Diffusion Tensor Tractography Characteristics of White Matter Tracts are Associated with Post-Stroke Depression

Visualization of human optic nerve by diffusion tensor mapping and degree of neuropathy

Diffusion-weighted magnetic resonance imaging of the human optic nerve and tract is technically difficult because of its small size, the inherent strong signal generated by the surrounding fat and the cerebrospinal fluid, and due to eddy current-induced distortions and subject movement artifacts. The effects of the bone canal through which the optic nerve passes, and the proximity of blood vessels, muscles and tendons are generally unknown. Also, the limited technical capabilities of the scanners and the minimization of acquisition times result in poor quality diffusion-weighted images. It is challenging for current tractography methods to accurately track optic pathway fibers that correspond to known anatomy. Despite these technical limitations and low image resolution, here we show how to visualize the optic nerve and tract and quantify nerve atrophy. Our visualization method based on the analysis of the diffusion tensor shows marked differences between a healthy male subject and a male subject with progressive optic nerve neuropathy. These differences coincide with diffusion scalar metrics and are not visible on standard morphological images. A quantification of the degree of optic nerve atrophy in a systematic way is provided and it is tested on 9 subjects from the Human Connectome Project.

Relationship between the Corticospinal and Corticocerebellar Tracts and Their Role in Upper Extremity Motor Recovery in Stroke Patients

The corticospinal tract (CST) and corticocerebellar tract (CCT) are both involved in the upper extremity (UE) function after stroke. Understanding the relationship between the tracts and their functions can contribute to developing patient-specific rehabilitative strategies. Seventy ischemic stroke patients who underwent diffusion tensor imaging (DTI) two weeks after the stroke onset and motor function assessments two weeks and three months after the stroke onset were included in this study. To obtain the CST and CCT integrity, the functional anisotropy (FA) values of both tracts were extracted from the DTI data. Linear regression was used to identify the relationship and predictive accuracy. The CST FA data had predictive values, but CCT FA did not. There were interaction effects between the CST and CCT FA values (p = 0.011). The CCT was significantly associated with high CST FA but not low CST FA. When the CST or CCT FA were applied to patients depending on the CST status, the stratified model showed higher predictive accuracy (R² = 0.380) than that of the CST-only model (R² = 0.320). In this study, the conditional role of CCT depending on CST status was identified in terms of UE recovery in stroke patients. This result could provide useful information about individualized rehabilitative strategies in stroke patients.

The efficacy and safety of agomelatine, sertraline, and escitalopram for senile post-stroke depression: A randomized double-blind placebo-controlled trial

OBJECTIVES

This study aims to investigate the efficacy and safety of agomelatine, sertraline, and escitalopram for patients with senile post-stroke depression (SPSD, aged over 65 years).

PATIENTS AND METHODS

A total of 165 patients (aged over 65 years) with post-stroke depression (PSD) were recruited. These patients were randomly assigned to one of four groups and given an anti-depressant or a placebo as follows: group A (agomelatine in combination with conventional cerebrovascular disease medication) 48 patients; group B (sertraline in combination with conventional cerebrovascular disease medication) 47 patients; group C (escitalopram in combination with conventional cerebrovascular disease medication) 50 patients; and, a control group (conventional treatment alone) 20 patients. The efficacy of the different treatments was evaluated using the Hamilton Depression Scale (HAMD), the National Institute of Health Stroke Scale (NIHSS), and the Activities of Daily Living (ADL) Barthel index (BI) at one, two, four, and six weeks after treatment began.

RESULTS

According to the HAMD, NIHSS score, and BI index, the patients who received one of the three antidepressant treatments showed significant improvement compared with the control group (p < 0.05), but there was no significant difference between the three groups receiving anti-depressant medication (p > 0.05). Laboratory tests showed that the general adverse effects of the treatments were mild in all three groups, and patients generally tolerated the treatments.

CONCLUSION

A decrease of HAMD and NIHSS scores and an increase in the BI index could be observed in the patients receiving agomelatine, sertraline, or escitalopram treatment. Thus, it would appear that the condition of SPSD in older patients can be improved with the use of either agomelatine, sertraline, or escitalopram.