Tinnitus is the perception of sound within the ears or head when no actual external acoustic stimulus is present. It is not a disease itself but rather a symptom arising from an underlying change or issue within the auditory system. Tinnitus is a common experience, affecting a significant portion of the population, though the severity and persistence vary widely. The internal sound perception can be generated at any level of the auditory pathway, from the inner ear to the brain’s central processing centers.
The Spectrum of Tinnitus Sounds
The noise experienced by those with tinnitus is highly individualized, often described using a wide range of terms beyond the commonly cited “ringing in the ears.” Subjective tinnitus accounts for approximately 99% of all cases and is a phantom sound that only the affected person can hear. The brain generates this noise signal in the absence of external input, often to compensate for reduced auditory stimulation, such as from hearing loss.
The most frequently reported sounds include:
- A high-pitched, tonal ringing.
- A persistent hissing like static.
- A low-frequency buzzing or humming.
- A steady roaring sound, similar to the ocean.
- A sharp whistling noise.
In rare instances, individuals may experience complex sounds, such as music or singing, a phenomenon known as Musical Ear Syndrome.
Key Characteristics of the Sound Experience
The experience of tinnitus is defined by several variable characteristics, including pitch, loudness, and constancy.
Pitch
The perceived pitch of the sound can range dramatically from a low-frequency rumble (often below 500 Hertz) to a high-frequency whine (sometimes above 4,000 Hertz). High-pitched tinnitus is frequently associated with noise-induced or age-related hearing loss. This pitch often corresponds to the frequency where hearing is most impaired.
Loudness
The loudness, or intensity, of the sound is highly subjective, ranging from barely noticeable background noise to a sound perceived as louder than most environmental stimuli. Clinically, the sound is often matched by a tone at a very low sensation level, typically 6 to 20 decibels above the patient’s hearing threshold. Due to a phenomenon called loudness recruitment, this quiet internal sound can be perceived as significantly louder.
Constancy
The sound’s constancy can be either intermittent, coming and going unpredictably, or continuous, presenting as a steady, unrelenting tone. The intensity of the noise can also fluctuate, sometimes increasing noticeably in quiet environments when there is no competing sound to mask the internal perception. These parameters can change over time or in response to factors like stress or caffeine intake.
Specialized Sound Variations
A less common but distinct experience is Pulsatile Tinnitus, where the sound is rhythmic and often perceived as a whooshing, thumping, or rushing noise. This sound is synchronized precisely with the individual’s heartbeat or pulse, and can be identified by checking the pulse while listening to the noise. Pulsatile tinnitus is often linked to changes in blood flow or turbulence in the blood vessels near the ear.
An even rarer category is Objective Tinnitus, representing less than one percent of all cases. This type is unique because the sound is physically generated and can occasionally be heard by an examiner using a stethoscope or a specialized microphone. The sound is typically caused by mechanical sources near the ear, such as involuntary rhythmic muscle spasms in the middle ear or the soft palate, or vascular sounds from blood flow transmitted to the inner ear.