The main purpose of this study is to learn how transcranial magnetic stimulation (TMS) helps improve negative symptoms of schizophrenia. These 'negative symptoms' include anhedonia (the inability to enjoy things), low motivation, and decreased facial expression. TMS is a noninvasive way of stimulating the brain. TMS uses a magnetic field to cause changes in activity in the brain. The magnetic field is produced by a coil that is held next to the scalp. In this study we will be stimulating the brain to learn more about how TMS may improve these symptoms from schizophrenia.
This study proposes to test the hypothesis that the medication refractory experiential (anhedonia and amotivation) and expressive deficits named 'negative symptoms' are mediated by network pathophysiology and the functional connectivity of a cerebellar-prefrontal cortical network mediates the severity of these deficits. To accomplish this participants will be recruited who are diagnosed with schizophrenia or schizoaffective disorder who demonstrate negative symptoms despite stable outpatient treatment. Participants will undergo an initial screening session to complete informed consent and undergo baseline assessments of negative symptom severity. These assessments include reporter-based measures such as the Positive And Negative Syndrome Scale (PANSS) as well as quantitative tests of amotivation/anhedonia and diminished expressivity. Participants will then undergo an MRI scan that includes structural and resting state functional magnetic resonance imaging (rsfMRI). These rsfMRI images will be used to isolate individual resting-state networks for targeting of rTMS modulation. Participants will then undergo five days of twice daily rTMS sessions in one of the four arms of this study. One week after the last rTMS session, Participants will undergo follow-up MRI imaging and the same assessments described above. Aims: Aim 1: To determine if network dysconnectivity is causally linked to negative symptom severity and if amelioration of this dysconnectivity results in reduced symptom severity. Symptom severity will be measured via both reporter-based and quantitative measures. Aim 2: To determine if the relationship between functional connectivity and symptom severity arises from interactions between specific nodes of the default mode network (DMN): the cerebellum and DLPFC, or is the result of interactions between multiple nodes in the DMN (both cerebral and cerebellar). Exploratory Aim: As an exploratory aim, additional genetic data will be collected which may be related to TMS efficacy. Hypothesis: Brain-derived neurotrophic factor (BDNF) homozygous val-allele carriers of the val66met BDNF gene will show greater response than met-carriers.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
QUADRUPLE
Enrollment
47
rTMS is a technique of TMS that allows the selective external manipulation of neural activity in a non-invasive manner. During TMS, a rapidly changing current is passed through an insulated coil placed against the scalp. This generates a temporary magnetic field that in turn induces electrical current in neurons and allows the modulation of neural circuitry. The combination of TMS with fMRI allows the selective targeting and modulation of brain networks. The repeated application of rTMS can cause long term changes in behavior and task performance that is reflected in altered brain network connectivity. The pattern of rTMS will consist of either: intermittent Theta Burst Stimulation (iTBS) pattern consisting of 2 s trains of 3 pulses at 50 Hz, repeated at 5 Hz, every 10s for a total of 600 pulses. OR sham stimulation
Beth Israel Deaconess Medical Center
Boston, Massachusetts, United States
Change in Negative Symptom Severity
We will evaluate the effect of sham vs active rTMS on negative symptom severity in the group with Cerebellar targeted rTMS and in the group with DLPFC targeted rTMS
Time frame: Before treatment (Baseline) and 1 week post treatment
Change in Cerebellar - Prefrontal Functional Connectivity
We will evaluate the effect of sham vs active rTMS on cerebellar-prefrontal cortex functional connectivity in the group with Cerebellar targeted rTMS and in the group with DLPFC targeted rTMS
Time frame: Before treatment (Baseline) and 1 week post treatment
Change in Auditory Hallucination Severity
We will evaluate the effect of sham vs active rTMS on the frequency and severity of auditory hallucinations in the group with Cerebellar targeted rTMS and in the group with DLPFC targeted rTMS
Time frame: Before treatment (Baseline) and 1 week post treatment
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