**Acknowledgements**

Possible prospects for the use of melatonin in elderly patients with CI are due to its antioxidant, neuroprotective and nootropic effects. The positive effect of exogenous forms of melatonin on sleep in elderly patients is confirmed by the results of two placebo-controlled studies

Using 6 mg of melatonin once a day before bedtime for 10 days in patients with moderate CI (MCI) led to significant improvement in memory and regression of depressive symptoms simultaneously with normalization of the sleep-wake cycle [103]. H. Jean-Louis et al. [108], Peck et al. [109], observed 26 patients with MCI syndrome received similar results. While 1 mg melatonin administration just before sleep for 4 weeks, there was a significant decrease in forgetfulness in the auditory memory modality and improvement in night sleep compared with placebo. By Cardinali et al. there was made the retrospective analysis of the effect of melatonin therapy on cognitive functions, night sleep and wakefulness in 96 patients with MCI (61 patients received melatonin in doses of 3–9 mg once daily for 9–18 months). It has been proven that melatonin therapy contributes to significant cognitive improvement and

The high efficiency of the combination of memantine and melatonin in the correction of MCI

There is a discussion about the importance of light therapy in correcting of CI. Most of the studies demonstrate the stabilization of CR sleep-wakefulness and a reduction in the time of

The prevalence and correction of sleep disorders in patients with CVD need further study in randomized clinical trials in large groups of patients for understanding their impact and establishing cause-effect relationships in the development of CI. These investigations results

Thus, literature data show that stroke has a peculiar organization in time. Тhe vegetative dysrhythmia and failure in the work of the Central control of biorhythms regulation play a

The night sleep structure investigation is essential part in patients with stroke and patients with cardiovascular disease risk factors. The CR violation leads to the syndrome of desynchronosis—mismatched dynamics of different indicators of the internal environment. This is

Therefore, including the restoration of the CR with the chronotherapeutics methods is need for the vascular diseases prevention and treatment. Distribution of daily cases of stroke depends on individual properties of CR hemostasis and cerebral hemodynamics, and the specific of the night sleep structure of the of patients. In this regard, there must be a differentiated approach in the treatment of "day" and "night" strokes. The main aspect of reducing the probability of primary and secondary cardiovascular "accidents" development should be the timely detection of sleep disorders and desynchronosis, as one of the leading risk factors.

a potential basis for the cerebrovascular and cardiovascular pathology.

in which more than 500 patients over the age of 55, with primary insomnia [1107].

regression of depressive symptoms [110].

96 Circadian Rhythm - Cellular and Molecular Mechanisms

will help to develop a treatment strategy.

**5. Conclusion**

key role in these processes.

sleep in dementia with melatonin and light therapy [112].

was shown in the experiment [111].

We thank Dmitry Petrov for his assistance in translation of the text. We wish to acknowledge the patients who participated in our studies. The content of the chapter is solely the responsibility of the authors.
