Neuropathologically confirmed Alzheimer's disease may begin with symptoms other than memory problems, for instance visual perceptual disorders, difficulties in linguistic functions and expression in spoken language or executive functioning, occasionally even with behavioral symptoms. Among the forms of Alzheimer's disease appearing with atypical symptoms, the best know is the so-called posterior variant. The diagnosis is based on neuropsychological examination and findings in imaging. Additional diagnostic help is provided by the determination of markers for Alzheimer's disease in cerebrospinal fluid, as changes in markers correspond to the findings in traditional Alzheimer's disease.