This study compares the efficacy of low and high frequency repetitive transcranial magnetic stimulation (rTMS) as a means of treating subjects with schizophrenia. Magnetic pulses delivered over the scalp cause brain activity. This activity has been shown to help decrease the intensity and frequency of auditory hallucinations (AH) in schizophrenia. The investigators will compare whether low or high frequencies work best. The investigators will also examine what changes occur in the brain that are related to improvement.
Background. The sub-Investigator Dr. Mennemeier has been using repetitive transcranial magnetic stimulation (rTMS) to treat phantom sound perception in subjects with tinnitus. The Principal Investigator (PI), Dr. Messias, now aims to team up with Drs. Mennemeier and James, to learn how rTMS influences phantom sound perception in schizophrenia. rTMS has already been shown to be an effective treatment for both tinnitus and schizophrenia. rTMS is a non-invasive method of regional brain stimulation that can significantly reduce phantom sound perception temporarily in 50% of subjects with tinnitus and schizophrenia. This study will go further than previous investigations by analyzing how different frequencies of rTMS influence not only auditory hallucinations (AH) in schizophrenia but also brain connectivity in schizophrenia. The investigators want to learn if rTMS decreases AH by normalizing brain connectivity. Whereas this study focuses on schizophrenic subjects with AH, the design is very similar to ongoing work on tinnitus so the findings will be comparable. Tinnitus and AH in schizophrenia are prevalent and disabling disorders of sound perception. The investigators understanding of the precise mechanisms of these disorders is lacking. Interestingly, the symptoms of both disorders respond positively to rTMS of the temporal cortex in ways that defy contemporary understanding of the nature of these symptoms and of how rTMS should work to improve them. For example, phantom sound perception in both tinnitus and schizophrenia are linked to maladaptive, hyperactivity of auditory processing regions of temporal cortex; however, it is increasingly clear that these pathological changes alone are insufficient to explain the pronounced intrusiveness and negative emotional valance of symptoms in each disorder. Therefore, a barrier to understanding these disorders lies in understanding how changes in auditory cortex are synchronized with changes in other cortical regions that regulate perception and emotion. Additionally, at present, the decision of which rTMS frequency to apply as a treatment for phantom sound perception has no firm theoretical or empirical basis. Whereas, low frequency rTMS has traditionally been used, based upon contemporary models, to "inhibit" hyperactivity in auditory cortex; high frequency rTMS, which should induce an opposite effect on neuronal processing, not only works to improve symptoms but may be more effective for some subjects than low frequency rTMS. Therefore, contemporary models designed to explain how the frequency of rTMS influences neuronal activity immediate following stimulation are insufficient to explain how low and high frequencies of rTMS can mitigate phantom sound perception for days, weeks and months following a single course of treatment. Hypothesis. The investigators propose that phantom sound perception in schizophrenia result from an imbalance of excitatory and inhibitory neural process in auditory networks and from synchronized, maladaptive changes in linked brain regions that regulate perception and emotion. Treating auditory cortex with repetitive, external magnetic stimulation can decrease phantom sound perception and distress by reversing the maladaptive brain reorganization that is set in motion by these underlying neural imbalances.
active rTMS delivered at 1Hz frequency over temporal cortex
active rTMS delivered at 10 Hz frequency over temporal cortex
active rTMS delivered at either 1 Hz frequency over the vertex
University of Arkansas for Medical Sciences
Little Rock, Arkansas, United States
Changes in Auditory Hallucinations Questionnaire (AHQ).
The Auditory Hallucinations Questionnaire (AHQ) will be used to determine the patient's perceptions of change in auditory hallucinations(s). Normal controls do not fill out this measure because they do not have auditory hallucinations. Change in the average results of this test between the baseline and active treatment weeks (1 and 10 Hz) will be measured. The range of scores is 0-70, higher scores mean more symptoms.
Time frame: change between the baseline time point and 4 days of active treatment (patients) or 2 days of sham or active treatment (controls)"
Overall Change in the Percent Habituation of the P50 Evoked Response Potential at 250 Inter Stimulus Interval (ISI) Between the Control and Active Treatments (1 and 10 Hz).
Percent habituation refers to change in the amplitude of the P50 evoked response potential following a 250 ms inter stimulus interval. Change in the average results of this test between the baseline and active treatment weeks (1 and 10 Hz) will be measured.
Time frame: change between the baseline time point and 4 days of active treatment (patients) or 2 days of sham or active treatment (controls)"
Depression Level Changes as Measured by the Hamilton Depression Inventory (HAMD).
HAM-D is a multiple choice questionnaire that clinicians administer to rate the severity of a subject's depression. There are 17 questions; each question has between 3-5 possible responses which increase in severity (range 0 to 52). The clinician chooses the correct response by interviewing the subject and by observing the symptoms. A score of 0-7 is considered to be normal, scores of 20 or higher indicate moderately severe depression. Change in the average results of this test between the baseline and active treatment weeks (1 and 10 Hz) will be measured.
Time frame: change between the baseline time point and 4 days of active treatment (patients) or 2 days of sham or active treatment (controls)"
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Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
SINGLE
Enrollment
26
sham rTMS delivered at 1Hz frequency over the vertex
Active 10 Hz rTMS delivered over the vertex