Using a standardized screening test of nasal chemosensory performance (Sniffin’ Sticks; Hummel et al., 1997; Kobal et al., 2000), odor identification and thresholds were assessed for each participant immediately before the OERP test. For testing odor thresholds, 2-phenylethanol (rose-like smell) was used as a pure olfactory alternative to n-butanol because of concerns of trigeminal co-activation with higher odor concentrations (Doty et al., 1978; Jacquot et al., 2004), as both odorants have produced reliable threshold results and were equally good to distinguish between patients and normosmic subjects (Croy et al., 2009).
