Languages
Conditions
Keywords
theta burst stimulation, Language switching, dorsolateral prefrontal cortex
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.
Interventions
DEVICESham iTBS
Placebo stimulation for the iTBS group
DEVICESham cTBS
Placebo stimulation for the cTBS group
DEVICEintermittent theta burst stimulation (iTBS)
Excitatory theta burst stimulation
inhibitory theta burst stimulation
Sponsors
Jean-Marie Annoni
Study design
Allocation
RANDOMIZED
Intervention model
FACTORIAL
Primary purpose
BASIC_SCIENCE
Masking
DOUBLE (Subject, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 45 Years
Healthy volunteers
Yes
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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| 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
| Measure | Time frame | Description |
|---|---|---|
| Nonverbal Switching | Within 30 minutes after intervention | Nonverbal Switching: response times |
Countries
Switzerland
Participant flow
Participants by arm
| Arm | Count |
|---|---|
| Intermittent Theta Burst Stimulation intermittent theta burst stimulation (iTBS) + Sham iTBS
Sham iTBS: Placebo stimulation
intermittent theta burst stimulation (iTBS): Excitatory rTMS | 21 |
| Continuous Theta Burst Stimulation continuous theta burst stimulation (cTBS) + Sham cTBS
Sham cTBS: Placebo stimulation
continuous theta burst stimulation (cTBS): inhibitory rTMS | 20 |
| Total | 41 |
Baseline characteristics
| Characteristic | Continuous Theta Burst Stimulation | Total | Intermittent Theta Burst Stimulation |
|---|---|---|---|
| Age, Continuous | 22.8 years STANDARD_DEVIATION 5.36 | 22.4 years STANDARD_DEVIATION 4.2 | 22.1 years STANDARD_DEVIATION 2.7 |
| Race and Ethnicity Not Collected | — | 0 Participants | — |
| Region of Enrollment Switzerland | 20 participants | 41 participants | 21 participants |
| Sex: Female, Male Female | 16 Participants | 31 Participants | 15 Participants |
| Sex: Female, Male Male | 4 Participants | 10 Participants | 6 Participants |
Adverse events
| Event type | EG000 affected / at risk | EG001 affected / at risk | EG002 affected / at risk | EG003 affected / at risk |
|---|---|---|---|---|
| deaths Total, all-cause mortality | 0 / 20 | 0 / 20 | 0 / 21 | 0 / 20 |
| other Total, other adverse events | 0 / 20 | 0 / 20 | 1 / 21 | 0 / 20 |
| serious Total, serious adverse events | 0 / 20 | 0 / 20 | 0 / 21 | 0 / 20 |
Outcome results
Primary
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
Population: As a primary outcome we compared RTs following iTBS vs cTBS. Sham-TBS is only used to have a baseline control between the two groups
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| RTs for PN After Intermittent Theta Burst Stimulation | RTs for Picture Naming With the Factors Language (L1, L2) and Block (Switching, Non-Switching) | 1103.32 Milliseconds | Standard Deviation 126 |
| RTs for PN After Continuous Theta Burst Stimulation | RTs for Picture Naming With the Factors Language (L1, L2) and Block (Switching, Non-Switching) | 1107.26 Milliseconds | Standard Deviation 131 |
| RTs for Picture Naming in L1 | RTs for Picture Naming With the Factors Language (L1, L2) and Block (Switching, Non-Switching) | 1098.82 Milliseconds | Standard Deviation 405 |
| RTs for Picture Naming in L2 | RTs for Picture Naming With the Factors Language (L1, L2) and Block (Switching, Non-Switching) | 1158.91 Milliseconds | Standard Deviation 432 |
| RTs for Picture Naming in the Non-switching Blocks | RTs for Picture Naming With the Factors Language (L1, L2) and Block (Switching, Non-Switching) | 1081.14 Milliseconds | Standard Deviation 414 |
| RTs for Picture Naming in the Switching Blocks | RTs for Picture Naming With the Factors Language (L1, L2) and Block (Switching, Non-Switching) | 1175.24 Milliseconds | Standard Deviation 420 |
p-value: 0.932Mixed Models Analysis
Secondary
Nonverbal Switching
Nonverbal Switching: response times
Time frame: Within 30 minutes after intervention
Population: Data are compared between iTBS and cTBS Sham-TBS is only used to have a baseline control between the two groups
| Arm | Measure | Value (MEAN) | Dispersion |
|---|---|---|---|
| RTs for PN After Intermittent Theta Burst Stimulation | Nonverbal Switching | 772.07 Milliseconds | Standard Deviation 159.28 |
| RTs for PN After Continuous Theta Burst Stimulation | Nonverbal Switching | 739.32 Milliseconds | Standard Deviation 137.23 |
p-value: 0.642Mixed Models Analysis