[Neurovegetative diseases in dementia]

Dementia is the result of the dysfunction and death of cells in the central and peripheral nervous system. Of diverse etiology, these processes are insidious in their onset and are characterized by a progressive neural depletion resulting in a range of cognitive deficits, including a deterioration in the capacity to learn and a tendency to forget what has been learned. Neurodegenerative diseases resulting in dementia include: Alzheimer, Parkinson, Huntington, Pick, and Creutzfeld Jakob, as well as dementias with multiple etiologies. The population with the highest probability of suffering from one of these diseases are those over 50 years of age, because they have reduced circulating levels of gonadal hormones, one of several risk factors associated with the onset of dementia. Anatomical areas most commonly affected include the hippocampus, the primary motor and somatosensory areas, various limbic structures, and the parieto-temporal, frontal, and entorhinal corticies. Affliction of this last area has been suggested to account for the early olfactory dysfunction often shown by patients after the onset of Alzheimer and Parkinson, leading to the suggestion that olfactory testing could be useful in the early diagnosis of such neurodegenerative diseases.