Bilateral Parietal Lobe Dysfunction

Balint’s syndrome 8 Patients have characteristic lesions in bilateral parietal or parieto-occipital lobes (typically part of superior parietal lobule and angular gyrus)

• May occur from invasive tumors, global cerebral hypoperfusion affecting watershed areas between middle and posterior cerebral arteries, neurodegenerative disease (PCA), or traumatic injury. Patients experience a chaotic world around them, as unreachable objects appear and disappear out of mind; may bump into objects and have difficulty eating/drinking due to difficulties reaching for food.

Comprises of three main symptoms:

• Simultanagnosia – a lost ability to comprehend more than one object in a scene. Dorsal simultanagnosia: resulting from impaired spatial awareness of more than one object, as seen in Balint’s syndrome. Ventral simultanagnosia: damage to left temporo-occipital regions (left posterior ventral cortex) resulting in alexia and impaired reporting of multiple letters

• Oculomotor apraxia – difficulty with voluntary shifting of gaze direction without evidence of paralysis. Eye movements guided by sound or touch may remain intact

• Optic ataxia – inability to point to or grasp objects under visual guidance o No difficulty when guided by sound or touch