Sensory Deficits in Visual Agnosia

claimed that the so-called " higher " perceptual disorders are secondary to sensory impairment, to general intellectual loss, to language disturbance, or to a combination of these three factors. He denies strongly that agnosia in its classical sense of a circumscribed defect of recognition, specific to a single sense modality, in reality exists. Bay main-tains that abnormal alterations in visual function (pathologischer Funktionswandel) may be present in cases conventionally held to display symptoms of agnosia and may play an important role in the genesis of this disorder. Although these sensory deficits may escape detection on routine examination of the visual fields, it is argued that they are measur-able by means of a special test of local adaptation.