Autonomic cardiovascular responses to tilting in patients with Alzheimer's disease and in healthy elderly women.

The cardiovascular responses to tilting and breathing were studied in 24 patients with late-onset Alzheimer's disease (AD) and 54 healthy control women aged between 75 and 96 years in order to study the parasympathetic and sympathetic heart-rate control. The cardiovascular response to tilting and breathing showed no age-associated decrease in the healthy control women. During rest, the AD patients had lower mean systolic and diastolic blood pressure but the same heart rate as the control patients. After tilting, the AD patients had a greater increase in heart rate, and the mean systolic blood pressure fell to 126 mmHg compared with 160 mmHg in the control women (p less than 0.001). After the initial acceleration, the following deceleration of the heart rate, an expression of parasympathetic nervous activity, was lower in the AD patients (p less than 0.001). The deep-breathing test showed no significant difference between the two groups, but the changes of acceleration and brake indices could indicate a dysfunction of the autonomic nervous system since the AD patients were not recumbent.