Olfactory function in children assessed with psychophysical and electrophysiological techniques.

The olfactory information processing abilities of children undergo changes during early life. The aims of the present study were to describe these changes and to probe for their electrophysiological correlates. These aims were investigated in two experiments. In Experiment 1, responses of 146 subjects (3-12 years) were tested with psychophysical tools. Approximately 2/3 of the subjects completed the olfactory tests ("Sniffin' Sticks"). In Experiment 2, 12 additional subjects (3-10 years) were tested with electrophysiological tools. Event-related potentials (ERPs) were recorded in response to olfactory stimulation with H(2)S. Results from Experiment 1 indicated that data from the group of 3-5-year olds were very unreliable, with 44% of incomplete measures rendering the tests unsuitable for routine use with 3-5-year olds. From an age of 6 years on the results suggested that the development of olfactory function was well advanced with a significant increase found only for odor identification, but not for odor thresholds, or odor discrimination. Results from Experiment 2 indicated an increase of the P2 latency with age, although the small sample size has to be considered in the interpretation of these data. While more research is needed, these results may be interpreted such that children attach more meaning to odorous stimuli with age.