Stroke-related ipsilateral haemiparesis: a single-centre case series and literature review

Abstract Introduction Ipsilateral haemiparesis (ILH) in stroke is rare and challenges the conventional understanding of motor system organisation. We aim to describe ILH strokes from our academic stroke centre, complemented by a literature review. Patients and methods All patients with haemiparesis and an acute ischaemic lesion on neuroimaging were selected from 2003 to 2023 in our stroke registry. Ipsilateral haemiparesis cases were identified, and all their investigations were reviewed, including MRI tractography, functional MRI and transcranial magnetic stimulation (if performed). We also performed a review of the literature of ILH cases in ischaemic and haemorrhagic strokes. We compared selected cases with patients with contralateral haemiparesis in our local registry. Results Among 2433 acute ischaemic stroke patients with haemiparesis and unilateral, MRI-confirmed supratentorial lesions, we identified 4 ILH cases (0.16%). All 4 showed normal corticospinal tract (CST) decussation on neuroimaging, while functional MRI revealed bilateral motor activation in at least 1 upper limb. Our literature review identified 61 additional ILH cases meeting inclusion criteria. In exploratory analyses of the assembled dataset, ILH appeared more frequently reported in younger patients and those with prior stroke. Additional investigations were consistent with multiple potential mechanisms, including CST reorganisation, bilateral motor representation and CST anatomical variation. Conclusion Ipsilateral haemiparesis is a rare manifestation of acute stroke that appeared more frequently reported among younger patients and those with prior strokes. However, these findings should be interpreted cautiously given the heterogeneous nature of the data sources. Some ILH may involve corticospinal reorganisation, potentially highlighting the importance of neuroplasticity in post-stroke motor control.