Methodological considerations in assessment of language lateralisation with fMRI: a systematic review

Bradshaw, Abigail R.; Bishop, Dorothy V. M.; Woodhead, Zoe

doi:10.7717/peerj.3557

Cited by 70 publications

(47 citation statements)

References 63 publications

(147 reference statements)

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“…Lateralization was assessed using the bootstrapping procedure implemented within the LI toolbox ( Wilke and Schmithorst, 2006 ; Wilke and Lidzba, 2007 ) in SPM. This is a robust tool that deals with the threshold dependency of assessing laterality from neuroimaging data ( Bradshaw et al, 2017 ). We assessed lateralization for a main effect of group and interactions of group and tasks.…”

Section: Methodsmentioning

confidence: 99%

How Auditory Experience Differentially Influences the Function of Left and Right Superior Temporal Cortices

et al. 2017

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To investigate how hearing status, sign language experience, and task demands influence functional responses in the human superior temporal cortices (STC) we collected fMRI data from deaf and hearing participants (male and female), who either acquired sign language early or late in life. Our stimuli in all tasks were pictures of objects. We varied the linguistic and visuospatial processing demands in three different tasks that involved decisions about (1) the sublexical (phonological) structure of the British Sign Language (BSL) signs for the objects, (2) the semantic category of the objects, and (3) the physical features of the objects.Neuroimaging data revealed that in participants who were deaf from birth, STC showed increased activation during visual processing tasks. Importantly, this differed across hemispheres. Right STC was consistently activated regardless of the task whereas left STC was sensitive to task demands. Significant activation was detected in the left STC only for the BSL phonological task. This task, we argue, placed greater demands on visuospatial processing than the other two tasks. In hearing signers, enhanced activation was absent in both left and right STC during all three tasks. Lateralization analyses demonstrated that the effect of deafness was more task-dependent in the left than the right STC whereas it was more task-independent in the right than the left STC. These findings indicate how the absence of auditory input from birth leads to dissociable and altered functions of left and right STC in deaf participants.SIGNIFICANCE STATEMENT Those born deaf can offer unique insights into neuroplasticity, in particular in regions of superior temporal cortex (STC) that primarily respond to auditory input in hearing people. Here we demonstrate that in those deaf from birth the left and the right STC have altered and dissociable functions. The right STC was activated regardless of demands on visual processing. In contrast, the left STC was sensitive to the demands of visuospatial processing. Furthermore, hearing signers, with the same sign language experience as the deaf participants, did not activate the STCs. Our data advance current understanding of neural plasticity by determining the differential effects that hearing status and task demands can have on left and right STC function.

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Section: Methodsmentioning

confidence: 99%

How Auditory Experience Differentially Influences the Function of Left and Right Superior Temporal Cortices

et al. 2017

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“…One of the most common application is the localization of language areas and their lateralization, which is an essential information in the treatment of patients with epilepsy (32)(33)(34)(35)(36)(37)(38). In most occasions, this clinical application of fMRI shows comparable results as the invasive WADA test but might deviate in cases with atypical language dominance (39).…”

Section: Current Clinical Applications Of Fmrimentioning

confidence: 99%

Current Challenges in Translational and Clinical fMRI and Future Directions

Specht

2020

Front. Psychiatry

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Translational neuroscience is an important field that brings together clinical praxis with neuroscience methods. In this review article, the focus will be on functional neuroimaging (fMRI) and its applicability in clinical fMRI studies. In the light of the "replication crisis," three aspects will be critically discussed: First, the fMRI signal itself, second, current fMRI praxis, and, third, the next generation of analysis strategies. Current attempts such as restingstate fMRI, meta-analyses, and machine learning will be discussed with their advantages and potential pitfalls and disadvantages. One major concern is that the fMRI signal shows substantial within-and between-subject variability, which affects the reliability of both taskrelated, but in particularly resting-state fMRI studies. Furthermore, the lack of standardized acquisition and analysis methods hinders the further development of clinical relevant approaches. However, meta-analyses and machine-learning approaches may help to overcome current shortcomings in the methods by identifying new, and yet hidden relationships, and may help to build new models on disorder mechanisms. Furthermore, better control of parameters that may have an influence on the fMRI signal and that can easily be controlled for, like blood pressure, heart rate, diet, time of day, might improve reliability substantially.

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“…LI values thus range from +1 (left dominant) to -1 (right dominant). However, a major limitation of this approach is the strong dependence of the LI on the arbitrarily chosen activation threshold value [23][24][25].…”

Section: Introductionmentioning

confidence: 99%

“…To overcome this limitation, various threshold-independent laterality index calculation methods have been reported in the literature [25]. For example, Knecht and colleagues define the activation threshold by a fixed total number of voxels and from this calculate a single LI value [26].…”

Section: Introductionmentioning

confidence: 99%

“…Branco, Suarez and colleagues proposed to integrate the weighted histogram of voxel counts against threshold in order to calculate a global LI [23,28]. The review by Bradshaw and colleagues [25] highlights the lack of standardization in assessment of language lateralization using fMRI. The multitude of LI calculation methods, tasks and ROIs used in previously published reports makes comparison of results between studies difficult.…”

Section: Introductionmentioning

confidence: 99%

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Implementation of clinically relevant and robust fMRI-based language lateralization: Choosing the laterality index calculation method

et al. 2020

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The assessment of language lateralization has become widely used when planning neurosurgery close to language areas, due to individual specificities and potential influence of brain pathology. Functional magnetic resonance imaging (fMRI) allows non-invasive and quantitative assessment of language lateralization for presurgical planning using a laterality index (LI). However, the conventional method is limited by the dependence of the LI on the chosen activation threshold. To overcome this limitation, different threshold-independent LI calculations have been reported. The purpose of this study was to propose a simplified approach to threshold-independent LI calculation and compare it with three previously reported methods on the same cohort of subjects. Fifteen healthy subjects, who performed picture naming, verb generation, and word fluency tasks, were scanned. LI values were calculated for all subjects using four methods, and considering either the whole hemisphere or an atlas-defined language area. For each method, the subjects were ranked according to the calculated LI values, and the obtained rankings were compared. All LI calculation methods agreed in differentiating strong from weak lateralization on both hemispheric and regional scales (Spearman's correlation coefficients 0.59-1.00). In general, a more lateralized activation was found in the language area than in the whole hemisphere. The new method is well suited for application in the clinical practice as it is simple to implement, fast, and robust. The good agreement between LI calculation methods suggests that the choice of method is not key. Nevertheless, it should be consistent to allow a relative comparison of language lateralization between subjects.

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Methodological considerations in assessment of language lateralisation with fMRI: a systematic review

Cited by 70 publications

References 63 publications

How Auditory Experience Differentially Influences the Function of Left and Right Superior Temporal Cortices

How Auditory Experience Differentially Influences the Function of Left and Right Superior Temporal Cortices

Current Challenges in Translational and Clinical fMRI and Future Directions

Implementation of clinically relevant and robust fMRI-based language lateralization: Choosing the laterality index calculation method

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