[The effect of insomnia on mild cognitive impairment in patients with vascular risks: results of a three-year longitudinal study]

OBJECTIVE

To assess the dynamics of sleep parameters based on the analysis of three items of HDRS-17, designed to measure the severity of insomnia, during 36 months of follow-up and their relationship with indicators of the cognitive phenotype in patients with vascular risk factors.

MATERIAL AND METHODS

The longitudinal study included 51 patients (mean age 57.7±6.2 years, 19 (37.3%) men)) who met the inclusion criteria. All participants underwent a general clinical examination with assessment of vascular risks and neuropsychological testing using the Montreal Cognitive Assessment (MoCA) and HDRS-17 at baseline and after 36 months. During the study, patients received stable basic therapy to prevent modifiable vascular risk factors. Sleeping pills were taken sporadically when there were complaints of problems falling asleep.

RESULTS

During the 36-month study, as vascular cognitive impairment progressed from 23.7±2.6 to 22.1±2.4 points on the MoCA scale (p=0.01), mainly due to decreased attention (p=0.01), executive functions (EF) (p=0.01), memory (p=0.02), speech (p=0.02), an increase in sleep disturbances was observed (item 4: 0.8±0.02 to 1.9±0.1 points, p=0.01; point 5: 0.6±0.02 to 1.7±0.1 points, p=0.01) and depression (7.5±0.5 to 13.7±3.0 points, p=0.01) in patients with vascular risks. A strong inverse correlation was revealed between the values of items 4, 5, 6 on the HDRS-17 and the average MoCA-total scores (r=-0.85; r=-0.87; r=-0.8 (p<0.05)), memory index (r=-0.8; r=-0.75; r=-0.81 (p<0.05)), attention index (r=-0.88; r=-0.86; r=-0.83 (p<0.05)), index of executive functions (r=-0.87; r=-0.85; r=-0.8 (p<0.05)), respectively.

CONCLUSION

The progression of cognitive impairment is associated with worsening insomnia disorders and depression in patients with vascular risks.

Parameters of Auditory Evoked Related Potentials P300 in Disorders of Different Cognitive Function Domains (Visuospatial/Executive and Memory) in Elderly Hypertensive Persons

The neurophysiological correlates of certain types of cognitive impairment in relation to the spatial pattern of auditory cognitive evoked-related potentials (ERPs) in hypertensive persons remain unclear. The aim of this study was to determine the parameters of ERPs (N200, P300) in impaired different domains (visuospatial/executive and memory) of cognitive function in arterial hypertension, including cardiovascular ischemic events. A total of 46 patients (65-84 years) were observed. The clinical diagnosis of vascular dementia, the Montreal Cognitive Assessment Scale (MoCA test) and the spatial pattern of ERPs (N200, P300) were the parameters used to identify three groups: the Control Group without cognitive impairment (n = 13), the group with a leading memory disturbance (Memory Group, n = 20) and the group with a leading visuospatial/executive disturbance (VS/E Group, n = 13). In persons belonging to the Memory Group, N2 latency was prolonged in the central (C3 C4) and right parietal (P4) brain parts; latency of the motor component (P300) may remain similar to that of the ControlGroup. In persons belonging to theVS/E Group, maximal prolonged recognition time (N2), especially in the left central (C3), frontal-midline (Fz), right parietal (P3) and temporal (P4) brain parts, was observed; P300 latency in the central-midline (Cz) and left anterior-temporal (F7) brain parts among all the groups was revealed.

[Disruption of corpus callosum microstructural integrity by diffusion MRI as a predictor of progression of cerebral microangiopathy]

OBJECTIVE

To assess the microstructural integrity of the corpus callosum in patients with cerebral small vessel disease (cSVD) using signal and biophysical diffusion MRI models and to identify the most sensitive markers of disease progression.

MATERIAL AND METHODS

Diffusion MRI (3 Tesla) was performed in 166 patients (51.8% women; mean age 60.4±7.6) with cSVD and cognitive impairment of varying severity and in 44 healthy volunteers (65.9% women; mean age 59.6±6.8), followed by calculation of signal (diffusion tensor and diffusion kurtosis) and biophysical (WMTI, NODDI, MC-SMT) models, from which profiles of three corpus callosum segments were constructed.

RESULTS

The best results were obtained for metrics in the forceps minor and body of the corpus callosum. Among the metrics of the signal models in the forceps minor, fraction anisotropy (FA) and mean diffusion (MD), which characterize the overall loss of microstructural integrity and increase in extra-axonal water, as well as indirect markers of demyelination when considering transverse diffusion parameters (radial diffusion and radial kurtosis), had the larger area under the curve according to the ROC analysis. Among the metrics of the biophysical models in the forceps minor, a larger area under the curve was found in the MC-SMT model for extra-axonal transverse diffusion (ETR), mean diffusion (EMD), and intra-axonal water fraction (INTRA), and in the WMTI model for intra-axonal water fraction (AWF). ETR had high inverse correlations with INTRA and AWF, while INTRA and AWF had high direct intercorrelations.

CONCLUSION

Metrics of signaling (FA, MD, RD, RK) and biophysical patterns (ETR, EMD, INTRA, AWF) in the forceps minor and the corpus callosum body can be considered as indicators of cSVD progression. They indicate disease progression, mainly by an increase in extra-axonal water with the development of demyelination and tissue degeneration in the corpus callosum.