Advanced Perimetry for the Evaluation of Neuroplasticity in the Visual Cortex

Several studies report evidence for training-induced neuroplasticity in the visual parts of the human brain, while other studies suggest that these findings reflect methodological shortcomings such as inadequate eye fixation control rather than actual improvement. Whether neuropsychological trainings improve visual field loss after a stroke or traumatic brain injury is therefore as yet uncertain. Neuroplasticity after stroke or trauma is heavily discussed in the scientific community, which also affects the accuracy of the diagnosed extent of the visual field loss and ultimately the clinical course of affected patients. Therefore we developed a completely new paradigm for visual field diagnosis which offers a greatly improved diagnosis and therefore can answer the questions regarding neuroplasticity in the human brain. First investigations show that this new paradigm is indeed superior to existing instruments used in the research for neuroplasticity regarding visual field analysis. We are confident that this approach, using modern eye tracking and virtual reality (VR) technology, represents a both practicable and most precise method. In the present project, we will first adapt our new method to VR-hardware. In a first study we will show that the system takes individual eye movement behavior into account and uses eye-tracking to increase the diagnosis process significantly. Subsequently, the new system will be used to evaluate the therapeutical effects of neuropsychological trainings for the treatment of patients suffering from visual field loss. As a result of this research we will be able to show if neuroplasticity in the visual parts of the human brain indeed exists.

In an increasingly aging society, the precise diagnosis and efficient treatment of neuropsychological diseases is becoming increasingly important. The project developed a precise and objective tool for diagnosing visual field defects, which are often the result of a stroke. This diagnostic tool subsequently allowed us to examine the efficiency of a treatment method - visual restitution training - with previously unattainable accuracy and objectivity. The principle of the training is based on the repeated stimulation of remaining, healthy brain cells between the healthy and damaged parts of the visual cortex. This should lead to a gradual enlargement of the healthy portion of the visual cortex and, as a result, to a larger field of vision. We implemented the stimulation with a virtual reality device that the patients could wear on their heads. The device allowed patients to train anywhere and at any time. The patients exercised for 30 minutes daily for approximately 6 months. Despite the intensity and long duration of the training and the outstanding commitment of the patients, the training proved to be ineffective. This is an important finding because it may prevent patients from spending time and monetary resources on inefficient treatment in the future. A chance finding of the project was that patients who do not suffer from cortical blindness but from visual neglect (disorder of visual attention) may benefit from visual restitution training. In addition, the implementation of neuropsychological intervention measures in virtual reality turned out to be promising for the future.