The Motor Dimension of Spatial Neglect: A short review on Directional Deficits and their Clinical Relevance

Spatial neglect is an acquired and disabling neuropsychological condition whose multifaceted clinical manifestations warrant its conceptualization as a syndrome. The hallmark of spatial neglect consists of a failure to attend, perceive, or respond to stimuli located in the contralesional space or on the contralesional side of the body (Heilman et al., 1987; Vallar & Calzolari, 2018). Although spatial neglect is primarily described in perceptual-attentional terms, converging evidence indicates that it also frequently encompasses motor-intentional and executive components of spatial behavior. These latter disturbances, commonly referred to as output neglect, reflect dysfunctions in the processes underlying the preparation, initiation, and directional control of goal-directed actions toward contralesional space (Mattingley et al., 1992). However, despite their functional relevance and significant impact on activities of daily living (ADLs), directional motor manifestations remain comparatively under-characterized in the literature, partly due to terminological inconsistency, limited theoretical integration, and methodological heterogeneity (Vallar & Calzolari, 2018). The present thesis aims to clarify the conceptual and clinical boundaries of directional neglect, offering an in-depth analysis of its definitions, underlying mechanisms, clinical signs, lesion correlates, and available assessment methods. By systematically analyzing its main subtypes - directional akinesia, hypokinesia, bradykinesia, and hypometria - this work aims to advance a nuanced understanding of the motor-intentional dimension of neglect and to highlight its relevance for accurate diagnosis, theoretical interpretation, and rehabilitation strategies.