The objective of this study is to evaluate the usefulness of a cortical visual prosthesis based on intracortical microelectrodes to provide a limited but useful sense of vision to profoundly blind. This pilot study will provide important information on safety and efficacy for the development of an useful cortical visual neuroprosthesis for the blind.
Visual impairment is one of the ten most prevalent disabilities and poses extraordinary challenges to individuals in our society, which is heavily dependent on sight. Drug development and genetic engineering have had only marginal success as possible treatments but new hope has been generated by recent advances in neuroscience, micro-fabrication technologies, biomaterials, neuromorphic engineering and information and communication technologies leading to the development of highly sophisticated neural prosthetic devices which interact with the nervous system. Such assistive devices have already allowed thousands of deaf patients to hear sounds and acquire language abilities and the same hope exists in the field of visual rehabilitation. Several research groups worldwide are engaged in attempts to restore vision through retinal prosthesis. However these devices are not viable for all causes of blindness. Thus, if the communication link between eye and brain is destroyed (e.g. for Glaucoma or optic nerve atrophy), as is the case for 148 million people worldwide, then visual cortical prosthesis holds the dominant hope for visual restoration. Consequently, there are many compelling reasons to pursue the development of a cortical prosthesis capable of restoring some useful vision in profoundly blind patients and this approach may be the only treatment available for end-stage retinitis pigmentosa patients and for pathologies such as glaucoma optic atrophy, trauma to the retina and/or optic nerves, and for diseases of the central visual pathways due to brain injuries or stroke. The investigators will implant the CORTIVIS vision neuroprosthetic system, which utilizes a FDA cleared microelectrode array, into blind human volunteers and obtain descriptive feedback about visualized percepts. The experiments are designed to learn if volunteers can learn to integrate the electrical stimulation of brain visual areas into meaningful percepts. It is expected that a cortical device can create truly meaningful visual percepts that can be translated into functional gains such as the recognition, localization and grasping of objects or skillful navigation in familiar an unfamiliar environments resulting in a substantial improvement in the standard of living of blind and visually impaired persons. All the experiments will be carried out at the patient's hospital room (Hospital IMED Elche) during the post-surgical period or in a human psychophysical laboratory (University Miguel Hernández).
Study Type
INTERVENTIONAL
Allocation
NA
Purpose
OTHER
Masking
NONE
Enrollment
5
The surgical method for the implantation of the intracortical microelectrodes is straightforward and follows the standard neurosurgical procedures. Briefly, after the scalp is prepped with an antiseptic, a small skin incision is made. Then the skin and muscles are lifted off from the bone and folded back. Next, one small burr hole or a minicraniotomy of approximately 1.5 cm is made in the skull. This is a minimally invasive procedure that allows an easy access to the brain and is a standard procedure widely used in neurosurgery.
Hospital IMED Elche
Elche, Alicante, Spain
RECRUITINGUniversidad Miguel Hernandez de Elche
Elche, Alicante, Spain
RECRUITINGThresholds of visual perceptions elicited by intracortical microstimulation
Charges needed for eliciting visual perceptions through electrical stimulation of the human cortex
Time frame: Within implantation period (up to 6 months)
Phosphene mapping
Location of induced perceptions within the visual field by pointing with the finger where the phosphene is perceived
Time frame: Within implantation period (up to 6 months)
Visual Acuity
Spatial resolution measured by computerized visual tests
Time frame: Within implantation period (up to 6 months)
Motion perception
Correct perception of movement with a coarse pattern moving in one of four directions
Time frame: Within implantation period (up to 6 months)
Visual function
Effectiveness of intracortical microstimulation to recognize letters, habitual objects and complex stimulation patterrns as measured by a suite of visual function tests. Questionnaire.
Time frame: Within implantation period (up to 6 months)
Number of participants with significant adverse events.
Complications and adverse events will be assessed through participant description of any possible adverse event, neurological examination, clinical tests and a specific questionnaire.
Time frame: Within implantation period (up to 6 months)
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