Reliability of modified adheremeter and digital pressure algometer in measuring normal abdominal tissue and C-section scars.

OBJECTIVE: This study tested inter- and intrarater reliability of the digital pressure algometer and modified adheremeter and concurrent validity in the algometer in both normal abdominal tissue and in chronically painful C-section scars. STUDY DESIGN: Correlational Reliability/Validity. BACKGROUND: The algometer is used to measure pressure-pain threshold (PPT). The adheremeter is a tool to measure tissue extensibility. Painful abdominal scars are being treated successfully with soft-tissue techniques yet reliable measurement tools for this tissue have not been reported. METHODS AND MEASURES: 59 subjects with normal abdominal tissue were marked at a point 2 inches inferolateral to the umbilicus. Two separate testers measured PPT twice with an algometer and tissue extensibility in superior/left/inferior/right directions with a modified adheremeter. 29 subjects with painful C-section scars were marked at 2.5 cm intervals along the scar. A total of 115 points were measured in the same manner as above. C-section subjects also were asked to rate their pain using the numeric pain rating scale (NPRS). Each tester was blinded to all other measurements. RESULTS: For PPT, intraclass correlations (ICC's) ranged from 0.814 to 0.933 with a standard error of measurement (SEM) ranging from 1.65N to 5.9 N. For tissue mobility, ICC's ranged from 0.430 to 0.914; SEM ranging from 1.67 mm to 3.7 mm. All but 2 measures had ICCs that were good-excellent. Inferior glide in C-section tissues showed the least and multi-directional measurement the strongest reliability. The PPT had a moderate negative correlation (r = -0.551) with the NPRS. CONCLUSIONS: The algometer showed excellent inter- and intra-rater reliability on normal abdominal tissue and C-section scars. It showed moderate criterion validity when compared against the NPRS. The modified adheremeter showed good-excellent inter- and intra-rater reliability on both normal abdominal tissue and C-section scars. Both measures have clinical and research applications for women's health practitioners.