How visual and auditory inputs affect the tactile detection of the hand: A study on healthy individuals

Introduction: The objective of this study is to undertake a comparative analysis of the values obtained from the Semmes-Weinstein Monofilament Test (SWMT) when conducted with the eyes open, eyes closed, and in a noisy environment, in a sample of healthy individuals. Methods: The SWMT was applied to 70 healthy individuals with a mean age of 29.0 ± 10.51 years under three conditions: eyes open, eyes closed, and in a noisy environment. The first, second, and fifth fingertips of the subjects were evaluated, with the dominant and non-dominant hands being considered separately. The evaluations conducted with the eyes open and eyes closed were carried out in a quiet environment. The evaluation conducted with the individual’s eyes open was performed with a screen. In the test conducted in a noisy environment, the participants’ eyes were kept open. Results: The median SWMT values were #2.83 for all tested distal phalanx palmar surfaces in both dominant and non-dominant hands. It was determined that the tests performed with eyes closed on the thumb of the dominant hand gave better results than the tests performed with eyes open (p < 0.01). No statistically significant differences were detected between noisy and quiet testing conditions across the tested sites. Discussion: Visual deprivation can enhance tactile detection in healthy individuals. We highlight the significance of visual input in tactile assessments and propose that visual manipulation may serve as a promising approach in somatosensory re-education.