Autonomic Reflexes May Contribute to the Symptomatology of Mal de Debarquement Syndrome

Abstract

Mal de debarquement syndrome (MdDS) is the phantom perception of self‐motion triggered by a passive motion event such as sea or air travel. To test the hypothesis that autonomic reflexes are altered in MdDS, head‐down rotation (HDR) was used to test vestibular reflexes and 60° head‐up tilt (HUT) was used to test combined baroreceptor and vestibular reflexes in 9 female MdDS patients and 9 age‐ and sex‐matched controls. Heart rate (HR, ECG), arterial blood pressure (ABP, finger photoplethysmography), and cardiac output (CO), stroke volume and systemic vascular resistance (SVR) were calculated (Modelflow) in 6 min bins for steady‐state and dynamic (FFT) analysis during baseline, perturbation (HDR or HUT), and recovery. HDR decreased stroke volume and CO in both groups, but SVR increased in MdDS. No changes in the ABP power spectrum were observed during HDR. HUT increased mean ABP, HR, and SVR while decreasing pulse pressure, stroke volume, and CO in both groups. Increases in mean ABP and SVR in MdDS were augmented compared to controls. HUT increased the ABP low frequency spectral power and R‐to‐R interval low frequency/high frequency ratios in both groups. These pilot data identified exaggerated vascular resistances to a postural change in MdDS possibly due to increased sympathetic reflex gain. Thus, altered autonomic reflexes appear to be a part of MdDS symptomatology.Funding: MdDS Balance Disorder Foundation