Targeting Cerebellum to Treat Psychosis: a Transcranial Magnetic Stimulation (TMS) Study

Study Overview
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Brief Summary
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The goal of this study is to use transcranial magnetic stimulation (TMS) to investigate the impact of modulating cerebellar activity on time perception, executive function, and mood and psychotic symptoms in psychosis patients (i.e., schizophrenia, schizoaffective disorder, and bipolar disorder with psychotic features). The investigators hypothesize that abnormally reduced activity in the cerebellum contributes to the abnormalities in patients, that cerebellum-mediated disruptions in time perception may partially underlie executive dysfunction and symptoms, and that cerebellar stimulation will normalize disease-relevant outcome measures.

Detailed Description
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The cerebellum plays a major role in integrative processing of higher order cognitive and affective functions, but it has not been considered a major treatment target for psychotic disorders. The goal of this study is to administer three different conditions of transcranial magnetic stimulation (TMS)-- excitatory, inhibitory, and sham TMS-- in a cross-over design in psychosis patients (i.e., schizophrenia, schizoaffective disorder, and bipolar disorder with psychotic features) to investigate with causal explanatory power the role of the cerebellum as a treatment target for psychotic disorders. More specifically, the investigators will measure the effects of cerebellar excitation and inhibition on time perception, executive function, and symptomatology. TMS will be administered using a theta-burst stimulation (TBS) protocol applied to the posterior cerebellar vermis. Participants will undergo three study sessions, one for each of the three TMS conditions. During each session, the investigators will administer validated cognitive paradigms and clinical measures immediately before and after TMS. The specific aims are to: 1: Investigate the role of the cerebellum in abnormalities of time perception, executive function, and mood and psychotic symptoms by evaluating these functions before and immediately after excitatory, inhibitory, or sham TMS applied to the cerebellar vermis in patients with psychosis. (1a) Time perception hypothesis: Patients with psychotic disorders will have impaired timing perception, i.e., higher number of errors and/or greater inter-trial variability in an interval discrimination task both at baseline and after sham TMS. The investigators predict that the abnormalities in patients will improve after excitatory but not inhibitory TMS. (1b) Executive function hypothesis: Patients will show a higher number of errors and longer reaction times on the N-back working memory task, both at baseline and after sham TMS. The investigators predict that these deficits in patients will improve after excitatory but not inhibitory TMS. (1c) Symptom hypothesis: Symptom ratings using visual analog scales will improve in the period immediately after excitatory but not inhibitory TMS, and show no significant change after sham TMS. 2: Investigate the relationship between time perception and symptomatology in patients with psychotic disorders. Hypothesis: The investigators predict that performance on the time perception task will correlate with performance on a working memory task as well as with mood and psychotic symptoms. This study may improve understanding about the role of the cerebellum in the pathophysiology of psychotic disorders. Such knowledge can potentially guide the development of cerebellar TMS as a therapeutic intervention for psychosis.

Official Title
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Cerebellar Transcranial Magnetic Stimulation (cTMS) in Psychotic Disorders: Effect on Time Perception, Executive Function, and Mood and Psychotic Symptoms

Conditions
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Schizophrenia, Schizoaffective Disorder, Bipolar Disorder I

Intervention / Treatment
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* Device: Excitatory TMS
* Device: Inhibitory TMS
* Device: Sham TMS


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients Men and women Ages 18-50 years Patients diagnosed with schizophrenia (SZ), schizoaffective disorder (SZA), or psychotic bipolar disorder (BP). On a stable psychiatric medication regimen for at least a month prior to and during study participation Healthy Controls: Men and women Ages 18-50 years Without major psychiatric illness Exclusion Criteria: Patients Any change in psychiatric medications within a month prior to and during study participation Legal or mental incompetency Intellectual disability Substance use disorder (abuse or dependence) with active use within the last 3 months Significant medical or neurological illness Prior neurosurgical procedure History of seizures History of electroconvulsive therapy (ECT) or clinical TMS within the past three months History of participation in a cerebellar TMS study Implanted cardiac pacemakers Patients who have conductive, ferromagnetic or other magnetic-sensitive metals implanted in their head or neck, or are non-removable and within 30 cm of the treatment coil. These include: Aneurysm clips or coils Carotid or cerebral stents Metallic devices implanted in the head (e.g. Implanted pacemaker, medication pump, vagal stimulator, deep brain stimulator, TENS unit, or ventriculo-peritoneal shunt) Magnetically active dental implants Cochlear/otologic implants CSF shunts Ferromagnetic ocular implants Pellets, bullets, fragments less than 30 cm from the coil Facial tattoos with metallic ink, permanent makeup less than 30 cm from the coil Pregnant women Healthy Controls: History of major psychiatric illness, including psychosis Has a first-degree relative with psychosis Active use of psychotropic medications Legal or mental incompetency Intellectual disability Substance use disorder (abuse or dependence) with active use within the last 3 months Significant medical or neurological illness Prior neurosurgical procedure History of seizures History of ECT treatment or clinical TMS within the past three months History of participation in a cerebellar TMS study Implanted cardiac pacemakers Individuals who have conductive, ferromagnetic or other magnetic-sensitive metals implanted in their head or neck, or are non-removable and within 30 cm of the treatment coil. These include: Aneurysm clips or coils Carotid or cerebral stents Metallic devices implanted in the head (e.g. Implanted pacemaker, medication pump, vagal stimulator, deep brain stimulator, transcutaneous electrical nerve stimulation (TENS) unit, or ventriculo-peritoneal shunt) Magnetically active dental implants Cochlear/otologic implants Cerebrospinal fluid (CSF) shunts Ferromagnetic ocular implants Pellets, bullets, fragments less than 30 cm from the coil Facial tattoos with metallic ink, permanent makeup less than 30 cm from the coil Pregnant women

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 50 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Intermittent TBS (iTBS)<br>Single session of intermittent theta-burst stimulation (600 pulses in blocks of 2s, separated by 8s of pause) to cerebellar vermis. | Device: Excitatory TMS<br>* Single session of intermittent theta-burst stimulation (600 pulses in blocks of 2s, separated by 8s of pause) to cerebellar vermis.<br>* Other names: iTBS;|
| Active Comparator: Continuous TBS (cTBS)<br>Single session of continuous theta-burst stimulation of 600 pulses to cerebellar vermis. | Device: Inhibitory TMS<br>* Single session of continuous theta-burst stimulation of 600 pulses to cerebellar vermis.<br>* Other names: cTBS;|
| Sham Comparator: Sham TBS<br>Single session, using the exact same procedures as the active arms but with a sham coil, which is designed to induce the same nonspecific sensory effects of TMS (auditory and somatosensory activation) without inducing the neuromodulatory magnetic fields. | Device: Sham TMS<br>* Single session, using the exact same procedures as the active arms but with a sham coil, which is designed to induce the same nonspecific sensory effects of TMS (auditory and somatosensory activation) without inducing the neuromodulatory magnetic fields.<br>* Other names: shamTBS;|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Change (Δ) in Accuracy of Time Interval Discrimination Pre- and Post-TMS | In each trial, participants are presented with two tones separated by 1200 ms (the standard interval), a 1s delay, then a comparison pair of tones. The time interval of the second tone pair will be either equal to (E-condition), longer than (L-condition), or shorter than (S-condition) that of the first pair. Participants are asked to indicate using a keyboard whether the second time interval is equal, longer, or shorter than the first. The tones for all conditions were 700Hz in frequency, 50ms in duration, and presented binaurally via headphones. Participants completed 15 trials during each pre- or post-TMS session for a total of up to 90 total trials across the three study visits. Prior to each IDT session, participants performed a practice run consisting of six trials. The primary outcome for this task was overall accuracy (proportion of correct responses). | In each of the 3 study visits (separated by at least 36h), participants undergo (a) pre-TMS assessments (15-20min), (b) TMS (15min), and (c) post-TMS assessments (15-20min). Approximately 30-45 min separate the pre- and post-TMS task performances. | 
| Change (Δ) in Accuracy of N-back Working Memory Task Pre- and Post-TMS | Participants are presented with a series of words or numbers and prompted to indicate as quickly as possible whether the currently presented stimulus is the same as the one presented n-stimuli previously. For example, in a 2-back task a subject would be asked to indicate whether the current stimulus was identical to that presented 2 stimuli before. To increase the likelihood of detecting change in task performance with each TMS condition (and minimize potential ceiling or floor effects), the difficulty level was individualized so that each participant performed at approximately 80% accuracy; during the pre session of the first study visit, a trial session established the difficulty level, i.e., how many presentations back (n-stimuli) at which the task would start. After the trial session, a session with 50 presentations was carried out and recorded whether the response was correct (accuracy) and the time from presentation to response (reaction time). | In each of the 3 study visits (separated by at least 36h), participants undergo (a) pre-TMS assessments (15-20min), (b) TMS (15min), and (c) post-TMS assessments (15-20min). Approximately 30-45 min separate the pre- and post-TMS task performances. | 
| Change (Δ) in Reaction Time (RT) of N-back Working Memory Task Pre- and Post-TMS | Participants are presented with a series of words or numbers and prompted to indicate as quickly as possible whether the currently presented stimulus is the same as the one presented n-stimuli previously. For example, in a 2-back task a subject would be asked to indicate whether the current stimulus was identical to that presented 2 stimuli before. To increase the likelihood of detecting change in task performance with each TMS condition (and minimize potential ceiling or floor effects), the difficulty level was individualized so that each participant performed at approximately 80% accuracy; during the pre session of the first study visit, a trial session established the difficulty level, i.e., how many presentations back (n-stimuli) at which the task would start. After the trial session, a session with 50 presentations was carried out and recorded whether the response was correct (accuracy) and the time from presentation to response (reaction time). | In each of the 3 study visits (separated by at least 36h), participants undergo (a) pre-TMS assessments (15-20min), (b) TMS (15min), and (c) post-TMS assessments (15-20min). Approximately 30-45 min separate the pre- and post-TMS task performances. | 
| Change (Δ) in Symptoms (Depressed Mood) | Participants will take a brief computerized survey pre- and post-TMS, in which they will be presented with visual analogue scales (VAS, range 0-100, 0=absent, 100=most severe) and asked to indicate current levels of depression, anxiety, euphoria, auditory hallucinations, visual hallucinations, paranoia, referential thinking, and delusions of control. The VAS format will allow participants to self-report ratings quickly and easily with simple mouse clicks. | In each of the 3 study visits (separated by at least 36h), participants undergo (a) pre-TMS assessments (15-20min), (b) TMS (15min), and (c) post-TMS assessments (15-20min). Approximately 30-45 min separate the pre- and post-TMS task performances. | 
| Change (Δ) in Symptoms (Anxiety) | Participants will take a brief computerized survey pre- and post-TMS, in which they will be presented with visual analogue scales (VAS, range 0-100, 0=absent, 100=most severe) and asked to indicate current levels of depression, anxiety, euphoria, auditory hallucinations, visual hallucinations, paranoia, referential thinking, and delusions of control. The VAS format will allow participants to self-report ratings quickly and easily with simple mouse clicks. | In each of the 3 study visits (separated by at least 36h), participants undergo (a) pre-TMS assessments (15-20min), (b) TMS (15min), and (c) post-TMS assessments (15-20min). Approximately 30-45 min separate the pre- and post-TMS task performances. | 
| Change (Δ) in Symptoms (Elated Mood) | Participants will take a brief computerized survey pre- and post-TMS, in which they will be presented with visual analogue scales (VAS, range 0-100, 0=absent/no elation, 100=most severe) and asked to indicate current levels of depression, anxiety, euphoria, auditory hallucinations, visual hallucinations, paranoia, referential thinking, and delusions of control. Higher VAS scores for elation indicate more elation (suggestive of mania). The VAS format will allow participants to self-report ratings quickly and easily with simple mouse clicks. | In each of the 3 study visits (separated by at least 36h), participants undergo (a) pre-TMS assessments (15-20min), (b) TMS (15min), and (c) post-TMS assessments (15-20min). Approximately 30-45 min separate the pre- and post-TMS task performances. | 
| Change (Δ) in Symptoms (Auditory Hallucinations) | Participants will take a brief computerized survey pre- and post-TMS, in which they will be presented with visual analogue scales (VAS, range 0-100, 0=absent, 100=most severe) and asked to indicate current levels of depression, anxiety, euphoria, auditory hallucinations, visual hallucinations, paranoia, referential thinking, and delusions of control. The VAS format will allow participants to self-report ratings quickly and easily with simple mouse clicks. | In each of the 3 study visits (separated by at least 36h), participants undergo (a) pre-TMS assessments (15-20min), (b) TMS (15min), and (c) post-TMS assessments (15-20min). Approximately 30-45 min separate the pre- and post-TMS task performances. | 
| Change (Δ) in Symptoms (Visual Hallucinations) | Participants will take a brief computerized survey pre- and post-TMS, in which they will be presented with visual analogue scales (VAS, range 0-100, 0=absent, 100=most severe) and asked to indicate current levels of depression, anxiety, euphoria, auditory hallucinations, visual hallucinations, paranoia, referential thinking, and delusions of control. The VAS format will allow participants to self-report ratings quickly and easily with simple mouse clicks. | In each of the 3 study visits (separated by at least 36h), participants undergo (a) pre-TMS assessments (15-20min), (b) TMS (15min), and (c) post-TMS assessments (15-20min). Approximately 30-45 min separate the pre- and post-TMS task performances. | 
| Change (Δ) in Symptoms (Paranoid Ideation) | Participants will take a brief computerized survey pre- and post-TMS, in which they will be presented with visual analogue scales (VAS, range 0-100, 0=absent, 100=most severe) and asked to indicate current levels of depression, anxiety, euphoria, auditory hallucinations, visual hallucinations, paranoia, referential thinking, and delusions of control. The VAS format will allow participants to self-report ratings quickly and easily with simple mouse clicks. | In each of the 3 study visits (separated by at least 36h), participants undergo (a) pre-TMS assessments (15-20min), (b) TMS (15min), and (c) post-TMS assessments (15-20min). Approximately 30-45 min separate the pre- and post-TMS task performances. | 
| Change (Δ) in Symptoms (Ideas/Delusions of Reference) | Participants will take a brief computerized survey pre- and post-TMS, in which they will be presented with visual analogue scales (VAS, range 0-100, 0=absent, 100=most severe) and asked to indicate current levels of depression, anxiety, euphoria, auditory hallucinations, visual hallucinations, paranoia, referential thinking, and delusions of control. The VAS format will allow participants to self-report ratings quickly and easily with simple mouse clicks. | In each of the 3 study visits (separated by at least 36h), participants undergo (a) pre-TMS assessments (15-20min), (b) TMS (15min), and (c) post-TMS assessments (15-20min). Approximately 30-45 min separate the pre- and post-TMS task performances. | 
| Change (Δ) in Symptoms (Delusions of Control) | Participants will take a brief computerized survey pre- and post-TMS, in which they will be presented with visual analogue scales (VAS, range 0-100, 0=absent, 100=most severe) and asked to indicate current levels of depression, anxiety, euphoria, auditory hallucinations, visual hallucinations, paranoia, referential thinking, and delusions of control. The VAS format will allow participants to self-report ratings quickly and easily with simple mouse clicks. | In each of the 3 study visits (separated by at least 36h), participants undergo (a) pre-TMS assessments (15-20min), (b) TMS (15min), and (c) post-TMS assessments (15-20min). Approximately 30-45 min separate the pre- and post-TMS task performances. | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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time perception, executive function, psychosis, mood symptoms