Snell studies how the human brain processes language. His research focuses primarily on visual language processing, or reading.
In the project Preserving reading ability in macular degeneration, he is investigating the reading brain, together with his team members from the Snell Language Lab. They are working on various issues, such as the role of attention and memory during reading, and the cause of dyslexia. They do this using various techniques, such as behavioural experiments, eye movement measurements, EEG and computer simulations.
The research is being conducted in collaboration with experts by experience and Bartiméus, a leading institute for the visually impaired. ‘In addition to testing the reading interface with patients, we are also conducting large-scale experiments with healthy subjects in which we simulate blindness using eye tracking while measuring brain activity. Simulating blindness has the advantage that we can fully control the experiment, allowing us to systematically uncover the relationship between different degrees of blindness and cognitive processes.’
Macular degeneration
Macular degeneration (MD) is a common type of blindness that mainly leads to loss of central vision. This hinders many daily tasks, particularly reading ability. 'In this Vidi project, we are testing a new reading interface designed to maintain reading ability in MD. The interface automatically adapts to the individual reader by continuously adjusting various parameters (e.g. number of words on the screen, word locations, text size, contrast) while tracking reading speed. This should maximise the effectiveness of the interface, regardless of the disease progression, which varies greatly in MD,' says Snell.
Objectives of the research
Scientists have been studying how the brain reads for a century and a half. Although there are now several valuable theories about visual language processing, there is also a major shortcoming: all theories assume healthy eyes. But what if that is not the case? One in forty people will sooner or later develop macular degeneration (MD), which particularly impairs reading ability. Snell explains: ‘The desired outcome of the research is, on the one hand, that patients can continue to read and, on the other hand, that we arrive at a more complete theory of the reading brain, which does not only apply to readers with healthy eyes, but to all readers.’