A novel way to design rehabilitation strategies for neuro- visual disorders

Prof. Netta Levin, Dept. of Neurology, Hadassah University Hospital

There is a dramatic high incidence of visual and visual-related disorders in neurologically impaired patients (following traumatic brain injury, cerebral vascular accidents, multiple sclerosis, neurodegenerative diseases, etc.). In fact, visual-perceptual dysfunction is one of the most common devastating residual impairments of head injury. When the visual system is not working properly, there is a wide-ranging impact on our daily living activities. It is important to emphasize that although we are used to think of vision as something we can see, vision also includes how our brains interpret what we see. Unfortunately, despite the fact that almost one-third of patients suffer from visual deficits following brain damage, neuro-visual rehabilitation to compensate for visual field deficits is relatively neglected in the clinical setting. Moreover, programs that address coping with dementia usually concentrate on language, memory and cognitive skills, however often fail to address the deficits experienced by the subset of patients suffering from progressive cortico-visual dysfunction.

Prof. Netta Levin, a Senior Physician in the Department of Neurology, operates a unique Diagnostic and Rehabilitation Clinic dealing with visual disorders of cerebral source, focusing on the visual cortex area to ultimately allow neuro-visual rehabilitation. Prof. Levin and her research team (Drs. Raz, Bick and three Ph.D. candidates) are exploring how the brain compensates for visual damage by using novel imaging methods such as functional MRI (fMRI) and diffusion tensor imaging (DTI). fMRI enables a multisystem view of the brain and measures changes in the brain while different physical and mental tasks are performed. This technology enables the researchers to witness what happens in the visual cortex from the eyes all the way to the visual cortex and be able to map it and pinpoint where the damage is located. Using DTI, the research team track white matter fiber bundles and evaluate their structural integrity. By comparing cohorts of patients and control subjects, they are able to evaluate/diagnose the outcome of localized white matter damage in the entire visual pathway. fMRI and DTI, as well as other neuro-anatomical findings are then compared with patients’ clinical symptoms in order to understand the neuroanatomical basis of the clinical deficit. For instance, Prof. Levin and her research team have recently demonstrated that the impaired motion perception in patients is associated with the level of optic nerve demyelination, a condition that results in damage to the protective covering (myelin sheath) that surrounds nerve fibers in the brain and spinal cord. Demyelination was probably the cause for these temporal deficits in perception.

The brain is extremely plastic (neuroplasticity) and constantly rewires itself as it learns new tasks and adjusts to new situations as has been observed in many different levels of the visual system. With the use of high advanced tools such as fMRI, electro-physiology test and behavioral analysis, Prof. Levin is able to observe and map the residual structures in the visual cortex and reactivate/strengthen them by having patients engage in specialized training. Prof. Levin’s objective is to bridge the gap between research and the clinical setting and to design rehabilitation strategies to encourage recovery of function after different insults to the visual system.

Prof. Netta Levin is a senior physician in the Department of Neurology and leads the clinical service and the research lab in the fMRI Unit at the Hadassah Ein Kerem University Hospital. Prof. Levin graduated from the Hebrew University Medical School and specialized in Neurology. In addition, Prof. Levin holds a Ph.D. degree from the Department of Neurobiology of the Hebrew University. Her doctorate work dealt with brain reorganization following peripheral damages to the visual system. After completing her doctorate, Prof. Levin did her post-doctoratal fellowship at the Department of Psychology, Stanford University, USA, where she specialized in novel functional imaging methods. Upon her return to Israel, she established the Functional Imaging Unit. In addition to her interest in the visual system, Prof. Levin has been working in the field of imaging and functional imaging in a variety of subjects. Her work regarding brain activity in unconscious patients received widespread media attention. Her studies in the field resulted in winning the Excellence in Research at Hadassah Award, the National Multiple Sclerosis Society Research Grant Award and invitations to lecture at international conferences in Israel and abroad.