COGNITIVE DYSFUNCTION, SLEEP-WAKE CYCLE ALTERATIONS, AND AUTONOMIC ACTIVITY IN PATIENTS WITH MILD COGNITIVE IMPAIRMENT

MARÍA FLORENCIA VIDAL; ELIANA ROLDÁN; DANIEL P. CARDINALI; DANIEL E. VIGO; SALVADOR M. GUINJOAN

Conferencia; 10th International Conference AD/PD; 2011

Introduction: Autonomic system imbalance favoring sympathetic activity could be a link between sleep abnormalities and cognitive dysfunction in MCI. Aims: To characterize the relationship between severity of cognitive impairment, autonomic dysfunction and sleep-wake cycle disturbances in amnestic MCI patients. Methods: Fourteen MCI patients were assesed with a Mini-Mental Status Examination and an Addenbrooke Cognitive Examination, a Pittsburgh sleep quality scale, and Epworth diurnal somnolence test. 24-h sleep/wake activity was quantified with wrist accelerometers. Peripheral autonomic activity in the 24 h cycle was estimated with linear and nonlinear parameters of heart rate variability (HRV). Measures included heart rate, global HRV; low-frequency HRV (influenced by sympathetic and vagal activity), high-frequency HRV (reflecting primarily parasympathetic activity), and non-linear HRV in the form of Approximate Entropy (ApEn, primarily related to parasympathetic output). Results: A Spearman´s rho test detected a significant association between sleep efficiency and ApEn (rho=0.648; p=0.012). Autonomic and sleep variables were not related with cognitive performance in this preliminary study. Conclusions: In a sample of amnestic MCI individuals, sleep-wake pattern was related to the profile of peripheral autonomic activity but not to degree of cognitive impairment.