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Quadrantanopia clinical trials

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NCT ID: NCT06352086 Not yet recruiting - Stroke, Ischemic Clinical Trials

Understanding Visual Processing After Occipital Stroke

Start date: September 2024
Phase:
Study type: Observational

The purpose of this study is to investigate how visual orientation discrimination and metacognition (i.e., perceptual confidence) are affected by occipital stroke that causes hemianopia and quadrantanopia in adults. This research will provide insight as to how the residual visual system, which not directly damaged by the occipital stroke, processes orientation (assayed in terms of orientation discrimination) and metacognition (by measuring perceptual confidence for orientation discrimination). These measures will be used to refine computational models that attempt to explain how the brain copes with loss of primary visual cortex (V1) as a result of stroke. This knowledge is essential to devise more effective visual rehabilitation therapies for patients suffering from occipital strokes.

NCT ID: NCT06121219 Active, not recruiting - Stroke, Ischemic Clinical Trials

Effect of Visual Retraining After Stroke

urochester
Start date: May 7, 2024
Phase: N/A
Study type: Interventional

This project is intended to collect data using standard clinical tests and psychophysics to quantify the effect of visual cortical damage on the structure of the residual visual system, visual perception, spatial awareness, and brain function. The investigators will also assess the effect of intensive visual retraining on the residual visual system, processing of visual information and the use of such information in real-world situations following damage. This research is intended to improve our understanding of the consequences of permanent visual system damage in humans, of methods that can be used to reverse visual loss, and of brain mechanisms by which visual recovery is achieved.

NCT ID: NCT06047717 Recruiting - Stroke, Ischemic Clinical Trials

Vision Loss Impact on Navigation in Virtual Reality

Start date: November 28, 2023
Phase: N/A
Study type: Interventional

The purpose of this research is to better understand the impact of cortically-induced blindness (CB) and the compensatory strategies subjects with this condition may develop on naturalistic behaviors, specifically, driving. Using a novel Virtual Reality (VR) program, the researchers will gather data on steering behavior in a variety of simulated naturalistic environments. Through the combined use of computer vision, deep learning, and gaze-contingent manipulations of the visual field, this work will test the central hypothesis that changes to visually guided steering behaviors in CB are a consequence of changes to the visual sampling and processing of task-related motion information (i.e., optic flow).

NCT ID: NCT05098236 Active, not recruiting - Stroke, Ischemic Clinical Trials

Effect of Visual Retraining on Visual Loss Following Visual Cortical Damage

Start date: September 26, 2003
Phase: N/A
Study type: Interventional

This project is intended to collect data using standard clinical tests and psychophysics to quantify the effect of visual cortical damage on the structure of the residual visual system, visual perception, spatial awareness, and brain function. The investigators will also assess the effect of intensive visual retraining on the residual visual system, processing of visual information and the use of such information in real-world situations following damage. This research is intended to improve our understanding of the consequences of permanent visual system damage in humans, of methods that can be used to reverse visual loss, and of brain mechanisms by which visual recovery is achieved.

NCT ID: NCT05085210 Recruiting - Stroke Clinical Trials

Improving Visual Field Deficits With Noninvasive Brain Stimulation

Start date: January 25, 2022
Phase: N/A
Study type: Interventional

This is a randomized, pilot interventional study in participants with visual field deficit (VFD) caused by cortical lesion. Damage to the primary visual cortex (V1) causes a contra-lesional, homonymous loss of conscious vision termed hemianopsia, the loss of one half of the visual field. The goal of this project is to elaborate and refine a rehabilitation protocol for VFD participants. It is hypothesized that visual restoration training using moving stimuli coupled with noninvasive current stimulation on the visual cortex will promote and speed up recovery of visual abilities within the blind field in VFD participants. Moreover, it is expected that visual recovery positively correlates with reduction of the blind field, as measured with traditional visual perimetry: the Humphrey visual field test. Finally, although results will vary among participants depending on the extension and severity of the cortical lesion, it is expected that a bigger increase in neural response to moving stimuli in the blind visual field in cortical motion area, for those participants who will show the largest behavioral improvement after training. The overarching goals for the study are as follows: Group 1 will test the basic effects of transcranial random noise stimulation (tRNS) coupled with visual training in stroke cohorts, including (i) both chronic and subacute VFD stroke participant, and (ii) longitudinal testing up to 6 months post-treatment. Group 2 will examine the effects of tRNS alone, without visual training, also including chronic and subacute VFD stroke participants and longitudinal testing.

NCT ID: NCT04878861 Recruiting - Hemianopia Clinical Trials

Rehabilitating Visual Deficits Caused by Stroke

Start date: December 13, 2020
Phase: N/A
Study type: Interventional

This research aims to understand the efficacy of a visual training task to improve visual loss after stroke, also known as hemianopia. The investigators aim to understand whether training can improve vision and which areas or pathways in the brain are responsible for this improvement.

NCT ID: NCT04798924 Recruiting - Stroke, Ischemic Clinical Trials

Visual Rehabilitation After Occipital Stroke

Start date: July 19, 2021
Phase: N/A
Study type: Interventional

This research aims to examine changes in plastic potential of the visual system with time from stroke affecting primary visual cortex. We will measure structural and mechanistic aspects of progressive degeneration along the early visual pathways, correlating them with changes in visual performance, and in responsiveness to visual restoration training. This project will advance both scientific knowledge, as well as technical capability and clinical practices for restoring vision and quality of life for people suffering from cortical blindness.

NCT ID: NCT03350919 Completed - Hemianopia Clinical Trials

Visual Restoration for Hemianopia

Start date: March 15, 2018
Phase: N/A
Study type: Interventional

The purpose of this research is to assess the efficacy of a visual training task on reducing the size of a visual field deficit caused by brain damage in adults, and its ability to improve visual functions in this patient population.

NCT ID: NCT01418820 Completed - Stroke Clinical Trials

Paraorbital-Occipital Alternating Current Stimulation Therapy of Patients With Post-Chiasmatic Lesions

Start date: March 2011
Phase: Phase 2
Study type: Interventional

Visual field areas, which are not absolutely blind, are hypothesized to have some residual capacities that constitute their potential for vision restoration. Vision restoration can be achieved by varies methods including behavioral training and electrical brain stimulation such as transcranial direct current stimulation (tDCS) and repetitive transorbital alternating current stimulation (rtACS) which are able to influence the excitability and activity of cortical areas. It is hypothesized that transorbital alternating current stimulation (tACS) can improve the residual field of vision in patients with post-chiasmatic lesions.

NCT ID: NCT00921427 Completed - Hemianopia Clinical Trials

The Use of Transcranial Direct Current Stimulation (TDCS) to Enhance the Rehabilitative Effect of Vision Restoration Therapy

Start date: November 2007
Phase: Phase 0
Study type: Interventional

The purpose of our study is to explore the efficacy of combination of brain stimulation with visual rehabilitation in patients with visual field loss resulting from brain lesions. It is shown that the effect of sensorimotor training of hand can be enhanced in patients with stroke using brain stimulation. We decided to explore this combination for visual field loss because visual dysfunction following brain lesions is considered intractable. We hypothesize that combination of noninvasive brain stimulation, in the form of transcranial direct current stimulation (tDCS), with visual rehabilitation would have greater efficacy than visual rehabilitation alone.