Objective assessment of automatic language comprehension mechanisms in the brain: Novel E/MEG paradigm

Abstract

Assessing the brain activity related to language comprehension is required in a range of situations. Particularly in cases when subjects’ cooperation with instructions cannot be guaranteed (e.g., in neurological patients), a protocol is needed that could be independent from attention and behavioral tasks. In this study, we aimed at designing a novel approach for neuromagnetic recordings of brain activity which could allow for probing the neural foundations underpinning three key levels of speech comprehension: lexical, semantic, and (morpho)syntactic, without requiring active attention on speech input or any active task, while keeping the recording session duration as short as possible. To this end, we designed two different auditory paradigms using the same set of single word‐based lexical, semantic, and syntactic contrasts: a modified version of the multifeature oddball paradigm and an equiprobable design. Combined magnetoencephalography/electroencephalography data were recorded form young, healthy participants, presented with these stimuli while watching a silent movie. Data from the equiprobable design yielded significant activations in temporal and inferior frontal areas associated with the lexical, semantic, and morphosyntactic contrasts. In turn, neural dissociations observed in the multifeature paradigm emerged mainly in temporal cortices, and were confined to the lexical and semantic conditions with a striking lack of any statistically significant effects for syntactic violations. Our findings indicate that, by employing the equiprobable design, a comprehensive range of key linguistic processes could be assessed in a passive, attention‐free manner within a relatively short time (here, ~27 min), thus making this paradigm a time‐efficient and patient‐friendly tool.

STN‐DBS affects language processing differentially in Parkinson's disease: Multiple‐case MEG study

“…Stimulus presentation was done using an equiprobable paradigm that we have previously validated for use with patients 36 . The paradigm allows simultaneous testing of different linguistic contrasts while keeping the testing session very short and not requiring any focused attention or overt stimulus‐related task from the patient 36 . The paradigm included two separate sequences, one for the semantic stimuli and one for the morphosyntactic ones.…”

Applied potential of task-free event-related paradigms for assessing neurocognitive functions in disorders of consciousness

“…This effect is generally referred to as an automatic lexical enhancement and has been found in both repetitive oddball designs and non-oddball paradigms. Such attention-independent responses that do not depend on overt tasks may therefore be of use in situations when the subject’s cooperation cannot be obtained ( Gansonre et al , 2018 ; Hyder et al , 2020 ), and thus may be of use for assessing patients with DoC or CMD. While ELAN/syntactic MMN and lexical enhancement certainly hold a promise as potential assessment tools, they have so far not been tested in DoC, which, we suggest, should be tackled in future studies.…”

Functional connectivity of spoken language processing in early-stage Parkinson’s disease: An MEG study

“…For stimulus presentation we adapted the so-called equiprobable paradigm, optimised for patient-friendliness, presentation time, and the number of linguistic contrasts tested simultaneously, as shown in previous MEG research using healthy participants ( Hyder et al, 2020 ). Stimuli were presented in two sequences.…”