What types of sounds are classified as tinnitus?

Types of Sounds Classified as Tinnitus

Tinnitus encompasses a wide spectrum of perceived sounds including ringing, buzzing, clicking, pulsations, hissing, roaring, humming, and various noise-like qualities—all occurring without an external acoustic source. 1

Primary Sound Categories

Pulsatile Tinnitus

• Pulsatile tinnitus is a repetitive sound that synchronizes with the patient's heartbeat, representing a distinct category that almost always requires imaging evaluation due to identifiable vascular or structural causes in over 70% of cases 2
• This rhythmic, pulse-synchronous sound can indicate serious underlying pathology including arterial dissection, dural arteriovenous fistulas, atherosclerotic carotid disease, or venous sinus abnormalities 2

Non-Pulsatile Tinnitus

• Non-pulsatile tinnitus presents as continuous or constant sounds that do not synchronize with heartbeat 1
• Patients describe these sounds using various descriptors:
  • Ringing (most common description) 1
  • Buzzing 1
  • Hissing 1
  • Roaring 1
  • Humming 1

Psychoacoustic Classification

Pure Tone Tinnitus

• Pure tone tinnitus resembles a single-frequency sound, similar to what an audiometer produces, and accounts for approximately 51% of tinnitus complaints 3
• This type is typically perceived at high frequencies (162 of 181 complaints in one study) rather than low frequencies 3
• Patients with pure tone tinnitus report a mean loudness of 12.31 decibels above threshold 3

Noise-Type Tinnitus

• Noise-type tinnitus resembles broadband sounds (like white noise or static) rather than pure tones, accounting for approximately 49% of tinnitus complaints 3
• This category includes sounds described as "noise-like" that cannot be matched to a single frequency 3
• Patients with noise-type tinnitus report slightly higher distress (mean Visual Analog Scale of 6.66) compared to pure tone tinnitus (5.47) 3

Objective Versus Subjective Classification

Subjective Tinnitus

• Subjective tinnitus is perceived only by the patient and represents 70-80% of all tinnitus cases, typically associated with sensorineural hearing loss 1
• This is the most common form and does not produce sounds audible to the examining clinician 1

Objective Tinnitus

• Objective tinnitus is audible to the examining healthcare provider and represents a rare but critical category that strongly suggests vascular pathology requiring immediate workup 2, 1
• Specific subtypes include:
  • Clicking sounds from palatal or tympanic myoclonus (muscle contractions in the middle ear or palate) 1
  • Vascular sounds from arteriovenous malformations or other high-flow vascular lesions 2

Frequency Characteristics

• High-frequency tinnitus (typically above 3000 Hz) is far more common than low-frequency tinnitus, with 162 of 181 complaints occurring at high frequencies in psychoacoustic studies 3
• Low-frequency tinnitus (below 1000 Hz) is less common but may respond differently to masking strategies, particularly when narrow-band noise is used 3

Laterality Patterns

• Tinnitus can be perceived unilaterally (one ear), bilaterally (both ears), or as originating from within the head 1
• Unilateral pulsatile tinnitus has a higher likelihood of identifiable structural or vascular cause compared to bilateral presentations 2
• Bilateral, symmetric, non-pulsatile tinnitus without localizing features typically does not warrant imaging 2

Critical Clinical Distinctions

Red Flag Sound Characteristics

• Tinnitus severe enough to wake a patient from sleep is highly unusual and should immediately raise suspicion for objective tinnitus with vascular or neuromuscular etiology 1
• Any pulsatile component—even if intermittent—requires vascular evaluation, as this distinguishes potentially life-threatening causes from benign subjective tinnitus 2
• Clicking or typewriter-like sounds suggest neurovascular compression of the cochlear nerve or middle ear myoclonus 1

Modifiable Tinnitus

• Some patients can modulate their tinnitus through somatic maneuvers (jaw movements, neck positioning, or muscle contractions), suggesting somatosensory system involvement 4
• Tinnitus relieved by carotid or jugular compression suggests venous etiology (sigmoid sinus abnormalities, jugular bulb variants) or arterial dissection 2

Common Pitfalls to Avoid

• Never dismiss pulsatile tinnitus as benign without imaging, regardless of how the patient describes the sound quality, as treatable and life-threatening causes are common 2
• Do not assume that "ringing" automatically means benign subjective tinnitus—always determine if there is any pulsatile component through careful history 2
• Recognize that patients may struggle to accurately describe their tinnitus sounds, so use comparison techniques (matching to pure tones versus noise, high versus low pitch) to better characterize the percept 3
• Multiple simultaneous tinnitus sounds can occur in the same patient (pure tone in one ear, noise-type in the other), and these patients report higher distress levels (mean Tinnitus Handicap Inventory of 61.38) 3