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

Not Applicable

Completed

• Conditions: Languages
• Interventions: Device: Sham cTBS; Device: Sham iTBS; Device: intermittent theta burst stimulation (iTBS); Device: continuous theta burst stimulation (cTBS)

• Registration Number: NCT03148470
• Lead Sponsor: Jean-Marie Annoni

Brief Summary

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.

Detailed Description

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 Timeline

• Study Start: 2016-09
• Study First Submitted: 2017-05-01
• Study First Submitted QC: 2017-05-08
• Study First Posted: 2017-05-11
• Primary Completion: 2018-07
• Study Completion: 2019-07
• Results First Submitted: 2019-10-07
• Results First Submitted QC: 2020-03-27
• Status Verified: 2020-04
• Results First Posted: 2020-04-10
• Last Update Submitted: 2020-04-11
• Last Update Posted: 2020-04-22

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 41

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

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: FACTORIAL

Arm && Interventions

Group	Intervention	Description
continuous theta burst stimulation	Sham cTBS	continuous theta burst stimulation (cTBS) + Sham cTBS
intermittent theta burst stimulation	intermittent theta burst stimulation (iTBS)	intermittent theta burst stimulation (iTBS) + Sham iTBS
continuous theta burst stimulation	continuous theta burst stimulation (cTBS)	continuous theta burst stimulation (cTBS) + Sham cTBS
intermittent theta burst stimulation	Sham iTBS	intermittent theta burst stimulation (iTBS) + Sham iTBS

Primary Outcome Measures

Name	Time	Method
RTs for Picture Naming With the Factors Language (L1, L2) and Block (Switching, Non-Switching)	Within 30 minutes after intervention	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.

Secondary Outcome Measures

Name	Time	Method
Nonverbal Switching	Within 30 minutes after intervention	Nonverbal Switching: response times

Trial Locations

Locations (1)

Laboratory for Cognitive and Neurological Sciences; 🇨🇭 Fribourg, Switzerland