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 +/- 1.65, 10 male) and thirteen healthy subjects (15.92 age +/- 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), C(3), C(4)) 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), C(3), C(4)) the amplitude measurements of the blind group found higher than the control group and the difference found statistically significant in C(4) electrode area (p < 0.05). The durations in each electrode area (C(z), C(3), C(4)) for the blind group found statistically longer than the control group (for each one p < 0.05).