Effect of Focus Lateralization on Memory Assessment during the Intracarotid Amobarbital Procedure

Rouleau, Isabelle; Robidoux, Janik; Labrecque, R; Denault, Carole

doi:10.1006/brcg.1997.0894

Cited by 10 publications

(7 citation statements)

References 29 publications

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“…Impaired memory performance is observed in about 20–30% of cases after injection into the epileptic hemisphere, whereas this proportion reaches 60–80% after contralateral injection (Powell et al., 1987; Rausch et al., 1989; Wyllie et al., 1991). Based on these data, several authors advocate IAT performance as a way to predict task‐specific memory decline after surgery (and eventually to propose surgical abstention if global amnesia is predicted), and as an adjunct to determine seizure focus laterality (Wyllie et al., 1991; Perrine et al., 1993; Rouleau et al., 1997).…”

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confidence: 99%

Metabolic evidence for episodic memory plasticity in the nonepileptic temporal lobe of patients with mesial temporal epilepsy

et al. 2011

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SUMMARYPurpose: Metabolic changes have been described in the nonepileptic temporal lobe of patients with unilateral mesiotemporal lobe epilepsy (MTLE) associated with hippocampal sclerosis (HS). To better understand the functional correlate of this metabolic finding, we have sought to characterize brain regions in patients with MTLE that show correlation between unilateral episodic memory performances, as assessed by intracarotid amobarbital test (IAT), and interictal regional cerebral metabolism measured by [18 F]-fluorodeoxyglucose positron emission tomography (FDG-PET). Methods: Resting FDG-PET was performed interictally in 26 patients with unilateral MTLE caused by HS (16 female, mean age: 36 years; 16 left HS). Using statistical parametric mapping (SPM8), we performed a group comparison analysis comparing brain metabolism in the patients and in 54 adult controls (27 female, mean age: 32 years), with FDG-PET data of right HS patients being flipped. IAT scores of nonepileptic hemisphere functions (amobarbital injection ipsilateral to HS) were used as covariates of interest in a correlation analysis with regional brain metabolism. Key Findings: The group comparison analysis revealed significant hypometabolic areas in a widespread temporofrontal network ipsilateral to HS. In addition, a significant increase in metabolism was found in mesial and lateral temporal regions contralateral to HS. Significant positive correlations were found between IAT scores of nonepileptic hemisphere functions and mesial temporal metabolism in this hemisphere. Significance: This study demonstrates the existence of significant increase in relative regional cerebral glucose metabolism in mesial and lateral temporal regions contralateral to the epileptic focus in patients with unilateral MTLE associated with HS. The positive correlation in these brain regions between IAT scores and metabolism supports the role of disease-induced plasticity mechanisms contralateral to HS in the preservation of episodic memory processes.

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confidence: 99%

Metabolic evidence for episodic memory plasticity in the nonepileptic temporal lobe of patients with mesial temporal epilepsy

et al. 2011

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“…Impaired memory performance is observed in about 20-30% of cases after injection on the side of the epileptic hemisphere, whereas this proportion reaches 60-80% after contralateral injection [65,69,95]. Based on these data, several authors advocate IAT performance as a way to predict task-specific memory decline after surgery (and possibly to propose surgical abstention if global amnesia is predicted), and as an adjunct to determine seizure focus laterality [61,74,95]. However, considering the above mentioned drawbacks of the IAT plus the uncertain proper delivery of the sodium amobarbital to the hippocampal formation [57], several studies have assessed the potential clinical added-value of functional neuroimaging in this clinical indication (for reviews or commentaries, see, e.g., [57,58,68]).…”

Section: Preoperative Mapping Of Episodic Memory Functionmentioning

confidence: 99%

Presurgical electromagnetic functional brain mapping in refractory focal epilepsy

et al. 2018

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Background: Electroencephalography (EEG) and magnetoencephalography (MEG) are neurophysiological methods used to investigate non-invasively the spatial, temporal and spectral dynamics of human brain functions. Objectives: This paper reviews data about the use of EEG and MEG for presurgical functional brain mapping in patients with refractory focal epilepsy. Focus is on the localization of the primary sensorimotor (SM1) cortex as well as the verbal language and episodic memory functions. Material and Methods: The English literature was reviewed based on PubMed search. Relevant references within the selected papers were also included. Results: Presurgical MEG functional localization of SM1 cortex generally overlaps with intracranial mapping. MEG allows for determination of hemispheric verbal (receptive and expressive) language dominance in neurosurgical patients with a high degree of concordance with the intracarotid amobarbital test. MEG represents an interesting technique to assess postoperative memory outcome in patients with mesial temporal lobe epilepsy. Very few studies have evaluated the yield of EEG in these three clinical indications. High-density EEG might be a promising technique that needs further validation. Conclusions: MEG is a validated and robust technique for non-invasive functional mapping of SM1 cortex and verbal language hemispheric dominance in patients with refractory focal epilepsy. Data also suggest that MEG is a promising technique to assess the hemispheric dominance of memory function. Further studies are needed to assess the clinical added value of high-density EEG in these clinical indications.

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“…Milner et al expanded the use of the Wada test to measure unilateral memory function in epilepsy surgery candidates in order to predict postoperative amnesia 12 . Since then, the contributions of the Wada test have been widely extended and include: (i) lateralisation of seizure focus [25][26][27][28][29][30][31][32] ; (ii) prediction of seizure control outcome 29,[33][34][35] ; and (iii) prediction of neuropsychological outcome [36][37][38][39][40][41] . On the other hand, its value to preclude postoperative amnesic syndromes still remains open to question 42,43 .…”

Section: The Wada Testmentioning

confidence: 99%

“…The laterality of Wada memory performance is based on the assumption that memory function mediated by medial temporal structures reflects the damage caused by or underlying epileptogenesis: intact performance on the non-epileptogenic side and impaired performance on the epileptogenic hemisphere 13 . Using absolute or comparative lateralising criteria of Wada memory performance from both hemispheres, 50-80% of patients with temporal lobe epilepsy are correctly lateralised [25][26][27][28][29][30][31][32] . In the remainder, Wada memory performance is symmetrical and therefore the laterality is indeterminate.…”

Section: False/reverse Lateralisationmentioning

confidence: 99%

Presurgical assessment of memory-related brain structures: the Wada test and functional neuroimaging

Akanuma

Koutroumanidis

Adachi³

et al. 2003

Seizure

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Medial temporal lobe structures are known to play a major role in memory processing. Recent work has revealed that extratemporal structures (e.g. the frontal lobe and thalamus) may also be important in memory function. In candidates for epilepsy surgery, particularly in those with temporal lobe seizures, presurgical evaluation of memory function is essential, since seizures may originate in the neural substrate that is critical for memory. In this article, we review the tools used for presurgical evaluation and their contribution to the understanding of memory function, focusing on the Wada test, [18F]fluorodeoxy-glucose positron emission tomography ([18F]FDG-PET) and functional magnetic resonance imaging (fMRI). We also explore perspectives on future studies that may elucidate the role of the temporal and extratemporal structures in memory function and the mechanisms of cerebral plasticity.

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Effect of Focus Lateralization on Memory Assessment during the Intracarotid Amobarbital Procedure

Cited by 10 publications

References 29 publications

Metabolic evidence for episodic memory plasticity in the nonepileptic temporal lobe of patients with mesial temporal epilepsy

Metabolic evidence for episodic memory plasticity in the nonepileptic temporal lobe of patients with mesial temporal epilepsy

Presurgical electromagnetic functional brain mapping in refractory focal epilepsy

Presurgical assessment of memory-related brain structures: the Wada test and functional neuroimaging

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