Immediate electronystagmography in the diagnosis of the dizzy patient.
STUDY OBJECTIVES: To determine whether the results of electronystagmography (ENG) testing improve an emergency physician's diagnosis of dizziness. DESIGN: Prospective, one-year. SETTING: University and three community hospital emergency departments. TYPE OF PARTICIPANTS: Ninety-three consecutive patients presenting with dizziness. INTERVENTIONS: ED impression was recorded after complete ED evaluation. An ENG was performed within one hour by an audiologist, who gave a reading of "central," "peripheral," or "normal." The result was given to the emergency physician, who was invited to revise his or her impression (the "ED impression after ENG result"). Final diagnosis was based on the ED impression and by contact with the patient's physician(s) as well as the patient by telephone after one and four weeks. Accuracy of ENG was assessed by comparing ENG reading with the final diagnosis using the chi(2) test. In addition, the contribution of ENG to ED diagnosis was assessed by comparing the accuracy of the ED impression after ENG reading with the ED impression alone using McNemar's test (hit versus no-hit). MEASUREMENTS AND MAIN RESULTS: Both ED impression and the ENG significantly correlated with the final diagnostic category (chi(2) = 104.9, P < .001; chi(2) = 70.79, P < .001, respectively). ENG correctly diagnosed nine of 11 patients with central dizziness. Of 23 patients with undetermined cause after ED evaluation, ENG correctly identified seven patients with peripheral dizziness and three with central dizziness. ED impression after ENG reading was more accurate than ED impression alone (chi(2) = 6.13, P < .05). CONCLUSION: Emergency physicians correctly categorized most dizzy patients, but audiologist performance and interpretation of an ENG significantly improved this categorization. ENG may have the potential to identify clinically unsuspected central dizziness and to categorize dizziness of "unknown" cause. Further study is needed to determine whether ENG could be performed by modifying certain types of heart monitors available in the ED.