[Initial deficits in Alzheimer's disease: 3 practical examples]

The aim of the first studies to determine the neuropsychological features of Alzheimer's disease (AD) were based on the concept of the disease as an homogeneous entity. However, clinical observations and the most recent research studies have demonstrated that Alzheimer's disease may present several other neuropsychological deficits on its clinical onset.

in the initial process of cognitive function loss, memory deficits are seen as a consequence of hippocampal degeneration; however, a great interindividual variability is observed in the appearance of other cortical deficits. In addiction, new advances in epidemiology, neurochemistry and neuropathology support the idea that AD represents a neuropsychologically heterogeneous disorder. In AD three different subgroups have been established: patients with initial deficits in visuospatial abilities, patients with a major deterioration of linguistic abilities, and a third group with altered visuospatial and linguistic abilities. The most sensitive neuropsychological tests capable of distinguish among these differences were The Boston Naming Test (BNT) and the copy of a drawing. These results have been confirmed with single photon emission computed tomography (SPECT) images, and has been observed that patients with a pattern of a elevated right-hemispheric deterioration presented also a higher right-hipofunctionality. At the same time, patients with an elevated linguistic deficit showed a higher hipofunctionality image in the left hemisphere.

In this work we present three patients from a prospective study in course, who have similar background, education, gender and disease evolution, but with an onset of the illness corresponding to each of the patterns previously described All three patients were explored with an extense neuropsychological battery of tests specially chosen for this study.