Study of Laterality Judgment and Tactile Acuity in Patients with Chronic Unilateral Shoulder Pain: A Cross-Sectional Study

Context: Cortical organization of the painful body region may be disrupted in several chronic pain conditions. The two-point discrimination test (TPDT) and the Left/Right Judgement Task (LRJT) have been used to identify changes in the cortical body schema in these conditions. Whether changes in the cortical body schema are impaired in people with chronic shoulder pain remains unknown. Aim: To study laterality judgment and tactile acuity in chronic unilateral shoulder pain patients. Materials and Method: The study included an experimental group of patients with unilateral shoulder pain and a control group of healthy relatives. Shoulder pain intensity was assessed using an 11-point scale (0-10). Tactile acuity was measured with a two-point discrimination test (precision: 1 mm). Laterality discrimination was tested using shoulder images rotated randomly (0, 90, or 180 degrees). Results: In a study of 86 subjects (mean age 49.16, 28% males, 72% females), no significant differences were found in TPDT, accuracy, or response time between affected and unaffected shoulders within Group A, or between Groups A and B. Pain intensity (NRS) did not correlate with these measures. Conclusion: Shoulder pain showed no impact on TPDT and LRJT measures. Therefore, the above study does not provide clear evidence of altered cortical organization in chronic unilateral shoulder pain. Key words: TPDT, LRJT, NRS