ID 221 – Disturbed eye movement control in Parkinson’s disease correlates with intrinsic functional connectivity within cortical networks

Abstract

Objective To investigate whether impaired eye movement control as a common non-motor manifestation in Parkinson’s disease (PD) is associated with alterations of intrinsic functional connectivity. Methods We recorded smooth pursuit and saccadic eye movements using video-oculography and ‘resting-state’ fMRI in 31 PD patients and 22 matched healthy controls. Eye movement parameters were correlated with functional connectivity measures in-between connectivity networks. Results In agreement with the present literature, oculomotor deficits in PD included interrupted smooth pursuit, hypometric saccades, and increased error rate in anti-saccades. We demonstrated significant correlations between eye movement parameters and functional connectivity measures, i.e. the functional connectivity declined with disturbed eye movement performance. Connectivity between major nodes of the default mode network was strongly correlated with the rate of saccadic intrusions as a measure of executive function. Conclusions Oculomotor deficits in PD appear to be predominantly associated with executive dysfunctions and to be attributable to impaired higher functional networks rather than to brainstem oculomotor circuitry. These results support the notion that dopamine depletion alone is insufficient to explain executive oculomotor abnormalities in PD. Key message Deficits in eye movement control in PD may reflect a behavioral correlate of altered intrinsic brain activity within cortical function networks.