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Simultaneous Recording of Electroretinography and Visual Evoked Potentials in Anesthetized Rats
Published on: July 1, 2016
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Introducing chaotic codes for the modulation of code modulated visual evoked potentials (c-VEP) in normal adults for
Zahra Shirzhiyan1,2, Ahmadreza Keihani1,2, Morteza Farahi1,2
1Medical Physics & Biomedical Engineering Department, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran.
Plos One
|March 7, 2019
Summary
New chaotic codes for brain-computer interfaces (BCI) show similar accuracy to m-sequences but significantly reduce user fatigue. These findings offer a more comfortable BCI experience for users.
Area of Science:
- Neuroscience
- Biomedical Engineering
- Signal Processing
Background:
- Code modulated Visual Evoked Potentials (c-VEP) brain-computer interfaces (BCI) commonly use m-sequences.
- Subjective user fatigue is a significant limitation with current m-sequence based c-VEP BCI.
Purpose of the Study:
- Introduce and evaluate novel chaotic codes as an alternative to m-sequences in c-VEP BCI.
- Compare the decoding accuracy and subjective fatigue levels of chaotic codes versus m-sequences.
Main Methods:
- Generated chaotic codes from a one-dimensional logistic map and compared them with 31-bit m-sequence codes.
- Conducted a c-VEP study with 44 normal subjects, recording EEG signals.
- Utilized Canonical Correlation Analysis (CCA) and Spatiotemporal Beamforming (STB) for decoding and compared subjective fatigue using a Visual Analog Scale (VAS).
Main Results:
- Chaotic codes were successfully decoded from EEG signals using CCA and STB methods.
- Maximum accuracies achieved were comparable for both chaotic (93.6 ± 11.9%) and m-sequence codes (94 ± 14.4%) using STB.
- A significant reduction in subjective fatigue was reported for chaotic codes compared to m-sequence codes.
Conclusions:
- Chaotic codes offer a viable alternative to m-sequences in c-VEP BCI, providing similar performance.
- The use of chaotic codes can significantly mitigate user fatigue, enhancing the usability of c-VEP BCI systems.
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