A revised intracarotid etomidate memory (Wada) procedure.

OBJECTIVES: To evaluate unilateral memory function by the means of a modified Montreal etomidate speech and memory procedure (e-SAM) in epilepsy patients who were candidates for standard anterior temporal lobectomy involving resection of mesial temporal lobe structures. MATERIALS AND METHODS: After the first three patients experienced significant side effects with the e-SAM procedure, we modified the procedure to a single bolus injection. The neuropsychological data of all 21 patients who underwent unilateral memory testing by means of intracarotid injection of etomidate were analyzed. RESULTS: There was a significant difference in memory scores when injections were on the side ipsilateral to the epileptogenic focus compared with when the injections were on the contralateral side (P < 0.01), supposedly reflecting unilateral hippocampal memory function and dysfunction. In addition, the procedural modification resulted in eradication of all major side effects in the ensuing 18 patients. CONCLUSIONS: The technical modification of the Montreal procedure from continuous to bolus injection effectively enabled the demonstration of the relative weakness of the memory function of the epileptogenic hemisphere. The revised etomidate procedure provided the clinical information on unilateral hippocampal memory function necessary for surgical decision.

Possible remote functional reorganization in left temporal lobe epilepsy.

OBJECTIVE: To provide functional magnetic resonance imaging-based insight into the impact of left temporal lobe epilepsy (TLE) on language-related functional re-organization. MATERIALS AND METHODS: Ten right-handed patients with left TLE were compared with 10 matched healthy controls. Regional brain activation during the language task was measured in the inferior frontal gyrus (IFG) and in the superior temporal gyrus (STG), and the regional inter-hemispheric lateralization index (LI) was calculated. RESULTS: Left language lateralization was documented in all the patients and controls. Reduced lateralization in the IFG was due to decreased activity in the left frontal region rather than to increased activity in the right frontal region. The LI values in the STG correlated with the LI values in the IFG in the controls but not in the patients. CONCLUSIONS: The left IFG was most probably involved in the epileptogenesis and concomitant language-related cortical plasticity in patients with left TLE.

Right hemisphere specialization for the identification of emotional words and sentences: evidence from stroke patients.

This study examines the contribution of the lexical/verbal channel to emotional processing in 16 right brain-damaged (RBD), 16 left brain-damaged (LBD) and 16 normal control (NC) right-handed adults. Emotional lexical perception tasks were developed; analogous nonemotional tasks were created to control for cognitive and linguistic factors. The three subject groups were matched for gender, age and education. The brain-damaged groups were similar with respect to cerebrovascular etiology, months post-onset, sensory-motor status and lesion location. Parallel emotional and nonemotional tasks included word identification, sentence identification and word discrimination. For both word tasks, RBDs were significantly more impaired than LBDs and NCs in the emotional condition. For all three tasks, RBDs showed a significantly greater performance discrepancy between emotional and nonemotional conditions than did LBDs or NCs. Results were not affected by the valence (i.e. positive/negative) of the stimuli. These findings suggest a dominant role for the right hemisphere in the perception of lexically-based emotional stimuli.

Hemispheric specialization for discourse reports of emotional experiences: relationships to demographic, neurological, and perceptual variables.

This study examined hemispheric specialization for discourse reports of emotional and nonemotional experience in 16 right-brain-damaged (RBD), 16 left-brain-damaged (LBD), and 16 demographically-matched normal control (NC) right-handed adults. Patient groups did not differ on etiology, months post-CVA onset, and intrahemispheric lesion location. Subjects were requested to produce monologues about positive and negative emotional and nonemotional experiences. The lexical content of written transcriptions of these monologues was later rated for "emotionality" by naive judges. Overall, RBDs described experiences with less emotional intensity than did NCs and LBDs, providing support for right hemisphere involvement in lexical emotion. Although the RBDs in the current study demonstrated similar patterns of deficits in a prior study [9] on tasks involving lexical emotional perception, there were no significant relationships between the current measures of emotional expression and the previous measures of emotional perception. Finally, the expression and the perception data were examined with respect to intrahemispheric factors. Among the brain-damaged subjects, subcortical structures were more involved in reports of emotional experience, and cortical structures were more involved in the perception of emotion.

Verbal pragmatics following unilateral stroke: emotional content and valence.

Verbal pragmatic aspects of discourse production were examined in 16 right brain-damaged (RBD), 16 left brain-damaged (LBD), and 16 normal control right-handed adults. The facilitation effect of emotional content, valence hypothesis, and relationship between pragmatics and emotion were evaluated. Participants produced monologues while recollecting emotional and nonemotional experiences. Transcribed monologues were rated for appropriateness on 6 pragmatic features: conciseness, lexical selection, quantity, relevancy, specificity, and topic maintenance. Overall, brain-damaged groups were rated as significantly less appropriate than normals. Consistent with the facilitation effect, emotional content enhanced pragmatic performance of LBD aphasic participants yet suppressed performance of RBD participants. Contrary to the valence hypothesis, RBD participants were more impaired for positive emotions and LBD participants for negative emotions. Pragmatic appropriateness was not strongly correlated with a measure of emotional intensity.

Psychometric aspects of verbal pragmatic ratings.

This study examined the psychometric aspects of a verbal pragmatic rating scale. The scale contained six pragmatic features (i.e., Conciseness, Lexical Selection, Quantity, Relevancy, Specificity, and Topic Maintenance) based on Grice's cooperative principles. Fifteen right brain-damaged (RBD), 15 left brain-damaged (LBD), and 16 healthy normal control (NC) right-handed adult participants produced narratives while recollecting emotional and nonemotional experiences. Naive raters evaluated each pragmatic feature for appropriateness on a 5-point Likert scale. When reliability was examined, the overall internal consistency of the pragmatic scale was extremely high (alpha =.96). Factor analysis was conducted to examine the theoretical relations among the six pragmatic features. Three meaningful factors involving discourse content, conceptual unity, and parsimony were identified. Findings are discussed in light of Grice's model and the construct validity of the scale.

[Presurgical neuropsychological assessment in epilepsy: the Wada test].

37 candidates for epilepsy surgery underwent the intracarotid amytal procedure (IAP; also known as the Wada test) to determine hemispheric speech dominance and memory capacity. 31 demonstrated left hemisphere speech dominance, 2 showed evidence for bilateral language and 4 demonstrated right hemispheric language dominance. Our study supports a correlational relationship between handedness, lesion laterality and age of onset of seizures, as reported in earlier studies. Left-handed patients with a left hemisphere lesion whose seizures began to an early age had a strong tendency for reversed language dominance. Asymmetry of at least 20% in performing the memory test was taken as the cutoff score for demonstrating laterality of lesions. The asymmetry score correctly predicted laterality of lesions in all 28 patients; 6 did not have asymmetry scores and 3 were examined for language only. None of the patients who successfully passed the Wada memory test had any significant postsurgical memory deficits; 1 had transient reduction in verbal memory and 4 who did not pass the test were not operated on for this reason. Our results demonstrate the importance of the Wada test in determining cerebral speech dominance, in predicting post-surgical amnesia, and support its usefulness in predicting laterality of seizure focus in candidates for temporal lobectomy.

Is there any correlation between severity of epilepsy and cognitive abilities in patients with temporal lobe epilepsy?

Frequent refractory seizures may cause cognitive deterioration when they present at an early age, especially in infants. The findings of previous studies designed to examine the impact of repetitive seizures on cognition in adolescents and adults, however, have shown wide variation. We analyzed the data of neuropsychological evaluations of patients before they underwent temporal lobe resection because of refractory seizure disorder in our institution from 1998 to 2001. Forty-four consecutive patients aged 12-48 years underwent a comprehensive neuropsychological evaluation that included a battery of selected visual and verbal memory tests. Statistical analysis revealed no significant correlation between disease-related parameters, such as age of onset, duration of active disease, estimated cumulative number of complex partial seizures and secondarily generalized seizures, and the results of neuropsychological tests. These findings support the hypothesis that factors other than repetitive seizures are responsible for cognitive dysfunction among adolescents and adults.

Quality of life self-assessment as a function of lateralization of lesion in candidates for epilepsy surgery.

PURPOSE: This prospective study aimed to investigate the relationship(s) of the laterality of the epileptogenic lesion to personality factors, emotional processing, and the subjective experience of quality-of-life (QOL) self-assessment in candidates for epilepsy surgery. METHODS: Patients who were candidates for epilepsy surgery were studied. Eighteen of them (aged 19-61 years) had localization-related epilepsy in the right temporal lobe (RTLE), 18 (aged 21-50 years) had localization-related epilepsy in the left temporal lobe (LTLE), and 20 were demographically matched normal subjects. The Spielberger Trait/State Anxiety questionnaire and the QOLIE-31 questionnaire for self-assessment of quality of life were used. One-way analysis of variance, Pearson correlations, and linear regression analyses were performed on group and anxiety levels and QOLIE variables. RESULTS: LTLE patients systematically showed higher levels of anxiety and lower self-estimates of the quality of their lives when compared with RTLE patients. All anxiety measures were highly correlated with Total QOL in LTLE (p < 0.05) but not in RTLE patients; however, different parameters of QOL showed different relationships with measures of anxiety. Results of multiple regression analyses suggested that the level of anxiety was relatively stable and less affected by QOL factors in LTLE as compared with RTLE patients (p = 0.03). CONCLUSIONS: A high level of anxiety shown by LTLE patients may represent a personality trait and cause a response bias in overreporting of negative symptoms and a decreased self-assessment of QOL. It may also present a presurgical risk factor, particularly for patients with LTLE lesions. Appropriate patient counseling is advised.