Persistent Hyperschematia With Over-Generation Following Recovery From Unilateral Spatial Neglect: A Case Report

Hyperschematia is characterized by excessive representation of left-sided space and typically improves alongside unilateral spatial neglect (USN). The role of white matter disconnection, particularly involving ventral visual pathways, in the persistence of hyperschematia remains poorly understood. We report a case of a 44-year-old right-handed man who developed USN following a right putaminal hemorrhage. While his USN symptoms improved with rehabilitation, he exhibited persistent hyperschematia characterized by a unique "over-generation" phenomenon, where he produced excessive elements in drawing tasks (e.g., additional flower petals and clock numbers). Notably, this occurred without accompanying asomatognosia. Neuroimaging and disconnection analysis revealed significant disruption of the inferior fronto-occipital fasciculus (IFOF) and middle longitudinal fasciculus (MdLF), suggesting impairment of ventral visual processing pathways. The Behavioural Assessment of the Dysexecutive Syndrome (BADS) indicated executive dysfunction, particularly in tasks requiring feature monitoring and boundary maintenance. While the patient showed improvement in spatial awareness on the Catherine Bergego Scale, the "over-generation" phenomenon persisted throughout the rehabilitation period. This case suggests that hyperschematia can persist independently of USN recovery and without body schema disturbances. Ventral pathway disruption may impair integration between visual object processing and frontal monitoring systems, contributing to persistent over-generation. These findings highlight potential neural mechanisms underlying hyperschematia and inform targeted rehabilitation strategies.