Skip to main content

ORIGINAL RESEARCH article

Front. Neurol.
Sec. Epilepsy
Volume 15 - 2024 | doi: 10.3389/fneur.2024.1419047

Test-retest reliability of the "Home Town Walk" fMRI paradigm for memory activation and lateralisation in the pre-surgical evaluation of patients with temporal lobe epilepsy

Provisionally accepted
Rosa S. Panchuelo Rosa S. Panchuelo 1Robert Flintham Robert Flintham 1Roman Wesolowski Roman Wesolowski 1Roya Jalali Roya Jalali 1Jane Herbert Jane Herbert 2Shanika Samarasekera Shanika Samarasekera 3Andrew P. Bagshaw Andrew P. Bagshaw 4Ramesh Chelvarajah Ramesh Chelvarajah 3Nigel P. Davies Nigel P. Davies 1Vijay Sawlani Vijay Sawlani 4,5*
  • 1 RRPPS, Medical Physics, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
  • 2 Imaging, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
  • 3 Complex Epilepsy Surgery, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom
  • 4 Centre for Human Brain Health, University of Birmingham, Birmingham, England, United Kingdom
  • 5 Imaging & Complex Epilepsy Surgery, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom

The final, formatted version of the article will be published soon.

    Functional magnetic resonance imaging (fMRI) can be used to assess language and memory function as part of pre-surgical decision making in refractory epilepsy. Although language paradigms are well established, memory paradigms are not widely used in clinical practice due to a lack of evidence for robust and reliable methods. Here, we aim to investigate the clinical utility of the Home Town Walk (HTW) paradigm for personalised treatment decisions in medial temporal lobe epilepsy. A cohort of 123 consecutive patients having HTW-fMRI as part of routine MRI scans over a 7.5 year period were included in this retrospective study. Of these, 111 patients underwent repeated HTW-fMRI in two scanning sessions one to three days apart. fMRI analysis was performed at the time of the scans using clinically approved software and retrospectively validated using FSL. We assessed the test-retest within subject reliability of activations within the posterior parahippocampal gyri (pPHG) at the individual subject level. Activations within the pPHG region were observed for 101 patients (91%) in at least one of the fMRI sessions and for 88 patients (79%) in both fMRI sessions, with 82 patients showing overlapping unilateral or bilateral activations and 8 further patients showing overlapping activations in one of the hemispheres but not the other. Reproducibility was evaluated using metrics based on the concordance ratios for size (Rsize) and location (Roverlap) within the pPHG region, as well as the lateralisation index (LI) metric to reflect the asymmetry of hemispheric activations, which is of crucial relevance to inform surgery. Test-retest reliability of visuo-spatial memory LIs, assessed by an intra-class correlation coefficient (ICC) yielded a value of 0.76, indicating excellent between session stability of memory lateralisation. In conclusion, the HTW-fMRI paradigm shows reproducible activations in the medial temporal lobes of individual epilepsy patients sufficient to consistently lateralise visuo-spatial memory function, demonstrating the clinical utility of HTW

    Keywords: fMRI, Memory, Epilepsy, home town walk, reproducibility

    Received: 17 Apr 2024; Accepted: 03 Jul 2024.

    Copyright: © 2024 Panchuelo, Flintham, Wesolowski, Jalali, Herbert, Samarasekera, Bagshaw, Chelvarajah, Davies and Sawlani. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

    * Correspondence: Vijay Sawlani, Imaging & Complex Epilepsy Surgery, University Hospitals Birmingham NHS Foundation Trust, Birmingham, United Kingdom

    Disclaimer: All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article or claim that may be made by its manufacturer is not guaranteed or endorsed by the publisher.