Some people have especially sensitive hearing and are unable to tolerate ordinary levels of noise. This can occur in both people who have a hearing loss as well as those who don't. There are different components which can contribute to sensitive hearing such as hyperacusis, misophonia and phonophobia.
Hyperacusis is the medical term used to describe the abnormal discomfort of everyday sounds that some people experience. Hyperacusis is due to an alteration in the central processing of sound in the auditory pathways where there is an abnormally strong reaction from exposure to moderate sound levels.
Misophonia is the intense dislike of being exposed to a certain sound. The auditory pathways may be functioning normally, but there is an abnormally strong reaction of the limbic (emotional system) and autonomic nervous system (body control system) to which the auditory system is intimately connected. Sometimes because of the belief that it will damage the ear it makes symptoms (sensitivity, or tinnitus) worse. Misophonia can lead to hyperacusis (changes in central auditory processing) and a consequent persistence of abnormal loudness perception.
Phonophobia - if the dislike of certain sounds is very strong we may call it ‘phonophobia’; literally - fear of sound. Often normal environmental sounds like traffic, kitchen sounds, doors closing, or even loud speech, cannot be tolerated.
In practice, most people with decreased sound tolerance have both hyperacusis and phonophobia/misophonia together in varying proportions. In treating these conditions, it is important to diagnose which condition is present and which is dominant.
Many people seek silence as a way to escape from the pressures of everyday life. However complete silence is not found in nature, and should be considered ‘unnatural’. The absence of sound stimulation leads to an increase in auditory gain (amplification) in the subconscious auditory pathways. The brain is always looking for the best way it can for auditory signals. This process is enhanced by silence which is considered to be one of the signs of possible predator activity. The auditory filters ‘open’ in an attempt to monitor the external sound environment. External sounds may then increase dramatically in their perceived intensity and intrusiveness.
Some people take to wearing ear plugs, perhaps at night, to avoid sounds becoming intrusive, and this simply worsens the sensitivity. When hyperacusis develops there is a great temptation to plug the ear to exclude unwelcome sounds. This is actually making things worse, as it encourages further increase in the amplification of sounds on their way to the auditory (hearing) cortex. When these sounds are heard in the absence of plugs, their perceived loudness is greatly increased.
Hyperacusis can be managed most effectively by using noise generators alongside a programme that aimed at reducing the fear and anxiety associated with sound exposure. Research in the 1980s (Hazell & Sheldrake 1991) showed that the use of wide band noise applied to the ear by wearable sound generators can help in the treatment of abnormal hypersensitivity of hearing. This is particularly true in hyperacusis, where on some occasions, particularly in young children, it is all the treatment required. The sound from the instruments needs to be applied very gently and gradually to the ear beginning at a low level, always to both ears, and under the supervision of an audiologist with experience in this process of desensitization and with training in TRT. The effect, which in some cases may be quite dramatic, results in a ‘turning down’ of central auditory gain and a reduced perception of loudness for previously distressing sounds.
Never undertake any sound therapy without proper advice. Sound tapes - e.g. pink noise, can make certain hyperacusis and phonophobic patients considerably worse. In each case, careful explanation of the mechanism of central processing must be given so people can understand and believe what has happened to them; the whole process is reversible with time and the appropriate therapy.
If you are experiencing these symptoms, please discuss with your medical professional for further advice on treatment and management.