Resting fMRI as an alternative for task-based fMRI for language lateralization in temporal lobe epilepsy patients: a study using independent component analysis

Smitha, K A; Arun, K; Rajesh, P.; Radhakrishnan, Ashalatha; Sarma, P. Sankara; Kesavadas, Chandrasekharan

doi:10.1007/s00234-019-02209-w

Cited by 10 publications

(6 citation statements)

References 39 publications

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“…However, this approach has been used by several investigators for assessing language IC. 3,12,29 Branco et al 9 have extracted a mean of 66.3 ICs, which was higher than the number of ICs in our study, and showed that for each subject, 1 IC was identified as the language component with high confidence by an expert. They also found that there was good agreement between the IC with the highest ranked Dice coefficient and the expert-selected language component.…”

Section: Discussioncontrasting

confidence: 55%

“…The 2 commonly used methods for analyzing rs-fMRI to lateralize language are ICA 9,12,13,29 or seed-based 11 approaches. ICA is data-driven and can be performed without any a priori assumptions.…”

Section: Discussionmentioning

confidence: 99%

“…Preliminary evidence suggests that rs-fMRI is promising for lateralizing language in healthy 7,8 and clinical populations of adults with tumor 9,10 and epilepsy, 11,12 though concordance rates are highly variable across studies. Only 2 studies have examined the use of rs-fMRI to determine language dominance in children with epilepsy compared with tb-fMRI, 13,14 and these 2 studies were limited by the use of visual assessment for classifying language laterality and/or small sample size, and in 1 study, bilateral language lateralization was excluded.…”

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confidence: 99%

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Resting-State Functional MRI for Determining Language Lateralization in Children with Drug-Resistant Epilepsy

Phillips

Shatil

Go³

et al. 2021

AJNR Am J Neuroradiol

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BACKGROUND AND PURPOSE: Task-based fMRI is a noninvasive method of determining language dominance; however, not all children can complete language tasks due to age, cognitive/intellectual, or language barriers. Task-free approaches such as resting-state fMRI offer an alternative method. This study evaluated resting-state fMRI for predicting language laterality in children with drug-resistant epilepsy. MATERIALS AND METHODS:A retrospective review of 43 children with drug-resistant epilepsy who had undergone resting-state fMRI and task-based fMRI during presurgical evaluation was conducted. Independent component analysis of resting-state fMRI was used to identify language networks by comparing the independent components with a language network template. Concordance rates in language laterality between resting-state fMRI and each of the 4 task-based fMRI language paradigms (auditory description decision, auditory category, verbal fluency, and silent word generation tasks) were calculated.RESULTS: Concordance ranged from 0.64 (95% CI, 0.48-0.65) to 0.73 (95% CI, 0.58-0.87), depending on the language paradigm, with the highest concordance found for the auditory description decision task. Most (78%-83%) patients identified as left-lateralized on task-based fMRI were correctly classified as left-lateralized on resting-state fMRI. No patients classified as right-lateralized or bilateral on task-based fMRI were correctly classified by resting-state fMRI.CONCLUSIONS: While resting-state fMRI correctly classified most patients who had typical (left) language dominance, its ability to correctly classify patients with atypical (right or bilateral) language dominance was poor. Further study is required before resting-state fMRI can be used clinically for language mapping in the context of epilepsy surgery evaluation in children with drug-resistant epilepsy.ABBREVIATIONS: ACT ¼ auditory category task; ADDT ¼ auditory description decision task; DRE ¼ drug-resistant epilepsy; IC ¼ independent component; ICA ¼ independent component analysis; LI ¼ laterality index; rs-fMRI ¼ resting-state fMRI; SWG ¼ silent word generation; tb-fMRI ¼ task-based fMRI; VF ¼ verbal fluency.

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Section: Discussioncontrasting

confidence: 55%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Resting-State Functional MRI for Determining Language Lateralization in Children with Drug-Resistant Epilepsy

Phillips

Shatil

Go³

et al. 2021

AJNR Am J Neuroradiol

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“…Currently, resting state functional MRI (rs-fMRI) has been widely utilized to study brain activity and network changes among patients with neurological and mental illness ( Nathan et al, 2014 ; Poldrack and Farah, 2015 ; Tessitore et al, 2019 ; Ge et al, 2020 ). Compared to fMRI in the task state, rs-fMRI is simple ( Park et al, 2020 ), easy to perform and highly repeatable ( Smitha et al, 2019 ). In fact, there have been a few studies that have used rs-MRI in order to study alterations in the brain activity during microlesions ( Jech et al, 2012 ; Holiga et al, 2015 ).…”

Section: Introductionmentioning

confidence: 99%

Altered Spontaneous Neural Activity and Functional Connectivity in Parkinson’s Disease With Subthalamic Microlesion

et al. 2021

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BackgroundTransient improvement in motor symptoms are immediately observed in patients with Parkinson’s disease (PD) after an electrode has been implanted into the subthalamic nucleus (STN) for deep brain stimulation (DBS). This phenomenon is known as the microlesion effect (MLE). However, the underlying mechanisms of MLE is poorly understood.PurposeWe utilized resting state functional MRI (rs-fMRI) to evaluate changes in spontaneous brain activity and networks in PD patients during the microlesion period after DBS.MethodOverall, 37 PD patients and 13 gender- and age-matched healthy controls (HCs) were recruited for this study. Rs-MRI information was collected from PD patients three days before DBS and one day after DBS, whereas the HCs group was scanned once. We utilized the amplitude of low-frequency fluctuation (ALFF) method in order to analyze differences in spontaneous whole-brain activity among all subjects. Furthermore, functional connectivity (FC) was applied to investigate connections between other brain regions and brain areas with significantly different ALFF before and after surgery in PD patients.ResultRelative to the PD-Pre-DBS group, the PD-Post-DBS group had higher ALFF in the right putamen, right inferior frontal gyrus, right precentral gyrus and lower ALFF in right angular gyrus, right precuneus, right posterior cingulate gyrus (PCC), left insula, left middle temporal gyrus (MTG), bilateral middle frontal gyrus and bilateral superior frontal gyrus (dorsolateral). Functional connectivity analysis revealed that these brain regions with significantly different ALFF scores demonstrated abnormal FC, largely in the temporal, prefrontal cortices and default mode network (DMN).ConclusionThe subthalamic microlesion caused by DBS in PD was found to not only improve the activity of the basal ganglia-thalamocortical circuit, but also reduce the activity of the DMN and executive control network (ECN) related brain regions. Results from this study provide new insights into the mechanism of MLE.

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“…Two previous studies challenged this issue in clinical patients with temporal lobe epilepsy [ 80 , 81 ], however, only one confronted imaging data to the Wada test [ 81 ]. They found a sensitivity and specificity of 96% in a small cohort of 23 patients.…”

Section: Discussionmentioning

confidence: 99%

Overt speech critically changes lateralization index and did not allow determination of hemispheric dominance for language: an fMRI study

et al. 2021

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Background Pre-surgical mapping of language using functional MRI aimed principally to determine the dominant hemisphere. This mapping is currently performed using covert linguistic task in way to avoid motion artefacts potentially biasing the results. However, overt task is closer to natural speaking, allows a control on the performance of the task, and may be easier to perform for stressed patients and children. However, overt task, by activating phonological areas on both hemispheres and areas involved in pitch prosody control in the non-dominant hemisphere, is expected to modify the determination of the dominant hemisphere by the calculation of the lateralization index (LI). Objective Here, we analyzed the modifications in the LI and the interactions between cognitive networks during covert and overt speech task. Methods Thirty-three volunteers participated in this study, all but four were right-handed. They performed three functional sessions consisting of (1) covert and (2) overt generation of a short sentence semantically linked with an audibly presented word, from which we estimated the “Covert” and “Overt” contrasts, and a (3) resting-state session. The resting-state session was submitted to spatial independent component analysis to identify language network at rest (LANG), cingulo-opercular network (CO), and ventral attention network (VAN). The LI was calculated using the bootstrapping method. Results The LI of the LANG was the most left-lateralized (0.66 ± 0.38). The LI shifted from a moderate leftward lateralization for the Covert contrast (0.32 ± 0.38) to a right lateralization for the Overt contrast (− 0.13 ± 0.30). The LI significantly differed from each other. This rightward shift was due to the recruitment of right hemispheric temporal areas together with the nodes of the CO. Conclusion Analyzing the overt speech by fMRI allowed improvement in the physiological knowledge regarding the coordinated activity of the intrinsic connectivity networks. However, the rightward shift of the LI in this condition did not provide the basic information on the hemispheric language dominance. Overt linguistic task cannot be recommended for clinical purpose when determining hemispheric dominance for language.

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Resting fMRI as an alternative for task-based fMRI for language lateralization in temporal lobe epilepsy patients: a study using independent component analysis

Cited by 10 publications

References 39 publications

Resting-State Functional MRI for Determining Language Lateralization in Children with Drug-Resistant Epilepsy

Resting-State Functional MRI for Determining Language Lateralization in Children with Drug-Resistant Epilepsy

Altered Spontaneous Neural Activity and Functional Connectivity in Parkinson’s Disease With Subthalamic Microlesion

Overt speech critically changes lateralization index and did not allow determination of hemispheric dominance for language: an fMRI study

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