Delta oscillatory responses to somatosensory stimuli in blind humans

The aim of this study was to investigate the delta oscillatory responses to non-painful tactile stimuli for the blind subjects. The measurements were performed with thirteen blind subjects (15.07 age plusmn1.65, 10 male) and thirteen healthy subjects (15.92 age plusmn 2.90, 8 male). One type of tactile stimuli, were applied to middle finger and index finger of the right hand. The electroencephalogram (EEG) was recorded from 64 channels, 3 of which (C_Z, C₃, C₄) were primarily analyzed. Peak-to-peak maximum amplitudes and durations of delta (0.5-3.5 Hz) were measured in 1000 ms following stimuli. For the statistical analysis Wilcoxon test was used. In this present study, increases in delta (0.5-3.5 Hz) responses for non-painful tactile stimuli in blind subjects were compared with the control group. In each electrode area (C_Z, C₃, C₄) the amplitude measurements of the blind group found higher than the control group and the difference found statistically significant in C₄ electrode area (p<0.05).The durations in each electrode area (C_Z, C₃, C₄) for the blind group found statistically longer than the control group ( for each one p<0.05).