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Kokkinos V, Seimenis I. Concordance of verbal memory and language fMRI lateralization in people with epilepsy. J Neuroimaging 2024; 34:95-107. [PMID: 37968766 DOI: 10.1111/jon.13171] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 10/29/2023] [Accepted: 11/01/2023] [Indexed: 11/17/2023] Open
Abstract
BACKGROUND AND PURPOSE This work investigates verbal memory functional MRI (fMRI) versus language fMRI in terms of lateralization, and assesses the validity of performing word recognition during the functional scan. METHODS Thirty patients with a diagnosis of epilepsy underwent verbal memory, visuospatial memory, and language fMRI. We used word encoding, word recognition, image encoding, and image recognition memory tasks, and semantic description, reading comprehension, and listening comprehension language tasks. We used three common lateralization metrics: network spatial distribution, maximum statistical value, and laterality index (LI). RESULTS Lateralization of signal spatial distribution resulted in poor similarity between verbal memory and language fMRI tasks. Signal maximum lateralization showed significant (>.8) but not perfect (1) similarity. Word encoding LI showed significant correlation only with listening comprehension LI (p = .016). Word recognition LI was significantly correlated with expressive language semantic description LI (p = .024) and receptive language reading and listening comprehension LIs (p = .015 and p = .019, respectively). There was no correlation between LIs of the visuospatial tasks and LIs of the language tasks. CONCLUSIONS Our results support the association between language and verbal memory lateralization, optimally determined by LI quantification, and the introduction of quantitative means for language fMRI interpretation in clinical settings where verbal memory lateralization is imperative.
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Affiliation(s)
- Vasileios Kokkinos
- Comprehensive Epilepsy Center, Northwestern Memorial Hospital, Chicago, Illinois, USA
- Department of Neurology, Feinberg School of Medicine, Northwestern University, Chicago, Illinois, USA
- Department of Medicine, School of Health Sciences, Democritus University of Thrace, Alexandroupoli, Greece
| | - Ioannis Seimenis
- Department of Medicine, School of Health Sciences, Democritus University of Thrace, Alexandroupoli, Greece
- Medical School, National and Kapodistrian University of Athens, Athens, Greece
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Audrain S, Barnett A, Mouseli P, McAndrews MP. Leveraging the resting brain to predict memory decline after temporal lobectomy. Epilepsia 2023; 64:3061-3072. [PMID: 37643922 DOI: 10.1111/epi.17767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 08/28/2023] [Accepted: 08/28/2023] [Indexed: 08/31/2023]
Abstract
OBJECTIVE Predicting memory morbidity after temporal lobectomy in patients with temporal lobe epilepsy (TLE) relies on indices of preoperative temporal lobe structural and functional integrity. However, epilepsy is increasingly considered a network disorder, and memory a network phenomenon. We assessed the utility of functional network measures to predict postoperative memory changes. METHODS Seventy-two adults with TLE (37 left/35 right) underwent preoperative resting-state functional magnetic resonance imaging and pre- and postoperative neuropsychological assessment. We compared functional connectivity throughout the memory network of each patient to a healthy control template (n = 19) to identify differences in global organization. A second metric indicated the degree of integration of the to-be-resected temporal lobe with the rest of the memory network. We included these measures in a linear regression model alongside standard clinical variables as predictors of memory change after surgery. RESULTS Left TLE patients with more atypical memory networks, and with greater functional integration of the to-be-resected region with the rest of the memory network preoperatively, experienced the greatest decline in verbal memory after surgery. Together, these two measures explained 44% of variance in verbal memory change, outperforming standard clinical and demographic variables. None of the variables examined was associated with visuospatial memory change in patients with right TLE. SIGNIFICANCE Resting-state connectivity provides valuable information concerning both the integrity of to-be-resected tissue and functional reserve across memory-relevant regions outside of the to-be-resected tissue. Intrinsic functional connectivity has the potential to be useful for clinical decision-making regarding memory outcomes in left TLE, and more work is needed to identify the factors responsible for differences seen in right TLE.
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Affiliation(s)
- Sam Audrain
- Division of Clinical and Computational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Alexander Barnett
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
| | - Pedram Mouseli
- Division of Clinical and Computational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
- Centre for Multimodal Sensorimotor and Pain Research, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - Mary Pat McAndrews
- Division of Clinical and Computational Neuroscience, Krembil Research Institute, University Health Network, Toronto, Ontario, Canada
- Department of Psychology, University of Toronto, Toronto, Ontario, Canada
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Crow AJD, Thomas A, Rao Y, Beloor-Suresh A, Weinstein D, Hinds WA, Tracy JI. Task-based functional magnetic resonance imaging prediction of postsurgical cognitive outcomes in temporal lobe epilepsy: A systematic review, meta-analysis, and new data. Epilepsia 2023; 64:266-283. [PMID: 36522799 PMCID: PMC9944224 DOI: 10.1111/epi.17475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 11/21/2022] [Accepted: 12/01/2022] [Indexed: 12/23/2022]
Abstract
Task-based functional magnetic resonance imaging (tfMRI) has developed as a common alternative in epilepsy surgery to the intracarotid amobarbital procedure, also known as the Wada procedure. Prior studies have implicated tfMRI as a comparable predictor of postsurgical cognitive outcomes. However, the predictive validity of tfMRI has not been established. This preregistered systematic review and meta-analysis (CRD42020183563) synthesizes the literature predicting postsurgical cognitive outcomes in temporal lobe epilepsy (TLE) using tfMRI. The PubMed and PsycINFO literature databases were queried for English-language articles published between January 1, 2009 and December 31, 2020 associating tfMRI laterality indices or symmetry of task activation with outcomes in TLE. Their references were reviewed for additional relevant literature, and unpublished data from our center were incorporated. Nineteen studies were included in the meta-analysis. tfMRI studies predicted postsurgical cognitive outcomes in left TLE ( ρ ̂ = -.27, 95% confidence interval [CI] = -.32 to -.23) but not right TLE ( ρ ̂ = -.02, 95% CI = -.08 to .03). Among studies of left TLE, language tfMRI studies were more robustly predictive of postsurgical cognitive outcomes ( ρ ̂ = -.27, 95% CI = -.33 to -.20) than memory tfMRI studies ( ρ ̂ = -.27, 95% CI = -.43 to -.11). Further moderation by cognitive outcome domain indicated language tfMRI predicted confrontation naming ( ρ ̂ = -.32, 95% CI = -.41 to -.22) and verbal memory ( ρ ̂ = -.26, 95% CI = -.35 to -.17) outcomes, whereas memory tfMRI forecasted only verbal memory outcomes ( ρ ̂ = -.37, 95% CI = -.57 to -.18). Surgery type, birth sex, level of education, age at onset, disease duration, and hemispheric language dominance moderated study outcomes. Sensitivity analyses suggested the interval of postsurgical follow-up, and reporting and methodological practices influenced study outcomes as well. These findings intimate tfMRI is a modest predictor of outcomes in left TLE that should be considered in the context of a larger surgical workup.
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Affiliation(s)
- Andrew J. D. Crow
- Department of Neurology, Thomas Jefferson University Sidney Kimmel Medical College, Philadelphia, Pennsylvania, USA
| | - Alisha Thomas
- Department of Neurology, Thomas Jefferson University Sidney Kimmel Medical College, Philadelphia, Pennsylvania, USA
| | - Yash Rao
- Department of Neurology, Thomas Jefferson University Sidney Kimmel Medical College, Philadelphia, Pennsylvania, USA
- Department of Radiology, Rowan University School of Osteopathic Medicine, Glassboro, New Jersey, USA
| | - Ashithkumar Beloor-Suresh
- Department of Neurology, Thomas Jefferson University Sidney Kimmel Medical College, Philadelphia, Pennsylvania, USA
| | - David Weinstein
- Department of Neurology, Thomas Jefferson University Sidney Kimmel Medical College, Philadelphia, Pennsylvania, USA
- Department of Neurology, Drexel University College of Medicine, Philadelphia, Pennsylvania, USA
| | - Walter A. Hinds
- Department of Neurology, Thomas Jefferson University Sidney Kimmel Medical College, Philadelphia, Pennsylvania, USA
| | - Joseph I. Tracy
- Department of Neurology, Thomas Jefferson University Sidney Kimmel Medical College, Philadelphia, Pennsylvania, USA
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Sonoda M, Rothermel R, Carlson A, Jeong JW, Lee MH, Hayashi T, Luat AF, Sood S, Asano E. Naming-related spectral responses predict neuropsychological outcome after epilepsy surgery. Brain 2022; 145:517-530. [PMID: 35313351 PMCID: PMC9014727 DOI: 10.1093/brain/awab318] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 07/14/2021] [Accepted: 07/28/2021] [Indexed: 11/12/2022] Open
Abstract
This prospective study determined the use of intracranially recorded spectral responses during naming tasks in predicting neuropsychological performance following epilepsy surgery. We recruited 65 patients with drug-resistant focal epilepsy who underwent preoperative neuropsychological assessment and intracranial EEG recording. The Clinical Evaluation of Language Fundamentals evaluated the baseline and postoperative language function. During extra-operative intracranial EEG recording, we assigned patients to undergo auditory and picture naming tasks. Time-frequency analysis determined the spatiotemporal characteristics of naming-related amplitude modulations, including high gamma augmentation at 70-110 Hz. We surgically removed the presumed epileptogenic zone based on the intracranial EEG and MRI abnormalities while maximally preserving the eloquent areas defined by electrical stimulation mapping. The multivariate regression model incorporating auditory naming-related high gamma augmentation predicted the postoperative changes in Core Language Score with r2 of 0.37 and in Expressive Language Index with r2 of 0.32. Independently of the effects of epilepsy and neuroimaging profiles, higher high gamma augmentation at the resected language-dominant hemispheric area predicted a more severe postoperative decline in Core Language Score and Expressive Language Index. Conversely, the model incorporating picture naming-related high gamma augmentation predicted the change in Receptive Language Index with an r2 of 0.50. Higher high gamma augmentation independently predicted a more severe postoperative decline in Receptive Language Index. Ancillary regression analysis indicated that naming-related low gamma augmentation and alpha/beta attenuation likewise independently predicted a more severe Core Language Score decline. The machine learning-based prediction model suggested that naming-related high gamma augmentation, among all spectral responses used as predictors, most strongly contributed to the improved prediction of patients showing a >5-point Core Language Score decline (reflecting the lower 25th percentile among patients). We generated the model-based atlas visualizing sites, which, if resected, would lead to such a language decline. With a 5-fold cross-validation procedure, the auditory naming-based model predicted patients who had such a postoperative language decline with an accuracy of 0.80. The model indicated that virtual resection of an electrical stimulation mapping-defined language site would have increased the relative risk of the Core Language Score decline by 5.28 (95% confidence interval: 3.47-8.02). Especially, that of an electrical stimulation mapping-defined receptive language site would have maximized it to 15.90 (95% confidence interval: 9.59-26.33). In summary, naming-related spectral responses predict neuropsychological outcomes after epilepsy surgery. We have provided our prediction model as an open-source material, which will indicate the postoperative language function of future patients and facilitate external validation at tertiary epilepsy centres.
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Affiliation(s)
- Masaki Sonoda
- Department of Pediatrics, Children’s Hospital of Michigan, Detroit Medical Center, Wayne State University, Detroit, MI 48201, USA
- Department of Neurosurgery, Yokohama City University, Yokohama, Kanagawa 2360004, Japan
| | - Robert Rothermel
- Department of Psychiatry, Children’s Hospital of Michigan, Detroit Medical Center, Wayne State University, Detroit, MI 48201, USA
| | - Alanna Carlson
- Department of Pediatrics, Children’s Hospital of Michigan, Detroit Medical Center, Wayne State University, Detroit, MI 48201, USA
- Department of Psychiatry, Children’s Hospital of Michigan, Detroit Medical Center, Wayne State University, Detroit, MI 48201, USA
| | - Jeong-Won Jeong
- Department of Pediatrics, Children’s Hospital of Michigan, Detroit Medical Center, Wayne State University, Detroit, MI 48201, USA
- Department of Neurology, Children’s Hospital of Michigan, Detroit Medical Center, Wayne State University, Detroit, MI 48201, USA
| | - Min-Hee Lee
- Department of Pediatrics, Children’s Hospital of Michigan, Detroit Medical Center, Wayne State University, Detroit, MI 48201, USA
| | - Takahiro Hayashi
- Department of Neurosurgery, Yokohama City University, Yokohama, Kanagawa 2360004, Japan
| | - Aimee F Luat
- Department of Pediatrics, Children’s Hospital of Michigan, Detroit Medical Center, Wayne State University, Detroit, MI 48201, USA
- Department of Neurology, Children’s Hospital of Michigan, Detroit Medical Center, Wayne State University, Detroit, MI 48201, USA
- Department of Pediatrics, Central Michigan University, Mount Pleasant, MI 48858, USA
| | - Sandeep Sood
- Department of Neurosurgery, Children’s Hospital of Michigan, Detroit Medical Center, Wayne State University, Detroit, MI 48201, USA
| | - Eishi Asano
- Department of Pediatrics, Children’s Hospital of Michigan, Detroit Medical Center, Wayne State University, Detroit, MI 48201, USA
- Department of Neurology, Children’s Hospital of Michigan, Detroit Medical Center, Wayne State University, Detroit, MI 48201, USA
- Correspondence to: Eishi Asano, MD, PhD, MS (CRDSA) Division of Pediatric Neurology, Children’s Hospital of Michigan Wayne State University. 3901 Beaubien St., Detroit, MI 48201, USA E-mail:
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The Impact of Right Temporal Lobe Epilepsy On Nonverbal Memory: Meta-regression of Stimulus- and Task-related Moderators. Neuropsychol Rev 2021; 32:537-557. [PMID: 34559363 DOI: 10.1007/s11065-021-09514-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 05/24/2021] [Indexed: 11/08/2022]
Abstract
Nonverbal memory tests have great potential value for detecting the impact of lateralized pathology and predicting the risk of memory loss following right temporal lobe resection (TLR) for temporal lobe epilepsy (TLE) patients, but this potential has not been realized. Previous reviews suggest that stimulus type moderates the capacity of nonverbal memory tests to detect right-lateralized pathology (i.e., faces > designs), but the roles of other task-related factors have not been systematically explored. We address these limitations using mixed model meta-regression (k = 158) of right-lateralization effects (right worse than left TLE) testing the moderating effects of: 1) stimulus type (designs, faces, spatial), 2) learning format (single trial, repeated trials), 3) testing delay (immediate or long delay), and 4) testing format (recall, recognition) for three patient scenarios: 1) presurgical, 2) postsurgical, and 3) postsurgical change. Stimulus type significantly moderated the size of the right-lateralization effect (faces > designs) for postsurgical patients, test format moderated the size of the right-lateralization effect for presurgical-postsurgical change (recognition > recall) but learning format and test delay had no right-lateralization effect for either sample. For presurgical patients, none of the task-related factors significantly increased right-lateralization effects. This comprehensive review reveals the value of recognition testing in gauging the risk of nonverbal memory decline.
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Chaudhary K, Tripathi M, Chandra PS, Nehra A, Kumaran SS. Evaluation of memory in persons with mesial temporal lobe sclerosis: A combined fMRI and VBM study. J Biosci 2020. [DOI: 10.1007/s12038-020-00041-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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7
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Reduced hippocampal recruitment during response conflict resolution in mesial temporal lobe epilepsy. Neuroimage 2020; 213:116723. [PMID: 32173408 DOI: 10.1016/j.neuroimage.2020.116723] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Revised: 03/05/2020] [Accepted: 03/06/2020] [Indexed: 01/13/2023] Open
Abstract
Recent evidence suggests that the human hippocampus (HC) is not only involved in the processing of motivationally relevant approach-avoidance conflicts but is also engaged in the resolution of more general response conflicts as measured in the Stroop paradigm. Here we investigated whether neural activity in the HC is necessary for successful response conflict resolution. We compared hippocampal recruitment during an auditory Stroop paradigm in 20 patients with mesial temporal lobe epilepsy (MTLE) due to hippocampal sclerosis and 20 age-matched healthy controls using functional magnetic resonance imaging (fMRI). We analyzed hippocampal activation and behavioral performance in conflict trials relative to non-conflict trials. Moreover, functional connectivity (FC) analyses with left and right HCs as seeds were performed. Subjects' regional gray matter volumes were analyzed based on high-resolution T2-weighted MRI scans. The current study replicated previous results showing increased activation in left HC during the processing of conflict trials in healthy subjects. By contrast, MTLE patients showed higher behavioral costs of response conflict resolution and reduced conflict-related HC activation. In patients with left MTLE, left HC activation was predictive of faster conflict-related response times (RTs). By contrast, right HC activation was related to RT slowing, suggestive of a maladaptive compensation attempt in MTLE patients. Our results provide evidence that left hippocampal activation is required for the successful resolution of response conflicts.
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Diagnostica per immagini funzionale nell’epilessia. Neurologia 2020. [DOI: 10.1016/s1634-7072(20)43296-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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9
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Buck S, Sidhu MK. A Guide to Designing a Memory fMRI Paradigm for Pre-surgical Evaluation in Temporal Lobe Epilepsy. Front Neurol 2020; 10:1354. [PMID: 31998216 PMCID: PMC6962296 DOI: 10.3389/fneur.2019.01354] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Accepted: 12/09/2019] [Indexed: 12/05/2022] Open
Abstract
There has been increasing interest in the clinical and experimental use of memory functional Magnetic Resonance Imaging (fMRI). The 2017 American Academy of Neurology practice guidelines on the use of pre-surgical cognitive fMRI suggests that verbal memory fMRI could be used to lateralize memory functions in people with Temporal Lobe Epilepsy (TLE) and should be used to predict post-operative verbal memory outcome. There are however technical and methodological considerations, to optimize both the sensitivity and specificity of this imaging modality. Below we discuss these constraints and suggest recommendations to consider when designing a memory fMRI paradigm.
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Affiliation(s)
- Sarah Buck
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology of Neurology, London, United Kingdom
- Epilepsy Society MRI Unit, Chalfont Saint Peter, United Kingdom
| | - Meneka K. Sidhu
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology of Neurology, London, United Kingdom
- Epilepsy Society MRI Unit, Chalfont Saint Peter, United Kingdom
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10
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Abstract
Among the range of methods available to assess neurodevelopmental disorders, functional MRI (fMRI) has been a preferred tool of choice. Indeed, fMRI can reveal functional alterations in brain networks, irrespective of their structural integrity. Yet, whether fMRI studies have provided unique added value and influenced the clinical care and assessments in children with these conditions remains controversial. This chapter aims to give an overview of the clinical use of task-based as well as resting-state fMRI in children with neurodevelopmental disorders, such as dyslexia, DLD, and epilepsy. We introduce analysis methods that appear promising (namely PPI and machine learning) and describe strengths and limitations of fMRI in the field of pediatrics. Altogether, we suggest that fMRI has provided us with a unique understanding of some developmental conditions. Indeed, findings from group studies have both informed neuroanatomical models and revealed compensation mechanisms. In addition, improvements have made fMRI an increasingly child-friendly method. Nevertheless, clinicians should be aware of limitations, including (1) lack of replication of results, (2) the limited specificity as a diagnostic tool, and (3) difficulties with interpretation of findings. The use of fMRI in the clinic currently remains restricted, with the exception of epilepsy surgery planning, where it is used routinely.
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Affiliation(s)
- Frédérique Liégeois
- Cognitive Neuroscience and Neuropsychiatry Section, Great Ormond Street Institute of Child Health, University College, London, United Kingdom.
| | - Rachael Elward
- Cognitive Neuroscience and Neuropsychiatry Section, Great Ormond Street Institute of Child Health, University College, London, United Kingdom; (2)School of Applied Sciences, London South Bank University, London, United Kingdom
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Parra-Díaz P, García-Casares N. Evaluación de la memoria en la epilepsia del lóbulo temporal para predecir sus cambios tras la cirugía. Una revisión sistemática. Neurologia 2019; 34:596-606. [DOI: 10.1016/j.nrl.2017.02.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 02/12/2017] [Accepted: 02/17/2017] [Indexed: 10/19/2022] Open
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Parra-Díaz P, García-Casares N. Memory assessment in patients with temporal lobe epilepsy to predict memory impairment after surgery: a systematic review. NEUROLOGÍA (ENGLISH EDITION) 2019. [DOI: 10.1016/j.nrleng.2017.02.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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Comparing the Wada Test and Functional MRI for the Presurgical Evaluation of Memory in Temporal Lobe Epilepsy. Curr Neurol Neurosci Rep 2019; 19:31. [PMID: 31044310 DOI: 10.1007/s11910-019-0945-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
PURPOSE OF REVIEW The usefulness of the Wada test (WT) predicting memory impairment from temporal lobe epilepsy (TLE) surgery has been debated, and it has progressively been replaced by functional MRI (fMRI). We review the current role of WT and fMRI in the presurgical assessment of TLE, and how novel surgical techniques might improve cognitive outcomes. RECENT FINDINGS fMRI's ability to predict global amnesia has not been assessed. Although WT can produce false-positive results, it is still indicated in patients at risk for developing global amnesia: those with significant bilateral or contralateral memory deficits. In the current review, WT exhibited no added value, beyond preclinical data, for predicting material-specific memory impairment, whereas fMRI was reliable for either verbal or non-verbal memory decline. Abnormal functional connectivity on resting state fMRI (rs-fMRI) between the posterior cingulate and the hippocampus may be a predictor of postsurgical memory outcomes. Restricted resections to the pathogenic tissue, stereotactic laser, radiosurgery, and SEEG-guided thermos-coagulation were associated with better cognitive outcome. fMRI should be used routinely in the presurgical workup of TLE to predict verbal and/or non-verbal memory decline, whereas WT may be indicated when there is a high risk of postsurgical global amnesia. Rs-fMRI is a promising tool for the presurgical workup of TLE, and more restricted resections are recommended to enhance cognitive outcomes.
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Sepeta LN, Berl MM, Gaillard WD. Imaging episodic memory during development and childhood epilepsy. J Neurodev Disord 2018; 10:40. [PMID: 30541437 PMCID: PMC6292091 DOI: 10.1186/s11689-018-9255-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 11/14/2018] [Indexed: 01/31/2023] Open
Abstract
Epilepsy affects 2.2 million adults in the USA, with 1 in 26 people developing epilepsy at some point in their lives. Temporal lobe epilepsy (TLE) is the most common form of focal epilepsy as medial structures, and the hippocampus in particular, are prone to generating seizures. Selective anterior temporal resection (which removes the hippocampus) is the most effective intractable TLE treatment, but given the critical role of the mesial temporal lobe in memory functioning, resection can have negative effects on this crucial cognitive skill. To minimize the adverse impact of temporal lobe surgery on memory functioning, reliable pre-surgical guides are needed. Clinical functional magnetic resonance imaging (fMRI) provides reliable, noninvasive guidance of language functioning and plays a growing role in the pre-surgical evaluation for epilepsy patients; however, localization of memory function in children with epilepsy using fMRI has not been established. Aside from the lack of neuroimaging memory studies in children with TLE, studies of typical development are limited. This review will focus on the functional anatomy of memory systems throughout development, with a focus on TLE. TLE provides the ideal model from which to understand memory function and the limits of plasticity and compensation/reorganization throughout development.
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Affiliation(s)
- Leigh N. Sepeta
- Center for Neuroscience Research, Children’s National Medical Center, 111 Michigan Avenue NW, Washington, D.C., 20010 USA
- Clinical Epilepsy Section, National Institutes for Neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive, Bethesda, MD 20892 USA
| | - Madison M. Berl
- Clinical Epilepsy Section, National Institutes for Neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive, Bethesda, MD 20892 USA
| | - William Davis Gaillard
- Center for Neuroscience Research, Children’s National Medical Center, 111 Michigan Avenue NW, Washington, D.C., 20010 USA
- Clinical Epilepsy Section, National Institutes for Neurological Disorders and Stroke, National Institutes of Health, 10 Center Drive, Bethesda, MD 20892 USA
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Tsougos I, Kousi E, Georgoulias P, Kapsalaki E, Fountas KN. Neuroimaging methods in Epilepsy of Temporal Origin. Curr Med Imaging 2018; 15:39-51. [DOI: 10.2174/1573405613666170622114920] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2017] [Revised: 05/04/2017] [Accepted: 05/11/2017] [Indexed: 11/22/2022]
Abstract
Background:
Temporal Lobe Epilepsy (TLE) comprises the most common form of
symptomatic refractory focal epilepsy in adults. Accurate lateralization and localization of the
epileptogenic focus are a significant prerequisite for determining surgical candidacy once the
patient has been deemed medically intractable. Structural MR imaging, clinical,
electrophysiological, and neurophysiological data have an established role in the localization of the
epileptogenic foci. Nevertheless, hippocampal sclerosis cannot be detected on MR images in more
than 30% of patients with TLE, and the presurgical assessment remains controversial.
</P><P>
Discussion: In the last years, advanced MR imaging techniques, such as 1H-MRS, DWI, DTI,
DSCI, and fMRI, may provide valuable additional information regarding the physiological and
metabolic characterization of brain tissue. MR imaging has shifted towards functional and
molecular imaging, thus, promising to improve the accuracy regarding the lateralization and the
localization of the epileptogenic focus. Additionally, nuclear medicine studies, such as SPECT and
PET imaging modalities, have become an asset for the decoding of brain function and activity, and
can be diagnostically helpful as well, since they provide valuable data regarding the altered
metabolic activity of the seizure foci.
Conclusion:
Overall, advanced MRI, SPECT, and PET imaging techniques are increasingly
becoming an essential part of TLE diagnostics, when the epileptogenic area is not identified on
structural MRI or when structural MRI, clinical, and electrophysiological findings are not in
concordance.
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Affiliation(s)
- Ioannis Tsougos
- Department of Medical Physics, School of Medicine, University of Thessaly, Larisa, Greece
| | - Evanthia Kousi
- The Royal Marsden NHS Foundation Trust, London, United Kingdom
| | - Panagiotis Georgoulias
- Department of Medical Physics, School of Medicine, University of Thessaly, Larisa, Greece
| | - Eftychia Kapsalaki
- Department of Medical Physics, School of Medicine, University of Thessaly, Larisa, Greece
| | - Kostas N. Fountas
- Department of Medical Physics, School of Medicine, University of Thessaly, Larisa, Greece
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Encoding and immediate retrieval tasks in patients with epilepsy: A functional MRI study of verbal and visual memory. J Neuroradiol 2018; 45:157-163. [DOI: 10.1016/j.neurad.2018.02.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Revised: 12/26/2017] [Accepted: 02/08/2018] [Indexed: 11/30/2022]
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Cabrera OS, Lehéricy S, Masson V, Samson S, Dupont S. Adapting a memory fMRI research protocol in clinical routine: Feasibility and results. Epilepsy Behav 2018; 81:49-54. [PMID: 29477011 DOI: 10.1016/j.yebeh.2017.11.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 11/10/2017] [Accepted: 11/19/2017] [Indexed: 10/18/2022]
Abstract
OBJECTIVE The objective of this study was to test the reliability of functional magnetic resonance imaging (fMRI) evaluation of memory function in clinical practice to predict postoperative memory decline in patients with refractory medial temporal lobe epilepsy (MTLE) candidate to surgery. METHODS Twenty-six consecutive patients with MTLE who underwent a complete presurgical evaluation were included. All patients underwent fMRI memory study and complete neuropsychological assessment. Lesions consisted in hippocampal sclerosis in 18 patients (12 right and 6 left), dysembryoplastic neuroepithelial tumor (DNET) in 5 cases (4 right, 1 left), epidermoid cyst in one patient (right). Two patients had no lesion (2 left). RESULTS Nineteen patients (73%) underwent surgery. The other seven patients (27%) declined surgery, mainly because of the risk of memory deficit. The fMRI procedure correctly predicted both verbal and nonverbal memory postoperative outcome in 13 of the patients (72%), failed to predict a postoperative memory worsening in only two patients (12%), and predicted worsening in three patients (17%) that remained stable (versus 44%, 39%, and 17% with the sole neuropsychological testing). The reliability of the fMRI procedure was not influenced by the type of lesion, the side of the epileptic focus, or the type of preoperative memory profile (typical or atypical). SIGNIFICANCE Appearing as a valuable clinical tool to predict postoperative memory outcome, fMRI may add information over and above other available tests.
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Affiliation(s)
- Ovidio Solano Cabrera
- Epilepsy unit, AP-HP Groupe hospitalier Pitié-Salpêtrière-Charles Foix, F-75013 Paris, France; Epilepsy Clinic, Neurology department, Social Security Salvadoran Institute, San Salvador, El Salvador
| | - Stéphane Lehéricy
- Neuroradiology unit, AP-HP Groupe hospitalier Pitié-Salpêtrière-Charles Foix, F-75013 Paris, France; Inserm U 1127, CNRS UMR 7225, UMR S 1127, Institut du Cerveau et de la Moelle épinière - ICM, Centre de Neuroimagerie de Recherche - CENIR, F-75013 Paris, France; Sorbonne University, UPMC Univ. Paris 06, F-75005 Paris, France
| | - Véronique Masson
- Epilepsy unit, AP-HP Groupe hospitalier Pitié-Salpêtrière-Charles Foix, F-75013 Paris, France
| | - Séverine Samson
- Laboratoire PSITEC (EA 4072), Université de Lille, F-59000 Lille, France
| | - Sophie Dupont
- Epilepsy unit, AP-HP Groupe hospitalier Pitié-Salpêtrière-Charles Foix, F-75013 Paris, France; Inserm U 1127, CNRS UMR 7225, UMR S 1127, Institut du Cerveau et de la Moelle épinière - ICM, Centre de Neuroimagerie de Recherche - CENIR, F-75013 Paris, France; Sorbonne University, UPMC Univ. Paris 06, F-75005 Paris, France; Rehabilitation unit, AP-HP Groupe hospitalier Pitié-Salpêtrière-Charles Foix, F-75013 Paris, France.
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Pre-surgical mapping of eloquent cortex for paediatric epilepsy surgery candidates: Evidence from a review of advanced functional neuroimaging. Seizure 2017; 52:136-146. [DOI: 10.1016/j.seizure.2017.09.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 06/16/2017] [Accepted: 09/29/2017] [Indexed: 11/19/2022] Open
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Bhamidipati D, Goldhammer JE, Sperling MR, Torjman MC, McCarey MM, Whellan DJ. Cognitive Outcomes After Coronary Artery Bypass Grafting. J Cardiothorac Vasc Anesth 2017; 31:707-718. [DOI: 10.1053/j.jvca.2016.09.028] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Indexed: 12/17/2022]
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Wieser HG. Presurgical diagnosis of epilepsies – concepts and diagnostic tools. JOURNAL OF EPILEPTOLOGY 2016. [DOI: 10.1515/joepi-2016-0014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
SummaryIntroduction.Numerous reviews of the currently established concepts, strategies and diagnostic tools used in epilepsy surgery have been published. The focus concept which was initially developed by Forster, Penfield and Jasper and popularised and enriched by Lüders, is still fundamental for epilepsy surgery.Aim.To present different conceptual views of the focus concept and to discuss more recent network hypothesis, emphasizing so-called “critical modes of an epileptogenic circuit”.Method.A literature search was conducted using keywords: presurgical evaluation, epileptic focus concepts, cortical zones, diagnostic tools.Review and remarks.The theoretical concepts of the epileptic focus are opposed to the network hypothesis. The definitions of the various cortical zones have been conceptualized in the presurgical evaluation of candidates for epilepsy surgery: the seizure onset zone versus the epileptogenic zone, the symptomatogenic zone, the irritative and functional deficit zones are characterized. The epileptogenic lesion, the “eloquent cortex” and secondary epileptogenesis (mirror focus) are dealt with. The current diagnostic techniques used in the definition of these cortical zones, such as video-EEG monitoring, non-invasive and invasive EEG recording techniques, magnetic resonance imaging, ictal single photon emission computed tomography, and positron emission tomography, are discussed and illustrated. Potential modern surrogate markers of epileptogenicity, such asHigh frequency oscillations, Ictal slow waves/DC shifts, Magnetic resonance spectroscopy, Functional MRI,the use ofMagnetized nanoparticlesin MRI,Transcranial magnetic stimulation,Optical intrinsic signalimaging, andSeizure predictionare discussed. Particular emphasis is put on the EEG: Scalp EEG, semi-invasive and invasive EEG (Stereoelectroencephalography) and intraoperative electrocorticography are illustrated. Ictal SPECT and18F-FDG PET are very helpful and several other procedures, such as dipole source localization and spike-triggered functional MRI are already widely used. The most important lateralizing and localizing ictal signs and symptoms are summarized. It is anticipated that the other clinically valid surrogate markers of epileptogenesis and epileptogenicity will be further developed in the near future. Until then the concordance of the results of seizure semiology, localization of epileptogenicity by EEG and MRI remains the most important prerequisite for successful epilepsy surgery.Conclusions and future perspectives.Resective epilepsy surgery is a widely accepted and successful therapeutic approach, rendering up to 80% of selected patients seizure free. Although other therapies, such as radiosurgery, and responsive neurostimulation will increasingly play a role in patients with an unresectable lesion, it is unlikely that they will replace selective resective surgery. The hope is that new diagnostic techniques will be developed that permit more direct definition and measurement of the epileptogenic zone.
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Sidhu MK, Stretton J, Winston GP, McEvoy AW, Symms M, Thompson PJ, Koepp MJ, Duncan JS. Memory network plasticity after temporal lobe resection: a longitudinal functional imaging study. Brain 2016; 139:415-30. [PMID: 26754787 PMCID: PMC4805088 DOI: 10.1093/brain/awv365] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Accepted: 10/30/2015] [Indexed: 11/13/2022] Open
Abstract
Anterior temporal lobe resection can control seizures in up to 80% of patients with temporal lobe epilepsy. Memory decrements are the main neurocognitive complication. Preoperative functional reorganization has been described in memory networks, but less is known of postoperative reorganization. We investigated reorganization of memory-encoding networks preoperatively and 3 and 12 months after surgery. We studied 36 patients with unilateral medial temporal lobe epilepsy (19 right) before and 3 and 12 months after anterior temporal lobe resection. Fifteen healthy control subjects were studied at three equivalent time points. All subjects had neuropsychological testing at each of the three time points. A functional magnetic resonance imaging memory-encoding paradigm of words and faces was performed with subsequent out-of-scanner recognition assessments. Changes in activations across the time points in each patient group were compared to changes in the control group in a single flexible factorial analysis. Postoperative change in memory across the time points was correlated with postoperative activations to investigate the efficiency of reorganized networks. Left temporal lobe epilepsy patients showed increased right anterior hippocampal and frontal activation at both 3 and 12 months after surgery relative to preoperatively, for word and face encoding, with a concomitant reduction in left frontal activation 12 months postoperatively. Right anterior hippocampal activation 12 months postoperatively correlated significantly with improved verbal learning in patients with left temporal lobe epilepsy from preoperatively to 12 months postoperatively. Preoperatively, there was significant left posterior hippocampal activation that was sustained 3 months postoperatively at word encoding, and increased at face encoding. For both word and face encoding this was significantly reduced from 3 to 12 months postoperatively. Patients with right temporal lobe epilepsy showed increased left anterior hippocampal activation on word encoding from 3 to 12 months postoperatively compared to preoperatively. On face encoding, left anterior hippocampal activations were present preoperatively and 12 months postoperatively. Left anterior hippocampal and orbitofrontal cortex activations correlated with improvements in both design and verbal learning 12 months postoperatively. On face encoding, there were significantly increased left posterior hippocampal activations that reduced significantly from 3 to 12 months postoperatively. Postoperative changes occur in the memory-encoding network in both left and right temporal lobe epilepsy patients across both verbal and visual domains. Three months after surgery, compensatory posterior hippocampal reorganization that occurs is transient and inefficient. Engagement of the contralateral hippocampus 12 months after surgery represented efficient reorganization in both patient groups, suggesting that the contralateral hippocampus contributes to memory outcome 12 months after surgery.
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Affiliation(s)
- Meneka K Sidhu
- 1 Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK 2 Epilepsy Society MRI Unit, Chesham Lane, Chalfont St. Peter SL9 0RJ, Buckinghamshire, UK
| | - Jason Stretton
- 1 Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK 2 Epilepsy Society MRI Unit, Chesham Lane, Chalfont St. Peter SL9 0RJ, Buckinghamshire, UK 3 MRC Cognition and Brain Science Unit, Chaucer Road, Cambridge, CB2 7EF, UK
| | - Gavin P Winston
- 1 Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK 2 Epilepsy Society MRI Unit, Chesham Lane, Chalfont St. Peter SL9 0RJ, Buckinghamshire, UK
| | - Andrew W McEvoy
- 1 Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK 2 Epilepsy Society MRI Unit, Chesham Lane, Chalfont St. Peter SL9 0RJ, Buckinghamshire, UK
| | - Mark Symms
- 1 Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK 2 Epilepsy Society MRI Unit, Chesham Lane, Chalfont St. Peter SL9 0RJ, Buckinghamshire, UK
| | - Pamela J Thompson
- 1 Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK 2 Epilepsy Society MRI Unit, Chesham Lane, Chalfont St. Peter SL9 0RJ, Buckinghamshire, UK
| | - Matthias J Koepp
- 1 Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK 2 Epilepsy Society MRI Unit, Chesham Lane, Chalfont St. Peter SL9 0RJ, Buckinghamshire, UK
| | - John S Duncan
- 1 Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK 2 Epilepsy Society MRI Unit, Chesham Lane, Chalfont St. Peter SL9 0RJ, Buckinghamshire, UK
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Stylianou P, Kimchi G, Hoffmann C, Blat I, Harnof S. Neuroimaging for patient selection for medial temporal lobe epilepsy surgery: Part 2 functional neuroimaging. J Clin Neurosci 2016; 23:23-33. [DOI: 10.1016/j.jocn.2015.04.031] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2015] [Revised: 04/11/2015] [Accepted: 04/18/2015] [Indexed: 11/17/2022]
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Moon CM, Jeong GW. Functional neuroanatomy on the working memory under emotional distraction in patients with generalized anxiety disorder. Psychiatry Clin Neurosci 2015; 69:609-19. [PMID: 25781332 DOI: 10.1111/pcn.12295] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Revised: 03/05/2015] [Accepted: 03/13/2015] [Indexed: 11/30/2022]
Abstract
AIMS Patients with generalized anxiety disorder (GAD) suffer the symptoms of psychological distress, including excessive and uncontrollable anxiety. Until now, the functional neuroanatomy for working memory (WM) in conjunction with the major anxiety symptoms in GAD patients has not yet been clearly identified. This study investigated the neural activation patterns associated with the effect of neutral and anxiety-inducing distractors during the delayed-response WM task in GAD patients. METHODS Eighteen patients with GAD and 18 age-matched healthy controls participated in this study. The functional magnetic resonance images were obtained while the subjects performed a delayed-response WM task with neutral and anxiety-inducing distractors. RESULTS During the neutral distractor, GAD patients compared to controls showed significantly lower activities in the fusiform gyrus, superior parietal gyrus, precuneus, superior occipital gyrus, lingual gyrus, cuneus, calcarine gyrus, parahippocampal gyrus and cerebellar cortex. During the anxiety-inducing distractor, GAD patients showed significantly higher activity in the hippocampus, whereas they showed lower activities in the dorsolateral prefrontal cortex, fusiform gyrus, superior parietal gyrus, precuneus, superior occipital gyrus and cerebellar cortex. The blood-oxygen-level dependent signal changes in the dorsolateral prefrontal cortex in GAD patients during the anxiety-inducing distractor were negatively correlated with Anxiety Sensitivity Index-Revised scores. CONCLUSIONS This study identified the specific brain areas associated with the interaction between emotional regulation and cognitive function associated with neutral and anxiety-inducing distractors during WM maintenance in GAD patients. These findings will be helpful for understanding the neural mechanism on the WM-related cognitive deficits and emotional dysfunction with typical anxiety symptoms in GAD.
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Affiliation(s)
- Chung-Man Moon
- Research Institute for Medical Imaging, Chonnam National University Medical School, Gwangju, Republic of Korea
| | - Gwang-Woo Jeong
- Research Institute for Medical Imaging, Chonnam National University Medical School, Gwangju, Republic of Korea.,Department of Radiology, Chonnam National University Hospital, Chonnam National University Medical School, Gwangju, Republic of Korea
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Raslau FD, Mark LP, Sabsevitz DS, Ulmer JL. Imaging of Functional and Dysfunctional Episodic Memory. Semin Ultrasound CT MR 2015; 36:260-74. [PMID: 26233860 DOI: 10.1053/j.sult.2015.05.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
A foundational framework for understanding functional and dysfunctional imaging of episodic memory emerges from the last 3 decades of human and animal research. This comprehensive review is presented from the vantage point of the fornix, a white matter bridge that occupies a central position in this functional network. Salient insights are identified, spanning topics such as hippocampal efferent and afferent networks, input and processing streams, hemispheric specialization, dysfunctional effects of pathologic and surgical injury, optimization of functional magnetic resonance imaging design and neuropsychological tests, and rehabilitation strategies. Far-reaching implications are considered for radiologists, whose clinical effect stretches beyond imaging and interfaces with neurosurgeons, neuropsychologists, and other neurospecialists.
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Affiliation(s)
| | - Leighton P Mark
- Department of Radiology, Medical College of Wisconsin, Milwaukee, WI
| | - David S Sabsevitz
- Department of Neurology, Medical College of Wisconsin, Milwaukee, WI
| | - John L Ulmer
- Department of Radiology, Medical College of Wisconsin, Milwaukee, WI
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Voets NL, Menke RAL, Jbabdi S, Husain M, Stacey R, Carpenter K, Adcock JE. Thalamo-Cortical Disruption Contributes to Short-Term Memory Deficits in Patients with Medial Temporal Lobe Damage. Cereb Cortex 2015; 25:4584-95. [PMID: 26009613 PMCID: PMC4816801 DOI: 10.1093/cercor/bhv109] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Short-term (STM) and long-term memory (LTM) have largely been considered as separate brain systems reflecting fronto-parietal and medial temporal lobe (MTL) functions, respectively. This functional dichotomy has been called into question by evidence of deficits on aspects of working memory in patients with MTL damage, suggesting a potentially direct hippocampal contribution to STM. As the hippocampus has direct anatomical connections with the thalamus, we tested the hypothesis that damage to thalamic nuclei regulating cortico-cortical interactions may contribute to STM deficits in patients with hippocampal dysfunction. We used diffusion-weighted magnetic resonance imaging-based tractography to identify anatomical subdivisions in patients with MTL epilepsy. From these, we measured resting-state functional connectivity with detailed cortical divisions of the frontal, temporal, and parietal lobes. Whereas thalamo-temporal functional connectivity reflected LTM performance, thalamo-prefrontal functional connectivity specifically predicted STM performance. Notably, patients with hippocampal volume loss showed thalamic volume loss, most prominent in the pulvinar region, not detected in patients with normal hippocampal volumes. Aberrant thalamo-cortical connectivity in the epileptic hemisphere was mirrored in a loss of behavioral association with STM performance specifically in patients with hippocampal atrophy. These findings identify thalamo-cortical disruption as a potential mechanism contributing to STM deficits in the context of MTL damage.
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Affiliation(s)
- Natalie L Voets
- FMRIB Centre, Nuffield Department of Clinical Neurosciences Epilepsy Research Group, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | | | - Saad Jbabdi
- FMRIB Centre, Nuffield Department of Clinical Neurosciences
| | - Masud Husain
- FMRIB Centre, Nuffield Department of Clinical Neurosciences Epilepsy Research Group, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK Department of Experimental Psychology, University of Oxford, Oxford OX1 3UD, UK
| | - Richard Stacey
- Department of Neurosurgery, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | | | - Jane E Adcock
- FMRIB Centre, Nuffield Department of Clinical Neurosciences Epilepsy Research Group, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DU, UK
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Leyden KM, Kucukboyaci NE, Puckett OK, Lee D, Loi RQ, Paul B, McDonald CR. What does diffusion tensor imaging (DTI) tell us about cognitive networks in temporal lobe epilepsy? Quant Imaging Med Surg 2015; 5:247-63. [PMID: 25853083 DOI: 10.3978/j.issn.2223-4292.2015.02.01] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 01/22/2015] [Indexed: 12/14/2022]
Abstract
Diffusion tensor imaging (DTI) has provided considerable insight into our understanding of epilepsy as a network disorder, revealing subtle alterations in white matter microstructure both proximal and distal to the epileptic focus. These white matter changes have been shown to assist with lateralizing the seizure focus, as well as delineating the location/anatomy of key white matter tracts (i.e., optic radiations) for surgical planning. However, only recently have studies emerged describing the utility of DTI for probing cognitive networks in patients with epilepsy and for examining the structural plasticity within these networks both before and after epilepsy surgery. Here, we review the current literature describing the use of DTI for understanding language and memory networks in patients with temporal lobe epilepsy (TLE), as well as the extant literature on networks associated with executive functioning and global intelligence. Studies of memory and language reveal a complex network of frontotemporal fibers that contribute to naming and fluency performance in TLE, and demonstrate that these networks appear to undergo adaptive changes in response to surgical intervention. Although studies of executive functioning and global intelligence have been less conclusive, there is accumulating evidence that aberrant communication between frontoparietal and medial temporal networks may underlie working memory impairment in TLE. More recently, multimodal imaging studies have provided evidence that disruptions within these white matter networks co-localize with functional changes observed on functional MRI. However, structure-function associations are not entirely coherent and may breakdown in patients with TLE, especially those with a left-sided seizure focus. Although the reasons for discordant findings are unclear, small sample sizes, heterogeneity within patient populations and limitations of the current tensor model may account for contradictory and null findings. Improvements in imaging hardware and higher field strengths have now paved the way for the implementation of advanced diffusion techniques, and these advanced models show great promise for improving our understanding of how network dysfunction contributes to cognitive morbidity in TLE.
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Affiliation(s)
- Kelly M Leyden
- 1 Multimodal Imaging Laboratory, University of California, San Diego, CA, USA ; 2 San Diego State University/University of California, San Diego Joint Doctoral Program in Clinical Psychology, San Diego, CA, USA ; 3 Department of Cognitive Science, 4 Department of Biology, University of California, San Diego, CA, USA ; 5 Comprehensive Epilepsy Center, Department of Neurology, University of California, San Francisco, CA, USA ; 6 Department of Psychiatry, University of California, San Diego, CA, USA
| | - N Erkut Kucukboyaci
- 1 Multimodal Imaging Laboratory, University of California, San Diego, CA, USA ; 2 San Diego State University/University of California, San Diego Joint Doctoral Program in Clinical Psychology, San Diego, CA, USA ; 3 Department of Cognitive Science, 4 Department of Biology, University of California, San Diego, CA, USA ; 5 Comprehensive Epilepsy Center, Department of Neurology, University of California, San Francisco, CA, USA ; 6 Department of Psychiatry, University of California, San Diego, CA, USA
| | - Olivia K Puckett
- 1 Multimodal Imaging Laboratory, University of California, San Diego, CA, USA ; 2 San Diego State University/University of California, San Diego Joint Doctoral Program in Clinical Psychology, San Diego, CA, USA ; 3 Department of Cognitive Science, 4 Department of Biology, University of California, San Diego, CA, USA ; 5 Comprehensive Epilepsy Center, Department of Neurology, University of California, San Francisco, CA, USA ; 6 Department of Psychiatry, University of California, San Diego, CA, USA
| | - Davis Lee
- 1 Multimodal Imaging Laboratory, University of California, San Diego, CA, USA ; 2 San Diego State University/University of California, San Diego Joint Doctoral Program in Clinical Psychology, San Diego, CA, USA ; 3 Department of Cognitive Science, 4 Department of Biology, University of California, San Diego, CA, USA ; 5 Comprehensive Epilepsy Center, Department of Neurology, University of California, San Francisco, CA, USA ; 6 Department of Psychiatry, University of California, San Diego, CA, USA
| | - Richard Q Loi
- 1 Multimodal Imaging Laboratory, University of California, San Diego, CA, USA ; 2 San Diego State University/University of California, San Diego Joint Doctoral Program in Clinical Psychology, San Diego, CA, USA ; 3 Department of Cognitive Science, 4 Department of Biology, University of California, San Diego, CA, USA ; 5 Comprehensive Epilepsy Center, Department of Neurology, University of California, San Francisco, CA, USA ; 6 Department of Psychiatry, University of California, San Diego, CA, USA
| | - Brianna Paul
- 1 Multimodal Imaging Laboratory, University of California, San Diego, CA, USA ; 2 San Diego State University/University of California, San Diego Joint Doctoral Program in Clinical Psychology, San Diego, CA, USA ; 3 Department of Cognitive Science, 4 Department of Biology, University of California, San Diego, CA, USA ; 5 Comprehensive Epilepsy Center, Department of Neurology, University of California, San Francisco, CA, USA ; 6 Department of Psychiatry, University of California, San Diego, CA, USA
| | - Carrie R McDonald
- 1 Multimodal Imaging Laboratory, University of California, San Diego, CA, USA ; 2 San Diego State University/University of California, San Diego Joint Doctoral Program in Clinical Psychology, San Diego, CA, USA ; 3 Department of Cognitive Science, 4 Department of Biology, University of California, San Diego, CA, USA ; 5 Comprehensive Epilepsy Center, Department of Neurology, University of California, San Francisco, CA, USA ; 6 Department of Psychiatry, University of California, San Diego, CA, USA
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Sidhu MK, Stretton J, Winston GP, Symms M, Thompson PJ, Koepp MJ, Duncan JS. Memory fMRI predicts verbal memory decline after anterior temporal lobe resection. Neurology 2015; 84:1512-9. [PMID: 25770199 PMCID: PMC4408284 DOI: 10.1212/wnl.0000000000001461] [Citation(s) in RCA: 64] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2014] [Accepted: 12/08/2014] [Indexed: 11/15/2022] Open
Abstract
Objective: To develop a clinically applicable memory functional MRI (fMRI) method of predicting postsurgical memory outcome in individual patients. Methods: In this prospective cohort study, 50 patients with temporal lobe epilepsy (23 left) and 26 controls underwent an fMRI memory encoding paradigm of words with a subsequent out-of-scanner recognition assessment. Neuropsychological assessment was performed preoperatively and 4 months after anterior temporal lobe resection, and at equal time intervals in controls. An event-related analysis was used to explore brain activations for words remembered and change in verbal memory scores 4 months after surgery was correlated with preoperative activations. Individual lateralization indices were calculated within a medial temporal and frontal region and compared with other clinical parameters (hippocampal volume, preoperative verbal memory, age at onset of epilepsy, and language lateralization) as a predictor of verbal memory outcome. Results: In left temporal lobe epilepsy patients, left frontal and anterior medial temporal activations correlated significantly with greater verbal memory decline, while bilateral posterior hippocampal activation correlated with less verbal memory decline postoperatively. In a multivariate regression model, left lateralized memory lateralization index (≥0.5) within a medial temporal and frontal mask was the best predictor of verbal memory outcome after surgery in the dominant hemisphere in individual patients. Neither clinical nor functional MRI parameters predicted verbal memory decline after nondominant temporal lobe resection. Conclusion: We propose a clinically applicable memory fMRI paradigm to predict postoperative verbal memory decline after surgery in the language-dominant hemisphere in individual patients.
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Affiliation(s)
- Meneka K Sidhu
- From the Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London; and the Epilepsy Society MRI Unit, Chalfont St. Peter, UK
| | - Jason Stretton
- From the Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London; and the Epilepsy Society MRI Unit, Chalfont St. Peter, UK
| | - Gavin P Winston
- From the Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London; and the Epilepsy Society MRI Unit, Chalfont St. Peter, UK
| | - Mark Symms
- From the Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London; and the Epilepsy Society MRI Unit, Chalfont St. Peter, UK
| | - Pamela J Thompson
- From the Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London; and the Epilepsy Society MRI Unit, Chalfont St. Peter, UK
| | - Matthias J Koepp
- From the Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London; and the Epilepsy Society MRI Unit, Chalfont St. Peter, UK
| | - John S Duncan
- From the Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, London; and the Epilepsy Society MRI Unit, Chalfont St. Peter, UK.
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Towgood K, Barker GJ, Caceres A, Crum WR, Elwes RDC, Costafreda SG, Mehta MA, Morris RG, von Oertzen TJ, Richardson MP. Bringing memory fMRI to the clinic: comparison of seven memory fMRI protocols in temporal lobe epilepsy. Hum Brain Mapp 2015; 36:1595-608. [PMID: 25727386 PMCID: PMC4855630 DOI: 10.1002/hbm.22726] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2014] [Revised: 12/07/2014] [Accepted: 12/11/2014] [Indexed: 11/30/2022] Open
Abstract
fMRI is increasingly implemented in the clinic to assess memory function. There are multiple approaches to memory fMRI, but limited data on advantages and reliability of different methods. Here, we compared effect size, activation lateralisation, and between‐sessions reliability of seven memory fMRI protocols: Hometown Walking (block design), Scene encoding (block design and event‐related design), Picture encoding (block and event‐related), and Word encoding (block and event‐related). All protocols were performed on three occasions in 16 patients with temporal lobe epilepsy (TLE). Group T‐maps showed activity bilaterally in medial temporal lobe for all protocols. Using ANOVA, there was an interaction between hemisphere and seizure‐onset lateralisation (P = 0.009) and between hemisphere, protocol and seizure‐onset lateralisation (P = 0.002), showing that the distribution of memory‐related activity between left and right temporal lobes differed between protocols and between patients with left‐onset and right‐onset seizures. Using voxelwise intraclass Correlation Coefficient, between‐sessions reliability was best for Hometown and Scenes (block and event). The between‐sessions spatial overlap of activated voxels was also greatest for Hometown and Scenes. Lateralisation of activity between hemispheres was most reliable for Scenes (block and event) and Words (event). Using receiver operating characteristic analysis to explore the ability of each fMRI protocol to classify patients as left‐onset or right‐onset TLE, only the Words (event) protocol achieved a significantly above‐chance classification of patients at all three sessions. We conclude that Words (event) protocol shows the best combination of between‐sessions reliability of the distribution of activity between hemispheres and reliable ability to distinguish between left‐onset and right‐onset patients. Hum Brain Mapp 36:1595–1608, 2015. © 2015 The Authors Human Brain Mapping Published by Wiley Periodicals, Inc.
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Affiliation(s)
- Karren Towgood
- Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
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Imaging memory and predicting postoperative memory decline in temporal lobe epilepsy: Insights from functional imaging. Rev Neurol (Paris) 2015; 171:307-14. [PMID: 25726354 DOI: 10.1016/j.neurol.2014.12.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Revised: 12/23/2014] [Accepted: 12/29/2014] [Indexed: 11/24/2022]
Abstract
After medial temporal lobe epilepsy (MTLE) surgery, there is considerable individual variation in the extent, nature and direction of postoperative memory change. Before surgery, epileptic patients who are surgery candidates need precise information about the potential cognitive after effects, and particularly in temporal lobe epilepsy, postoperative memory changes. Clinical and neuropsychological data may bring useful information to predict the postoperative memory outcome, but, these data are not always sufficient to replace the Wada test, considered for a long time, as the gold standard to predict postoperative decline following surgery. In any case, numerous studies demonstrate that the Wada procedure can be nowadays reliably replaced by functional MRI (fMRI) activation studies. A vast majority of fMRI studies suggest that it is the functional adequacy of the resected hippocampus rather than the functional reserve of the contralateral hippocampus that determines the extent of postoperative memory decline. In addition, new functional neuroimaging procedures that explore more widespread network disruptions commonly found in MTLE such as diffusion-tensor imaging (DTI) or connectivity studies could in the future constitute a reliable approach combined with fMRI activation studies to significantly improve the prediction of postsurgical memory decline.
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Milian M, Zeltner L, Erb M, Klose U, Wagner K, Frings L, Veil C, Rona S, Lerche H, Klamer S. Incipient preoperative reorganization processes of verbal memory functions in patients with left temporal lobe epilepsy. Epilepsy Behav 2015; 42:78-85. [PMID: 25500359 DOI: 10.1016/j.yebeh.2014.11.026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 11/21/2014] [Indexed: 10/24/2022]
Abstract
We previously reported nonlinear correlations between verbal episodic memory performance and BOLD signal in memory fMRI in healthy subjects. The purpose of the present study was to examine this observation in patients with left mesial temporal lobe epilepsy (mTLE) who often experience memory decline and need reliable prediction tools before epilepsy surgery with hippocampectomy. Fifteen patients with left mTLE (18-57years, nine females) underwent a verbal memory fMRI paradigm. Correlations between BOLD activity and neuropsychological data were calculated for the i) hippocampus (HC) as well as ii) extrahippocampal mTL structures. Memory performance was systematically associated with activations within the right HC as well as with activations within the left extrahippocampal mTL regions (amygdala and parahippocampal gyrus). As hypothesized, the analyses revealed cubic relationships, with one peak in patients with marginal memory performance and another peak in patients with very good performance. The nonlinear correlations between memory performance and activations might reflect the compensatory recruitment of neural resources to maintain memory performance in patients with ongoing memory deterioration. The present data suggest an already incipient preoperative reorganization process of verbal memory in non-amnesic patients with left mTLE by simultaneously tapping the resources of the right HC and left extrahippocampal mTL regions. Thus, in the preoperative assessment, both neuropsychological performance and memory fMRI should be considered together.
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Affiliation(s)
- Monika Milian
- Department of Neurosurgery, University of Tuebingen, Tuebingen, Germany
| | - Lena Zeltner
- Department of Vascular Neurology, University of Tuebingen, Tuebingen, Germany
| | - Michael Erb
- Department of Biomedical Magnetic Resonance, University of Tuebingen, Tuebingen, Germany
| | - Uwe Klose
- Department of Neuroradiology, University of Tuebingen, Tuebingen, Germany
| | | | - Lars Frings
- Center of Geriatrics and Gerontology Freiburg, University Hospital Freiburg, Germany
| | - Cornelia Veil
- Department of Biomedical Magnetic Resonance, University of Tuebingen, Tuebingen, Germany
| | - Sabine Rona
- Department of Neurosurgery, University of Tuebingen, Tuebingen, Germany
| | - Holger Lerche
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany
| | - Silke Klamer
- Department of Neurology and Epileptology, Hertie Institute for Clinical Brain Research, University of Tuebingen, Tuebingen, Germany.
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Factors affecting reorganisation of memory encoding networks in temporal lobe epilepsy. Epilepsy Res 2014; 110:1-9. [PMID: 25616449 PMCID: PMC4315807 DOI: 10.1016/j.eplepsyres.2014.11.001] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 10/31/2014] [Accepted: 11/03/2014] [Indexed: 11/20/2022]
Abstract
AIMS In temporal lobe epilepsy (TLE) due to hippocampal sclerosis reorganisation in the memory encoding network has been consistently described. Distinct areas of reorganisation have been shown to be efficient when associated with successful subsequent memory formation or inefficient when not associated with successful subsequent memory. We investigated the effect of clinical parameters that modulate memory functions: age at onset of epilepsy, epilepsy duration and seizure frequency in a large cohort of patients. METHODS We studied 53 patients with unilateral TLE and hippocampal sclerosis (29 left). All participants performed a functional magnetic resonance imaging memory encoding paradigm of faces and words. A continuous regression analysis was used to investigate the effects of age at onset of epilepsy, epilepsy duration and seizure frequency on the activation patterns in the memory encoding network. RESULTS Earlier age at onset of epilepsy was associated with left posterior hippocampus activations that were involved in successful subsequent memory formation in left hippocampal sclerosis patients. No association of age at onset of epilepsy was seen with face encoding in right hippocampal sclerosis patients. In both left hippocampal sclerosis patients during word encoding and right hippocampal sclerosis patients during face encoding, shorter duration of epilepsy and lower seizure frequency were associated with medial temporal lobe activations that were involved in successful memory formation. Longer epilepsy duration and higher seizure frequency were associated with contralateral extra-temporal activations that were not associated with successful memory formation. CONCLUSION Age at onset of epilepsy influenced verbal memory encoding in patients with TLE due to hippocampal sclerosis in the speech-dominant hemisphere. Shorter duration of epilepsy and lower seizure frequency were associated with less disruption of the efficient memory encoding network whilst longer duration and higher seizure frequency were associated with greater, inefficient, extra-temporal reorganisation.
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Chaudhary UJ, Duncan JS. Applications of blood-oxygen-level-dependent functional magnetic resonance imaging and diffusion tensor imaging in epilepsy. Neuroimaging Clin N Am 2014; 24:671-94. [PMID: 25441507 DOI: 10.1016/j.nic.2014.07.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The lifetime prevalence of epilepsy ranges from 2.7 to 12.4 per 1000 in Western countries. Around 30% of patients with epilepsy remain refractory to antiepileptic drugs and continue to have seizures. Noninvasive imaging techniques such as functional magnetic resonance imaging (fMRI) and diffusion tensor imaging (DTI) have helped to better understand mechanisms of seizure generation and propagation, and to localize epileptic, eloquent, and cognitive networks. In this review, the clinical applications of fMRI and DTI are discussed, for mapping cognitive and epileptic networks and organization of white matter tracts in individuals with epilepsy.
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Affiliation(s)
- Umair J Chaudhary
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK; MRI Unit, Epilepsy Society, Chesham Lane, Chalfont St Peter, Buckinghamshire SL9 0RJ, UK.
| | - John S Duncan
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK; MRI Unit, Epilepsy Society, Chesham Lane, Chalfont St Peter, Buckinghamshire SL9 0RJ, UK; Queen Square Division, UCLH NHS Foundation Trust, Queen Square, London WC1N 3BG, UK
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Memory Assessment in the Clinical Context Using Functional Magnetic Resonance Imaging. Neuroimaging Clin N Am 2014; 24:585-97. [DOI: 10.1016/j.nic.2014.07.008] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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Bijanki KR, Hodis B, Brumm MC, Harlynn EL, McCormick LM. Hippocampal and left subcallosal anterior cingulate atrophy in psychotic depression. PLoS One 2014; 9:e110770. [PMID: 25338068 PMCID: PMC4206433 DOI: 10.1371/journal.pone.0110770] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2014] [Accepted: 09/16/2014] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Psychotic depression is arguably the most diagnostically stable subtype of major depressive disorder, and an attractive target of study in a famously heterogeneous mental illness. Previous imaging studies have identified abnormal volumes of the hippocampus, amygdala, and subcallosal region of the anterior cingulate cortex (scACC) in psychotic depression, though studies have not yet examined the role of family history of depression in these relationships. METHODS 20 participants with psychotic depression preparing to undergo electroconvulsive therapy and 20 healthy comparison participants (13 women and 7 men in each group) underwent structural brain imaging in a 1.5 T MRI scanner. 15 of the psychotic depression group had a first-degree relative with diagnosed affective disorders, while the healthy control group had no first-degree relatives with affective disorders. Depression severity was assessed with the Hamilton Depression Rating Scale and duration of illness was assessed in all patients. Automated neural nets were used to isolate the hippocampi and amygdalae in each scan, and an established manual method was used to parcellate the anterior cingulate cortex into dorsal, rostral, subcallosal, and subgenual regions. The volumes of these regions were compared between groups. Effects of laterality and family history of affective disorders were examined as well. RESULTS Patients with psychotic depression had significantly smaller left scACC and bilateral hippocampal volumes, while no group differences in other anterior cingulate cortex subregions or amygdala volumes were present. Hippocampal atrophy was found in all patients with psychotic depression, but reduced left scACC volume was found only in the patients with a family history of depression. CONCLUSIONS Patients with psychotic depression showed significant reduction in hippocampal volume bilaterally, perhaps due to high cortisol states associated with this illness. Reduced left scACC volume may be a vulnerability factor related to family history of depression.
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Affiliation(s)
- Kelly Rowe Bijanki
- Department of Psychiatry, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Brendan Hodis
- Department of Psychiatry, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Michael C. Brumm
- Department of Psychiatry, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Emily L. Harlynn
- Department of Psychiatry, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, United States of America
| | - Laurie M. McCormick
- Department of Psychiatry, University of Iowa Roy J. and Lucille A. Carver College of Medicine, Iowa City, Iowa, United States of America
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Aberrant functional connectivity in dissociable hippocampal networks is associated with deficits in memory. J Neurosci 2014; 34:4920-8. [PMID: 24695711 DOI: 10.1523/jneurosci.4281-13.2014] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In the healthy human brain, evidence for dissociable memory networks along the anterior-posterior axis of the hippocampus suggests that this structure may not function as a unitary entity. Failure to consider these functional divisions may explain diverging results among studies of memory adaptation in disease. Using task-based and resting functional MRI, we show that chronic seizures disrupting the anterior medial temporal lobe (MTL) preserve anterior and posterior hippocampal-cortical dissociations, but alter signaling between these and other key brain regions. During performance of a memory encoding task, we found reduced neural activity in human patients with unilateral temporal lobe epilepsy relative to age-matched healthy controls, but no upregulation of fMRI signal in unaffected hippocampal subregions. Instead, patients showed aberrant resting fMRI connectivity within anterior and posterior hippocampal-cortical networks, which was associated with memory decline, distinguishing memory-intact from memory-impaired patients. Our results highlight a critical role for intact hippocampo-cortical functional communication in memory and provide evidence that chronic injury-induced functional reorganization in the diseased MTL is behavioral inefficient.
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Denkova EJ, Manning L. FMRI contributions to addressing autobiographical memory impairment in temporal lobe pathology. World J Radiol 2014; 6:93-105. [PMID: 24778771 PMCID: PMC4000613 DOI: 10.4329/wjr.v6.i4.93] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 02/11/2014] [Accepted: 03/17/2014] [Indexed: 02/06/2023] Open
Abstract
Episodic autobiographical memory (AM) allows one, through the recollection of sensory-perceptual details, thoughts and feelings, to become aware of an event as belonging to one’s own past as well as being able to project into one’s future. Because AM provides a sense of self-continuity, contributes to the integrity of the self, and helps predicting future experiences, any deficit of AM may have debilitating consequences for everyday life functioning. Understanding AM failure and the underlying neural mechanisms has the potential to shed light on brain reorganization mechanisms and engagement of compensatory processes. Functional magnetic resonance imaging (fMRI) provides the most promising imaging method to tackle these issues. We reviewed evidence from the few studies that used fMRI to investigate the functionality of the residual tissue, the neural reorganization and compensatory mechanisms in patients with neurological conditions due to impaired medial temporal lobe. Overall, these studies highlight the importance of the left hippocampus, which when atrophied and not functional leads to AM deficits but its residual functionality may support relatively normal AM recollection. When damaged hippocampal tissue is not functional, other brain regions (e.g., the medial prefrontal cortex) may be involved to compensate impairment, but they appear generally ineffective to support detailed episodic recollection.
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Gold JJ, Trauner DA. Hippocampal volume and memory performance in children with perinatal stroke. Pediatr Neurol 2014; 50:18-25. [PMID: 24188909 PMCID: PMC4208717 DOI: 10.1016/j.pediatrneurol.2013.08.029] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2013] [Revised: 08/21/2013] [Accepted: 08/27/2013] [Indexed: 11/17/2022]
Abstract
BACKGROUND Pediatric neurologists and neonatologists often are asked to predict cognitive outcome after perinatal brain injury (including likely memory and learning outcomes). However, relatively few data exist on how accurate predictions can be made. Furthermore, although the consequences of brain injury on hippocampal volume and memory performance have been studied extensively in adults, little work has been done in children. METHODS We measured the volume of the hippocampus in 27 children with perinatal stroke and 19 controls, and measured their performance on standardized verbal and non-verbal memory tests. RESULTS We discovered the following: (1) As a group, children with perinatal stroke had smaller left and right hippocampi compared with control children. (2) Individually, children with perinatal stroke demonstrated 1 of 3 findings: no hippocampal loss, unilateral hippocampal loss, or bilateral hippocampal volume loss compared with control children. (3) Hippocampal volume inversely correlated with memory test performance in the perinatal stroke group, with smaller left and right hippocampal volumes related to poorer verbal and non-verbal memory test performance, respectively. (4) Seizures played a significant role in determining memory deficit and extent of hippocampal volume reduction in patients with perinatal stroke. CONCLUSIONS These findings support the view that, in the developing brain, the left and right hippocampi preferentially support verbal and nonverbal memory respectively, a consistent finding in the adult literature but a subject of debate in the pediatric literature. This is the first work to report that children with focal brain injury incurred from perinatal stroke have volume reduction in the hippocampus and impairments in certain aspects of declarative memory.
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Affiliation(s)
- Jeffrey J Gold
- University of California, San Diego, La Jolla, California; Rady Children's Hospital, San Diego, California.
| | - Doris A Trauner
- University of California, San Diego, La Jolla, California; Rady Children's Hospital, San Diego, California.
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40
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Höflich A, Savli M, Comasco E, Moser U, Novak K, Kasper S, Lanzenberger R. Neuropsychiatric deep brain stimulation for translational neuroimaging. Neuroimage 2013; 79:30-41. [DOI: 10.1016/j.neuroimage.2013.04.065] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2012] [Revised: 04/13/2013] [Accepted: 04/16/2013] [Indexed: 10/26/2022] Open
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Willment KC, Golby A. Hemispheric lateralization interrupted: material-specific memory deficits in temporal lobe epilepsy. Front Hum Neurosci 2013; 7:546. [PMID: 24032014 PMCID: PMC3759288 DOI: 10.3389/fnhum.2013.00546] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2013] [Accepted: 08/19/2013] [Indexed: 02/01/2023] Open
Abstract
The hemispheric lateralization of memory has largely been informed through the study of patients with temporal lobe epilepsy originating from medial temporal sources (mTLE). The material-specific model of memory relies on the basic framework that the left temporal lobe mediates verbal memories, while the right temporal lobe mediates non-verbal memories. Over the years, this model has been refined, and even challenged, as our understanding of the material-specific memory deficits in mTLE has been further elaborated in the neuropsychological and neuroimaging literature. The first goal of this mini-review is to highlight the major findings in the mTLE literature that have advanced and expanded our understanding of material-specific memory deficits in mTLE. Second, we will review how functional neuroimaging patterns of material-specific hemispheric lateralization in mTLE are being translated into the innovative clinical application of preoperative fMRI memory mapping.
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Affiliation(s)
- Kim Celone Willment
- Department of Neurology, Brigham and Women's Hospital , Boston, MA , USA ; Department of Psychiatry, Brigham and Women's Hospital , Boston, MA , USA ; Golby Lab, A Surgical Brain Mapping Laboratory, Department of Neurosurgery, Brigham and Women's Hospital , Boston, MA , USA
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Elliott RE, Bollo RJ, Berliner JL, Silverberg A, Carlson C, Geller EB, Barr WB, Devinsky O, Doyle WK. Anterior temporal lobectomy with amygdalohippocampectomy for mesial temporal sclerosis: predictors of long-term seizure control. J Neurosurg 2013; 119:261-72. [DOI: 10.3171/2013.4.jns121829] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
In this paper the authors' goal was to identify preoperative variables that predict long-term seizure freedom among patients with mesial temporal sclerosis (MTS) after single-stage anterior temporal lobectomy and amygdalohippocampectomy (ATL-AH).
Methods
The authors retrospectively reviewed 116 consecutive patients (66 females, mean age at surgery 40.7 years) with refractory seizures and pathologically confirmed MTS who underwent ATL-AH with at least 2 years of follow-up. All patients underwent preoperative MRI and video-electroencephalography (EEG); 106 patients (91.4%) underwent Wada testing and 107 patients (92.2%) had neuropsychological evaluations. The authors assessed the concordance of these 4 studies (defined as test consistent with the side of eventual surgery) and analyzed the impact of preoperative variables on seizure freedom.
Results
The median follow-up after surgery was 6.7 years (mean 6.9 years). Overall, 103 patients (89%) were seizure free, and 109 patients (94%) had Engel Class I or II outcome. Concordant findings were highest for video-EEG (100%), PET (100%), MRI (99.0%), and Wada testing (90.4%) and lowest for SPECT (84.6%) and neuropsychological testing (82.5%). Using binary logistic regression analysis (seizure free or not) and Cox proportional hazard analysis (seizure-free survival), less disparity in the Wada memory scores between the ipsilateral and contralateral sides was associated with persistent seizures.
Conclusions
Seizure freedom of nearly 90% can be achieved with ATL-AH in properly selected patients with MTS and concordant preoperative studies. The low number of poor outcomes and exclusion of multistage patients limit the statistical power to determine preoperative variables that predict failure. Strong Wada memory lateralization was associated with excellent long-term outcome and adds important localization information to structural and neurophysiological data in predicting outcome after ATL-AH for MTS.
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Affiliation(s)
| | - Robert J. Bollo
- 2Department of Neurosurgery, Division of Pediatric Neurosurgery, Baylor College of Medicine, Houston, Texas
| | | | - Alyson Silverberg
- 3Departments of Neurosurgery,
- 4Neurology, Comprehensive Epilepsy Center, and
| | | | - Eric B. Geller
- 5Institute of Neurology & Neurosurgery, Saint Barnabas Medical Center, Livingston, New Jersey
| | - William B. Barr
- 4Neurology, Comprehensive Epilepsy Center, and
- 6Psychiatry, New York University Langone Medical Center, New York, New York; and
| | - Orrin Devinsky
- 4Neurology, Comprehensive Epilepsy Center, and
- 5Institute of Neurology & Neurosurgery, Saint Barnabas Medical Center, Livingston, New Jersey
- 6Psychiatry, New York University Langone Medical Center, New York, New York; and
| | - Werner K. Doyle
- 3Departments of Neurosurgery,
- 4Neurology, Comprehensive Epilepsy Center, and
- 5Institute of Neurology & Neurosurgery, Saint Barnabas Medical Center, Livingston, New Jersey
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Bonnici HM, Sidhu M, Chadwick MJ, Duncan JS, Maguire EA. Assessing hippocampal functional reserve in temporal lobe epilepsy: a multi-voxel pattern analysis of fMRI data. Epilepsy Res 2013; 105:140-9. [PMID: 23352740 PMCID: PMC3682189 DOI: 10.1016/j.eplepsyres.2013.01.004] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2012] [Revised: 12/29/2012] [Accepted: 01/03/2013] [Indexed: 11/27/2022]
Abstract
Assessing the functional reserve of key memory structures in the medial temporal lobes (MTL) of pre-surgical patients with intractable temporal lobe epilepsy (TLE) remains a challenge. Conventional functional MRI (fMRI) memory paradigms have yet to fully convince of their ability to confidently assess the risk of a post-surgical amnesia. An alternative fMRI analysis method, multi-voxel pattern analysis (MVPA), focuses on the patterns of activity across voxels in specific brain regions that are associated with individual memory traces. This method makes it possible to investigate whether the hippocampus and related structures contralateral to any proposed surgery are capable of laying down and representing specific memories. Here we used MVPA-fMRI to assess the functional integrity of the hippocampi and MTL in patients with long-standing medically refractory TLE associated with unilateral hippocampal sclerosis (HS). Patients were exposed to movie clips of everyday events prior to scanning, which they subsequently recalled during high-resolution fMRI. MTL structures were delineated and pattern classifiers were trained to learn the patterns of brain activity across voxels associated with each memory. Predictable patterns of activity across voxels associated with specific memories could be detected in MTL structures, including the hippocampus, on the side contralateral to the HS, indicating their functional viability. By contrast, no discernible memory representations were apparent in the sclerotic hippocampus, but adjacent MTL regions contained detectable information about the memories. These findings suggest that MVPA in fMRI memory studies of TLE can indicate hippocampal functional reserve and may be useful to predict the effects of hippocampal resection in individual patients.
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Affiliation(s)
- Heidi M. Bonnici
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, 12 Queen Square, London WC1N 3BG, United Kingdom
| | - Meneka Sidhu
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom
- Epilepsy Society, Chalfont St Peter, Buckinghamshire, United Kingdom
| | - Martin J. Chadwick
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, 12 Queen Square, London WC1N 3BG, United Kingdom
| | - John S. Duncan
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, United Kingdom
- Epilepsy Society, Chalfont St Peter, Buckinghamshire, United Kingdom
| | - Eleanor A. Maguire
- Wellcome Trust Centre for Neuroimaging, UCL Institute of Neurology, 12 Queen Square, London WC1N 3BG, United Kingdom
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Byrne RW. Temporal lobectomy. J Neurosurg 2013; 119:257-60. [PMID: 23706052 DOI: 10.3171/2013.1.jns122326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Bonelli SB, Thompson PJ, Yogarajah M, Powell RHW, Samson RS, McEvoy AW, Symms MR, Koepp MJ, Duncan JS. Memory reorganization following anterior temporal lobe resection: a longitudinal functional MRI study. ACTA ACUST UNITED AC 2013; 136:1889-900. [PMID: 23715092 PMCID: PMC3673465 DOI: 10.1093/brain/awt105] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Anterior temporal lobe resection controls seizures in 50-60% of patients with intractable temporal lobe epilepsy but may impair memory function, typically verbal memory following left, and visual memory following right anterior temporal lobe resection. Functional reorganization can occur within the ipsilateral and contralateral hemispheres. We investigated the reorganization of memory function in patients with temporal lobe epilepsy before and after left or right anterior temporal lobe resection and the efficiency of postoperative memory networks. We studied 46 patients with unilateral medial temporal lobe epilepsy (25/26 left hippocampal sclerosis, 16/20 right hippocampal sclerosis) before and after anterior temporal lobe resection on a 3 T General Electric magnetic resonance imaging scanner. All subjects had neuropsychological testing and performed a functional magnetic resonance imaging memory encoding paradigm for words, pictures and faces, testing verbal and visual memory in a single scanning session, preoperatively and again 4 months after surgery. Event-related analysis revealed that patients with left temporal lobe epilepsy had greater activation in the left posterior medial temporal lobe when successfully encoding words postoperatively than preoperatively. Greater pre- than postoperative activation in the ipsilateral posterior medial temporal lobe for encoding words correlated with better verbal memory outcome after left anterior temporal lobe resection. In contrast, greater postoperative than preoperative activation in the ipsilateral posterior medial temporal lobe correlated with worse postoperative verbal memory performance. These postoperative effects were not observed for visual memory function after right anterior temporal lobe resection. Our findings provide evidence for effective preoperative reorganization of verbal memory function to the ipsilateral posterior medial temporal lobe due to the underlying disease, suggesting that it is the capacity of the posterior remnant of the ipsilateral hippocampus rather than the functional reserve of the contralateral hippocampus that is important for maintaining verbal memory function after anterior temporal lobe resection. Early postoperative reorganization to ipsilateral posterior or contralateral medial temporal lobe structures does not underpin better performance. Additionally our results suggest that visual memory function in right temporal lobe epilepsy is affected differently by right anterior temporal lobe resection than verbal memory in left temporal lobe epilepsy.
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Affiliation(s)
- Silvia B Bonelli
- Epilepsy Society MRI Unit, Epilepsy Society, Chalfont St Peter, SL9 0RJ, UK
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Sidhu MK, Stretton J, Winston GP, Bonelli S, Centeno M, Vollmar C, Symms M, Thompson PJ, Koepp MJ, Duncan JS. A functional magnetic resonance imaging study mapping the episodic memory encoding network in temporal lobe epilepsy. ACTA ACUST UNITED AC 2013; 136:1868-88. [PMID: 23674488 PMCID: PMC3673458 DOI: 10.1093/brain/awt099] [Citation(s) in RCA: 103] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Functional magnetic resonance imaging has demonstrated reorganization of memory encoding networks within the temporal lobe in temporal lobe epilepsy, but little is known of the extra-temporal networks in these patients. We investigated the temporal and extra-temporal reorganization of memory encoding networks in refractory temporal lobe epilepsy and the neural correlates of successful subsequent memory formation. We studied 44 patients with unilateral temporal lobe epilepsy and hippocampal sclerosis (24 left) and 26 healthy control subjects. All participants performed a functional magnetic resonance imaging memory encoding paradigm of faces and words with subsequent out-of-scanner recognition assessments. A blocked analysis was used to investigate activations during encoding and neural correlates of subsequent memory were investigated using an event-related analysis. Event-related activations were then correlated with out-of-scanner verbal and visual memory scores. During word encoding, control subjects activated the left prefrontal cortex and left hippocampus whereas patients with left hippocampal sclerosis showed significant additional right temporal and extra-temporal activations. Control subjects displayed subsequent verbal memory effects within left parahippocampal gyrus, left orbitofrontal cortex and fusiform gyrus whereas patients with left hippocampal sclerosis activated only right posterior hippocampus, parahippocampus and fusiform gyrus. Correlational analysis showed that patients with left hippocampal sclerosis with better verbal memory additionally activated left orbitofrontal cortex, anterior cingulate cortex and left posterior hippocampus. During face encoding, control subjects showed right lateralized prefrontal cortex and bilateral hippocampal activations. Patients with right hippocampal sclerosis showed increased temporal activations within the superior temporal gyri bilaterally and no increased extra-temporal areas of activation compared with control subjects. Control subjects showed subsequent visual memory effects within right amygdala, hippocampus, fusiform gyrus and orbitofrontal cortex. Patients with right hippocampal sclerosis showed subsequent visual memory effects within right posterior hippocampus, parahippocampal and fusiform gyri, and predominantly left hemisphere extra-temporal activations within the insula and orbitofrontal cortex. Correlational analysis showed that patients with right hippocampal sclerosis with better visual memory activated the amygdala bilaterally, right anterior parahippocampal gyrus and left insula. Right sided extra-temporal areas of reorganization observed in patients with left hippocampal sclerosis during word encoding and bilateral lateral temporal reorganization in patients with right hippocampal sclerosis during face encoding were not associated with subsequent memory formation. Reorganization within the medial temporal lobe, however, is an efficient process. The orbitofrontal cortex is critical to subsequent memory formation in control subjects and patients. Activations within anterior cingulum and insula correlated with better verbal and visual subsequent memory in patients with left and right hippocampal sclerosis, respectively, representing effective extra-temporal recruitment.
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Affiliation(s)
- Meneka K Sidhu
- Department of Clinical and Experimental Epilepsy, UCL Institute of Neurology, Queen Square, London WC1N 3BG, UK
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Abstract
Children with epilepsy are at risk for behavioral and cognitive comorbidities. Potential etiologies can be assessed in part by neuroimaging. Functional magnetic resonance imaging (MRI) has a major role in presurgical evaluation and prediction of postoperative outcome by mapping of language and memory. Structural MRI and functional MRI have shown changes in children and adolescents with attention deficit hyperactivity disorder and disruptive behavior, common comorbidities in children with epilepsy. Neuroimaging has the potential for significantly increasing understanding of the basis of cognitive and behavioral problems in children with epilepsy.
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48
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Abstract
Forty-four patients with temporal lobe epilepsy (TLE) (25 left) and 40 healthy control participants performed a complex visual scene-encoding fMRI task in a 4-T Varian scanner. Healthy controls and left temporal lobe epilepsy (LTLE) patients demonstrated symmetric activation during scene encoding. In contrast, right temporal lobe (RTLE) patients demonstrated left lateralization of scene encoding which differed significantly from healthy controls and LTLE patients (all p≤.05). Lateralization of scene encoding to the right hemisphere among LTLE patients was associated with inferior verbal memory performance as measured by neuropsychological testing (WMS-III Logical Memory Immediate, p = 0.049; WMS-III Paired Associates Immediate, p = 0.036; WMS-III Paired Associates Delayed, p = 0.047). In RTLE patients, left lateralization of scene encoding was associated with lower visuospatial memory performance (BVRT, p = 0.043) but improved verbal memory performance (WMS-III Word List, p = 0.049). These findings indicate that, despite the negative effects of epilepsy, memory functioning is better supported by the affected hemisphere than the hemisphere contralateral to the seizure focus.
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Affiliation(s)
- Cristina Bigras
- Department of Psychology, University of Cincinnati Academic Health Center, Cincinnati, OH, USA.
| | - Paula K. Shear
- Department of Psychology, University of Cincinnati Academic Health Center, Cincinnati, OH, USA.
,Center for Imaging Research, University of Cincinnati Academic Health Center, Cincinnati, OH, USA.
| | - Jennifer Vannest
- Division of Pediatric Neurology, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
,Pediatric Neuroimaging Research Consortium, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
| | - Jane B. Allendorfer
- Department of Neurology, University of Cincinnati Academic Health Center, Cincinnati, OH, USA.
| | - Jerzy P. Szaflarski
- Department of Psychology, University of Cincinnati Academic Health Center, Cincinnati, OH, USA.
,Department of Neurology, University of Cincinnati Academic Health Center, Cincinnati, OH, USA.
,Center for Imaging Research, University of Cincinnati Academic Health Center, Cincinnati, OH, USA.
,Pediatric Neuroimaging Research Consortium, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, USA
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Rzezak P, Guimarães CA, Fuentes D, Guerreiro MM, Valente KD. Memory in children with temporal lobe epilepsy is at least partially explained by executive dysfunction. Epilepsy Behav 2012; 25:577-84. [PMID: 23159382 DOI: 10.1016/j.yebeh.2012.09.043] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Revised: 08/24/2012] [Accepted: 09/29/2012] [Indexed: 11/24/2022]
Abstract
An association between memory and executive dysfunction (ED) has been demonstrated in patients with mixed neurological disorders. We aimed to investigate the impact of ED in memory tasks of children with temporal lobe epilepsy (TLE). We evaluated 36 children with TLE and 28 controls with tests for memory, learning, attention, mental flexibility, and mental tracking. Data analysis was composed of comparison between patients and controls in memory and executive function; correlation between memory and executive function tests; and comparison between patients with mild and severe ED in memory tests. Children with TLE had worse performance in focused attention, immediate and delayed recall, phonological memory, mental tracking, planning, and abstraction. Planning, abstraction, and mental tracking were correlated with visual and verbal memory. Children with severe ED had worse performance in verbal and visual memory and learning tests. This study showed that ED was related to memory performance in children with TLE.
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Affiliation(s)
- Patricia Rzezak
- LIM-21, Laboratory for Medical Research 21-Neuroimaging Laboratory, Department of Psychiatry, University of São Paulo, São Paulo, Brazil.
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The functional anatomy of non-verbal (pitch memory) function in left and right anterior temporal lobectomy patients. Clin Neurol Neurosurg 2012; 115:934-43. [PMID: 23031747 DOI: 10.1016/j.clineuro.2012.09.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 08/14/2012] [Accepted: 09/16/2012] [Indexed: 11/21/2022]
Abstract
An fMRI pitch memory task was administered to left and right anterior temporal lobectomy (ATL) patients. The goal was to verify the neuroanatomical correlates of non-verbal memory, and to determine if pitch memory tasks can identify cognitive risk prior to ATL. The data showed that the bilateral posterior superior temporal lobes implement pitch memory in both ATL patients and NCs (normal controls), indicating that the task can be accomplished with either anterior temporal lobe resected. NCs activate the posterior temporal lobes more strongly than ATL patients during highly accurate performance. In contrast, both ATL groups activate the anterior cingulate in association with accuracy. While our data clarifies the functional neuroanatomy of pitch memory, it also indicates that such tasks do not serve well to lateralize and functionally map potentially "at risk" non-verbal memory skills prior to ATL.
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