Training Cognition With Neurofeedback After Stroke

Stroke is a major source of cognitive impairment including slowdown of processing speed, executive functions disturbances, attention and memory loss, that can lead to invisible disability, even before the ultimate stage of dementia. The traditional techniques of cognitive remediation have been reported to have a small effect, and european scientific societies stated on the need to foster research in the field of PSCI, with the goal of preventing cognitive decline. PSCI mechanisms arising from functional MRI studies include a disconnexion of brain networks, with a loss of segregation between networks and integration within networks, centered on the frontoparietal network. Rt-fMRI NF is a psychophysiological procedure of brain-machine interface enabling to a subject to learn to self-regulate his brain activity in a desired direction, based on the brain haemodynamic response. Promising results in the treatment of mental disorders have been reported using rt-fMRI NF, but data are scarce in the field of cognitive rehabilitation after stroke. Based on the mechanisms of PSCI reported in fMRI studies, the goal of the present study is to evaluate the ability of stroke patients to learn to self-regulate a brain target using rt-fMRI NF. The brain target is defined by the difference of activation between the central executive network (CEN, or frontoparietal network) and the default mode network (DMN), known to be highly anticorrelated with the CEN in the healthy brain. The experimental procedure will include four training sessions of rt-fMRI NF (1/week), preceded by a localizer session for the identification of the target networks, and followed by a tranfer session where the subjects will be asked to try to self-regulate their brain activity but without receiving feedback. A control group will perform the four fMRI sessions but without receiving feedback. The two groups will receive cognitive remediation therapy as treatment as usual. Resting state scans and diffusion tensor imaging seqences will be performed before and after the intervention, to measure the changes in functional and structural connectivity. A neuropsychological assessment will be also performed before and after the intervention, to measure the changes in cognitive performances.

• Evolution of global cognition assessed by the Montreal Cognitive Assessment (MoCA) [Time frame: Through study completion, an average of 6 weeks]
• Evolution of executive functions assessed by a composite score [Time frame: through study completion, an average of 6 weeks]
• Evolution of attentional functions assessed by the Mesulam cancellation task [Time frame: Through study completion, an average of 6weeks]
• Evolution of processing speed assessed by the Symbol Digit Modalities Test (SDMT) [Time frame: Through study completion, an average of 6 weeks]
• Evolution of memory functions assessed by the 16-item Free and Cued Recall [Time frame: Through study completion, an average of 6 weeks]
• Evolution of visuospatial functions assessed by the Rey figure [Time frame: Through study completion, an average of 6 weeks]
• Evolution of language functions assessed byt the 40-item neuropsychological semantic battery [Time frame: Through study completion, an average of 6 weeks]
• Evolution of the Central Executive Network (CEN) activity [Time frame: Through study training completion, an average of 4 weeks]
• Evolution of the Default Mode Network (DMN) activity [Time frame: Through study training completion, an average of 4 weeks]
• Evolution of activity in the whole brain [Time frame: Through study training completion, an average of 4 weeks]
• Evolution of resting state CEN and DMN activity [Time frame: Through study completion, an average of 6 weeks]
• Microstructural changes assessed by Fractional Anisotropy (FA) [Time frame: Through study completion, an average of 6 weeks]