The main difference between the two being that Alzheimers is categorized by atrophy to both sides of the brain while semantic dementia is categorized by loss of brain tissue in the front portion of the left temporal lobe. With Alzheimers disease in particular, interactions with semantic memory produce different patterns in deficits between patients and categories over time which is caused by distorted representations in the brain. For example, in the initial onset of Alzheimers disease, patients have mild difficulty with the artifacts category. As the disease progresses, the category specific semantic deficits progress as well, and patients see a more concrete deficit with natural categories. In other words, the deficit tends to be worse with living things as opposed to non-living things. Diagnosis
SD patients generally have difficulty generating familiar words or recognizing familiar objects and faces. Clinical signs include fluent aphasia, anomia, impaired comprehension of word meaning, and associative visual agnosia (inability to match semantically related pictures or objects). As the disease progresses, behavioral and personality changes are often seen similar to those seen in frontotemporal dementia.SD patients perform poorly on tests of semantic knowledge. Published tests include both verbal and non-verbal tasks, e.g., The Warrington Concrete and Abstract Word Synonym Test, and The Pyramids and Palm Trees task. Testing also reveals deficits in picture naming (e.g. "dog" for a picture of a hippopotamus) and decreased category fluency. The question "What is a Stapler?"
Refractory cytopenia with multilineage dysplasia is a form of myelodysplastic syndrome.It is abbreviated "RCMD". References


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