If you ask healthy adults the loss of which one of their senses would affect their lives most, the vast majority would probably say their “sight”.
Vision is seemingly effortless. The moment you open your eyes, you are able to explore your surroundings and try to find what you are searching for. The process is highly efficient, taking very little effort both physically or mentally. The issues of ease of use and complexity of seeing however are widely apart. This seemingly effortless task relies on complex molecular structure translating light information into electric signals, transporting that signal into numerous highly specialised neuronal networks which in turn perform segmentation of the images into objects, and determine their features such as light and surface textures and colours, leading to recognition and/or interaction with the objects. When any part of this elaborate circuit is damaged, it may lead to loss of sight.
Stroke is the leading cause of brain injury and almost a third of stroke cases will result in visual deficits. There are many eye diseases that can cause blindness, but the process of their resultant vision loss is often gradual. Blindness after stroke however is both sudden and extensive. People will need to re-learn how to use their remaining sight to explore and navigate their surrounds. This process is neither easy nor intuitive. The problem is that people get stuck only searching the places they can see, very much like checking the kitchen counter for a lost set of keys, when you have already done so several times without success, and not searching the trousers pockets where the keys may be lurking!
A research programme led by Aberdeen researchers included clinicians and scientist from the US, Germany and Italy in collaboration with industrial partners have developed a rehabilitation technique aimed at retraining those with sudden sight loss to improve their eye movement efficiency, making it easier to find objects, go to supermarkets or navigate busy crossings.
In one of the largest cohort studies reported, systematic training led to faster exploration of the environment which in turn led to improved activities of daily living. An important aspect of the findings was that improvements did not depend on the age of the individual at the onset of brain injury or start of the training, their sex or side of the brain damage, indicating the wide spectrum of those who can benefit from rehabilitation.
You can read about the research here.
Professor Arash Sahraie, School of Psychology
