Neurogenic tinnitus refers to abnormal sound sensations in the absence of any external stimuli. The sensation of monotonous or mixed sounds such as cicadas, buzzing and hissing in the ear may be accompanied by deafness, vertigo and headache. Acute tinnitus can be treated clinically with vasodilators and nerve nutrients, anxiolytics, antidepressants, carbamazepine anticonvulsants, lidocaine, hormones and tranquillisers.