Mal de Débarquement Syndrome (MdDS) and Persistent Postural-Perceptual Dizziness (PPPD) are both chronic vestibular disorders, but they differ primarily in their triggers and symptom behavior. MdDS is typically triggered by a period of passive motion, such as a cruise, flight, or long car ride; once the person returns to "solid ground," they feel a persistent sensation of rocking, bobbing, or swaying. Uniquely, MdDS symptoms often improve when the person is back in motion (e.g., driving a car). In contrast, PPPD is often triggered by a discrete vestibular event (like vertigo) or high stress, and its symptoms—usually a persistent sense of unsteadiness or "heavy-headedness"—are typically worsened by motion, upright posture, or complex visual environments. While both conditions involve a brain that is struggling to re-calibrate its sense of balance, MdDS is a failure to "readapt" to stillness after motion, whereas PPPD is a state of "hyper-awareness" and over-reliance on visual cues following a balance system disruption.