Neuroplasticity in Blind Subjects After Repetitive Tactile Stimulation

Study Overview
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Brief Summary
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Brain plasticity of cortical activity caused by repetitive tactile stimulation could have a progressive development that was from primary parietal areas, passing over parieto-occipital areas and came secondary to primary occipital areas. This process allows to understand the existence of neurons in the brain and specific areas for certain functions independent of the type of stimulation is performed. By performing repetitive tactile stimulation over a period of 3 months,using a tactile stimulator, our group will try to prove several that repetitive tactile stimulation can create cross-modality and improve recognition and localization of patterns in blind people.

Detailed Description
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The investigators will use passive repetitive tactile stimulation over a period of 3 months, one hour a day for five days a week, with vertical, horizontal and oblique lines generated randomly by a tactile stimulator. Our aim is (a) to study if repetitive tactile stimulation can create cross-modality and improve recognition and localization of patterns in blind people, (b) to evaluate the impact of this training on brain activity the investigators performed high-density scalp EEG recording during the initial stimulation session and in the last one. And (c) measure the functional connectivity of the brain with resting state MRI pre and post training. The resting state MRI protocol consist on one run of T1WI and three bold runs (TE=30ms,TR=3000ms, flip angle 90º,voxel size 3mm, 124 time points, 0 gap). Cross-modality sensory stimulation may offer a good opportunity to improve recognition, localization and navigation in blind people. Although the neural substrate of this multimodality integration is not fully understood yet. Some areas of the brain, mainly the lateral occipital cortex, are specialized for visual object recognition and they can be activated by tactile stimuli. This activation of the visual cortex might lead to visual-like perception, regardless of the sensory input modality. In the blind the high demand required by object recognition appears to recruit also ventral and dorsal occipital areas. Blindness modifies neocortical processing of non-visual tasks, including frontoparietal and visual regions during tactile stimulation. It is also known that people with blindness proficient in the use of a visuo-tactile sensory substitution device that presents visual images as patterns of electric stimuli to the subject's tongue, like Bach-y-Rita and Ptito said, show occipital cortex activation in an orientation-discrimination task. As far as the investigators know there are no studies aimed at understanding the relationship between activation of lateral occipital cortex and the ability to recognize objects presented to the hand along time. In particular, the investigators tested if repetitive passive tactile stimulation leads to activation of visual areas and recognition of spatial patterns in people with blindness.

Official Title
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Neuroplasticity in Blind Subjects After Repetitive Tactile Stimulation

Conditions
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Blindness

Intervention / Treatment
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* Other: Tactile Training


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Clinical Diagnosis: Different Causes of blindness were diverse: congenital nystagmus, glaucoma, retinopathy, congenital cataracts, lenticular fibroplasia, macular degeneration, optic atrophy, Peter's anomaly with microphthalmia, retinal detachment, retina necrosis, retinitis pigmentosa and uveitis Exclusion Criteria: No history of neurological, psychiatric, cognitive or sensorimotor deficits other than blindness.

Ages Eligible for Study
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Minimum Age: 7 Years
Maximum Age: 70 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Functional Connectivity MRI<br>Functional Connectivity will be measured by MRI, we will perform one T1WI run as well as three resting state bold based runs. Bold runs parameters: TE 30ms, TR 3000ms, flip angle 90º, gap 0mm, 124 time points, voxel size 3mm, duration 6min18s each, FOV 240x240x141. | Other: Tactile Training<br>* Tactile Training to induce neuroplasticity in the visual pathway, measured with functional connectivity MRI<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| MRI Functional Connectivity of the visual pathway | Functional Connectivity analysis (fcMRI) is a tool that allows functionally associated brain regions to be identified. fcMRI takes advantage of the observation that the brain regions exhibit spontaneous, low frequency variations as measured using blood oxygenation level-dependent (BOLD) imaging. | 1 year | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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blind, tactile stimulation, cross-modality, visual qualia, resting state MRI, functional connectivity, neuroplasticity