Contralateral interictal and ictal EEG epileptiform activity accentuate memory impairment in unilateral mesial temporal sclerosis patients.

Pinto, Lécio Figueira; Adda, Carla Cristina; Silva, Liliane C. A.; Banaskiwitz, Natalie H. C.; Passarelli, Valmir; Jorge, Carmen Lisa; Valério, Rosa; Castro, Luiz Henrique Martins

doi:10.1037/neu0000342

Cited by 6 publications

(6 citation statements)

References 35 publications

(56 reference statements)

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“…Many patients with unilateral mTLE also showed significant contralateral interictal and ictal epileptiform activity during scalp and invasive electroencephalogram (EEG) recordings, which was thought to be related to surgical outcome and memory impairment ( Passarelli et al, 2015 , Jehi et al, 2010 , Pinto et al, 2017 ). Does abnormal ipsilateral hippocampus affect the contralateral hippocampus which seemed normal?…”

Section: Introductionmentioning

confidence: 99%

Structural and functional reorganization of contralateral hippocampus after temporal lobe epilepsy surgery

Jiang

Qin

et al. 2021

NeuroImage: Clinical

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Section: Introductionmentioning

confidence: 99%

Structural and functional reorganization of contralateral hippocampus after temporal lobe epilepsy surgery

Jiang

Qin

et al. 2021

NeuroImage: Clinical

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“…The same EEG classification strategy was adopted in previous studies that demonstrated that bilateral epileptiform activity negatively impacts verbal and nonverbal memory in unilateral HS patients 14,15 . Based on these studies, we hypothesized that patients with bilateral electrographic ictal involvement would present less pronounced postoperative memory decline when compared to patients with ictal involvement restricted to the HS side.…”

Section: Discussionmentioning

confidence: 99%

“…Patients with unilateral HS and bilateral epileptiform activity present worse baseline cognitive performance compared to patients with epileptiform activity restricted to the HS side. 14,15 Epileptiform activity contralateral to the HS side may be reverted after successful epilepsy surgery, leading to improved function in the contralateral hippocampus.…”

Section: Introductionmentioning

confidence: 99%

Bilateral ictal EEG is associated with better memory outcome after hippocampal sclerosis surgery

Castro‐Lima,

Passarelli,

Ribeiro

et al. 2023

Epilepsia Open

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ObjectiveTo compare memory outcomes after surgery for unilateral Hippocampal Sclerosis (HS) associated epilepsy in patients with unilateral and bilateral ictal electrographic involvement.MethodsWe prospectively evaluated HS patients, aged 18 to 55 years and IQ≥70. Left (L) and right (R) surgical groups underwent noninvasive video‐EEG monitoring and Wada test. We classified patients as Ipsilateral if ictal EEG was restricted to the HS side, or Bilateral, if at least one seizure onset occurred contralaterally to the HS, or if ictal discharge evolved to the opposite temporal region. Patients who declined surgery served as controls. Memory was evaluated on two occasions with Rey Auditory‐Verbal Learning Test and Rey Visual‐Design Learning Test. Baseline neuropsychological test scores were compared between groups. Pre‐ and postoperative scores were compared within each group. Reliable Change Index Z‐scores (RCI) were obtained using controls as references, and compared between surgical groups.ResultsWe evaluated 64 patients. Patients were classified as: L‐Ipsilateral(9), L‐Bilateral(15), L‐Control(9), R‐Ipsilateral(10), R‐Bilateral (9), R‐Control(12). On preoperative evaluation, memory performance did not differ among surgical groups. Right HS patients did not present postoperative memory decline. L‐Ipsilateral group presented postoperative decline on immediate (p=0.036) and delayed verbal recall (p=0.011), while L‐Bilateral did not decline. L‐Ipsilateral had lower RCI Z‐scores, indicating delayed verbal memory decline compared to L‐Bilateral (p=0.012).SignificanceDominant HS patients with bilateral ictal involvement presented less pronounced postoperative verbal memory decline compared to patients with exclusive ipsilateral ictal activity. Surgery was indicated in these patients regardless of memory impairment on neuropsychological testing, since resection of the left sclerotic hippocampus could result in cessation of contralateral epileptiform activity, and, therefore, improved memory function.

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“…Second, epileptiform EEG activity may have negatively affected performance in our patient sample with chronic therapy‐refractory epilepsy. A recent study showed an impairment in the visual Stroop paradigm only in patients with unilateral HS who had concordant epileptiform EEG activity while patients with contralateral EEG epileptiform activity showed preserved Stroop test performance (Pinto et al , ). However, a previous review across various studies concluded that direct effects of epileptiform EEG discharges on cognition are rather mild (Aldenkamp & Arends, ).…”

Section: Discussionmentioning

confidence: 99%

“…Few neuropsychological studies used paradigms specifically targeting conflict resolution. An impairment in the colour word Stroop task was indicated in two studies (Pinto et al , ; Wang et al , ), whereas another study found no differences between mesial TLE and frontal epilepsy (Corcoran & Upton, ). In contrast to the fMRI findings in healthy subjects showing left lateralized BOLD responses during conflict resolution (Bach et al , ; Oehrn et al , ), the neuropsychological studies did not report a lateralization effect for unilateral mesial TLE.…”

Section: Introductionmentioning

confidence: 98%

Impaired processing of response conflicts in mesial temporal lobe epilepsy

Ramm

Möddel

Sundermann

et al. 2019

Journal of Neuropsychology

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Increasing evidence from neuroimaging studies points towards a hippocampal role in resolving approach-avoidance goal conflicts. Furthermore, previous neuroimaging findings suggest that the hippocampus (HC) contributes to successful conflict resolution as it is measured, for example, in a Stroop paradigm. However, it is still an open question whether the hippocampus is indeed causally relevant for resolving cognitive conflicts. Here, we investigated whether conflict resolution performance is affected by hippocampal pathology. N = 30 patients with mesial temporal lobe epilepsy (MTLE), almost exclusively showing MRI signs of hippocampal sclerosis, and an equal number of agematched healthy controls performed an auditory Stroop paradigm. Participants listened to the words 'high' and 'low', spoken in either a high or a low pitch. Subjects' response time and accuracy to the phonetic information in the presence of incongruent (conflict trials) or congruent (non-conflict trials) semantic information were assessed. In addition, patients' regional grey matter (GM) brain volumes were analysed. We observed an increased effect of conflict on accuracy in patients with MTLE compared to healthy controls. This effect was negatively correlated with right HC volume. The results suggest that the impairment in the resolution of a response conflict is related to hippocampal structural integrity and thus add further support to the notion that the HC is not only involved but even causally relevant for successful cognitive conflict processing.

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Contralateral interictal and ictal EEG epileptiform activity accentuate memory impairment in unilateral mesial temporal sclerosis patients.

Cited by 6 publications

References 35 publications

Structural and functional reorganization of contralateral hippocampus after temporal lobe epilepsy surgery

Structural and functional reorganization of contralateral hippocampus after temporal lobe epilepsy surgery

Bilateral ictal EEG is associated with better memory outcome after hippocampal sclerosis surgery

Impaired processing of response conflicts in mesial temporal lobe epilepsy

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