Mental state classification in Alzheimer patients using classical conditioning with affective auditory stimuli: an fMRI study
(2013) Belgian Association of Psychological Sciences (28.May.2015)
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- Abstract
- We adopted a classical conditioning paradigm to assess the possibility to discriminate between affirmative (“yes”) and negative (“no”) thinking in Alzheimer’s disease (AD) patients, by associating congruent and incongruent word-pairs to pleasant and unpleasant affective stimuli respectively, in view of the development of a brain-computer interface (BCI) for the communication of basic mental states. 6 AD patients and 7 age-matched controls participated to the study. The experiment comprised 3 blocks. In the first block, all incongruent and congruent word-pairs (conditioned stimuli, CS1 and CS2) were immediately followed by pleasant (laughter) unpleasant (scream) affective stimuli (unconditioned stimuli, US1 and US2) respectively, in order to associate negative and affirmative thinking to negative and positive emotions. In the second and third blocks, only 50% of the word-pairs were followed by emotional stimulation, to verify the possibility to discriminate between the activation elicited by affirmative and negative thinking, when the emotional stimulation was no more present. A Support Vector Machine (SVM) classifier was used, focusing on insula, amygdala and anterior cingulate cortex (ACC). Following conditioning, the classifier was able to discriminate between the BOLD signal relative to congruent and incongruent word-pairs (eliciting respectively affirmative and negative thinking) with a mean accuracy of 70% for both control subjects and patients, reaching 85% in one of the patients. The encouraging results replicate findings that were previously obtained on healthy young subjects. Further developments include the implementation of an online SVM for real-time classification and experimentation with patients suffering from other kinds of dementia (e.g. frontotemporal dementia).
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Liberati, G., Dalboni da Rocha, J., Veit, R., von Arnim, C., Jenner, A., Lulé, D., Kim, S., Raffone, A., Olivetti Belardinelli, M., Birbaumer, N., Sitaram, R., & et al. (2013). Mental state classification in Alzheimer patients using classical conditioning with affective auditory stimuli: an fMRI study. Belgian Association of Psychological Sciences. https://hdl.handle.net/2078.5/258358