Hyperacusis
What Is Hyperacusis?
The Hyperacusis definition is an abnormally strong and negative reaction to sound or an inordinate loudness of sound that other people tolerate well. The sounds can be soft, medium, or loud. It may cause distress, fear, or even pain to the person experiencing it.
Why Does Hyperacusis Occur?
It is postulated that hyperacusis occurs because of hyperactivity within the hearing system.
The auditory system provides an automatic gain or volume control, modifying its sensitivity at both peripheral and central levels. Consequently, when a person is normally exposed to even a low level of sound, the signal is amplified by the outer hair cell system by up to 60 dB. If mechanisms controlling this gain modification are producing higher levels of amplification when it is not needed, then overstimulation occurs within the auditory system resulting in a perception of sound as abnormally loud, even painful.
The auditory system provides an automatic gain or volume control, modifying its sensitivity at both peripheral and central levels. Consequently, when a person is normally exposed to even a low level of sound, the signal is amplified by the outer hair cell system by up to 60 dB. If mechanisms controlling this gain modification are producing higher levels of amplification when it is not needed, then overstimulation occurs within the auditory system resulting in a perception of sound as abnormally loud, even painful.
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Hyperacusis CausesOccupational noise exposure increases one's risk of developing hyperacusis and tinnitus. Noise exposure could possibly be a leading cause of hyperacusis but more research data is needed. Intense sound or an acoustic shock can result in hyperacusis. This intense impulse seems to trigger what is known as a tonic tensor tympani syndrome. This is an involuntary, anxiety-driven reflex that activates the tensor tympani muscle in the middle ear resulting in frequent spasms being encountered. Other symptoms can include sensations of eardrum tension or fluttering, trigeminal nerve irritation, and middle ear equalization difficulties.
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Hyperacusis Treatment Methods
In pure hyperacusis, the limbic and autonomic nervous systems and their connections within the auditory system are functioning normally. Excessively high levels of activity are found to be contained within the auditory pathways.
Hyperacusis treatment is based on a desensitization principle. Systematic exposure to soothing, non-annoying sound results in an increased threshold of sound tolerance over time. Treatment works at a subconscious level and does not involve retraining of conditioned reflexes and does not involve cognitive processes.
Carefully monitored and therapeutically applied sound therapy can be a useful way to reset the system to its previous level of activity. Severe emotional reactions may occur, but these are associated with activation of non-auditory centers controlling emotion and fear in the brain's limbic system, and are not considered part of the hyperacusis mechanism. These reactions can be successfully addressed utilizing adjunctive cognitive behavior therapy centered approaches.
Hyperacusis treatment is based on a desensitization principle. Systematic exposure to soothing, non-annoying sound results in an increased threshold of sound tolerance over time. Treatment works at a subconscious level and does not involve retraining of conditioned reflexes and does not involve cognitive processes.
Carefully monitored and therapeutically applied sound therapy can be a useful way to reset the system to its previous level of activity. Severe emotional reactions may occur, but these are associated with activation of non-auditory centers controlling emotion and fear in the brain's limbic system, and are not considered part of the hyperacusis mechanism. These reactions can be successfully addressed utilizing adjunctive cognitive behavior therapy centered approaches.
The Hyperacusis and Tinnitus connection
Hyperacusis occurs with tinnitus symptoms in nearly 50% of cases and up to 100% of cases caused by head trauma. It can also occur with symptoms of phonophobia and misophonia.
Hyperacusis treatment must be completed first to allow effective treatment for tinnitus symptoms or hearing loss. In clinical practice where significant tinnitus, hyperacusis and hearing loss are all occurring together, the correct procedure is to implement a step-by- step sequence of sound therapy treatment. Proper evaluation for the specific form of decreased sound tolerance (DST) present is essential, and failure to treat the specific types of sound tolerance problems can lead to using the wrong or insufficient methods, thus resulting in treatment failure. As some form of decreased sound tolerance occurs in over 50% of tinnitus cases, it is essential to see an expert trained in the evaluation and treatment of all forms of decreased sound tolerance, in addition to tinnitus, misophonia and hearing loss.
Hyperacusis treatment must be completed first to allow effective treatment for tinnitus symptoms or hearing loss. In clinical practice where significant tinnitus, hyperacusis and hearing loss are all occurring together, the correct procedure is to implement a step-by- step sequence of sound therapy treatment. Proper evaluation for the specific form of decreased sound tolerance (DST) present is essential, and failure to treat the specific types of sound tolerance problems can lead to using the wrong or insufficient methods, thus resulting in treatment failure. As some form of decreased sound tolerance occurs in over 50% of tinnitus cases, it is essential to see an expert trained in the evaluation and treatment of all forms of decreased sound tolerance, in addition to tinnitus, misophonia and hearing loss.
Medical Conditions Associated with HyperacusisHyperacusis has many known causes and associations, however, in most clinical cases the cause remains unknown. The following are diseases and syndromes associated with hyperacusis: Bell's Palsy, Ramsay-Hunt Syndrome, Stapedectomy, Perilymphatic Fistula, Migraine, Depression, Post-Traumatic Stress Disorder, Head Injury, Lyme Disease, Fibromyalgia, William's syndrome, Addison's Disease, Autism, Myasthenia Gravis, Middle Cerebral Aneurysm, and Cerebrospinal Fluid (CSF) High Pressure. |
Hyperacusis Testing and Medical EvaluationThe intent of the medical evaluation is to make a differential diagnosis of possible associated or underlying disease processes. A complete neurotologic examination should be conducted as well as evaluation for temporomandibular joint dysfunction, which has been found to be associated with hyperacusis. Laboratory Evaluation Blood testing should include a whole blood count and include measures of sodium, potassium, thyroid stimulating hormone, and free thyroxine to assess for infections and endocrinological diseases. Deficiencies in magnesium and vitamin B6 should be explored. Serological tests (measure specific levels of antibodies in the blood) can help diagnose diseases associated with hyperacusis such as syphilis, herpes zoster, and Lyme disease. |