Memory dysfunction and vigilance: neurophysiological and psychopharmacological aspects.

Human brain function as measured by the computer-assisted spectral analyzed electroencephalogram (EEG) shows significant alterations in normal and pathological aging characterized by an increase of delta and theta activity and by a decrease of alpha and alpha-adjacent beta activity as well as by a slowing of the dominant frequency. These changes are indicative of deficits in the vigilance-regulatory systems. By the term vigilance we understand the availability and grade of organization of man's adaptive behavior, which in turn is dependent of the dynamic state of the total neural activity. An impairment of vigilance was found to be significantly correlated with the clinical symptomatology of the organic brain syndrome (OBS) as well as with mnestic performance deficits. Elderly subjects with bad memory exhibit slower activity and less alpha and alpha-adjacent beta activity than those with good memory. This was found to be true for both the time of acquisition and recall. Antihypoxidotic/nootropic drugs, such as the ergotalkaloids dihydroergotoxine and nicergoline, vincamine-alkaloids, piracetam, aniracetam, etiracetam, piridoxilate and others, induce interestingly just oppositional changes in human brain function, thereby improving vigilance. Other methods for proving therapeutic efficacy in man, like experimentally induced hypoxic hypoxidosis and the reversible alcoholic OBS, are discussed.