<p>According to a review by <a href="http://www.tcts.fpms.ac.be/biomed/private/papers/croft_barry00.pdf" rel="nofollow noreferrer">Croft &amp; Barry (2000)</a>, a number of possible methods exist to prevent, or reject ocular artifacts in the EEG;</p>

<p><strong>Prevention/reduction of artifact instances</strong></p>

<ul>
<li>Recording with eyes closed -<br>
A very effective method, but eye closure alters the EEG, <em>e.g.</em>, it increases <a href="http://neurosky.com/2015/05/greek-alphabet-soup-making-sense-of-eeg-bands/" rel="nofollow noreferrer">alpha band activity</a>;</li>
<li>Let subjects fixate on a target -<br>
Method reduces blinks, but does not eliminate them.</li>
</ul>

<p><strong>Rejection</strong>  </p>

<ul>
<li>Exclude trials with amplitudes larger than, <em>e.g.</em>, 50 microV  -<br>
Method works only with a trial-based approach; artifacts below criterion level will remain.</li>
</ul>

<p><strong>Reduction</strong></p>

<ul>
<li>Subtract a certain standard voltage when an artifact occurs  -<br>
A crude method;</li>
<li>Online attenuation of the EEG signal when an artifact is detected  -<br>
Works better as the former technique, but is still crude;</li>
<li>Regression techniques where different electrodes are used to estimate the artifact component in other electrodes  -<br>
A more sophisticated method with apparently good results. </li>
</ul>

<p>For details I refer to <a href="http://www.tcts.fpms.ac.be/biomed/private/papers/croft_barry00.pdf" rel="nofollow noreferrer">Croft &amp; Barry (2000)</a> and the primary literature cited therein.</p>

<p><sub><strong>Reference</strong><br>
<strong>-</strong> <a href="http://www.tcts.fpms.ac.be/biomed/private/papers/croft_barry00.pdf" rel="nofollow noreferrer">Croft &amp; Barry <em>Neurophysiol Clin</em> (2000); <strong>30</strong>: 5-19</a></sub></p>

CC BY-SA 3.0
2017-02-16T09:26:52.477Z
2017-02-16T09:26:52.477Z
AliceD
<p>Is there any way to remove ocular artifacts from an EEG signal, other than applying independent <a href="https://en.wikipedia.org/wiki/Independent_component_analysis" rel="nofollow noreferrer">component analysis</a>, or manual rejection?</p>

<eeg><signal-processing>
What are the methods to reject ocular artifacts in the EEG?
Hanish Kataria
# What are the methods to reject ocular artifacts in the EEG?

(Asked by: username_0 on 2017-02-09)

Is there any way to remove ocular artifacts from an EEG signal, other than applying independent [component analysis](https://en.wikipedia.org/wiki/Independent_component_analysis), or manual rejection?

**Tags:** eeg, signal-processing


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## 1 answers

### Answer by username_1 on 2017-02-16. Score: 2 | Accepted answer

According to a review by [Croft & Barry (2000)](http://www.tcts.fpms.ac.be/biomed/private/papers/croft_barry00.pdf), a number of possible methods exist to prevent, or reject ocular artifacts in the EEG;

**Prevention/reduction of artifact instances**

* Recording with eyes closed -  
  A very effective method, but eye closure alters the EEG, *e.g.*, it increases [alpha band activity](http://neurosky.com/2015/05/greek-alphabet-soup-making-sense-of-eeg-bands/);
* Let subjects fixate on a target -  
  Method reduces blinks, but does not eliminate them.

**Rejection**

* Exclude trials with amplitudes larger than, *e.g.*, 50 microV -  
  Method works only with a trial-based approach; artifacts below criterion level will remain.

**Reduction**

* Subtract a certain standard voltage when an artifact occurs -  
  A crude method;
* Online attenuation of the EEG signal when an artifact is detected -  
  Works better as the former technique, but is still crude;
* Regression techniques where different electrodes are used to estimate the artifact component in other electrodes -  
  A more sophisticated method with apparently good results.

For details I refer to [Croft & Barry (2000)](http://www.tcts.fpms.ac.be/biomed/private/papers/croft_barry00.pdf) and the primary literature cited therein.

**Reference**  
**-** [Croft & Barry *Neurophysiol Clin* (2000); **30**: 5-19](http://www.tcts.fpms.ac.be/biomed/private/papers/croft_barry00.pdf)


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