Modification of the Brief Smell Identification Test by Introduction of a Placebo

Objective: To introduce the concept that there might be "nothing to smell" to the Brief Smell Identification Test (B-SIT), with a view to masking olfactory deficits, particularly from healthy control participants in research studies.Methods: Seventy-one elderly individuals, healthy for their age, were recruited to the study.They were blindfolded and carried out a modified B-SIT where one item had been replaced with a placebo, and one odour alternative answer to three other items was replaced by the alternative "none/other" (actual odour unchanged).Results: There was no overall difference in the median or mean score achieved by the cohort compared to results obtained previously using the conventional B-SIT.The replacement of the item "turpentine" with a placebo resulted in an improved score for the item in a Norwegian setting.The overall scores were not improved.Conclusions: It is possible to introduce the concept that there may be "nothing to smell" to the B-SIT without compromising the test for healthy control individuals.This may be a more appropriate approach to olfactory testing of control individuals or patients with suspected early neurodegenerative diseases.