ANALYSIS OF HEART RATE VARIABILITY AND CORTISOL DIURNAL PROFILES IN PSYCHOGENIC MOVEMENT DISORDER PATIENTS
Myriam Alcantar Rama, Carine Mauer.
National Institute of Neurological Disorders and Stroke, National Institutes of Health, Bethesda, MD.
We are interested in measurements of stress biomarkers in psychogenic movement disorder (PMD) patients given the hypothesis that abnormal movements seen in PMD patients are the result of converted psychological stress. Cortisol, a major stress hormone in the hypothalamic pituitary adrenal (HPA) axis is a stress biomarker. Its secretion is not understood in PMD patients. Heart rate variability (HRV) measurements provide quantitative assessment of autonomic activity. While reduced HRV has been seen in an assortment of anxiety disorders, it has not been well studied in the PMD population. As a result, we sought to determine cortisol diurnal profiles and heart rate variability in patients with PMD compared to healthy subjects. PMD patients and age-and-gender-matched healthy control subjects were hospitalized overnight for electrocardiogram (ECG) recording. The ECG data was analyzed using Impresario software, artifacts removed, and ECG data was imported into Matlab for calculation of HRV parameters including standard deviation of the N-N intervals (SDNN), number of adjacent N-N intervals differing by more than 50 milliseconds (NN50). During hospitalization, saliva samples were collected at 5 different times and later analyzed by a commercial laboratory. Thirty-six PMD patients and 34 healthy controls were assessed in an ongoing investigation. Although not reaching statistical significance, cortisol levels were higher in PMD patients as compared to the healthy controls at 2 of the 5 times collected. Subjects with shorter symptom duration were found to have greater cortisol values on average.