METHODS: Static 2-point discrimination and palpation thresholds of the skin in the dominant index finger were measured in 102 subjects taken from the first and final years of a chiropractic degree/masters course and practicing field chiropractors. Two-point discrimination measurements were obtained by applying modified electronic engineering calipers mounted on a lever arm, which allowed the points to be lowered onto the skin at a constant rate and pressure. Palpation measurements were made by locating a nylon monofilament under a variable number of sheets of paper held in a purpose-designed frame. Paper thickness was measured by using electronic engineering calipers. Differences in the 2-point discrimination and palpation threshold measurements recorded between cohorts were analyzed by using 1-way analysis of variance (ANOVA) and Tukey-Kramer multiple comparison tests.
RESULTS: A statistically significant reduction was observed in 2-point discrimination thresholds between first-year (control group) and fifth-year chiropractic students (P <.001) but not between the control group and the practicing field chiropractors. A progressive increase was observed in palpatory sensibility, as determined by the thickness of paper through which the nylon monofilament could be felt, from first-year chiropractic students to practicing field chiropractors. A significant difference in palpatory threshold was also found between first year students and chiropractors (P <.05). Although both 2-point discrimination and palpatory discrimination thresholds were different between groups, no statistically significant correlation could be made to link statically recorded 2-point discrimination acuity with palpatory sensibility.
CONCLUSION: These investigations support previous research that 2-point discrimination improved through the chiropractic training program at the Anglo-European College of Chiropractic but that this appeared not to be retained into field practice. However, the changes in palpatory ability were maintained and improved on in professional practice, suggesting that 2-point discrimination thresholds do not provide a good measure of palpatory ability.
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