Tinnitus can be defined as a sound hallucination, i.e. perceiving a sound that does not exist. The tinnitus patient perceives a sound that no one else can hear. This is an approximate definition, since a first classification of tinnitus divides it into subjective and objective tinnitus. Subjective tinnitus is the one that most closely fits the above definition. Objective tinnitus is that which, with the appropriate means, could be heard by another person external to the patient.
Causes
The causes can be varied. An objective tinnitus can be due for example to small lesions in the temporomandibular joint, that when mobilized produces audible clicks, or a dysfunction of the Eustachian tube…. If it is pulsatile, it could be justified by hypertension, where the patient hears his own heartbeat, benign intracranial hypertension, etc.
In the case of subjective tinnitus, it is often related to a hearing loss. It is thought that the auditory pathway is then reorganized at the subcortical level and sends to the auditory cortex a somewhat “strange” electrical signal, compared to the “normal” signal that would result from the unmodified auditory pathway. This modified signal is interpreted by the auditory cortex as noise.
Diagnosis
The diagnosis of tinnitus is based on the clinical history. When the patient tells us that he/she notices a beep or a noise such as that of an engine, a pressure cooker, a fan, the sound of running water… we already have tinnitus. The first test to be performed, inevitably, is an audiometry to know if the patient hears well or not. The second test is called acuphenometry.
With the aquufenometry we try to characterize the tinnitus, to find a sound that resembles it as much as possible and thus to know its frequency and intensity. Diagnostically it is not very useful but it could have implications for treatment. Then there are several questionnaires available for tinnitus.
Personally I usually use the Tinnitus Handicap Inventory: in this questionnaire, the patient is asked several questions related to his tinnitus, assigning a score depending on the answer. According to the final score we can get an idea of the impact that tinnitus has on the patient’s life.
Another questionnaire, the Tinnitus Hypersensitivity Test, explores hyperacusis, a phenomenon that can be associated with tinnitus, where the patient feels great discomfort or even pain, to sounds whose intensity does not produce discomfort in other people. Patients with hyperacusis are those who cannot stand, for example, being at a party with several people talking at the same time. It also has an important impact on treatment.
Other diagnostic methods: exploration of anxiety levels, brain MRI, exploration of the tempormandibular joint and somatosensory trigger points, etc, depending on our diagnostic suspicion.
Treatments
The treatment depends on the diagnosis. If the tinnitus is due to a hearing loss, the most logical would be to restore or improve the patient’s hearing. Depending on the cause of the hearing loss, surgery or hearing aids may be used. If the tinnitus is due to a dysfunction of the temporomandibular joint, we can resort to mandibular unloading splints, orthodontic techniques… If it is due to excessive stress, relaxation techniques, anxiolytics?
In general, most patients come looking for a “magic pill” to remove tinnitus. That pill simply does not exist. Many drugs have been used but most of them have no appreciable effect. In general, anxiolytics and treatments that affect the auditivolimbic dopaminergic pathway seem to have some effect, but they also produce drowsiness and this is a side effect poorly tolerated by many patients.
Behavioral measures are quite effective in general. They probably do not make tinnitus disappear, but they do make it bearable and do not influence the patient’s daily life, so that tinnitus becomes, for example, like the noise that is always present when one lives on a busy street: there is always a background noise, but there comes a time when those who live in that house practically do not notice that noise.
These measures are aimed at “teaching the brain what to hear and what sounds to ignore”: avoiding quiet environments and using other sounds to mask tinnitus, engaging in activities that distract attention and avoid being focused on tinnitus. Sound therapies are very interesting: tinnitus and hyperacusis are treated using other sounds, such as fractal sounds, maskers, residual inhibition, tinnitus retraining therapy, sequential sound therapy…