2019 Research Forum

APPLICANT: Surag Gohel MPH MD R3 FACULTY SPONSOR: Mohammed Molla MD

Multiple Neuroimaging Modalities Consistently Implicating Location of Auditory Visual Hallucination (AVH) in patients with schizophrenia to left temporal gyri

Surag Gohel MPH MD R3, Arezou Babaesfahani MS IV, Peter De Mola MS IV, Mohammed Molla MD

OBJECTIVE The purpose of study to review multiple neuroimaging modalities including MRI imaging at rest, Functional MRI (fMRI), cerebral blood flow, diffuse tensor imaging (DTI), and PET scan in patients with schizophrenia to localize auditory visual hallucination (AVH). All neuroimaging modalities implicates abnormal anatomical and functional connectivity within left temporal gyri can be the cause of AVH. More importantly, many of the neuroimaging studies reinforce the possibility to manipulate the abnormal connectivity within the left temporal gyri to reduce AVH. METHOD Extensive PubMed search using the terms “schizophrenia imaging”, “schizophrenia auditory visual hallucination imaging”, “Schizophrenia fMRI”, “schizophrenia diffuse tensor imaging” and “transcranial magnetic stimulation schizophrenia” was performed. Various neuroimaging modalities in patients with schizophrenia were reviewed using 20 peer-reviewed articles. RESULTS Upon review of 20 articles, data results consistently indicated AVH in-patient with schizophrenia being localized to the left hemisphere; specifically, the left temporal gyri were found to be statistically significant in 18 of the studies. Cerebral blood flow studies showed that patients with AVH without insight showed increased blood flow to left temporal gyri. High-resolution MRI studies indicated smaller gray matter volumes in the left middle temporal gyrus in patients with AVH. Further MRI studies indicated that the left middle part of the middle temporal gyrus was significantly thinner in patients with AVH. Diffuse tensor imaging (DTI) measures showed increased mean diffusivity bilaterally in superior temporal gyrus (STG) gray matter and in left sided STG white matter. DTI studies revealed hallucination proneness of patients was negatively correlated with the neurite complexity of the left STG. Furthermore, real time fMRI studies indicated not only the hyperactivity of the superior temporal gyrus for hallucination prone patients, but that through real time neurofeedback, patients were able to decrease the activity within the gyri and as a result reported decreased hallucinations. CONCLUSION The review of studies consistently provided strong evidence connecting the generation of AVH in patients with schizophrenia to the left temporal gyri. The key anatomical variances in these patients, revealed across multiple imaging modalities (including resting MRI, DTI, fMRI, real time-FMRI, cerebral blood flow and PET scan) can be used as a disease marker not only to diagnose the severity of AVH, but also potentially to track the progress of novel and existing therapies. Regarding novel treatment approaches, the ability to modulate activity and exploit neuroplasticity in these aberrant regions is of great interest in the field of psychiatry. Particularly, in patients who are refractory to antipsychotic medications, neurofeedback, transcranial magnetic stimulation, and even cognitive behavior therapy may ameliorate AVH.

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