Analysis of Cortical Thickness in Language Processing Brain Regions Associated with Hallucinations and Delusions in Early Psychosis

Emily Johns, AB Candidate

Brigham and Women’s Hospital
Analysis of Cortical Thickness in Language Processing Brain Regions Associated with Hallucinations and Delusions in Early Psychosis

Scientific Abstract

Background: Aberrations of brain regions underpinning language process may be associated with severity of both hallucinations and delusions, even in the early course of psychosis. In this study, we aimed to characterize the variation in thickness of the brain’s gray matter in language processing regions as a function of presence and severity of hallucinations and delusions in patients to determine if these distinct positive symptoms have a central neural basis.

Methods: We examined subjects who participated in the Human Connectome Project for Early Psychosis which included 157 individuals (sex- 101M:56F, age (y)- 22.8 ± 3.53) suffering from psychosis and 72 comparable healthy individuals (sex- 46M:26F, age (y)- 24.7 ± 4.4).

T1-weighted MR images were quality controlled and processed through FreeSurfer. Differences in cortical thickness in three groups of language-related brain regions of interest (ROI), the left frontal, dorsal, and temporal gyri, were evaluated using analysis of covariances (ANCOVAs) and post-hoc Tukey’s HSD. Presence and severity of hallucinations and delusions were measured for each patient using the Positive and Negative Syndrome Scale (PANSS).

Results: After controlling for age, sex, handedness, estimated intracranial volume, scanner site, and IQ, we observed significant differences in the cortical thickness of dorsal and temporal ROI when comparing patients with psychosis to healthy controls. We also observed a significant difference in cortical thickness of the temporal ROI, F(8, 219) = 6.583, p= 0.002, partial η2=5.672e-02, between controls, asymptomatic patients (i.e., no hallucinations or delusions present; PANSS P3 and P1 < 3), and symptomatic patients (i.e., hallucinations and/or delusions present; PANSS P3 and/or P1 > 3). Of note, cortical thickness showed a reduction in symptomatic patients compared to controls, with asymptomatic patients intermediate in dorsal and temporal ROI. 

Conclusions: Language processing gray matter regions play an important role in the symptoms of hallucinations and delusions in individuals suffering from early psychosis.

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research Areas

Authors

Emily Johns, Brynn E. Vessey, B.S., Johanna Seitz-Holland, M.D., Ph.D., Sylvain Bouix, Ph.D., Michael J. Coleman, M.A., Ofer Pasternak, Ph.D., Evdokiya Knyazhanskaya, B.A., Raquelle Mesholam-Gately, Ph.D., Eve Lewandowski, Ph.D., Matcheri S. Keshavan, M.D., Dost Ongur, M.D., Ph.D., Alan Breier, M.D., Martha E. Shenton, Ph.D., Amanda E. Lyall, Ph.D.

Principal Investigator

Martha E. Shenton, PhD

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