Chapter 13: Neglect & Related Neuropsychological Disorders

Neglect & Related Neuropsychological Disorders systematically categorizes the disorder into spatial, personal, attentional, and intentional neglect, distinguishing between sensory awareness deficits and motor initiation failures such as akinesia, hypokinesia, and motor impersistence. The text highlights critical behavioral manifestations, including extinction to double simultaneous stimulation—where bilateral input causes a failure to detect the contralesional stimulus—and anosognosia, the profound denial of illness or hemiparesis. Beyond mere behavioral description, the chapter presents an integrated neuroanatomical model involving a corticolimbic-reticular network. This system, which includes the inferior parietal lobe, dorsolateral frontal cortex, cingulate gyrus, and midbrain reticular formation, is essential for mediating arousal and directing attention based on biological significance. The discussion emphasizes the right hemisphere's unique dominance in attentional processes and the role of dopaminergic pathways in intentional behavior, explaining why neglect is more prevalent after right-sided injuries. Clinical assessment methods, such as the line bisection task, cancellation tests, and the crossed-response task, are detailed to illustrate how clinicians differentiate between primary sensory loss and higher-order attentional dysfunction. Finally, the chapter addresses recovery patterns and experimental treatments, including dopamine agonist therapy, prism adaptation, and vestibular stimulation, providing a thorough overview of how neuropsychology approaches this complex disruption of the brain's representational and orienting systems.