Focal degenerative dementia syndromes

This article outlines various clinical syndromes found in degenerative conditions that affect a focal area of the brain. The lobar approach used here for discussion purposes is somewhat artificial in that, although the pathology may be fairly restricted in the initial stages of the disease, the pathology often evolves to affect several brain regions more diffusely. Indeed, as is the case for most patients with FTD, both the frontal and temporal lobes are involved, often bilaterally. The lobar approach, however, remains useful as a clinical tool, because specific neurologic, cognitive, or behavioral functions are affected depending on which specific regions of the brain bear the brunt of the pathology. Interestingly, the underlying pathologic processes found in the different focal degenerative conditions are more uniform than previously believed (Table 1). It is in this context that the term Pick complex has been introduced, to underline the presence of a spectrum disease with similar underlying pathology.