Measurement of engagement and cortical reorganization in brains of stroke patients via electroencephalography (eeg) as a result of visual feedback therapy
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Date
2018-05
Authors
Law, Khuan Foo
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Abstract
In line with recent advancement in medical field, there are various innovations
in the stroke rehabilitation field in order to reduce the boredom of patients while
enhancing their participation in the repetitive rehab exercises. This includes the visual
feedback therapy. Besides, the measurement of the state of brains before and after rehab
is important in monitoring the recovery of patients. This research covers two major
aspects, the influence of the goal-oriented visual feedback rehab system on the
engagement of stroke patients in their rehabilitation exercises, as well as the design of
brain functional recovery quantification algorithm via Electroencephalography (EEG).
EMOTIV EPOC+ is the EEG device used in this research to quantify engagement index
as well as the brain functional recovery through its recorded EEG signals.
An experiment is carried out on five healthy subjects using an iLLSRM rehab
machine with and without visual feedback display. Engagement index (EI) is measured
using formula 𝑬𝑰 =𝛃𝛂+𝛉. At the end of the experiment, the mean value of engagement
index of healthy subjects using this machine with visual feedback was found 24.53%
higher than without visual feedback. This indicated that the use of visual feedback can
help stroke patients to be more engaged during the rehab session and hence
strengthening the neuromotor pathways. For the brain functional recovery
quantification, coherence values are computed among the EEG signals recorded from
electrodes lying above motor cortex. The system is then compared with the established
technique based on the functional magnetic resonance imaging (fMRI). From the
results, the resting-state EEG beta coherence index of healthy subjects was found to be
0.494±0.0591, whereas the average fMRI functional connectivity between left and right
primary motor areas of healthy subjects was 0.537±0.0958. The percentage difference
was only 8.01% and this shows that the two methods are comparable. Hence, it is
deduced that EEG is capable to be used as an alternative to fMRI in quantifying the
brain functional recovery. For the future work, a clinical trial will be carried out to
involve stroke patients in assessing the efficacy of the visual feedback treatment in
facilitating stroke recovery as well as to further validate the reliability of EEG brain
beta coherence index throughout their recovery processes.