Sunday, June 10, 2007

Tactile Quilts

The Quilt of Valor Foundation has asked for tactile quilts to give to blind or sight-impaired soldiers. The tactile sense training seems to help them train the brain to "see" in other ways. The reason is not fully understood, but is known as sensory substitution. This refers to the capacity of the brain to replace the functions of a lost sense by another sensory modality. The most commonly used form of sensory substitution is Braille reading which allows the blind to read by touch (somatosensory system).

So instead of just using the usual quilting cottons, the tactile quilts are made of fabrics with interesting feel: corduroy, jeans, flannel, wool (washable), linen, pleated fabric, ruched fabric. The one constant is the fabric needs to be washable. I know that one of the things I love about fabric (and yarn) shops is "touching" the fabrics. I won't buy a fabric (or yarn) if I don't like the way it "feels" to my touch.

So I tried to find more information as to how this "touch" (somatosensory system) was so important in training the vision impaired. I found a few sources, like this study done by Nicholas A. Giudice at the Minnesota Lab for Low-Vision, Center for Cognitive Sciences,University of Minnesota, it was shown that "blind participants demonstrated activation in primary visual, extrastriate and higher level visual cortices in response to tactile stimulation, whereas sighted subjects showed no such consistent "visual" activation to the same tactile stimuli. An important new finding is the observation of functionally relevant reorganization in all three blind participants. That is, while meaningful stimuli, like the Braille, embossed roman letters and tactile shapes showed the greatest and most defuse occipital activation in the blind subjects, the presentation of tactile noise alone showed little activation in these regions. In concert with this progression of salience and functional relevance is a fairly consistent pattern of areas associated with higher visual processing being activated by the more meaningful tactile stimuli across the blind participants."

Brain plasticity: from pathophysiological mechanisms to therapeutic applications. by Duffau H in J Clin Neurosci. 2006 Nov; 13 (9):885-97


The Occipital Cortex in the Blind, Lessons About Plasticity and Vision by Amir Amedi, Lotfi B. Merabet, Felix Bermpohl and Alvaro Pascual-Leone; 1Department of Neurology, Harvard Medical School, Beth Israel Deaconess Medical Center

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