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. 2021 Jan 28;12:657. doi: 10.1038/s41467-021-20939-5

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Fig. 2 — a Two-point discrimination task on palm. Aβ-deafferented participants (N = 2) were unable to discriminate ≤20 mm cutoff. 7/8 control participants performed near the normal range⁴⁹ (one-sided permutation test p = 0.07). b A cartoon depicting the custom-built leg compression sleeve device (from Case et al.⁵⁰). A computer controlled inflation rate and pressure around the left calf. c. Intensity of the compression sleeve oscillating between 10–30 mmHg (low) or 15–65 mmHg (high) was rated on a VAS scale (no sensation = 0; pain threshold = 50). Controls (N = 8) rated significantly higher intensity than patients (N = 2) for high (one-sided permutation test *p = 0.02) but not low (one-sided permutation test p = 0.16) pressure. Bars display median ratings and interquartile intervals. d Two-alternative forced choice discrimination task of sequential pressure pulses differing by 30 mmHg. For <75% accuracy, differences were increased to 60 and 90 mmHg. Aβ-deafferented participants (N = 2) were significantly poorer than controls (N = 8) at 30 mmHg differences (chance = 50%; one-sided permutation test *p = 0.02) and remained unable to discriminate 90 mmHg differences. Bars display median ratings and interquartile intervals. e Cartoon depicting the standard manual blood pressure cuff used to obtain pressure thresholds. f A blood pressure cuff (e) was inflated on the calf until first report of pressure sensation, then pain. Both thresholds were elevated in Aβ-deafferented participants (N = 2) compared to controls (N = 8) (pressure threshold one-sided permutation test * p = 0.02; pressure pain threshold one-sided permutation test p = 0.06). Bars display mean ratings and SD. g To examine pressure perception over a smaller surface area, a pressure algometer was pressed on the left thumbnail. h The experimenter gradually increased algometer pressure from 0 kg/cm². Participants reported first perception of pressure (pressure threshold) or pain (pressure pain threshold). The pressure detection threshold was higher in Aβ-deafferented participants (N = 1) than in healthy controls (N = 8) (one-sided permutation test p = 0.11), but pressure pain thresholds did not differ significantly (N = 2 patients and 8 controls) (one-sided permutation test p = 0.38). Bars display median ratings and interquartile intervals.