Right-side spatial neglect and white matter disconnection after left-hemisphere strokes

Area of Science:

• Neuroscience
• Neurology
• Neuroimaging

Background:

• Spatial neglect commonly results from right-hemisphere damage, affecting left-sided awareness.
• The precise anatomical basis of spatial neglect, particularly less common forms, remains under investigation.
• Fronto-parietal white matter disconnections are implicated in spatial neglect.

Purpose of the Study:

• To investigate the neuroanatomical correlates of right-sided spatial neglect following left-hemisphere stroke.
• To describe the clinical presentation and neuroimaging findings in patients with left-hemisphere-induced right-sided neglect.

Main Methods:

• Case series of three right-handed patients with left-hemisphere stroke and right-sided neglect symptoms.
• Standardized neuropsychological testing for spatial neglect (visual search, line bisection).
• Structural and Diffusion Tensor (DT) MRI with tractography to analyze grey and white matter integrity, focusing on fronto-parietal connections like the superior longitudinal fasciculus (SLF).

Main Results:

• Patients exhibited mild right-sided neglect in visual search and line bisection tasks.
• Structural MRI revealed left parietal strokes in two patients and a left frontal stroke in one patient.
• DT MRI tractography identified disconnections within the left fronto-parietal white matter, primarily involving the superior longitudinal fasciculus (SLF).

Conclusions:

• Left-sided SLF disconnection is a significant factor contributing to right-sided spatial neglect.
• These findings complement existing research linking right-sided SLF disconnections to left-sided neglect.
• This study highlights the crucial role of interhemispheric white matter pathways in maintaining spatial awareness.