[Pathophysiological rationale for the use of piracetam in sudden deafness]

To determine if blood viscosity disorders affect the clinical course of idiopathic sudden deafness, we studied the usefulness of the rheoactive agent piracetam and prednisolone compared with steroid/vasodilator therapy. The piracetam group (n = 17) showed clinical improvement in 82.3% and a mean hearing gain in 54.1%, compared with 68.7% and 49.3%, respectively, for the group without piracetam (n = 6). In both groups, clinical severity correlated with increased whole blood viscosity and erythrocyte aggregability and filterability rates. On the seventh day after onset, all the viscosity parameters had returned to normal in the piracetam group, but the non-piracetam group still showed no improvement in whole blood viscosity and erythrocyte filterability. Piracetam seemed to be effective in this sensorineural deafness, probably as a result of its effect on the viscoelastic properties of blood. Measurement of these properties seven days after beginning therapy provides information about long-term potential for hearing recovery.