Table 2. Classification of tinnitus and its underlying etiology.

Types	Causes
Tonal tinnitus
Bilateral
	Chronic noise exposure
	Ototoxic medication
	Head trauma with/without acoustic trauma
	Meningitis
	Neurosyphilis
Unilateral
Neurologic signs	Brainstem lesion such as stroke, tumor, demyelinating disease, etc.
No neurologic signs	Chronic noise exposure on one ear
	Ear infection
	Ear drum lesion
	Meniere disease
	Semicircular canal dehiscence
Somatosound
Bilateral or unilateral
Pulse synchronous	Systemic hypertension
	Arterial bruits
	High jugular bulb
	Arteriovenous malformation
	Intracranial aneurysm
	Vascular tumors
	Idiopathic intracranial hypertension
Pulse asynchronous	Middle ear muscle myoclonus
	Palatal muscle contraction
	Eustachian tube contraction