Tinnitus is the perception of sound without an external acoustic source, affecting millions of people. This internal sound possesses measurable characteristics, most notably a specific frequency or range of frequencies. Understanding this frequency provides a direct physiological link to the underlying cause and guides targeted management strategies. The frequency, measured in Hertz (Hz), serves as a precise marker that helps clinicians diagnose the origin of the disturbance within the auditory system. This article explores how the subjective frequency of tinnitus is determined, what it reveals about hearing health, and how that information is applied to personalize treatment.
Characterizing the Sound You Hear
Pitch matching is the clinical process required to identify the subjective pitch of tinnitus. During this assessment, a patient compares the internal sound to external tones presented by an audiologist. The patient adjusts the external tone’s frequency until it matches the perceived pitch, providing a measurement in Hertz.
Tinnitus manifests in various forms, influencing the matching procedure. Tonal tinnitus, the most common type, is characterized by a single, distinct frequency, often described as a high-pitched ringing. Broadband or noise-like tinnitus is perceived as static, hissing, or buzzing, encompassing a range of frequencies. For noise-like tinnitus, the clinician tries to match the most prominent frequency component or the overall spectral shape.
Pitch matching is a necessary step for characterizing the phantom sound. Test results can vary between sessions, highlighting the brain’s dynamic perception. This measurement establishes a baseline psychoacoustic characteristic essential for linking the patient’s experience to physiological mechanisms of hearing.
How Tinnitus Frequency Relates to Auditory Damage
The frequency identified through pitch matching often correlates directly with the specific area of physical damage within the inner ear. Sound waves are processed along the cochlea: high frequencies stimulate hair cells near the base, and low frequencies stimulate those near the apex. When hair cells in a region are damaged, the brain receives reduced input at the corresponding frequency.
Chronic tinnitus links this peripheral damage to a central nervous system response called deafferentation. When the brain is deprived of expected auditory signals, it compensates by increasing neural activity in the corresponding frequency area of the auditory cortex. This hyperactivity is interpreted by the brain as the phantom sound.
The tinnitus frequency typically aligns with the region on an audiogram where hearing loss is most pronounced. For instance, a patient reporting a high-pitched whine around 6,000 Hz often has the greatest hearing threshold elevation near that frequency. This correlation makes the tinnitus frequency a valuable diagnostic indicator of where the greatest auditory deprivation has occurred.
High-frequency tinnitus can occur even when a standard audiogram shows normal hearing thresholds, a phenomenon called “hidden hearing loss.” Here, the damage is subtle, affecting the synapses between the inner hair cells and the auditory nerve. Specialized tests can reveal a loss of function in the high-frequency regions, confirming that deafferentation drives the tinnitus perception.
Using Frequency Knowledge in Tinnitus Management
Knowing the precise frequency allows for the creation of tailored sound therapies, moving beyond general sound masking. This frequency data is used to develop therapeutic signals that specifically target hyperactive neural circuits in the brain. The goal of these frequency-specific approaches is to promote neuroplasticity, encouraging the brain to reorganize and reduce its perception of the phantom sound.
One technique is notched sound therapy, which involves presenting a broadband sound with the patient’s specific tinnitus frequency completely filtered out. Creating this “notch” means the therapy does not directly compete with or mask the tinnitus. The filtered sound trains the auditory cortex to reduce the hyperactivity in the neuronal network responsible for generating the tinnitus frequency.
This targeted approach, often delivered through hearing aids, aims to quiet the neurons overcompensating for peripheral damage. Unlike simple masking, notched sound therapy is designed to produce a lasting reduction in the perceived loudness or annoyance of the tinnitus. The accuracy of the initial frequency measurement is central to the effectiveness of these retraining therapies.