ABSTRACT
This chapter deals largely with visual perception and related processes. It describes areas that are considered to be mainstream neuropsychology. This includes the basic neuropsychology theory of perception and the clinical syndromes that describe the different disorders of perception. The chapter describes the disorders of sensation with reference to the process of sensory analysis. The terms ‘hemianopia’/‘hemianopsia’ and ‘quadrantanopia’ are introduced as disorders in which a patient loses visual sensation in a particular area of their visual field. A cardinal rule is therefore that when there is a disorder of visual sensation which affects one side of the visual field it can often be assumed that the damage causing the problem is in the contralateral or opposite brain hemisphere. The reverse hierarchies model reveals something of the nature of the tuning process. The term ‘agnosia’ comes from the Greek meaning ‘without knowledge’, which accurately describes the predicament of the patient with agnosia.
