Impact of Theta Burst Stimulation Over the Left DLPFC on Language Switching

Jean-Marie Annoni41 enrolled

Overview

The purpose of this study is to investigate whether theta burst stimulation (TBS) over the left dorsolateral prefrontal cortex (DLPFC) influences language switching and cognitive flexibility. The experimental paradigm will assess the impact of inhibitory and excitatory prefrontal stimulation by TBS versus sham-TBS over the DLPFC in healthy bilinguals.

Background: Clinical observations and neuroimaging studies seem to confirm the role of executive functions and frontal structures in language processing in bilingual subjects. Repetitive transcranial magnetic stimulation, such as for example theta burst stimulation (TBS), is increasingly being used as a valuable tool for neuroscientists investigating the underlying mechanisms of cognitive functions. Case studies have shown a change in language switching after bilingual patients received repetitive magnetic stimulation to the left DLPFC. However, there is no study investigating the effect of TBS applied to the DLPFC on language switching in healthy participants. Procedure: A planned total of 40 unbalanced bilingual participants will be included. Half of the participants will receive inhibitory theta burst stimulation (continuous TBS), the other half excitatory theta burst stimulation (intermittent TBS). After TBS, different language and nonverbal tasks will be performed while an EEG is measured. Before being stimulated, each subject will conduct the same tasks with a sham-TBS as a baseline measure.

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

BASIC_SCIENCE

Masking

DOUBLE

Enrollment

Conditions

Languages

Interventions

Sham iTBSDEVICE

Placebo stimulation for the iTBS group

Sham cTBSDEVICE

Placebo stimulation for the cTBS group

intermittent theta burst stimulation (iTBS)DEVICE

Excitatory theta burst stimulation

Eligibility

Sex: ALLMin age: 18 YearsMax age: 45 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria: * L1 (Swiss)German, knowledge of English as a foreign language * 18-45 years of age * right-handedness Exclusion Criteria: * epilepsy / family history of epilepsy * brain surgery, traumatic brain injuries * cardiac pacemaker, metallic objects in the head * history of neurological diseases or severe psychiatric disorders * drug use (alcohol, psychoactive medication) * strong headache * pregnancy

Locations (1)

Laboratory for Cognitive and Neurological Sciences

Fribourg, Switzerland

Outcomes

Primary Outcomes

RTs for Picture Naming With the Factors Language (L1, L2) and Block (Switching, Non-Switching)

Picture naming with the factors Language (L1, L2) and Block (Switching, Non-Switching): Speech onset times (msec) L1 refers to the mother tongue. L2 refers to the late acquired (\> age 7) second language. Switching Block refers to a language switching block with picture naming alternated between the mother tongue and the second language. Non-Switching Block refers to a block of picture naming either only in the mother or only in the second language.

Time frame: Within 30 minutes after intervention

Secondary Outcomes

Nonverbal Switching

Nonverbal Switching: response times

Time frame: Within 30 minutes after intervention

Data from ClinicalTrials.gov

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