Re-evaluation of normative electronystagmography data in healthy ageing

Previous work by our group questions the validity of existing electronystag mography (ENG) reference ranges in the elderly. We aim to establish valid r eference ranges for ENG in people over 65 on the Nicolet Nystar Plus system . Ninety-six healthy asymptomatic subjects over 65 underwent ENG, including spontaneous and positional nystagmus, saccades, smooth pursuit, optokineti c nystagmus and bithermal calorics; 95% reference ranges with confidence in tervals were calculated. The newly determined reference ranges were far wid er than those provided by the ENG equipment manufacturer for eight out of 1 1 parameters (all P < 0.001). Vestibular function is known to deteriorate a nd become more variable with age. The failure to reflect this change in cur rently used reference ranges may have contributed to the high rates of vest ibular disease reported in some series of dizzy elderly patients. Clinical interpretation of ENG depends on valid reference ranges.