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

Abstract

Spatial neglect usually concerns left-sided events after right hemisphere damage. Its anatomical correlates are debated, with evidence suggesting an important role for fronto-parietal white matter disconnections in the right hemisphere. Here we describe the less frequent occurrence of neglect for rightsided events, observed in three right-handed patients after a focal stroke in the left hemisphere. Patients were tested one month and three months after stroke. They performed a standardised paper-and-pencil neglect battery and underwent brain MRI with both structural and Diffusion Tensor (DT) sequences, in order to assess both grey matter and white matter tracts metrics. Lesions were manually reconstructed for each patient. Patients presented signs of mild right-sided neglect during visual search and line bisection, as well as pathological performance in real-life situations. Structural MRI demonstrated left parietal strokes in two patients, in the region extending from the postcentral gyrus to the temporo-parietal junction. One of these two patients also had had a previous occipital stroke. The remaining patient had a left frontal stroke, affecting the precentral, the postcentral gyri and the basal ganglia. DT MRI tractography showed disconnections in the fronto-parietal regions, concerning principally the superior longitudinal fasciculus (SLF). These results suggest an important role for left SLF disconnection in rightside neglect, which complements analogous evidence for right SLF disconnection in left-side neglect.

Lesion Network Mapping for Neurological Deficit in Acute Ischemic Stroke

“…36 Previous studies proposed that neglect is sometimes presented after left hemisphere lesions affecting the right hemispace. Toba et al 37 showed that the left superior longitudinal fasciculus disconnection plays an essential role in right-side neglect. A previous randomized clinical trial showed that transcranial direct current stimulation targeting the supraorbital area is a viable therapy to improve visuospatial and functional impairments in patients with unilateral spatial neglect after stroke.…”

Listening to classical music influences brain connectivity in post-stroke aphasia: A pilot study

“…Using standard computational algorithms, fractional anisotropy (FA) was calculated in the native space and white matter (WM) tractography was then performed by following a region-of-interest (ROI) approach [13]. Specifically, on the basis of previous work on tractography in stroke patients [15][16][17], we considered the following white matter bundles: arcuate fasciculus (AF), inferior longitudinal fasciculus (ILF), inferior fronto-occipital fasciculus (IFOF), fronto-parietal superior longitudinal fasciculus (SLF), frontal aslant tract, and corpus callosum (see Additional material).…”

Brain disconnections refine the relationship between brain structure and function

“…First are articles that directly measure disconnection in the human brain in individuals with brain lesions. These analyses highlight the diversity of disconnectome research in including lesions of different etiologies (tumors, stroke, neurodegeneration) and measurements of disconnection using different modalities, including diffusion MRI, functional connectivity MRI, and EEG (Russo et al 2022;Saviola et al 2022;Gallina et al 2022;Sedghizadeh et al 2022;Godefroy et al 2022;Toba et al 2022;Zhu et al 2022;Bassignana et al 2022;Egorova-Brumley et al 2022;De Luca et al 2022). Second, are articles that indirectly measure disconnections in the brain by inferring disruptions based on imaging from large groups of healthy individuals with high-quality imaging or brain atlases (Thiebaut de Schotten et al 2015;Boes et al 2015).…”