The contributions of memory and attention processes to cognitive abilities.

In two experiments, the contributions of memory and attention processes to the cognitive abilities of reasoning and perceptual speed were investigated. Two measures of speed of information retrieval from long-term and short-term memory (Posner paradigm, Sternberg paradigm) and two attention measures (continuous attention test, attention switching test) were included in the first experiment (N = 220). The memory tests led to correlations with the measures of cognitive abilities, whereas the attention test did not. The same tests as well as one additional memory test and one attention test (working memory test, test of covert orientation) were administered in the second experiment (N = 116). Again, the memory tests led to the larger correlations with the measures of cognitive abilities. Two components were obtained in components analysis, of which the first was characterized by high loadings of the memory tests and the second by high loadings of the attention tests. Only the memory component contributed to the prediction of cognitive abilities.

Effects of the novel NMDA-receptor antagonist SDZ EAA 494 on memory and attention in humans.

Effects of the novel competitive N-methyl-D-aspartate (NMDA)-receptor antagonist SDZ EAA 494 were investigated on memory and attention in humans. SDZ EAA 494 was administered either as single doses at a dose range of 1-50 mg, or as multiple doses over the course of 1 week at doses of 25 mg once or twice daily. Selected cognitive functions were assessed at baseline, 2 and 4 h after single dose administration, and at baseline, 2, 4 and 8 h on days 1 and 7 of multiple dose administration. The assessments included simple and complex reaction time tests to assess attention, and verbal, non-verbal and spatial memory tests with immediate and late recall. Verbal and non-verbal memory test performance was significantly impaired at a dose level of 50 mg after single administration, and of 25 mg twice daily after multiple administration, without concomitant significant impairment of reaction time. Spatial memory test performance was not significantly affected. The maximum effect occurred 2 h postmedication and was more pronounced after repeated administration. These results suggest that the inhibition of NMDA-receptors in humans may impair memory processes.

Memory and attention test performance of young and elderly subjects after retest practice.

The effects of training on two memory and two attention tasks were investigated in 24 healthy elderly and 23 young subjects. Two training periods, each consisting of four sessions, were performed, and the effects of training were assessed during two test sessions 1 week thereafter. Significant age-related effects at the pretraining test session were found for reaction times to a simple visual stimulus, retrieval time of information from long-term storage, and the speed of focusing attention. In both age groups, performance of the first two tasks was significantly improved by training; however, the age-related effect remained significant after training. In the focused attention task, the age difference at baseline disappeared after training due to an opposite learning trend in young and elderly subjects. Thus, the cognitive performance of elderly subjects could be trained to a large extent. Significant age differences, however, could be decreased only if the test performance of young subjects did not improve.

Covariation of physiological sleep parameters in coronary patients and their relationships to sleep quality.

Relationships between the time series of five physiological sleep parameters were examined and related to sleep quality. Twenty-eight male coronary patients participated in the investigation. Recordings were carried out with a mobile device consisting of two Medilog 4-24 recorders and one DMI-recorder assessing five biosignals: EEG, EOG, EMG, ECG and body movements. Relationships between the time series of physiological sleep parameters were obtained by partitioning of covariance. The investigation showed that substantial relationships exist between the time series of the EEG, the number of eye movements and heart rate. Moreover, the time series of body movements showed substantial relationships to the time series of the EMG and heart rate. High correlations between the time series of the EEG and heart rate were related to a better sleep quality.