Influence of attention alternation on movement-related cortical potentials in healthy individuals and stroke patients

Abstract

Objective: In this study, we analyzed the influence of artificially imposed attention variations using the auditory oddball paradigm on the cortical activity associated to motor preparation/execution.Methods: EEG signals from Cz and its surrounding channels were recorded during three sets of ankle dorsiflexion movements. Each set was interspersed with either a complex or a simple auditory oddball task for healthy participants and a complex auditory oddball task for stroke patients. Results:The amplitude of the movement-related cortical potentials (MRCPs) decreased with the complex oddball paradigm, while MRCP variability increased. Both oddball paradigms increased the detection latency significantly (p<0.05) and the complex paradigm decreased the true positive rate (TPR) (p = 0.04).In patients, the negativity of the MRCP decreased while pre-phase variability increased, and the detection latency and accuracy deteriorated with attention diversion. Conclusion:Attention diversion has a significant influence on MRCP features and detection parameters, although these changes were counteracted by the application of the laplacian method.Significance: Brain-computer interfaces for neuromodulation that use the MRCP as the control signal are robust to changes in attention. However, attention must be monitored since it plays a key role in plasticity induction. Here we demonstrate that this can be achieved using the single channel Cz.

Classification of Movement Preparation Between Attended and Distracted Self-Paced Motor Tasks

“…Since these areas correspond to those of the attention networks, interference from the firing of their neurons with firing of neurons involved in motor planning and execution will lead to reduced detection accuracies. In our previous studies [23][24][25], we demonstrated that changes in attention significantly deteriorate MRCP detection in synchronous BCIs, using auditory distractors. Further, classification of different states of attention attains accuracies of 68% but only for EEG channels located over the motor cortex [25].…”

“…Central channels over the motor cortical representation of either leg or arm muscles are also optimal for detecting and classifying lower limb or upper limb movements [50][51][52]. In our previous studies [23,25], we have shown that the temporal features of MRCPs from the motor cortex were significantly influenced under attention alterations. In this way, the outputs of the central channels may be reliably used for detection of attention variations with the intent to provide appropriate neuro-feedback to the user of the BCI system.…”

“…In previous studies, we have shown that temporal features of the MRCP can detect attention diversion in a cue-based BCI [23]. Specifically, the preparation phase was significantly altered when attention was diverted [23,25] due to lower signal to noise ratio and less prominent features. Furthermore, additional components such as the P300 affected the MRCP signals and thus increased the differences between focused and diverted attention levels.…”

Effects of a dual task and different levels of divided attention on motor-related cortical potential

“…The ST and DT (S-DT and C-DT) were defined as low-, medium-, and high-load divided attention tasks, respectively. The paradigm used here is similar to that employed in previous studies [9][10][11] . This paradigm can reduce the effects of mental or cognitive fatigue 18,19) .…”

“…Highload divided attention leads to a reduction in specific features of MRCP 9,10) . For example, in stroke patients, the negativity of MRCP decreases, while pre-phase variability increases 11) .…”