FMRI correlates of apraxia in Parkinson's disease patients OFF medication

► Exploring limb-kinetic apraxia in Parkinson's disease is possible using fMRI. ► Impaired dexterity in PD is related to typical fMRI activation of perirolandic area. ► Postcentral underactivation of perirolandic area is associated with apraxia in PD. ► The “perirolandic index” as a potential imaging marker of limb-kinetic apraxia in PD.