Self-Administered Testing of Odor Threshold and Discrimination Using Sniffin’ Sticks—Reviving the “Odor-Curves-On-Paper” Method

Abstract

Olfactory testing helps in diagnosing olfactory dysfunction (OD). The Sniffin’ Sticks odor test kit is widely used for research and can be reused and summed scores of threshold (T), discrimination (D), and identification (I) allow comparison to normative data. Testing can be time consuming and odor pens have to be presented by an examiner. The aim of this study was to investigate for a self-administration strategy for testing T and D.

Fifty healthy subjects (30 female, 20 male, mean age 27.3?years?±?8.1, range 18–58) were included. T was tested by an examiner (T-as) in a reversed staircase manner and self-tested with randomly presented concentrations (T-rand) and ascending methods of limits (T-aml). D testing was performed with assistance (D-as) and self-administered (D-s). For self-testing, examinees were instructed to perform the “odor-curves-on-paper” method.

Mean TDI was 35.9?±?3.0, range 26.5–42.8. T-as scores were significantly lower than T-aml (p?<?0.001) and T-rand (p?<?0.05). T-aml was significantly faster than T-rand and T-as modalities (p?<?0.001); Paired t test revealed no significant difference of D-as and D-s, in terms of scores and time needed (p?>?0.05) and the mean difference was small (0.3).

The results of this study demonstrate the “odor-curves-on-paper” method is applicable for D and with restrictions for T testing.

Self-administration of olfactory testing using Sniffin’ Sticks can, with appropriate instructions, easily be performed and may improve patient care in personnel and (with limitations) time-restricted settings.