A statistical study of ENoG test error.

Electroneurography (ENoG) is currently the most sophisticated and objective test available for assessing nerve degeneration in patients suffering from facial nerve paralysis. However, the test requires considerable experience before error due to intertest variability can be brought within reasonable limits. In a statistical study on normal participants, the error associated with two conventional recording techniques--optimized lead placement (OLP) and standardized lead placement (SLP)--was determined to be 17.8% and 20.7%, respectively. A significant increase in error was observed with the OLP approach (22.9%) if responses could not be monitored oscilloscopically, a common situation in patients with severe degeneration. In a final study, however, a previously unreported factor was found to significantly reduce test error: recording electrode size. In particular, unconventionally small recording electrodes (3 to 7 mm) produced as much as 4% less error when administering the technique.