Directeur : Mr S. PERREY (PR).
Improving Usability in Human Computer Interfaces: an investigation into cognitive fatigue and its influence on the
performance of hybrid brain computer interfaces
Presented by Gérard Derosière
06/14/2012
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I. Supervisors of the project and partners
Codirection in the context of a PhD thesis :
Supervisors Partners Specifities / Competences Logo
Tomas Ward
Department of Electronic
Engineering, National University of Ireland
Maynooth.
Specialized in the development of Brain
Computer Interfaces (BCIs).
Stéphane Perrey
Movement to Health (M2H) Laboratory,
Montpellier 1 University.
Understanding of the cerebral correlates during :- A motor task with fatigue
occurrence;- The cognitive tasks.
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II. Introduction
Brain-Computer Interfaces (BCIs): allow the control of an electrical system without
voluntary movement needed, just by the mean of the cerebral activity (Gouy-Pailler, 2010).The user have to :- Do mental imagery or mental arithmetic;- Focus his attention to a light.
How is it possible?
These tasks require sustained attention.
One main characteristic of the sustained attention:
The time-on-task (TOT) effect.
Characterized by:
- A progressive decrease of the attentional resources with time measured through the increase of the reaction times (RTs) (Lim et al., 2010);
- A modification of the cerebral activation (e.g., Paus et al.,
1997) non-stationarity.
Attentional resources
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II. Introduction
TOT effect must be reduced during the use of a BCI for 2 reasons:
- Decrease of attentional capacities exhaustion, inability to use the BCI;
- Modification of cerebral activation ↓ of classification accuracy.
Proposed solutions (Baï et al., 2010): to develop BCIs requiring minimal training, and thus, less mental load
Pfurtscheller et al. (2010): the hybrid BCIs (hBCIs) allow to enhance classification accuracy.Allison et al. (2010): development of a simultaneous hBCI. Event-Related Desynchronization (ERD): mental imagery. Steady-State Visual Evoked Potential (SSVEP): focalization of attention to a light.
Enhancement of the classification accuracy in the simultaneous condition.
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III. Definition of the problematic
Summary
BCIs require sustained attention;
Sustained attention is characterized by a "Time-On-Task" effect; TOT effect must be reduced during the use of a BCI; A new type of BCI to enhance classification accuracy: the simultaneous hBCI;
Incompatibility between simultaneous hBCI and the aim to reduce TOT effect.
Questions:
- Does the simultaneous condition generate an early TOT effect?
- If so, is it linked to an early modification of the cerebral activation?
- Finally, does it generate an early decrease of the classification accuracy?
Simultaneous hBCIs require divided attention the mental load = higher than a simple
condition.
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IV. Proposed protocol
PASAT PASAT PASAT PASAT
RTs RTs RTs RTs
...
Time
RTs RTs RTs RTs
...
Time
SSVEP SSVEP SSVEP SSVEP
...
Time
SSVEP + PASAT SSVEP + PASAT SSVEP + PASAT SSVEP + PASAT
RTs RTs RTs RTs
Session 2: Steady State Visual Evoked Potential (SSVEP) only
Session 3: hybrid condition
Session 1: Mental arithmetic onlyPASAT: Paced Auditory Serial Addition Test (mental arithmetic task).RTs: Reaction times.
Concomitant measurements:Electroencephalography (EEG), functional NIRS. Subjective aspects of fatigue.
Classification accuracy tested in the three conditions, in a monomadal and multimodal manner.
RTs
RTs
RTs
Comments:
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V. Expected results and conclusion
Expected results:
RTs
TOT
SSVEP + Mental arithmetic
Mental arithmetic
SSVEP
SSVEP + Mental arithmetic
Mental arithmetic
SSVEP
TOT
Classification accuracy
Project partly financed by the LABEX NUMEV this will conduct to new development for pathological people.
Classification accuracy
TOT
Multimodal (EEG+fNIRS)
Monomodal fNIRS
Monomodal EEG
Tested in the three conditons:
Directeur : Mr S. PERREY (PR).
Thank you for your (sustained) attention.