Letter to the Editor Letters to the Editor are invited for comment on a topic of current interest or on material published in GENERAL HOSPITAL PSYCHIATRY. Letters should be typed double-spaced and are subject to editing according to space limitations. Insight into Phosphene: A Case with Occipital Lobe Damage Visual hallucinations following occipital lobe damage characteristically tend to appear in hemianopic fields, and in such cases patients usually retain full insight into the images [1–3]. Kölmel [2,3] divided these hallucinations into formed and unformed (“phosphene”) images, and described their features in considerable detail. This article describes an elderly patient who initially developed colored phosphenes in the right visual field, lost insight into them, and was subsequently diagnosed as having left occipital subcortical hematoma and right homonymous hemianopia. Case Report A 78-year-old, right-handed male farmer without prior psychiatric problems was referred to us by his general practitioner for evaluation of his mental state. One afternoon the patient suddenly became perplexed: “I forgot how to use the grasscutter.” Although he had been accustomed to using it, he attached the blade oddly and then gave up handling it. Thereafter, he vaguely complained of difficulty in watching the television screen, and slept soundly that night. The next morning, he became puzzled again and said pointing at the right corner of the kitchen: “Fire is burning. Who lit the fire? It is very dangerous.” Although the visual images repeatedly appeared in his right visual field for several hours, he was unaware that they were not real. At that time he continued to have the images and was slightly delayed in his responses. He was then brought to our department. At age 68, he had sustained a left frontal intracerebral hemorrhage after a fall. After conservative measures, he had recovered from this injury with no evidence of intellectual impairment or personality change. He had no history of alcohol abuse, and was not receiving any medication. Despite bilateral senile cataracts, he was able to read and see reasonably well. 260 ISSN 0163-8343/98/$19.00 On examination, he was slightly drowsy and therefore unable to give a clear description of his hallucinations or visual disturbance. His blood pressure was 190/90 mmHg. Neither weakness nor pathological reflexes were present. Thereafter, he complained of headache, vomited, lost his sense of orientation, and became severely confused. Computed tomographic (CT) scan of the brain performed approximately 40 hours after the onset of symptoms disclosed a left occipital subcortical hematoma centered in the optic radiation, associated with surrounding edema (Fig. 1). He then underwent surgical evacuation of the hematoma at the neurosurgical unit of another hospital. Cortical biopsy specimens stained with Congo red revealed the presence of cerebral amyloid angiopathy (CAA). Laboratory tests showed normal prothrombin time, partial prothrombin time, and platelet count. Postoperatively, right homonymous hemianopia was diagnosed by confirming that he was unaware of the existence of objects in the right half of his visual space, and by the confrontation method. Visual hallucinations did not recur. In previous studies [1–3] a group of patients were examined who perceived visual hallucinations in hemianopic fields due to occipital lobe damage (stroke, tumor, or other cause). It was concluded that a focal lesion in the retrogeniculate visual system is significant in generating such hallucinations. Therefore, it is likely in the present case that the phosphenes, which appeared in the right visual field, may have been caused by left occipital hematoma. Since CAA is a leading cause of cerebral lobar hemorrhage in the elderly, and since the parietooccipital region is a common bleeding site due to CAA [4], the unusual hallucinations described in the present case may be expected to occur with regularity. Additionally, according to Kölmel [2], phosphenes are related to a small circumscribed lesion in the striate cortex and adjacent white matter, usually appear at the onset of hemianopia, and General Hospital Psychiatry 20, 260 –261, 1998 © 1998 Elsevier Science Inc. All rights reserved. 655 Avenue of the Americas, New York, NY 10010 Letter to the Editor our department, although as mentioned earlier, patients experiencing phosphenes usually retain full insight into them. Second, our patient did not complain of hemianopia when the phosphenes appeared, although it is considered that he had developed the visual field defect at that time. These discrepancies may be explained, at least in part, by mild clouding of consciousness, because he was delayed in his responses at the onset of the hallucinations, and drowsy on examination. Based on these observations, the following conclusion can be drawn: When treating visual hallucinations, in order to avoid overlooking focal damage in the retrogeniculate visual system, psychiatrists should pay attention to the properties of the images and the visual field into which the images are projected, regardless of the presence or absence of a complaint of visual field defect. The authors are grateful for the support of Drs. A. Nagase, H. Seo, M. Konishi, and J. Hatta. toshiro kishi, m.d. and hiroshi ishino, m.d., ph.d. Department of Psychiatry Shimane Medical University Izumo, Japan rokuichi naganuma, m.d., ph.d. Department of Psychiatry Matsugaoka Hospital Masuda, Japan Figure 1. Axial images from a cranial CT scan obtained without contrast material. disappear within several days. All of these characteristics were observed also in the present case. Our patient initially demonstrated disability in systematically operating a tool which he had been accustomed to using, although he recognized what the object was, and had no motor disturbance. Therefore, this is interpreted as the ideational apraxia, which may be attributed to edema extending as far as the left parietal lobe [5]. The present case is interesting in two respects. First, our patient was unaware that the visual images were not real, and therefore was referred to PII S0163-8343(98)00029-2 References 1. Lance JW: Simple formed hallucinations confined to the area of a specific visual field defect. Brain 99:719– 734, 1976 2. Kölmel HW: Coloured patterns in hemianopic fields. Brain 107:155–167, 1984 3. Kölmel HW: Complex visual hallucinations in the hemianopic field. J Neurol Neurosurg Psychiatry 48: 29–38, 1985 4. Vinters HV: Cerebral amyloid angiopathy: a critical review. Stroke 18:311–324, 1987 5. Poeck K, Lehmkuhl G: Das Syndrom der ideatorischen Apraxie und seine Lokalisation. Nervenarzt 51:217– 225, 1980 261