A New Method for a Shorter and Valid Assessment of Olfactory Threshold in Repeated Measurement Designs Based on the Sniffin’ Sticks Test

Introduction The Sniffin’ Sticks threshold test is widely used to assess olfactory threshold due to its high reliability and validity. Nevertheless, this test procedure is quite long with an average duration of 10 to 20 min. In study designs that require multiple olfactory threshold tests on short intervals, this could exhaust participants. To counteract this limitation, we developed the informed-four-reversal (INFOUR) short version of the Sniffin’ Sticks threshold test for repeated measurement designs and piloted it in a sample of normosmic participants. Methods Forty-two participants performed the original Sniffin’ Sticks version before being assigned either to the control group that repeated the original version or to the test group that conducted the INFOUR short version. Results The correlation between the original version at T1 and INFOUR at T2 was r = .75 and did not differ significantly from the retest reliability of the original version. Compared to the original version, the INFOUR took 42% less time to perform. Conclusion The INFOUR leads to a significant time saving, while maintaining good validity. Implications Therefore, this approach has the potential to be a useful tool for study protocols with repeated olfactory threshold measurements. In particular, when research protocols are time intensive or testing needs to the shortened, because the interventional effects are short or subtle.