Ideative-emotive behavioral characteristics of patients following left or right temporal lobectomy

On the psychopathology of unilateral temporal lobe epilepsy

Personality adjustment of patients with unilateral temporal lobe epilepsy (TLE) was investigated in the light of special characteristics of the epilepsy process, psychosocial stressors, and the cognitive status of the patients. Thirty-seven patients with medically intractable unilateral temporal lobe epilepsy (16-55 years of age; 20 right temporal and 17 left temporal foci) were examined with standardized personality inventories (FPI, STAI, IPC, TSK) supplemented by a rating scale evaluated by the neuropsychologist (GEWLE). Patients with left temporal lobe epilepsy were characterized by increased emotional dependency, less externally judged composedness, increased depressive drive and mood, increased nervousness, increased search for information and exchange of disease experience, and greater tendency to persevere (P < 0.05). Cognitive status and psychosocial status did not significantly differ. The evaluation of personality adjustment contributes to the lateralization of the epileptogenic focus and reveals interesting patterns in the preoperative diagnostic puzzle, and in addition provides a strategy to individualize psychotherapeutic strategies.

Effect of lateralized epileptic discharges on the thought flow

PURPOSE

Pauses in verbal expression of thought flow in patients with partial epilepsy was studied in order to achieve a best comprehension of brain interhemispheric influences.

METHOD

We studied thirty nine patients with partial epileptic seizures and twenty four volunteers (control group). Free association of ideas was used as a method to establish the thought flow, starting with a stimulus word (subject name) that must be followed by spontaneous and consecutive word-phrase. Patients were instructed to say any thought that came to their minds without any kind of censoring. Subject responses were recorded through a PC keyboard and time intervals (pauses) between each word-phrase were processed by a software developed for this purpose.

RESULTS

Time intervals reduction among associations in right lesional group were compared to left lesional, right non-lesional and control groups. An increase of associative time intervals was observed in the right non-lesional group compared to left non-lesional group.

CONCLUSIONS

We suggest a possible inhibitory inter-hemispheric function of the right hemisphere modulating verbal expression of the thought flow. Considering the hypothesis of the inter-hemispheric inhibition by the right hemisphere on left hemisphere, we admit that in epileptic patients with right hemispheric lesion there is an attenuation of the inter-hemispheric inhibition and an increase in thought flow, whereas in patients without a lesion but a paroxysmal epileptic activity in right temporal lobe there is an exacerbation of this inhibitory function and consequent reduction in the thought flow.

Automatic activation of the medial temporal lobe during encoding: lateralized influences of meaning and novelty

In contrast to early failures, recent functional brain imaging studies have shown that medial temporal lobe (MTL) structures are active during performance of a variety of tasks. These studies have revealed three properties of the MTL that are consistent with its critical role in establishing new declarative memories. First, the MTL is automatically engaged whenever an event is experienced, with the side of activation (left, right) dependent on the nature of the material presented (verbal, nonverbal). Second, the strength or amount of activity depends on how well the material is encoded. Deep encoding will produce more MTL activity than shallow encoding. Depth of encoding-related increases in activity are more commonly seen on the left, because deep encoding is nearly always synonymous with encoding for meaning, and, therefore, depends on left-lateralized language mechanisms. Third, the amount of MTL activity depends on novelty. Unfamiliar events and contexts will produce more MTL activity than familiar events and contexts. Novelty-related increases are more commonly seen on the right, perhaps reflecting the greater role of the right hemisphere in maintaining tonic attention and arousal. These findings suggest a hemispheric division of labor involving encoding for meaning (left) and novelty detection (right), both of which lead to better remembering.

Lateralized mediation of arousal and habituation: differential bilateral electrodermal activity in unilateral temporal lobectomy patients

The purpose of the present study was to increase our understanding of the differential hemispheric processing of arousal and habituation. Subjects were unilateral temporal lobectomy patients and controls. Each was exposed to an arousal/habituation task consisting of a series of tones and an auditory discrimination paradigm. Electrodermal activity was recorded from the left and right hands throughout. Results provide evidence for a state of hypoarousal in right temporal patients and some support for hyperarousability in lefts. This is consistent with data showing that right hemisphere damage is associated with inattention and denial and left hemisphere damage with hypervigilance and anxiety. The concept of laterally differentiated mediation of arousal and habituation was supported.

Interictal behavioral features of patients with epilepsy

Three questions are dealt with in this paper. (1) Do patients with epilepsy differ behaviorally from normal control groups and from persons with other medical and neurological conditions with respect to emotional adjustment, and if so, in what ways? (2) Are patients with temporal lobe epilepsy different emotionally or behaviorally from patients with other types of epilepsy? (3) To what degree does underlying brain dysfunction create a substrate for abnormal and maladaptive behavior? A review of the literature reveals the following. Persons with epilepsy demonstrate more emotional and psychiatric problems than normal individuals and more difficulties than other patient groups having nonneurological disorders, but have about the same incidence of these problems as persons with other neurological disorders. Increased emotional and psychiatric problems are not found among patients with temporal lobe epilepsy in comparison to patients with other types of epilepsy, although there are some behavioral peculiarities which appear in a small proportion of these patients. There is a mild tendency for impairment on neuropsychological tests to be associated with emotional and psychiatric problems in epilepsy.

Autonomic responsiveness to affective visual stimulation in temporal lobe epilepsy

Patients with temporal lobe epilepsy (TLE) have been posited by some to manifest a syndrome of interictal personality and behavioral change. Furthermore, this syndrome has been attributed to an underlying mechanism--enhanced affective responsiveness. The purpose of this investigation was to determine whether patients with TLE manifest increased emotional responsiveness relative to appropriate controls. Patients with TLE (n = 23) were compared with non-TLE (n = 7) and healthy controls (n = 16) as to their autonomic nervous system responsiveness to an emotionally stressing film. No differences were found among the groups. These results are related to the larger literature concerning epilepsy and psychopathology.