Changes of CSF neuropeptides after environmental stimulation in dementia

Reduced dendritic branching has been reported in animals reared in a poor environment. This has been found during brain development and in adults as well. The same type of degenerative changes has also been observed in dementia of Alzheimer type in man. These findings raise the possibility that a poor environment, in addition to biological factors, may contribute to morphological and biochemical changes in the central nervous system of demented patients. To test the hypothesis whether environmental stimulation can influence biochemical alterations in dementia, cerebrospinal fluid (CSF) concentrations of cholecystokinin (CCK), corticotropin releasing factor (CRF) and somatostatin were analysed before and after two months' of environmental stimulation in two groups of demented patients with senile onset. The experimental group of demented patients (n=11) participated in a program with intensified intellectual, emotional and environmental stimulation during a two month period. A control group of demented patients (n=13) had no such enriched environment and took part in the ordinary ward program. Both groups were subjected to psychological testings and ratings and a lumbar puncture was performed prior to and after the experimental period. Some of the psychological parameters were changed during the study period indicating slight improvement in the activated group and further deterioration in the control group. The dexamethasone suppression test was abnormal in 'A of the patients and these findings were not correlated with increased CSF CRF concentrations. At the start of the study the CSF somatostatin concentration was 87.5 $ 33.5 nmoles/1 (mean $ S. D.) in the control group and 57.6 $ 28.4 in the experimental group. The CSF concentration of somatostatin increased in the activated group during the treatment period (12.9 $ 24.5 nmoles/1) and decreased in the control group (8.7 $21.7). This difference was statistically significant (p < 0.05). The increase in the CSF somatostatin concentration might be a response to the increased environmental stimulation. D Cholecystokinin, corticotropin-releasing factor, CSF, dementia, mental stimulation, somatostatin.