This study was designed to compare circumference discrimination thresholds, as assessed by the Tacticon (Tacticon, Inc., Westtown, PA), a new quantitative sensory testing (QST) device, with vibratory thresholds, an assessment modality of large sensory nerve fibers, in individuals with diabetes.
In this study, 150 individuals with diabetes were evaluated. Vibratory thresholds and circumference discrimination thresholds, evaluated with the Tacticon, were determined using a two-alternative forced-choice procedure.
Vibratory thresholds increased with decreasing ability to discriminate differences in circumference (P < 0.001) for those below and above 50 years of age. Agreement between the two QST devices was assessed via the kappa-statistic in both age-groups (i.e., ≤ 50 years old [kappa = 0.67], > 50 years old [κ = 0.55]). In multiple logistic regression, where circumference discrimination thresholds were the dependent variable, age, duration of diabetes, and height were found to be independently associated for those > 50 years old.
The Tacticon offers a simple method of assessing the complex function of area discrimination. Our results suggest that the Tacticon can detect neuropathy in the primary care setting. Its cost, portability, and ease of use provide some advantages over existing QST equipment.