear sounds as muffled or blurry, have trouble understanding speech in noise and identify sounds delivered at high or low frequency or in close or distant position as indistinct. 

Differential Diagnoses

Meniere’s disease 

Sensorineural hearing loss 

Auditory processing disorder  

Central auditory processing disorder  

Autoimmune inner ear disease 

Laboratory Studies

Imaging Studies

Procedures

Histologic Findings

Staging

Treatment Paradigm

Hearing Aids: For people who lose their hearing to an extent that cannot be fully compensated by the aid of the hearing aids will go for hearing aids as the major form of therapy. 
 
Hearing implants: Considering hearing impairment, wherein it can be from severe to profound cochlear implants are the main choice. 
 
Auditory Brainstem Implants: Engineered to stimulate brainstem networks in those who lose their ability to hear because of damage to the auditory nerve.  

by Stage

by Modality

Chemotherapy

Radiation Therapy

Surgical Interventions

Hormone Therapy

Immunotherapy

Hyperthermia

Photodynamic Therapy

Stem Cell Transplant

Targeted Therapy

Palliative Care

lifestyle-modifications-in-treating-auditory-neuropathy

Environmental Adaptations: Improve home and work atmosphere by reducing the background noise using income conducive materials as well as arranging furniture properly to allow for sound clarity.

Visual Cues and Communication Strategies: This way the spoken language’s just two-third is covered hence the spoken language should be accompanied by other nonverbals like gestures and facial expressions.  

 Assistive Listening Devices: Adjust assisting listening devices including personal amplifiers and FM systems to better determine hearing within certain settings such as noisy or difficult acoustic situations.

Captioning and Subtitles: Installing captions and subtitles on TV PC and other multimedia gadgets will help in accelerating spoken content comprehension.
Utilize Smartphone Apps: Use smart apps to help hearing impaired individuals that come in all shapes and sizes. 
Hearing Protection: Use ear protection for noise exposure in loud environments or during things that give off substantial noise levels.   

hearing-aids-and-cochlear-implant-in-the-management-of-auditory-neuropathy

Studies consistently indicate that the use of cochlear implants help in the long run as with children that have ‘ANSD’ they exhibit similar hearing abilities to hearing children with sensorineural loss. In the instances when cochlear implantation does not achieve the results, brainstem implantation has been experimented on as an alternative approach. This ensure indications for cochlear implantation double the significance of understanding the pathophysiology of ANSD, which will enable you to select the potentials candidates who would benefit from this surgical procedure that is gaining more popularity. 

phases-of-management-in-the-treatment-of-auditory-neuropathy

Identification of Underlying Causes: Get to the root to this condition which cause or its associated feature and fix it. The investigators would perhaps conduct a genetic study and metabolic conditions infections or other medical problems which might be associated with the disorder. 
 
Communication Strategies and Rehabilitation: Adopt communication strategies that make it easy for that person to understand and access.   
 
Hearing Devices and Amplification: In-reference to the use of hearing devices such as ear devices or cochlear implants based on the degree of the problem and individual preference. 
 
Assistive Listening Devices and Technology: Examine the utilization of assistive listening facilities and other technologies such as FM systems and others to augment communication in some areas with background noise in addition to friendly ones. 
 
 
 

Medication

Future Trends

Media Gallary

References

Auditory Neuropathy Spectrum Disorders: From Diagnosis to Treatment: Literature Review and Case Reports – PMC (nih.gov)