Learning capacities during sleep: a preliminary study in a group of schizophrenic inpatients.

The relationship between sleep and learning processes is analysed in a sample of schizophrenic patients, starting from more recent hypotheses about the function of REM sleep in learning and memory processes. This is done by means of two experiments: in the first AA. evaluate the possibility to elicit a simple motor conditional reflex acquired during daytime in different sleep stages. With the second experiment daytime learning performances are evaluated with and without a reinforcement administered during REM sleep. Results for the first experiment underline a qualitative difference between REM and nREM sleep in a reflexological perspective. In nREM sleep the conditional response is better maintained than in REM sleep. The second experiment confirms the possibility to improve daytime learning performances after an additional presentation of learning material in REM. The joint study of sleep abnormalities and learning and cognitive impairment in schizophrenic patients is finally suggested.

Sleep, psychophysiological functioning and learning processes in schizophrenia.

Sleep research has underlined how sleep is a specific functional moment inserted in the more complex system of circadian psychobiological rhythms. Many experimental data have evidenced that in particular REM sleep is involved in information processing and cognitive processes. The authors examine correlations between daytime cognitive performances and sleep patterns in a group of 11 schizophrenic patients, and in a control group made of 11 non-schizophrenic (borderline, depressed, character disorders) patients. Results show that there exists a relationship between REM sleep and cognitive activities, beyond nosographic partitions. They on the other side suggest caution in using sleep as a means of discrimination between schizophrenic and non-schizophrenic patients.

Neurophysiological aspects and learning processes in schizophrenic patients.

Two groups of schizophrenic patients (acute and chronic subjects) were observed in order to study possible differences in neuropsychological performances and their relationship with symptomatology. 16 acute and 16 chronic patients, aged 18 to 35 years were tested with a battery of neuropsychological tests (Word Association Test, Serial Verbal Learning, Weigl's test, Simple Reaction Times, Choice Continuous Reaction Time). Clinical profiles were evaluated by means of MMPI and WAIS (Wechsler Adult Intelligence Scale). Findings concerning cognitive processes show no significant differences between the two groups. Results suggest a correlation between clinical profiles and performances in acute patients, whereas in chronic subjects this correlation seems markedly reduced. Finally, chronicity (i.e. the length of illness) does not seem so be an important factor in determining consistent defects in neuropsychological performances.