Clinical Research Directory

Visual Restoration Using Focused Ultrasound Stimulation and Immersive Virtual Reality After Stroke

This research will explore if brain stimulation combined with virtual reality therapy improves visual impairment. The stimulation technique is called low-intensity focused ultrasound stimulation (LIFUS). The treatment uses ultrasound to stimulate vision specific parts of the brain. Before this therapy, the participants will get structural brain imaging. Functional brain imaging will be performed before and after the study's completion to measure brain activity response to therapy. The purpose of this research study is to evaluate patients who have had a stroke between 6 and 24 months ago with a visual field impairment. The duration of active participation in the study is 1.5 months.

Vision Loss Impact on Navigation in Virtual Reality

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).

Screening and Rehabilitation of Visual Field Defects in Post-Stroke Patients

In this study, the investigators will use a wearable device capable of performing this bedside assessment to evaluate the incidence of visual field loss in post-stroke patients. Furthermore, for those with visual field loss, the investigators will investigate whether integrating multisensory audio-visual rehabilitation into the standard physical rehabilitation protocol can help improve visual field loss compared to standard rehabilitation alone.

Mechanisms of Visual Restoration After Occipital Stroke

This project will collect brain imaging data to quantify the effects of early visual cortex damage and visual training interventions on the structure and function of the residual visual system. Our goal is to improve understanding of the consequences of permanent visual cortex damage in humans, and to understand how visual training impacts the function of the residual visual system to restore perception.

Visual Rehabilitation After Occipital Stroke

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.

New Non-invasive Modalities for Assessing Retinal Structure and Function

This study investigates a new technology to assess the structure and function inside the eye. Retinal imaging of subjects with inner and outer retinal defects to detect areas of abnormal structure and function compared to other visual function tests.

Vision on the Road: Vision Rehabilitation for Driving After Stroke

The goal of this clinical trial is to learn if vision training works to improve functional vision in people with visual field loss after stroke. The investigators want to know more about how people perceive their own functional vision and ability to compensate for visual field loss in daily activities. The main questions the study aims to answer are: * Does vision training improve dimensions of functional vision? * How does vision training affect the participants's perception of functional vision and the ability to compensate for visual field loss? Researchers will compare the effect of home-based vision training to standard care (no vision training) on functional vision. Participants will: * Participate in home-based vision training or standard care for 8 weeks * Be contacted once a week by phone * Keep a training diary

Visual Plasticity Following Brain Lesions

The VIBRANT (Vision Improvement through Behavioral Rehabilitation And Neuroplasticity Training) study is a prospective, double-blind, crossover design (within-subject) in participants with homonymous hemianopia-a type of visual field loss resulting from damage to the post-chiasmatic visual pathways. It aims to investigate whether transcranial random noise stimulation (tRNS) combined with perceptual learning-based training has potential for improving visual impairments.

Effect of Visual Retraining After Stroke

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.

Biofeedback Training for Hemianopia

This is a prospective study that compares biofeedback training on the microperimetry (BT) to a control group in patient s with hemianopia. The patients receive 5 sessions of 20 minutes to stimulate with light and sound the brain in using the best residual area on the visual fields post-brain injury visual loss. Visual tests and quality of life questionnaire are performed pre-and-post-training.

Anatomical and Functional Predictions of Blindsight Capabilities in Patients With Lateral Hemianopsia

Homonymous lateral hemianopia (HLH) is characterized by loss of vision in half the visual field, and is the most common neurovisual disorder following stroke. Numerous behavioral and neuroanatomical studies have focused on the phenomenon of blindsight, corresponding to patients' unconscious residual visual capacities in the blind hemifield. Cohort studies of patients have highlighted different types of blindsight, and a low occurrence of the phenomenon initially described: (1) type 1 blindsight (≈12%), unconscious visual abilities; (2) type 2 blindsight, visual abilities associated with sensations in the blind field (≈18%); (3) blindsense, sensations in the blind field without visual abilities (≈30%); and (4) no blindsight (≈40%). The heterogeneity of these blindsight abilities in the HLH population is closely related to patients' neuroanatomical and functional profiles. In particular, resting-state functional imaging (r-fMRI) and default mode network analysis have highlighted a significant correlation between the degree of inter-hemispheric connection (between the healthy and injured hemispheres) and the rate of spontaneous visual field recovery. To our knowledge, this degree of functional connectivity has not yet been studied in relation to blindsight abilities. However, this functional MRI measurement tool represents a potential predictive factor for patients' residual performance in their blindsight field, in order to assess the level of visuo-cognitive impairment and, ultimately, to adapt care.