University of Maryland, College Park (Maryland)
Psychogenic Movement Disorders (PMD)are abnormal movements not explained by organic lesions in the nervous system, such as tremors, myoclonus or dystonia. This project aims to study cortisol levels and heart rate variability (HRV) as biomarkers of stress and autonomic function in patients with PMD. Cortisol is the final effector hormone of the hypothalamic pituitary adrenal (HPA) axis and functions as a measure of stress. The secretion of cortisol is altered in patients with depression, a trauma history, and other psychiatric disorder. HRV is a measurement of beat-to-beat variation in heart rate. It is controlled by parasympathetic and sympathetic nervous system input. In previous studies, a reduced HRV has been linked to increased cardiac morbidity and mortality. Reduced HRV have also been connected with patients with depression, anxiety disorders, and other psychiatric illnesses. In this study, subjects were hospitalized overnight for continuous electrocardiogram (ECG) recording and saliva samples were taken 5 times throughout the duration of their stay. Based on the data, PMD patients showed a reduced HRV in comparison to healthy volunteers that was statistically significant. HRV did not appear to correlate with depression. In addition, PMD subjects’ cortisol levels were higher than those of healthy volunteers, although this was not statistically significant.
Last updated November 27, 2013