Serotine Melatonin Timing Secretion In Real Life Conditions In Patients With Alzheimer Disease of Mild To Moderate Severity

Abstract Background Circadian dysfunction is thought to take part in the pathogenesis of sleep disorders in AD and in AD pathophysiology itself. Objective Our study aims to calculate dim light melatonin onset (DLMO) secretion in order to define the circadian phase in patients with AD at an early stage of the disease. Methods Twenty-one patients (M/F: 11/10; mean age 74.1±5.4 years; mean disease duration 3.4±1.6 years) with a diagnosis of AD and 17 healthy controls (HC; M/F: 10/7; mean age 67.47±3.8 years) were investigated for subjective nocturnal sleep quality and chronotype, for Dim Light Melatonin Onset (DLMO) and quantitative aspects of the serotine melatonin secretion by means of a five-point in-home serotine melatonin saliva test. Results Subjective sleep quality score on the Pittsburgh Sleep Quality Index questionnaire (PSQI) above five (p= 0.24), insomnia frequency as measured by Sleep Condition Indicator Questionnaire (p=0.823) and the subjective chronotype according to Morning Evening Questionnaire (MEQ) scores distribution (p=0.464) did not differ between AD and HC. However, DLMO occurred significantly later (55 minutes; p=0.028), and melatonin secretion following DLMO was significantly decreased in AD patients compared to HC. Conclusion Initial serotine secretion of melatonin proves to be delayed and mildly impaired in patients with a mild/moderate form of Alzheimer disease while patients’ subjective sleep parameters and chronotype are reported to be similar to HC. These results indicate that subclinical altered patterns of melatonin secretion occur in subjects with AD at an early stage of the disease.