EEG Reveals Alterations in Motor Imagery in People With Amnestic Mild Cognitive Impairment

Motor imagery has been used to investigate the cognitive mechanism of motor control. Although behavioral and electrophysiological changes in motor imagery in people with amnestic mild cognitive impairment (aMCI) have been reported, deficits in different types of imagery remain unclear. To explore this question, we used electroencephalography (EEG) to study neural correlates of visual imagery (VI) and kinesthetic imagery (KI) and their relationship to cognitive function in people with aMCI.

A hand laterality judgment task was used to induce implicit motor imagery in 29 people with aMCI and 40 healthy controls during EEG recording. Mass univariate and multivariate EEG analysis was applied to explore group differences in a data-driven manner.

Modulation of stimuli orientation to event-related potential (ERP) amplitudes differed significantly between groups at 2 clusters located in the posterior-parietal and frontal areas. Multivariate decoding revealed sufficient representation of VI-related orientation features in both groups. Relative to healthy controls, the aMCI group lacked accurate representation of KI-related biomechanical features, suggesting deficits in automatic activation of KI strategy. Electrophysiological correlates were associated with episodic memory, visuospatial function, and executive function. Higher decoding accuracy of biomechanical features predicted better executive function via longer response time in the imagery task in the aMCI group.

These findings reveal electrophysiological correlates related to motor imagery deficits in aMCI, including local ERP amplitudes and large-scale activity patterns. Alterations in EEG activity are related to cognitive function in multiple domains, including episodic memory, suggesting the potential of these EEG indices as biomarkers of cognitive impairment.