[Study of cognitive evoked potentials as a function of the affective value and significance of stimuli in anhedonic healthy subjects with dysfunctional attitudes].

In depression studies, it is important to consider healthy subjects with characteristics which may be predictive of depression. Such are anhedonia and some "dysfunctional" attitudes. For this reason, subjects with or without these characteristics were submitted to an experimental paradigm allowing an analysis of their electroencephalographical (CNV and P300) reactivity according to affective value and meaning of stimuli, and according to the probability of occurrence of these stimuli.

[Evoked potentials and the mode of cognitive development in boys 6 to 8 years of age presenting hyperactivity with attention deficit].

Event-related potentials were recorded in 2 groups (attention deficit hyperactivity disorder--ADHD--and normal controls) of 12 male children aged between 6-8 years during 4 categorization tasks. Each task was performed with a different type of visual stimulus; pictures, words, geometrical figures or digits. The amplitudes and latencies of a fronto-central P250 and a parieto-occipital P350 were examined.

Sensory and cognitive event related potentials in workers chronically exposed to solvents.

To obtain objective measures of possible impairment due to organic solvents, auditory, visual and somatosensory evoked potentials and cognitive event related potentials were recorded in a group of 13 workers occupationally exposed to a mixture of various solvents. The patients were compared to healthy subjects and to chronic alcoholics seen during post-alcohol withdrawal. Auditory and visual evoked potentials were almost normal but somatosensory evoked potentials showed a slight decrease of peripheral conduction velocities and an increase of central conduction times more marked in the solvent exposed workers who were also alcoholics.

Hemisphere asymmetry of alpha burst sequential organization in depression.

A new quantitative EEG index based on the sequential variability of the frequency of occurrence of alpha bursts (alpha-BVI) was utilized for investigating the respective role of the two hemispheres in depression and their relationship with two clinical dimensions of this illness: psychomotor retardation and blunted affect. The EEG (at P3 and P4 referred to Fz) was recorded during rest periods in two groups of patients selected according to their scores on various clinical scales: one consisted of 12 patients characterized by psychomotor retardation (PMR group), the other of 9 patients characterized by blunted affect (BA group). A control group of 12 normal subjects was recorded in the same conditions.

Attention impairment and psychomotor retardation in depressed patients: an event-related potential study.

The cerebral event-related potentials (ERPs) and reaction times (RTs) of 8 drug-free depressed in-patients (mean age 58, with marked psychomotor retardation) were recorded during a dichotic listening and choice RT task and compared to those of 9 healthy, age-matched controls. The depressed showed significantly longer, more variable RTs than the controls and made more mistakes. Their ERPs for targets in the attended ear differed significantly from those of the controls by the small amplitude (or absence) of the N2 vertex component elicited by the controls in such a situation and by the presence in the same situation of a late frontal slow negativity (LFN) that did not show up in the grand average ERP of the control group.