Increased posterior cingulate cortex efficiency may predict cognitive impairment in asymptomatic HIV patients.

Purpose Despite antiretroviral therapy, approximately half of individuals with human immunodeficiency virus (HIV) will develop HIV-associated neurocognitive disorder (HAND). Efficiency of brain networks is of great importance for cognitive functioning, since functional networks may reorganize or compensate to preserve normal cognition. This study aims to compare efficiency of the posterior cingulate cortex (PCC) between patients with and without HAND and controls. We hypothesize HAND negative (HAND-) patients will show higher PCC efficiency than HAND positive (HAND+) patients. Methods A total of 10 HAND + patients were compared with 9 HAND- patients and 17 gender-, age-, and education-matched controls. Resting-state functional MRI was acquired with a 3 Tesla scanner. Local efficiency, a measure of network functioning, was investigated for PCC. Network differences among HAND + , HAND- patients and controls were tested as well as correlations between network parameters and cognitive test performance in different domains. Results HAND- patients showed significantly increased PCC efficiency compared with healthy controls ( p = 0.015). No differences were observed between HAND + patients and either controls ( p = 0.327) or HAND- patients ( p = 0.152). In HAND- patients, PCC efficiency was positively related with cognitive performance in the attention/working memory domain ( p = 0.003). Conversely, in HAND + patients, PCC efficiency was negatively correlated with performance in the abstraction/executive domain ( p = 0.002). Conclusion HAND- patients showed a higher level of PCC efficiency compared with healthy subjects, and PCC efficiency was positively related to cognitive performance. These results support the functional reorganization hypothesis, that increased PCC efficiency is a compensation technique to maintain cognitive functioning.

Neuropsychiatric lupus: classification criteria in neuroimaging studies.

This systematic review described the criteria and main evaluations methods procedures used to classify neuropsychiatric systemic lupus erythematosus (NPSLE) patients. Also, within the evaluations methods, this review aimed to identify the main contributions of neuropsychological measurements in neuroimaging studies. A search was conducted in PubMed, EMBASE and SCOPUS databases with the terms related to neuropsychiatric syndromes, systemic lupus erythematosus, and neuroimaging techniques. Sixty-six abstracts were found; only 20 were completely analyzed and included. Results indicated that the 1999 American College of Rheumatology (ACR) criteria is the most used to classify NPSLE samples together with laboratorial, cognitive, neurological and psychiatric assessment procedures. However, the recommended ACR assessment procedures to classify NPSLE patients are being used incompletely, especially the neuropsychological batteries. Neuropsychological instruments and neuroimaging techniques have been used mostly to characterize NPSLE samples, instead of contributing to their classifications. The most described syndromes in neuroimaging studies have been seizure/cerebrovascular disease followed by cognitive dysfunctions as well as headache disorder.

Diffusion tensor MRI evaluation of the corona radiata, cingulate gyri, and corpus callosum in HIV patients.

PURPOSE: To evaluate the white matter integrity of the corona radiata, cingulate gyri, and corpus callosum in patients with human immunodeficiency virus (HIV) infection through diffusion tensor imaging (DTI). MATERIALS AND METHODS: Thirty-four patients with at least 5 years of HIV infection and 27 healthy controls underwent magnetic resonance imaging (MRI) in a 1.5 T scanner. A voxelwise-based technique was used to analyze the DTI data. RESULTS: We found that in the body of corpus callosum the fractional anisotropy (FA) was significantly reduced, whereas mean diffusivity (MD) and radial diffusivity (RD) were increased in HIV patients. Analyzing the corona radiata, axial diffusivity (AD) and MD were significantly increased in the left superior region, MD and RD were increased in the left posterior area, and, furthermore, MD was also increased in the right posterior region. No significant abnormalities were found on the cingulate gyri. The white matter damage, related to FA reduction, was associated with increased RD, indicating that demyelization might be the pathophysiological result of this damage. CONCLUSION: Since the DTI can detect abnormalities in the normal-appearing white matter, this technique may play a role as an early marker of HIV disease progression, including clinical manifestations such as cognitive impairment.