Fig 1.
First, the subjects had a 30-s pre-rest. Then, the subjects were given an olfactory stimulus for 10 s, followed by a 30-s post-rest period and a 30-s period to complete a questionnaire on odor intensity and subjective assessments of hedonic and irritating odors. The 130-s cycles for each odorant were repeated six times consecutively.
Table 1.
Demographic characteristics of the study population.
Fig 2.
Detection thresholds (A) and recognition thresholds (B) by patients with multiple chemical sensitivity (MCS) (n = 10) and controls (n = 6) in olfactory ability testing.
Y-axes present the mean values of five odorants.
Fig 3.
Rating of odor intensity (A) as well as hedonic (B) and irritating odors (C) by patients with multiple chemical sensitivity (MCS) (n = 10) and controls (n = 6) after olfactory stimulation.
Abbreviations: D1, γ-undecalactone and concentration level 1; D4, γ-undecalactone and concentration level 4; E1, skatole and concentration level 1; E4, skatole and concentration level 4; and NO, non-odorant. Numbers in parentheses in column 1 indicate the order of the six repetitions (1–6). Statistically significant differences between groups are indicated: *p < 0.05.
Fig 4.
Time-course of average z-scores of all channels for oxygenated hemoglobin (oxyHb) levels in patients with multiple chemical sensitivity (MCS) (n = 10) and controls (n = 6) during pre-rest (baseline, 10–30 s), stimulation (30–40 s), and post-rest (recovery, 40–70 s).
Y- and X-axes present the z-scored oxyHb values and times, respectively. Signals reflecting the oxyHb concentration changes in arbitrary units were calculated (millimolar–millimeter). The signal data were adjusted using a fast Fourier transform filter smoothing technique (OriginPro 2016 software of OriginLab Corporation). The cutoff frequency was determined at 35 points. The MCS group is indicated as a black line, and the control group is indicated as a gray line. Abbreviations: D1, γ-undecalactone, and concentration level 1; D4, γ-undecalactone, and concentration level 4; E1, skatole, and concentration level 1; E4, skatole, and concentration level 4; and NO, non-odorant. Numbers in parentheses in column 1 indicate the order of the six repetitions (1–6).
Fig 5.
Topographical maps of average z-scores for oxygenated hemoglobin (oxyHb) levels between patients with multiple chemical sensitivity (MCS) (n = 10) and controls (n = 6).
Abbreviations: D1, γ-undecalactone, and concentration level 1; D4, γ-undecalactone, and concentration level 4; E1, skatole, and concentration level 1; E4, skatole, and concentration level 4; and NO, non-odorant. Numbers in parentheses in column 1 indicate the order of the six repetitions (1–6).
Table 2.
The t-test results for all channels (1–52) comparing z-scores for oxygenated hemoglobin levels between patients with multiple chemical sensitivity (MCS) and controls.