Verbal memory compensation: application to left and right temporal lobe epileptic patients.

This study investigates the compensatory impact of cognitive aids on left and right temporal lobe epileptic patients suffering from verbal memory disorders, who were candidates for surgery. Cognitive aids are defined in the levels-of-processing framework and deal with the depth of encoding, the elaboration of information, and the use of retrieval cues. Results indicate differential compensatory impact for left and right epileptic patients and are discussed according to the HERA model and the compensation framework.

Levels of processing with free and cued recall and unilateral temporal lobe epilepsy.

This study investigates the role of the temporal lobes in levels-of-processing tasks (phonetic and semantic encoding) according to the nature of recall tasks (free and cued recall). These tasks were administered to 48 patients with unilateral temporal epilepsy (right "RTLE"=24; left "LTLE"=24) and a normal group (n=24). The results indicated that LTLE patients were impaired for semantic processing (free and cued recall) and for phonetic processing (free and cued recall), while for RTLE patients deficits appeared in free recall with semantic processing. It is suggested that the left temporal lobe is involved in all aspects of verbal memory, and that the right temporal lobe is specialized in semantic processing. Moreover, our data seem to indicate that RTLE patients present a retrieval processing impairment (semantic condition), whereas the LTLE group is characterized by encoding difficulties in the phonetic and semantic condition.

Time course of cognitive recovery after propofol anaesthesia: a level of processing approach.

The aim of this study was to investigate the time course of recovery of verbal memory after general anaesthesia, as a function of the level (shallow or deep) of processing induced at the time of encoding. Thirty-one patients anaesthetized with propofol and alfentanil were compared with 28 control patients receiving only alfentanil. Memory functions were assessed the day before and 1, 6 and 24 hr after operation. Results show that for the anaesthetized group, shallow processing was impaired for 6 hr after surgery whereas the deeper processing was not recovered even at 24 hr. In addition, no specific effect of age was found.

Effect of age of onset of temporal lobe epilepsy on the severity and the nature of preoperative memory deficits.

The nature and severity of pre-operative memory deficits observed in unilateral temporal lobe epilepsy depend upon a number of variables. Among these variables, age of seizure onset seems to be important. The age at which the lesion is sustained could modify the normal functional organization of the brain. Many studies have examined the effect of age of onset on the severity of memory deficits but have seldom focused on the nature of such deficits (verbal/nonverbal) as a function of epileptic focus laterality. This study investigates the effect of age of onset on the nature and severity of memory impairments. Fifty-six epileptics with unilateral temporal lobe epilepsy and 20 normal subjects were administered a neuropsychological evaluation. Four groups of patients were constituted: left or right temporal lobe epilepsy with early (0-5 years) or late (10 years and over) age of seizure onset. The early group showed major verbal and nonverbal memory deficits. The late group presented minor specific deficits: essentially verbal deficits with left temporal lobe seizures and nonverbal deficits with right temporal lobe seizures. These results may be interpreted in the framework of ontogenesis theories of hemispheric specialization.