1. BCI I: EEG-Based Cognitive Status Monitoring Scott Makeig & Tzyy-Ping Jung University of California San Diego November 13, 2007

2. Passive = Cognitive Status Monitoring (CSM) Active = Brain-Actuated control (BAC) Move the cursor Move the wheelchair Move the arm Evolve the video game Brain-Computer Interfaces (BCI) Interactive = Bio/Neurofeedback

3. Brain-Computer Interfaces DIRECT = Purely brain-based MIXED = Using a mixture of bio-signals INDIRECT = Based on EMG signals

4. DIRECT = EEG-based LFP-based Spike-based Brain-Computer Interfaces Measure = Unstimulated Evoked Induced

5. Cognitive status monitoring Possible … Attending or not attending? Encoding or not encoding? Rewarded or not? Threatened or not? Sure or unsure? Competent or incompetent? Lost or found? Currently … Alive or dead? Alert or asleep? Task loaded or overloaded?

6. Makeig & Inlow, 1993 Erratic Performance Records

7. Makeig & Inlow, 1993 Mean Performance Fluctuation Spectrum

8. Makeig & Inlow, 1993 Single Session Changes in EEG Power and Performance

9. Makeig & Inlow, 1993 Frequency (Hz) 50 Coherence 0.5 0.8 3.1 9.8 13.4 Hz Coherence of Spectral and Performance Changes Performance Cycle Length

10. Makeig & Inlow, 1993 Frequency (Hz) Correlation with Local Error Rate EEG Spectral Changes with Performance Decline are Similar for Most Subjects

11. Makeig & Inlow, 1993 EEG Spectral Changes with Performance Decline are Subject-Specific

12. Makeig & Inlow, 1993 EEG Spectral Changes are Tightly Linked to Performance Changes

13. Makeig & Jung, 1996 EEG Spectral Changes Linked to Performance Changes During Periods of Intermittent Performance Frequency (Hz) Error Rate (%) Power (dB) Pre-Hit (Cz)

14. Makeig & Jung, 1996 Frequency (Hz) Error Rate (%) Power (dB) Pre-Lapse (Cz) EEG Spectral Changes Linked to Performance Changes During Periods of Intermittent Performance

15. Makeig & Jung, 1996 Frequency (Hz) Error Rate (%) Power (dB) Lapse - Hit (Cz) EEG Spectral Changes Linked to Performance Changes During Periods of Intermittent Performance

16. Makeig & Jung, 1996 EEG Spectral Changes Around a Lapse Frequency (Hz) Target Latency (s)  Power (dB) Lapse - Hit (Cz)

17. Makeig & Jung, 1996 EEG Spectral Changes Around a Lapse  Error Rate Target Latency (s)  Power (rel. dB)

18. Makeig, Jung & Sejnowski, 2000 EEG Spectral Changes Around a Lapse  Error Rate Target Latency (s)  Power (rel. dB)

19. Cognitive Status Monitoring EEG-based alertness monitoring is possible Individualized models likely more accurate Natural EEG rhythms and time scales exist