EPV 12. Objective measurements of olfactory function in infants

Abstract

Objectives To objectively measure olfactory function in adults, olfactory event-related potentials (OERP) are widely used in clinical and scientific settings. So far this method has not been applied to infants. Previous studies relied on observations like grimacing or head turning to assess olfactory function of infants. Aim of this study was to evaluate olfactory event-related potentials as an objective measurement of olfactory function in infants. Materials & methods Thirteen infants, between 23 and 41 days of age, were included in the study. OERP to phenylethylalcohol were measured. The odor was delivered with a computer-controlled olfactometer. Recording electrodes were applied using the 10–20 system. Data from electrodes Fz, Cz, Pz, C3 and C4 was analyzed by Matlab’s “Letswave” toolbox using the canonical time-domain averaging as well as the time-frequency analyzing method. Results Ten out of 13 infants finished the recording session. In seven out of these ten infants we were able to observe OERP. Recordings were best in electrodes Fz and Cz. The N1 peak was visible at 328 ms followed by P2 at 505 ms. In addition the time-frequency analysis revealed an increase in low frequencies (4–7 Hz) around 550 ms after odor presentation. Conclusions In this study we were able to record OERP in infants. For data analysis both methods, the time-domain averaging as well as the time-frequency analysis proofed to be of value. Further studies are needed to evaluate the clinical relevance of measuring OERPs e.g. in the diagnosis of asphyxia or traumatic brain injury.