Once again researchers don't know what cause and effect is. If you want to know what possibilities for easy recovery are you have to map out the penumbra damages, probably via PET scans.
And do they possibly think that 'cold spots' are areas of completely dead neurons? What is the solution for bringing back the function those dead areas represent?
http://www.alphagalileo.org/ViewItem.aspx?ItemId=137733&CultureCode=en
According to Study Published in Restorative Neurology and Neuroscience
Scientists know that vision restoration training (VRT) can help
patients who have lost part of their vision due to glaucoma, optic nerve
damage, or stroke regain some of their lost visual functions, but they
do not understand what factors determine how much visual recovery is
achieved.
New evidence published in Restorative Neurology and Neuroscience
suggests that vision restoration depends mostly on activity of residual
vision that is still left after the injury and that both local neuronal
activity and activity in the immediate surround influence the
development of visual recovery “hot spots.” This shows that recovery of
vision is mediated by partially surviving neurons.
Researchers from the Institute of Medical Psychology and Department
of Computer Sciences, Otto-von-Guericke-University of Magdeburg, and the
Max Planck Institute for Dynamics and Self-Organisation, Goettingen,
Germany, conducted a retrospective analysis of multiple visual field
tests before and after at least six months of VRT in 32 stroke patients
with hemianopia, which is a loss of vision in half of the visual field.
The test, known as high-resolution perimetry (HRP), presents visual
stimuli on a computer monitor to which the patient has to respond by
pressing a key on the keyboard.
The result is a map that indicates areas that are intact (unaffected
by the injury), areas that are completely blind, and “areas of residual
vision,” where vision is reduced but not absent. Here, the response time
is slower or the correct response occurs only occasionally. Repetitive
stimulation through daily one-hour vision training with VRT was directed
at these “areas of residual function” to strengthen their performance.
“Hot spots” were defined as those locations that were initially
impaired at baseline but then recovered after VRT training, while “cold
spots” remained impaired where vision training did not help. Of almost
11,000 visual spots analyzed from the 23 patients, 688 were found to be
hot spots while 3,426 were cold spots. The average absolute improvement
due to VRT training was 6%.
The investigators used computer-based data mining technology to study
which features of the baseline HRP charts obtained before vision
training could predict vision recovery. They looked at different
topographic features and found that visual field areas have a higher
probability of becoming vision restoration “hot spots” if they had
higher local residual vision at baseline, more residual activity in a
spatially limited surrounding area (of 5 degrees of visual angle), and
if they were located closer to the blind field (scotoma). Vision
restoration was not influenced much by residual activity at further
distances, say the authors.
“Our findings confirm the special role of residual structures in
vision restoration, which is likely mediated by surviving cells in
partially damaged brain tissue,” says lead author Bernhard A. Sabel,
PhD, of the Institute of Medical Psychology,
Otto-von-Guericke-University of Magdeburg. Dr. Sabel suggests that the
massive visual stimulation presented during VRT enhances visual recovery
by forcing subjects to focus their attention on “compromised” sectors
of the visual field which are partially damaged and repeating this daily
helps recover vision loss. “This new understanding now allows us to
offer vision training on the internet through online training,” says Dr.
Sabel.
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