Impaired integrity of commissural and association fibers in essential tremor patients: Evidence from a diffusion tensor imaging study

Background/aim: The evolving understanding of essential tremors (ET) has led to a new definition of neurodegenerative disease, pointing to diffuse brain network involvement with a wide spectrum of associated motor and nonmotor symptoms. Considering the fact that white matter should also be affected by the nature of the disease, our study aimed to evaluate the integrity of white matter and its clinical correlations in ET patients. Materials and methods: Approximately 40 patients diagnosed with ET and 40 age-and sex-matched control subjects (ranging between 18­80 years old) were included in the study. The sociodemographic characteristics and clinical features of the patients were recorded. Tremors were assessed using the Fahn-Tolosa-Marin Tremor Rating Scale (FTM-TRS). Diffusion Tensor Imaging (DTI) was performed to evaluate the integrity of white matter. The selected white matter regions used for DTI assessment were the corpus callosum (CC) (i.e., the largest commissural tract in the human brain), the superior longitudinal fasciculus (SLF), and the inferior longitudinal fasciculus (ILF) (i.e., the largest association fiber bundles). Results: The mean age of the ET patients and control subjects was 44.23 ± 18.91 and 37.45 ± 10.95 years old (P = 0.542). The fractional anisotropy (FA) values of the CC body (P = 0.003), ILF (p = 0.016), average diffusion coefficient (ADC) values of the CC body (p = 0.001), genu (P = 0.049), SLF (V < 0.001), and ILF (P < 0.001) differed between groups. After controlling for age and sex, there was no correlation between tremor severity and DTI parameters, but impaired integrity in the genu of CC FA (P = 0.035, r = 0.442) and the splenium of CC ADC (P = 0.007, r = 0.543) were related with a longer duration of tremor. Finally, positive family history was correlated with the splenium of CC FA and ADC (P = 0.008, r = 0.536; P = 0.027, r = 0.461) and ILF ADC (P = 0.011, r = ­0.519). Conclusion: In our study, major white matter structure changes were found in the ET patients. The results suggest that possible neurodegeneration also affects white matter structures in ET patients and that the duration of the tremor and family history are related with impaired integrity of white matter.

Epicardial adipose tissue volume predicts long term major adverse cardiovascular events in patients with Type 2 diabetes.

OBJECTIVE: Epicardial adipose tissue (EAT) is a metabolically active visceral fat depot that plays an important role in coronary atherosclerosis. In this study, our aim was to investigate the relationship between long-term major adverse cardiovascular events (MACEs) and EAT volume detected by coronary computed tomography angiography (CCTA) in patients with Type 2 diabetes mellitus (T2-DM) without previous coronary events. METHODS: A total of 127 patients with diabetes who underwent CCTA between 2012 and 2014 were enrolled retrospectively. The study population was divided into 2 groups according to whether they experienced or did not experience MACE, which was defined as cardiac death, non-fatal myocardial infarction or unstable angina requiring hospitalization, coronary revascularizations (percutaneous coronary intervention or coronary artery bypass grafting surgery), heart failure, peripheral arterial disease, or ischemic stroke. In both groups, EAT volumes were measured by CCTA. RESULTS: During 60±7 months follow-up period, 22 participants experienced MACEs. Data were evaluated with univariate and multivariate analyses and receiver operating characteristic (ROC) analysis. Age, male sex, coronary artery disease, hemoglobin A1c, glucose, creatinine, C- reactive protein, and cholesterol levels were found to be associated with MACE. EAT volume (odds ratio [OR]: 1.027; 95% confidence interval [CI]: 1.010‒1.044, p=0.002) and low-density lipoprotein (OR: 1.015; 95% CI: 1.000‒1.030, p=0.050) were found to be independent predictors for MACE. ROC analysis indicated that EAT volumes >123.2 mL had a 72.7% sensitivity and a 77.1% specificity for predicting long-term MACE in patients with T2-DM (area under the curve: 0.820; 95% CI: 0.733-0.908). CONCLUSION: EAT volume is an independent predictor of long-term MACE in patients with T2-DM without previous coronary events. EAT volume may be used additionally in risk stratification for MACE besides the well-known vascular risk factors in patients with T2-DM.

Magnetic Resonance Spectroscopy Features of the Visual Pathways in Patients with Glaucoma.

PURPOSE: The aim of the study was to investigate any metabolic changes on magnetic resonance spectroscopy (MRS) throughout the visual pathway of the brain in patients with glaucoma and a control group and correlate the results with clinical findings. MATERIAL AND METHODS: A total of 87 patients were enrolled in the study, 30 healthy controls, 25 glaucoma, 16 suspected glaucoma (GS) and 16 ocular hypertension (OHT) patients. A single voxel MRS on TE 30 ms was performed by placing the volume of interest (VOI) on the corpus geniculatum laterale (CGL) and primary visual cortex (VC). Peak values of metabolites, such as N­acetyl aspartate (NAA), creatine (Cr), choline (Cho) and Myo-inositol (Ins) were investigated on MRS. The MRS results were correlated with age, intraocular pressure (IOP), retinal nerve fiber length (RNFL), mean deviation (MD) and cup disk ratio (CD). RESULTS: The NAA values obtained from the CGL in glaucoma and GS cases were lower than the healthy control group. The Cho values at CGL in glaucoma were lower than GS and controls. There was a negative correlation between NAA values of the VC and CD in glaucoma cases. Additionally, there was a negative correlation between age and RNFL in both glaucoma and GS cases. CONCLUSION: The use of MRS can reveal neurodegeneration in CGL and VC in patients with glaucoma. Depiction of metabolic changes throughout the visual pathways via MRS will guide the treatment planning and follow-up in glaucoma and GS cases.