Prediction of deterioration in mild cognitive disorder in old age--neuropsychological and neurochemical parameters of dementia diseases.

In normal senescence, an age-related impairment of cognitive function is observed. The difficult clinical question is in which cases of mild cognitive impairment (MCI) will there be a rapid cognitive decline to a dementia syndrome. Two ways to improve prognosis are discussed: neuropsychological tests and analysis of neurochemical markers. First, the question is asked as to whether there are clusters of MCI. Longitudinal neuropsychological data from the Berlin Aging Study (BASE) are presented, a population-based sample of 516 subjects aged 70 to 103 years. There are clusters found that in part match those clusters, which have been identified by a study from Ritchie et al. in 1996. Especially, a cluster of 13.8% of the nondemented participants with a decline in memory performance is observed. The validation of clusters of cognitive performance and decline opens up the possibility of diagnosing distinctive subgroups of MCI to improve prognosis in old age. Second, the existing data concerning the diagnostic laboratory analysis for Alzheimer's disease (AD) are reviewed. Especially, data regarding nerve growth factor (NGF) are reported. In MCI, preliminary data show a correlation between the NGF serum level and cognitive performance. It can be concluded that the combined investigation of neuropsychological functions and cognitive decline, as well as laboratory measurement of neurochemical markers, might allow an improved prognosis for mental health in very old age.