Melatonin effect on sleep?wake differences of autonomic activity in patients with mild cognitive impairment: an exploratory study

ABULAFIA, CAROLINA; BRUSCO, IGNACIO; VIGO, DANIEL EDUARDO; OLIVAR, NATIVIDAD; CARDINALI, DANIEL PEDRO; VIDAL, MARÍA FLORENCIA; GUINJOAN, SALVADOR MARTÍN

Congreso; XV Latin American Symposium on Chronobiology; 2019

Autonomic impairment including alterations of the sleep-wake rhythm reflect early manifestations of neuropathological changes of Alzheimer´s disease (AD) already present in preclinical stages, like mild cognitive impairment (MCI).Previous studies have suggested that melatonin influences several important physiological functions such as sleep and possibly modulates the autonomic nervous system, which in turn may explain its reported beneficial effects in MCI. The present exploratory study aims to describe the effect of melatonin on the autonomic activity in MCI patients.From a broader study focused on sleep-wake differences in MCI patients (n=22) vs control subjects (n=13), we analyzed available 24-hour heart rate variability (HRV) data of MCI patients with (n=10) and without (n=6) melatonin intake.Mann & Whitney tests showed significant differences (p≤0.05) in sleep HRV, evidencing increased parasympathetic activity during sleep in MCI subjects under melatonin treatment as measured by RRM (1109±63 vs 894±44, p=0.005), HF (8.4±0.3 vs 7.5±4, p=0.049), VLF (15.5±0.1 vs 15.1±0.1, p=0.003), LF (10.8±0.2 vs 9.9±0.1, p=0.005) and RMSSD (51±11 vs 23±9, p=0.036). The present preliminary results support the existing evidence in favor of melatonin?s chronobiotic and neuroprotective properties in preclinical stages of dementia.