What causes tinnitus?
The most common cause of tinnitus is damage and loss of the tiny sensory hair cells in the cochlea of the inner ear.
This damage typically occurs as a result of the normal aging process, and from prolonged exposure to excessively loud noise. Hearing loss coincides with tinnitus.
Research also suggests that the sensory loss of certain sound frequencies leads to changes in how the brain processes sound. As the brain receives less external stimuli around a specific frequency, it begins to adapt and change. Tinnitus may be the brain’s way of filling in the missing sound frequencies it no longer receives from its own auditory system.
Some medications such as aspirin, ibuprofen, certain antibiotics, and diuretics can be “ototoxic” – damage the inner ear, resulting in tinnitus.
So what exactly happens in the ear or the brain? At the moment there are several different theories as to where tinnitus may start, how it may start and what processes or parts of the brain may be involved in its maintenance. As an organization we are funding research at the University of Newcastle to try and delve into the possible different strata of states that we presently think tinnitus may have.
Robert Sweetow (PhD) gives a great explanation of the present theories of tinnitus origin:
– Disruption of auditory input (e.g., hearing loss) and resultant increased gain (activity) within the central auditory system.
– Decrease in inhibitory (efferent) function.
– Over-representation of edge-frequencies (cortical plasticity).
– Other somatosensory influences (Cervical disturbances, TMJ, etc.).
– Extralemniscal neurons, particularly in dorsal cochlear nucleus and AII area, receiving input from somatosensory system.
– Association with fear and threat (limbic system-emotional brain) and increased attention related to limbic system involvement.
– Widely distributed gamma network.
– Dysfunctional gating in basal ganglia or thalamic reticular nucleus.
The most common cause of tinnitus is damage and loss of the tiny sensory hair cells in the cochlea of the inner ear. This tends to happen as people age, and it can also result from prolonged exposure to excessively loud noise. Hearing loss may coincide with tinnitus.
- noise exposure from work, headphones, concerts, explosives, and so on
- gender, as men are affected more than women
- hearing loss
- age, as older individuals are more susceptible
Tinnitus is a non-auditory, internal sound that can be intermittent or continuous, in one or both ears, and either low- or high-pitched.
The varying sounds have been described as whistling, chirping, clicking, screeching, hissing, static, roaring, buzzing, pulsing, whooshing, or musical.
The volume of the sound can fluctuate. It is often most noticeable at night or during periods of quiet. There may be some hearing loss.
Tests and diagnosis
Anyone who is experiencing tinnitus should visit a doctor for an examination and evaluation to determine the underlying cause.
A medical evaluation can exclude any rare but life-threatening causes of tinnitus. A referral to an otolaryngologist, or ear, nose, and throat specialist, may be necessary.
Questions that a doctor might ask include:
How or when did it start?
- Are the noises constant, intermittent, or pulsating?
- Is there any hearing loss or dizziness?
- Is there any pain or jaw clicking?
- Have you had a recent illness or injury?
- Has there been any exposure to loud noise, such as a rock concert or explosives?
Tests may include:
- a complete examination of the ear, head, neck, and torso
- hearing tests
- laboratory blood tests
- imaging studies
The first step is to treat any underlying cause of tinnitus.
This may involve:
- prompt care for an ear infection
- discontinuing any ototoxic medications
- treating any temporomandibular joint (TMJ) problems, which affect the joint betwen the jaw bone and the cheek bone
There is no cure for most cases of tinnitus. Most people become accustomed to it and learn to tune it out. Ignoring it rather than focusing on it can provide relief.
When this does not work, the individual may benefit from treatment for the effects of tinnitus, insomnia, anxiety, hearing difficulties, social isolation, and depression. Dealing with these issues can significantly improve a person’s quality of life.