pulsatile tinnitus

   Also known as pulsing tinnitus. Both terms are indebted to the Latin verb pulsare, which means to hit, to knock, to pulsate. They are used to denote a type of "tinnitus (i.e. 'ringing in the ears') characterized by a rhythmic sound that can be heard not only by the individual affected but also by others, either with the aid of a stethoscope placed in a location around the ear, or -without any artificial aids - as emenating from the affected individual's ear. Pulsatile tinnitus is classified as a type of "objective tinnitus. Its incidence is relatively low. In a survey among 2,838 individuals with a clinical diagnosis of tinnitus, only 3.4% had pulsatile tinnitus. The condition is not necessarily accompanied by hearing loss. Pathophysiologically, pulsatile tinnitus is associated primarily with a variety of muscular and vascular mechanisms. The muscular types are generally attributed to degenerative diseases of the head and neck, such as amyotrophic lateral sclerosis (ALS), in which loss of neuromuscu-lar control may result in a repetitive flutter or myoclonus of the stapedius or the tensor tym-pani muscles. This may entail an audible flutter emanating from the ear. A rare cause of the muscular type of tinnitus is palatal myoclonus, a condition attributed to rhythmic discharges from the brainstem's inferior olivary nucleus. Such discharges are attributed to focal epileptic activity, which may in turn be caused by conditions such as stroke, trauma, encephalitis, multiple sclerosis, a local vascular malformation, or a degenerative disease. The vascular types of pulsatile tinnitus may be due, for example, to tortuosity of the carotid artery, the jugular bulb, or the jugular vein. This tortuosity may entail intravascular turbulence, perceived by the affected individual as a rhythmically vibrating, or low-pitched sound, rather than a ringing or clicking sound. Other medical conditions associated with an increased relative risk for pulsatile tinnitus include hypertension, intracranial hypertension syndrome, glo-mus tumours, and neurovascular compression of the acoustic nerve.

   References

   Henry, J.A., Dennis, K.C., Schechter, M.A. (2005). General review oftinnitus. Prevalence, mechanisms, effects, and management. Journal of Speech, Language, and Hearing Research, 48, 1204-1235.

   Vernon, J.A., Sanders, B.T. (2001). Tinnitus. Questions and answers. Boston, MA: Allyn and Bacon.