Open AccessBringing memory fMRI to the clinic: Comparison of seven memory fMRI protocols in temporal lobe epilepsy
Author(s) -
Towgood Karren,
Barker Gareth J.,
Caceres Alejandro,
Crum William R,
Elwes Robert D.C.,
Costafreda Sergi G.,
Mehta Mitul A.,
Morris Robin G.,
von Oertzen Tim J.,
Richardson Mark P.
Publication year - 2015
Publication title -
human brain mapping
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.005
H-Index - 191
eISSN - 1097-0193
pISSN - 1065-9471
DOI - 10.1002/hbm.22726
Subject(s) - temporal lobe , intraclass correlation , psychology , block design , lateralization of brain function , voxel , audiology , epilepsy , reliability (semiconductor) , neuroscience , computer science , medicine , artificial intelligence , developmental psychology , psychometrics , power (physics) , physics , mathematics , combinatorics , quantum mechanics
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.