Tinnitus is the perception of sound within the ears or head when no corresponding external acoustic stimulus is present. It can manifest as a ringing, buzzing, hissing, or roaring sound, varying widely in pitch and intensity. Tinnitus is not a disease but rather a symptom of an underlying auditory or neurological change. The experience can be intermittent or persistent, and for some individuals, it represents a substantial disturbance to their quality of life, sleep, and concentration.
Defining Subjective vs. Objective Tinnitus
Tinnitus is generally divided into two types: subjective and objective, with subjective being overwhelmingly more common. Subjective tinnitus, which accounts for over 99% of all cases, is a phantom auditory perception only heard by the individual experiencing it. The sound is generated internally, often due to changes within the auditory pathway, and cannot be detected by a clinician during an examination. This type is a neurological phenomenon, resulting from a sensory misfiring in the brain that creates the perception of noise.
Objective tinnitus is the rare form where a healthcare provider can physically hear the sound, usually by placing a stethoscope near the ear. This sound is generated by a real physical source inside the body, such as vascular issues or spasms of muscles in the middle ear. Because objective tinnitus has a mechanical or circulatory origin, it frequently presents as a rhythmic or pulsating sound, often synchronized with the patient’s heartbeat.
Underlying Mechanisms and Common Causes
The primary mechanism underlying subjective tinnitus involves neuroplastic changes within the central auditory system. When sensory input from the inner ear decreases, the brain attempts to compensate for this loss by increasing the spontaneous activity of nerve cells in the auditory cortex. This hyperactivity is interpreted by the brain as sound, resulting in the phantom perception.
The most frequent trigger for this chain of events is damage to the delicate hair cells within the cochlea, which translate sound vibrations into neural signals. Acute or chronic exposure to loud noise is a leading cause, as acoustic trauma physically injures the hair cells, leading to noise-induced hearing loss. Age-related hearing loss (presbycusis) is also a common cause in older adults as these cells naturally degenerate over time.
A variety of other factors can lead to or exacerbate subjective tinnitus. Certain medications are ototoxic, meaning they damage the auditory system; over 260 different drugs have been reported to cause tinnitus as a side effect. These include specific antibiotics, chemotherapy agents, and high doses of common pain relievers.
Underlying health conditions also frequently contribute to the onset of the sound. Issues such as Meniere’s disease, which affects the inner ear, can cause fluctuating tinnitus. Temporomandibular joint (TMJ) disorders and head or neck trauma are additional sources, as they can affect nerves and muscles that interact with the auditory system, sometimes creating a form of somatic tinnitus.
Clinical Assessment and Diagnosis
Identifying subjective tinnitus involves a systematic assessment to confirm the patient’s experience and exclude other medical conditions. Since the noise cannot be objectively measured, diagnosis relies heavily on the patient’s detailed medical history and description of the sound. Clinicians ask about the sound’s character, location, duration, and any accompanying symptoms like vertigo or hearing loss.
A comprehensive audiological evaluation, including a pure tone audiogram, is routinely performed to measure the patient’s hearing thresholds. Because subjective tinnitus is frequently associated with hearing loss, this test helps determine the extent and pattern of any auditory deficit.
To assess the impact of the sound on a person’s life, specialized questionnaires are often used, such as the Tinnitus Handicap Inventory (THI) or the Tinnitus Functional Index (TFI). If the patient reports unilateral tinnitus or if the physical examination suggests a neurological concern, imaging studies like an MRI or CT scan may be ordered. This is performed to rule out rare but serious causes, such as an acoustic neuroma or other structural abnormalities.
Current Management and Support Options
Since there is currently no universal cure for chronic subjective tinnitus, management strategies focus on reducing the perception of the sound and minimizing its negative impact. Cognitive Behavioral Therapy (CBT) is a recommended intervention that teaches the patient to reduce the emotional distress and anxiety associated with the perception. This therapy helps reframe negative thoughts and reduces the attention paid to the internal sound.
Sound therapy and masking techniques are widely employed to provide relief by introducing external noise to distract the brain. This involves using white noise generators, environmental sounds, or specialized music to make the internal sound less noticeable, promoting habituation. Tinnitus Retraining Therapy (TRT) combines sound therapy with structured counseling to train the brain to filter out the tinnitus signal.
For individuals with co-occurring hearing loss, the use of hearing aids often leads to a reduction in tinnitus severity. By amplifying external sounds, the hearing aid provides the brain with the auditory input it was lacking, which can suppress the perceived phantom noise. Other supportive measures include lifestyle adjustments, such as managing stress, limiting triggers like caffeine, and utilizing relaxation techniques to improve sleep quality.