| OCR Text |
Show NOVEL: Test Your Knowledge Collection A 65 year old woman had a cardiac arrest with brief loss of consciousness. When she regained full consciousness, she began to complain that “my vision is just not normal.” Yet visual acuity was normal and there were no abnormalities of eye movements or alignment. Visual fields were full to finger displays. The neurologic examination was normal except that her walking was tentative. She had difficulty when asked to pick objects out of an array. Where is the lesion? A) Frontal lobes B) Temporal lobes C) Parietal lobes D) Occipital lobes Courtesy: Jonathan D. Trobe Parietal lobes Correct Answer: C) Parietal lobes • This patient is simply unable to point accurately to objects in an array. Also, she forgets which ones she has already identified, so she miscounts. Her problem derives from a combination of visuospatial and attentional dysfunction. The term “simultanagnosia” has been applied to this deficit. The lesions lie in the inferior parietal lobules on both sides, interrupting the integration of visual and somatosensory information and the application of attention appropriate to the task. Called Balint syndrome, or Balint-Holmes syndrome, it most often arises acutely from biparietal stroke, usually in the setting of systemic hypotension (“watershed” or “border zone” infarction). • When these deficits appear chronically, the most common cause is the “visual variant” of Alzheimer disease, sometimes known as “posterior cortical atrophy.” |
