Department of Physiology, M.S. Ramaiah Medical College and Hospital, Bangalore, Karnataka, India.
Neurol Neurochir Pol. 2009 Sep-Oct;43(5):439-45.
Traditionally, vision has been considered the dominant modality in our multi-sensory perception of the surrounding world. Sensory input via non-visual tracts becomes of greater behavioural relevance in totally blind individuals to enable effective interaction with the world around them. These include audition and tactile perceptions, leading to an augmentation in these perceptions when compared with normal sighted individuals. The objective of the present work was to study the index finger somatosensory evoked potentials (SEPs) in totally blind and normal sighted individuals.
SEPs were recorded in 15 Braille reading totally blind females and compared with 15 age-matched normal sighted females. Latency and amplitudes of somatosensory evoked potential waveforms (N9, N13, and N20) were measured.
Amplitude of N20 SEP (a cortical somatosensory evoked potential) was significantly larger in the totally blind than in normal sighted individuals (p < 0.05). The amplitudes of N9 and N13 SEP and the latencies of all recorded SEPs showed no significant differences.
Blindness has a profound effect on the Braille reading right index finger. Totally blind Braille readers have larger N20 amplitude, suggestive of greater somatosensory cortical representation of the Braille reading index finger.
传统上，视觉一直被认为是我们对周围世界多感官感知的主导模态。在完全失明的个体中，通过非视觉束的感觉输入对于与周围世界进行有效互动变得更为重要。这些输入包括听觉和触觉感知，从而导致与正常视力个体相比，这些感知得到增强。本研究的目的是研究全盲和正常视力个体的食指体感诱发电位（SEP）。
在 15 名盲文阅读的全盲女性和 15 名年龄匹配的正常视力女性中记录 SEP。测量体感诱发电位波形（N9、N13 和 N20）的潜伏期和振幅。
全盲个体的 N20 SEP（皮质体感诱发电位）振幅明显大于正常视力个体（p<0.05）。N9 和 N13 SEP 的振幅以及所有记录的 SEP 的潜伏期均无显著差异。
失明对盲文阅读右食指有深远的影响。全盲盲文阅读者的 N20 振幅较大，提示盲文阅读食指的体感皮质代表更大。
