3Subjective vs Objective Tinnitus

FThe primary dichotomy

The most fundamental way to classify tinnitus is by its source. Subjective tinnitus is a percept with no real acoustic vibration behind it — it is generated by the nervous system and can be heard only by the patient. Objective tinnitus is a genuine sound produced somewhere inside the body that, at least in principle, an examiner can also detect [2013].

This split matters because it points the clinician in opposite directions: subjective tinnitus prompts an audiological and neural work-up, while objective tinnitus sends you hunting for a physical sound source that may be treatable or even curable [2013].

FSubjective tinnitus: a phantom of neural origin

More than 95% of all tinnitus is subjective [2014]. It is most commonly described as ringing, hissing or buzzing and is closely tied to sensorineural hearing loss — from noise exposure, ageing, ototoxic drugs or sudden hearing loss. The triggering event is usually damage to cochlear hair cells, which reduces input to the brain.

The brain responds to that loss of input with increased spontaneous firing and reorganised sound maps, so the percept persists even though no sound is present — the essence of a phantom auditory perception [1990]. Because the source is neural, nothing can be heard by an examiner with a stethoscope, and there is no waveform to record.

TObjective tinnitus: a real internal sound

Objective tinnitus is uncommon — well under 5% of cases — but conceptually distinct: there is a real sound, and it can sometimes be auscultated, recorded or even seen on imaging [2013]. The sources fall into three families. Vascular causes produce a pulsatile sound synchronous with the heartbeat — turbulent flow in stenotic carotids, dural fistulas, arteriovenous malformations, or anomalies of the jugular bulb; raised intracranial pressure can do the same [2013].

Muscular causes are rhythmic clicking from myoclonus of the middle-ear muscles (tensor tympani, stapedius) or the palatal muscles. Mechanical causes include a patulous Eustachian tube, which produces breathing-synchronous sound. The temporal character is a giveaway: pulsatile (with the pulse) suggests vascular; clicking suggests muscular; breath-synchronous suggests a patulous tube [2013].

CWhat each type implies for the work-up

The classification is not academic — it dictates the investigation. For subjective tinnitus, the foundation is a careful history and a comprehensive audiological assessment; guidelines specifically discourage routine imaging unless there are red flags such as unilateral, asymmetric or pulsatile symptoms [2014]. Management then targets the auditory deficit and the brain’s response: hearing aids where hearing loss coexists, sound enrichment, and structured counselling [2014].

For objective (especially pulsatile) tinnitus, the work-up pivots to finding the sound source: auscultation over the ear, mastoid and neck, then targeted vascular imaging — CT/MR angiography or venography — to identify a treatable lesion [2013]. The reward is that, unlike most subjective tinnitus, an objective cause can sometimes be definitively corrected.

CCaveats and overlap

The dichotomy is useful but imperfect. Some “objective” sounds (such as faint myoclonic clicks) cannot actually be heard by the examiner, and some authors prefer the terms neural versus mechanical/somatosounds to capture the real distinction — whether a true acoustic vibration exists [2014]. A practical clinical rule survives all of this: pulsatile tinnitus, particularly if unilateral, deserves a deliberate search for a vascular cause, because the differential includes serious, treatable disease [2013].

Conversely, the great majority of patients you will see have subjective, non-pulsatile tinnitus with associated hearing loss, in whom over-investigation adds cost and anxiety without benefit [2014].