Mental imagery after stroke: an exploratory study to investigate the relationship with cognitive and motor performance during rehabilitation

Introduction: Mental imagery (MI) is a crucial cognitive process involved in planning, memory, and motor skill rehearsal. While MI training has shown promise in stroke rehabilitation, research on MI ability and its impairment in stroke patients, particularly concerning its relationship with cognitive and motor performance, remains limited. This exploratory study aimed to describe MI ability in stroke patients during early rehabilitation and investigate its relationship with cognitive functioning, and to explore if MI can predict motor and cognitive outcomes. Methods: Thirty sub-acute stroke patients (within three months of onset) were recruited. Participants underwent neuropsychological assessment using the Mental Imagery Test (MIT), Mental Performance in Stroke (MEPS), Frontal Assessment Battery (FAB), Token Test (TT), and Vividness of Visual Imagery Questionnaire (VVIQ). Clinical variables and functional outcomes (Barthel Index at admission and discharge) were also collected. Statistical analyses included univariable associations and multiple linear regression models to assess the impact of MI on MEPS, FAB, and Barthel Index-derived measures (ΔBI, Rehabilitation Efficiency (REy), and Rehabilitation Effectiveness (REs)), controlling for relevant covariates. Results: The study found a significant positive correlation between MIT scores and overall cognitive performance as measured by MEPS (β = 0.48, t(21) = 2.64,p =.015) and FAB (β = 0.57,t(21) = 3.79,p =.001). This suggests that better MI ability is associated with better general cognitive functioning and executive efficiency in stroke patients. Further analysis revealed that the association with MEPS was primarily driven by visuo-spatial tasks. The presence of unilateral spatial neglect was found to detrimentally affect MIT performance. However, no significant relationship was found between MIT scores and any of the Barthel Index-derived measures of functional independence. Discussion: These findings indicate a strong link between general mental imagery ability and cognitive functions, particularly visuo-spatial and executive functions, in early-stage stroke rehabilitation. The lack of association with functional motor outcomes suggests that general MI tests might not be sensitive enough to predict physical recovery, possibly due to the distinction between general mental imagery and more specific motor imagery. The study highlights the importance of assessing MI ability, especially considering visuo-spatial and executive functions, before implementing imagery-based rehabilitation protocols. Further research is needed to develop individualised interventions that account for cognitive impairments in stroke patients.