Session 1 included a sociodemographic-based questionnaire and testing of cognitive ability using the verbal intelligence test (MWT-B) (Lehrl 1996 ), and the trail making test (TMT-A and -B) measuring executive functioning (Crowe 1998 (link)). Emotional states were tested using PANAS scales (Watson et al. 1988 (link)). As state of satiety is known to influence olfactory performance (Albrecht et al. 2009 (link)), subjects were also asked to rate their current state of hunger (1 = not hungry at all, 10 = very hungry), their desire for food (1 = very weak, 10 = very strong), and the fullness of their stomach (1 = not full at all, 10 = very full) on a visual analog scale.
The standard odors of the Sniffin’ Sticks test battery (Burghart Instruments) were used to test olfactory performance, hedonic, and intensity ratings. The original Sniffin’ Sticks test includes 3 subtests measuring nasal chemosensory function using pen-like devices for odor presentation: odor threshold, odor discrimination, and odor identification (Kobal et al. 1996 (link); Hummel et al. 1997 (link)). Detection thresholds of n-butanol were determined using a single-staircase, 3 alternative forced choice (3-AFC) procedure, that is, subjects were presented with 3 sticks and had to decide which one contained n-butanol. Odor discrimination was tested using 16 triplets of odorants, again presented as a 3-AFC procedure, that is, subjects again were confronted with 3 sticks and had to indicate which one smelled different. The odor identification test consisted of 16 commonly known every day odorants (orange, shoe leather, cinnamon, peppermint, banana, lemon, liquorice, turpentine, garlic, coffee, apple, clove, pineapple, rose, anise, and fish) using a multiple-choice answering format with 4 odors each. The standard testing procedure was extended by the assessment of odor intensity and hedonics for n-butanol in the highest concentration.
All 4 olfactory tests were carried out birhinally. The results of the 3 Sniffin’ Sticks subtests were summed up to the so-called “TDI score”, which characterizes the individual olfactory performance as the sum of odor threshold, discrimination, and identification ability (Kobal et al. 1996 (link); Hummel et al. 1997 (link)). Directly after the olfactory tests, emotional states using PANAS scales were assessed again.
The standard odors of the Sniffin’ Sticks test battery (Burghart Instruments) were used to test olfactory performance, hedonic, and intensity ratings. The original Sniffin’ Sticks test includes 3 subtests measuring nasal chemosensory function using pen-like devices for odor presentation: odor threshold, odor discrimination, and odor identification (Kobal et al. 1996 (link); Hummel et al. 1997 (link)). Detection thresholds of n-butanol were determined using a single-staircase, 3 alternative forced choice (3-AFC) procedure, that is, subjects were presented with 3 sticks and had to decide which one contained n-butanol. Odor discrimination was tested using 16 triplets of odorants, again presented as a 3-AFC procedure, that is, subjects again were confronted with 3 sticks and had to indicate which one smelled different. The odor identification test consisted of 16 commonly known every day odorants (orange, shoe leather, cinnamon, peppermint, banana, lemon, liquorice, turpentine, garlic, coffee, apple, clove, pineapple, rose, anise, and fish) using a multiple-choice answering format with 4 odors each. The standard testing procedure was extended by the assessment of odor intensity and hedonics for n-butanol in the highest concentration.
All 4 olfactory tests were carried out birhinally. The results of the 3 Sniffin’ Sticks subtests were summed up to the so-called “TDI score”, which characterizes the individual olfactory performance as the sum of odor threshold, discrimination, and identification ability (Kobal et al. 1996 (link); Hummel et al. 1997 (link)). Directly after the olfactory tests, emotional states using PANAS scales were assessed again.