Semi-automatic identification of independent components representing EEG artifact

Clin Neurophysiol. 2009 May;120(5):868-77. doi: 10.1016/j.clinph.2009.01.015. Epub 2009 Apr 3.


Objective: Independent component analysis (ICA) can disentangle multi-channel electroencephalogram (EEG) signals into a number of artifacts and brain-related signals. However, the identification and interpretation of independent components is time-consuming and involves subjective decision making. We developed and evaluated a semi-automatic tool designed for clustering independent components from different subjects and/or EEG recordings.

Methods: CORRMAP is an open-source EEGLAB plug-in, based on the correlation of ICA inverse weights, and finds independent components that are similar to a user-defined template. Component similarity is measured using a correlation procedure that selects components that pass a threshold. The threshold can be either user-defined or determined automatically. CORRMAP clustering performance was evaluated by comparing it with the performance of 11 users from different laboratories familiar with ICA.

Results: For eye-related artifacts, a very high degree of overlap between users (phi>0.80), and between users and CORRMAP (phi>0.80) was observed. Lower degrees of association were found for heartbeat artifact components, between users (phi<0.70), and between users and CORRMAP (phi<0.65).

Conclusions: These results demonstrate that CORRMAP provides an efficient, convenient and objective way of clustering independent components.

Significance: CORRMAP helps to efficiently use ICA for the removal EEG artifacts.

Publication types

  • Research Support, Non-U.S. Gov't
  • Validation Study

MeSH terms

  • Algorithms*
  • Artifacts*
  • Artificial Intelligence
  • Brain / physiology*
  • Brain Mapping / methods
  • Computer Simulation
  • Electroencephalography / methods*
  • Evoked Potentials / physiology*
  • Eye Movements / physiology
  • Heart Rate / physiology
  • Humans
  • Pattern Recognition, Automated / methods
  • Signal Processing, Computer-Assisted*
  • Software
  • Software Validation