[Olfactory evoked potentials and contingent negative variation in expert assessment of disordered sense of smell]

Normally, the sense of smell is assessed by means of traditional subjective tests (sniff test, gustatory smell test, and trigeminus test). When results are inconclusive, an objective smell test is indicated. Simultaneously registering olfactory evoked potentials (OEP) and contingent negative variation (CNV) permits evaluation of both odor perception and odor discrimination. We can even objectively assess the false olfactory sensations in parosmia patients who are unable to discriminate between different odors. In this study, the results of 59 patients with olfactory disorders are presented. Head trauma and upper respiratory infections were the most common causes of the patients' complaints. In twelve cases, lack of cooperation and patient unrest prevented us from evaluating the data. In anosmia, the objective results agreed completely with the patient's subjective assessment. In hyposmia and parosmia, the results agreed with the patient's subjective assessment in most cases; here we were able to arrive at a more specific diagnosis in several cases. The objective smell test can be used to supplement subjective methods and thus provide more reliable assessment of olfactory disorders.