Brain perfusion during manic episode and at 6-month follow-up period in bipolar disorder patients: Correlation with cognitive functions

Abstract

Background: Patterns of altered cerebral perfusion and cognitive dysfunction have been described in Bipolar Disorder (BD) acute episodes and euthymia. Knowledge of the relationship between cognitive function and perfusion in a manic state and status when followed up is still limited. Objective: To describe brain perfusion alterations and its relationship with cognitive impairment in patients with BD during manic episodes and after 6 months. Methods: Observational-prospective study in 10 type I BD adults during moderate-severe manic episodes. We assessed sociodemographic data and clinical variables as well as cognitive function through Screening for Cognitive Impairment in Psychiatry (SCIP-S). Finally, we performed a Brain Perfusion SPECT using a Tc99m-ethyl cysteine dimer. Results: During manic episodes, patients showed cognitive impairment with a mean SCIP-S score of 63.8 ± 17.16. This was positively correlated with perfusion measured as relative reuptake index (RRI) at the right temporal pole (ρ = 0.65 p =.0435) and negatively correlated with right the orbitofrontal cortex (ρ = −0.70 p =.0077) and the right subgenual cingulate cortex (ρ = −0.70 p =.0256). Episode severity measured by the Young Mania Rating Scale (YMRS) positively correlated with RRI at the right temporal pole (ρ = 0.75, p =.01). At follow-up, six patients were taking treatment and were euthymic, we found a negative correlation with the YMRS and RRI at the bilateral orbitofrontal cortex (ρ = −0.8827, p =.019). They did not show significant improvement in cognitive performance at SCIP-S, and there was negative correlation with the following of the SCIP-S subscales; processing speed with the bilateral dorsolateral prefrontal, the bilateral medial prefrontal, the left temporal pole cortex RRI, and verbal fluency with the bilateral anterior cingulate cortex RRI. Conclusion: Cognitive impairment was correlated with brain perfusion patterns at baseline and follow-up. Large sample size studies with longer follow-up are needed to describe the changes in perfusion and cognitive functions in BD.