A Cross-Sectional Observational Study Testing Reliability and Validity for Tactile Acuity with Grid Localization in Healthy Patients

Grid localization is a newer method to determine tactile acuity in individuals. To date the reliability of this testing is unknown. The primary objective of the study is to develop a standardized testing procedure with grid localization testing and establish inter-rater reliability for the tactile acuity testing. Secondary aim is to establish norms and minimal detectable changes for grid localization for the study population. The final secondary aim was to compare the more established measurement of tactile acuity of two-point discrimination (TPD) to the newer method of grid localization in healthy pain free individuals. Design Use of a cross sectional observational study for reliability testing of procedure. Methods Testing was conducted in one session. Individuals exposed the skin to their back while lying in the prone position. One researcher tested TPD with ascending and descending methods at spinal level L3. Two other researchers performed grid localization testing on the low back utilizing a 4x3 grid with 5 cm blocks and the use of 10 random tactile touches within the various blocks. Measurement was recorded for accuracy of tactile touch locations. Results 36 participants (female = 27) were studied. The ICC value for grid average measures was 0.735, with a MDD at the 95% confidence interval of 29%. Average correct for all individuals between the two testers was 78% (SD=20%) for grid localization. Pearson\u27s r data analysis revealed no significant correlation between TPD and either grid localization measurements. Conclusion Grid localization demonstrated good inter-rater reliability. It did not demonstrate any significant correlation to two-point discrimination, so it may be assessing a different form of tactile acuity in individuals compared to two-point discrimination