A patient with associative visual agnosia secondary to a penetrating bitemporooccipital lesion remained able to draw complex objects from memory but could not subsequently recognize his sketches. His retained ability to copy and draw briefly exposed objects indicates that this is not a problem of visual perception. On tasks of categorization, mental imagery, drawing, and object decision, he demonstrates many instances of preserved visual semantic memories and imagery despite a sense of unfamiliarity with the visual stimuli. We infer a preserved ability to derive internal visual images from semantic memory. Cues may help him visualize the named object, which then serves as a model for comparison with the actual stimulus. However, his adequate visual perception and mental visual imagery, even when assisted by cues, are still insufficient to correct fully his difficulty in recognizing objects. Unique to his case is an inability to match the representation of stimulus objects with his intact internal image of the same object. Deficient lateral inhibition between neural representations of similar objects may be responsible.

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The Baby Boomers are "coming of age." They are living longer, on average, than any generation before. With this increased life span comes some real challenges. One is the expected increase in Alzheimer disease (AD) and other dementias (see About dementia predictions). As people live longer, the chances of developing AD increase markedly. At age 60, less than 0.1% of people have dementia. By age 85, 30 to 40% have the disease. Scientists are racing against the clock to find a cure or at least a way to slow the process. In the meantime, the costs for the person with AD, the family, and society are mounting.

Stroke Is a Brain Attack When a person experiences severe chest pain and a heart attack is suspected, most people know to call 911. However, far fewer people know that a stroke demands equal urgency. A stroke is equivalent to a heart attack of the brain and should be thought of as a brain attack.

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