Patients who are blind in one side of their visual field benefit from presentation of sounds on the affected side. After passively hearing sounds for an hour, their visual detection of light stimuli in the blind half of their visual field improved significantly.
Neural pathways that simultaneously process information from different senses are responsible for this effect. “We have embarked on a whole new therapy approach” says PD Dr. Jörg Lewald from the RUB’s Cognitive Psychology Unit.
Together with colleagues from the Neurological University Clinic at Bergmannsheil (Prof. Dr. Martin Tegenthoff) and Durham University (PD Dr. Markus Hausmann), he describes the results in PLoS ONE.
Passive listening rather than extensive visual training
To investigate the effectiveness of the auditory stimulation, the research team carried out a visual test before and after the acoustic stimulation. Patients were asked to determine the position of light flashes in the healthy and in the blind field of vision. While performance was stable in the intact half of their field of vision, the number of correct answers in the blind half increased after the auditory stimulation. This effect lasted for 1.5 hours. “In other treatments, the patients undergo arduous and time-consuming visual training” explains Lewald. “The therapeutic results are moderate and vary greatly from patient to patient. Our result suggests that passive hearing alone can improve vision temporarily.”
The origin of visual field defects
If strokes or injuries cause damage to the area of the brain that processes the information of the visual sense, this results in a visual field defect. The area most commonly affected is the primary visual cortex, the first processing point for visual input to the cerebral cortex. The more neurons die in this brain area, the bigger the visual deficit. Usually the entire half of the visual field is affected, a condition known as hemianopia. “Hemianopia restricts patients immensely in their everyday life” says Lewald. “When objects or people are missed on the blind side, this can quickly lead to accidents.”
How the brain integrates sensory information
“There is increasing evidence that processing of incoming sensory information is not strictly separated in the brain”, says Lewald. “At various stages there are connections between the sensory systems.” In particular the nerve cells in the so-termed superior colliculus, part of the midbrain, process auditory and visual information simultaneously. This area is not usually affected by visual field defects, and thus continues to analyse visual stimuli. Therefore, remaining visual functions are retained in the blind half, which the patients, however, are not aware of. “Since the same nerve cells also receive auditory information, we had the idea to use acoustic stimuli to increase their sensitivity to light stimuli” says Lewald.
New research issues
The team of researchers now aims to further refine their therapy approach in order to reveal sustained improvement in visual functioning. They will also investigate whether the stimulation of the sense of hearing also has an effect on more complex visual functions. Finally, they aim to explore the mechanisms that underlie the effect observed.
J. Lewald, M. Tegenthoff, S. Peters, M. Hausmann (2012): Passive auditory stimulation improves vision in hemianopia, PLoS ONE, doi: 10.1371/journal.pone.0031603
Further informationPD Dr. Jörg Lewald, Department of Psychology at the Ruhr-Universität, 44780 Bochum, Germany, Tel.: +49/234/32-25137
firstname.lastname@example.orgProf. Dr. Martin Tegenthoff, Neurological Clinic and Outpatients’ Clinic, BG University Hospital Bergmannsheil, 44789 Bochum, Germany, Tel.: +49/234/3026809
Click for moreLink to the full text article
Plasmonic biosensors enable development of new easy-to-use health tests
14.12.2017 | Aalto University
ASU scientists develop new, rapid pipeline for antimicrobials
14.12.2017 | Arizona State University
MPQ scientists achieve long storage times for photonic quantum bits which break the lower bound for direct teleportation in a global quantum network.
Concerning the development of quantum memories for the realization of global quantum networks, scientists of the Quantum Dynamics Division led by Professor...
Researchers have developed a water cloaking concept based on electromagnetic forces that could eliminate an object's wake, greatly reducing its drag while...
Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.
To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...
The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.
Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...
With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong
Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...
11.12.2017 | Event News
08.12.2017 | Event News
07.12.2017 | Event News
14.12.2017 | Health and Medicine
14.12.2017 | Physics and Astronomy
14.12.2017 | Life Sciences