Commonly, visual agnosia presents as an inability to recognize an object in the absence of other explanations, such as blindness or partial blindness, anomia, memory loss, etc.. Other common manifestations of visual agnosia that are generally tested for include difficulty identifying objects that look similar in shape, difficulty with identifying line drawings of objects, and recognizing objects that are shown from less common views, such as a horse from a top-down view.Within any given patient, a variety of symptoms can occur, and the impairment of ability is not only binary but can range in severity. For example, Patient SM is a prosopagnosic with a unilateral lesion to left extrastriate cortex due to an accident in his twenties who displays behavior similar to congenital prosopagnosia. Although he can recognize facial features and emotions – indeed he sometimes uses a standout feature to recognize a face – face recognition is almost impossible purely from visual stimuli, even for faces of friends, family, and himself. The disorder also affects his memory of faces, both in storing new memories of faces and recalling stored memories.Nevertheless, it is important to note the reach of symptoms to other domains. SMs object recognition is similarly impaired though not entirely; when given line drawings to identify, he was able to give names of objects with properties similar to the drawing, implying that he is able to see the features of the drawing.
experienced many cognitive issues, mood swings, poor memory, and temper outbursts. C.K. also had motor weakness on the left side and a left homonymous hemianopia. He recovered well, retaining normal intelligence and normal visual acuity. He was able to complete a masters degree in history, later working as a manager at a large corporation. Although his recovery was successful in other areas of cognition, C.K. still struggles to make sense of the visual world. Associative visual agnosia
Magnetic resonance imaging (MRI) showed bilateral thinning of C.K.s occipital lobe which resulted in associative visual agnosia. Patients that have visual agnosia are unable to identify visually presented objects. They can identify these objects through other modalities such as touch but if presented visually, they are unable to. Associative agnosic patients cannot create a detailed representation of the visual world in their brains, they can only perceive elements of whole objects. They also cannot form associations between objects or assign meaning to objects.C.K. makes many mistakes when trying to identify objects. For example, he called an abacus "skewers on a kebab" and a badminton racquet a "fencers mask". A dart was a "feather duster" and a protractor was mistaken for a "cockpit". Despite this impairment in visual object recognition, C.K. retained many abilities such as drawing, visual imagery, and internal imagery. As a native of England, he was tasked with drawing England, marking London and where he was born. His accurate drawing of England is just one example of his excellent drawing abilities.As aforementioned, C.K.