Rate of spiral ganglion cell loss in idiopathic sudden sensorineural hearing loss

Objective: To calculate the spiral ganglion neural decay rate among patients diagnosed with idiopathic sudden sensorineural hearing loss (ISSNHL). Study Design: Retrospective. Setting: Temporal bone histopathology bank. Patients: Subjects diagnosed during life with unrecovered unilateral ISSNHL. Intervention(s): Spiral ganglion cell count in the bilateral reconstructed Rosenthal canal. Main Outcome Measure(s): Decay rate of spiral ganglion cells. Results: Nine patients were enrolled. The average age of ISSNHL diagnosis and death was 52 and 63 years, respectively. The total and segmental SGCC decay shows a temporal dependency. The time lag between the ISSNHL event and death was linearly proportional to the SGCC decay. Subjects who died less than 5 years from diagnosis of ISSNHL had no more than 13% loss of their total SGCC, and no more than 14% of SGCC per Rosenthal canal segment. When a longer period passed from ISSNHL diagnosis to death (19–20 yr), a loss of 16% and 13 to 18% of total and segmental SGCC occurred, respectively. Conclusions: SGCC decline from ISSNHL diagnosis through life.