CHRONIC VISUAL HALLUCINATIONS AND ILLUSIO NS AFTER CEREBRAL-LESIONS -A SINGLE-CASE STUDY

Lesions of the visual system do not necessarily lead to deficits in vi sual function. In some cases, there may even occur Positive Spontaneou s Visual Phenomena (PSVP) following cerebral damage. We present data f rom a male patient with continuous, long-term visual illusions after h aving experienced cerebral infarction at the age of 56. Basing on conv entional Magnetic Resonance Imaging, lesions could be located in areas supported by the lateral and medial occipital artery. Initially, homo nymous hemianopsia of the right visual field was found in perimetric e xaminations, but in the course of six months, visual function recovere d completely. Ever since the incident, the patient has been suffering from permanent photopsia, intense colourful visual hallucinations and perseverations located in the former defective area which continued un abated even after the remission of his visual field defects. While man y authors have published datae on PSVP lasting for several seconds, us ually vanishing completely within days or weeks after cerebral lesion, in our patient the symptoms continued over a period of so far nine mo nths. Surprisingly, he was even able to make drawings of his illusions so that we were able to include some of his pictures.