Handedness is a determining factor in lateralized olfactory discrimination

The study aimed to re-investigate differences in olfactory thresholds and odor discrimination between the left and right sides in relation to the handedness of healthy subjects. Twenty left- and 20 right-handers participated; all were in excellent health with no indication of any major nasal or health problems, and all were non-smokers. The two groups were comparable in terms of sex and age (left-handers: 11 women, 9 men, median age 25 years; right-handers: 9 women, 11 men, median age 26 years). Odor thresholds did not differ in relation to handedness. However, in the odor discrimination task the left-handers performed significantly better at the left side compared with the right nostril; this pattern was reversed in the right-handers. The data indicate that, similar to other sensory systems, higher olfactory functions exhibit a certain degree of lateralization.