Effects of rTMS on Impulsivity and Empathy

NCT ID: NCT03200873

Last Updated: 2018-05-02

Basic Information

• Recruitment Status: COMPLETED
• Clinical Phase: NA
• Total Enrollment: 33 participants
• Study Classification: INTERVENTIONAL
• Study Start Date: 2017-05-17
• Study Completion Date: 2017-12-30

Brief Summary

Impulsivity describes the tendency to make risky and unplanned decisions, to pick immediate reward over a bigger reward after a period of time or to not be able to resist the urge to do something. Empathy refers to the ability to be sensitive to and vicariously experience other people's feelings and to create working models of emotional states. Recent neuroscientific research have found that the right frontal part of the brain (left dorsal lateral frontal cortex, LDLPFC) is important in the control of impulsive behaviour and empathy. Self-report questionnaires have been proven valid measures at assessing impulsivity and empathy. Repetitive Transcranial Magnetic Stimulation (rTMS) is a widely used non-invasive brain stimulation procedure; stimulation can be applied at different brain regions depending on the administration method. It temporally changes the way that this part of the brain functions, providing us a further understanding of how this part works. Recent research has found that rTMS on the LDLPFC changes performance-based tasks measuring different types of impulsivity and empathy. This study aims to investigate this further to look at the RDLPFC stimulation and its effects on empathy and two different types of impulsivity. Of interest is also how innate impulsive personality type and empathy trait relate to performance on these tasks.

Detailed Description

Background Impulsivity describes the tendency to make risky and unplanned decisions, to pick immediate reward over a bigger reward after a period or to not be able to resist the urge to do something. Empathy refers to the ability to be sensitive to and vicariously experience other people's feelings and to create working models of emotional states. Recent neuroscientific research have found that the left frontal part of the brain (left dorsal lateral frontal cortex, RDLPFC) is important in the control of impulsive behaviour and empathy. Self-report questionnaires have been proven valid measures at assessing impulsivity and empathy. Repetitive Transcranial Magnetic Stimulation (rTMS) is a widely used non-invasive brain stimulation procedure; stimulation can be applied at different brain regions depending on the administration method. It temporally changes the way that this part of the brain functions, providing us a further understanding of how this part works. Recent research has found that rTMS on the LDLPFC changes performance based tasks measuring different types of impulsivity and empathy. This study aims to investigate this further to look at the LDLPFC stimulation using the newer form of high-frequency rTMS, intermittent theta burst stimulation (iTBS) and its effects on empathy and two different types of impulsivity. Of interest is also how innate impulsive personality type and empathy trait relate to performance on these tasks.

Aims The specific purposes of this study are to (i) examine whether iTBS is an effective technique for modulating impulsivity and empathy, and to (ii) examine the relationship between the modulatory effects of the iTBS and baseline self-reported impulsivity and empathy.

The key objectives of this study are to examine whether the specific iTBS protocol at RDLPFC can effectively modulate two subtypes of impulsivity (delayed discounting and reflection impulsivity) and empathy, and to examine whether the participant's baseline self-reported impulsivity and empathy scores mediate the modulatory effects of the iTBS on impulsivity and empathy respectively in normal healthy young adults. The secondary objectives of this study are to examine whether the self-reported measures of impulsivity and empathy correlate with their performance-based counterparts.

Experimental protocol and methods The proposed study will be a single-centre, crossover design study, taking place at Queens Medical Centre, Nottinghamshire NHS Trust. Participants (male students or staff) will be recruited from the University of Nottingham. A potential participant will be asked to complete the TMS screening questionnaire to ensure that there are no contraindications to using TMS. After the written informed consent is obtained, he will then be asked to complete an online questionnaire (Barratt Impulsiveness Scale -version 11, BIS-11) measuring self-report impulsivity. The scores obtained from BIS-11 will be one of the screening criteria. If the potential participant is eligible for taking part in the study, he will be invited to the two laboratory sessions. He will then be asked to perform three computerised tasks assessing impulsivity and empathy before and after the iTBS administration. Each session of iTBS will apply 600 pulses to the LDLPFC, with 20 2-second trains and an 8-second inter-train interval for a total stimulation time of 190 seconds. Sham iTBS condition will be administered with the same methodology used for active iTBS condition with a sham coil mimicking noises and vibrations without delivery of magnetic pulses. Participants will be asked to guess which rTMS condition is real after completing the whole study to ascertain that whether the sham manipulation is successful or not. Participants will be monitored if they experience any adverse events during the rTMS session and instructed to report any experience of adverse events after each rTMS session. Tolerability will be presented as the number of reported adverse events and the number of dropouts due to adverse events.

Measurable end points/statistical power of the study To detect the change in impulsivity and empathy resulted from the iTBS intervention, G*Power 3.1.9.2 was used to estimate sample size required in consideration of interaction effect (impulsivity group × iTBS conditions) of repeated measure ANOVA. The following parameters were selected: effect size f = 0.20 (equivalent to d = 0.40, estimated from the results of previous meta-analyses), alpha error probability = .05, power = (1- β error probability) = .80, number of groups = 2, number of measurements = 2 and correlation among repeated measurements = 0.6. A minimum of total sample size of 42 subjects will be required. Considering the dropout rate of 0.20 (according to previous rTMS studies), 54 subjects will be required for the study, including 27 high impulsivity participants and 27 low impulsivity participants.

Conditions

Impulsive Behavior; Empathy

Study Design

• Allocation Method: RANDOMIZED
• Intervention Model: CROSSOVER
• Primary Study Purpose: TREATMENT
• Blinding Strategy: SINGLE

Study Groups

high impulsivity

participants with high impulsivity (BIS \>62), receiving active and sham repetitive transcranial magnetic stimulation \[intermittent theta burst stimulation (iTBS)\] in a randomised order

Group Type: ACTIVE_COMPARATOR

repetitive transcranial magnetic stimulation

Intervention Type: DEVICE

Each session of iTBS will apply3 trains of 600 pulses to the RDLPFC, with 20 2-second trains and an 8-second inter-train interval. Sham iTBS condition will be administered with the same methodology used for active iTBS condition with a sham coil mimicking noises and vibrations without delivery of magnetic pulses.

low impulsivity

participants with low impulsivity (BIS between 52 to 62), receiving active and sham repetitive transcranial magnetic stimulation \[intermittent theta burst stimulation (iTBS)\] in a randomised order

Group Type: ACTIVE_COMPARATOR

repetitive transcranial magnetic stimulation

Intervention Type: DEVICE

Each session of iTBS will apply3 trains of 600 pulses to the RDLPFC, with 20 2-second trains and an 8-second inter-train interval. Sham iTBS condition will be administered with the same methodology used for active iTBS condition with a sham coil mimicking noises and vibrations without delivery of magnetic pulses.

Interventions

repetitive transcranial magnetic stimulation

Each session of iTBS will apply3 trains of 600 pulses to the RDLPFC, with 20 2-second trains and an 8-second inter-train interval. Sham iTBS condition will be administered with the same methodology used for active iTBS condition with a sham coil mimicking noises and vibrations without delivery of magnetic pulses.

Intervention Type: DEVICE

Other Intervention Names

intermittent theta burst stimulation

Eligibility Criteria

Inclusion Criteria

• Male students or staff in University of Nottingham
• aged 18-30 years.
• normal or corrected-to-normal vision
• BIS-11 scored above 71 or between 52 to 62
• Ability to give informed consent

Exclusion Criteria

• Have ever suffered an epileptic fit
• Have had a brain injury or neurological disorder
• Have any non-removable metal implants in your head
• Have a family history of brain injury or epilepsy
• Drink more than 20 units of alcohol per week on a regular basis
• Currently take any illicit drugs
• Ever were dependent on illicit drugs or alcohol
• Ever suffered from a serious mental illness such as schizophrenia, severe depression or bipolar disorder
• Currently take any psychiatric medication

• Minimum Eligible Age: 18 Years
• Maximum Eligible Age: 30 Years
• Eligible Sex: MALE
• Accepts Healthy Volunteers: Yes

Sponsors

University of Nottingham

OTHER

Sponsor Role: lead

Responsible Party

Responsibility Role: SPONSOR

Principal Investigators

Birgit Völlm, PhD

Role: PRINCIPAL_INVESTIGATOR

Division of Psychiatry and Applied Psychology, School of Medicine, University of Nottingham

Locations

Division of Psychiatry and Applied Psychology, School of Medicine, University of Nottingham

Nottingham, Nottinghamshire, United Kingdom

Countries

United Kingdom

Other Identifiers

C200317

Identifier Type: -

Identifier Source: org_study_id