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

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.

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.

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.

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.