Wooden wheel on the ship at sunset on Issyk Kul lake
Mal de Debarquement syndrome (MdDS) is a rare type of vestibular disorder characterized by a feeling of constant movement in the absence of motion. Movement can be experienced in the form of rocking, swaying, bobbing, or a pulling sensation. Although symptoms get better with passive motion (i.e. when you are a passenger in a car or on a boat), they can return after the passive motion ends. Symptoms may be triggered by motion (MT-MdDS) or occur spontaneously without motion (SO-MdDS). Other aggravating factor are exposure to busy environments (i.e. grocery store, airport), visual stimuli (i.e. computer use, phone use, video games), and fatigue.
The diagnosis criteria described by the International Classification of Vestibular Disorders is as follows: perception of continuous, non-spinning vertigo lasting a day; onset within 48-hours after passive motion is experienced; symptoms resolve temporarily after experiencing passive motion; and symptoms last greater than 48 hours. Undoubtedly, MdDS negatively impacts day to day activities, social interactions, recreational activities, ability to work, and ultimately quality of life. MdDS is not clearly understood, which makes it difficult to treat. In theory it originates in the central nervous system resulting from an abnormal vestibular ocular reflex (VOR). The role of the VOR is to maintain gaze stability during head movements, so when it’s not working properly symptoms of MdDS are experienced.
The purpose of this study was to determine the effectiveness of a treatment protocol directed at the maladaptive VOR. 101 subjects participated in the study, including males and females of various ages, with and without motion triggered MdDS. The basis of the treatment protocol was to apply head movements to the subjects as they simultaneously viewed a moving stripe pattern. The moving stripe pattern signifies an optokinetic stimulus (OKS) used to produce eye movements to aid in gaze stability. The type of stripe pattern was determined by clinical testing. The treatment began as the subject’s head was manually rotated by the clinician at a particular speed. During the manual head rotation, the subject was instructed to view the OKS, which was also set at a certain speed. The subjects received two, 4-minute treatment sessions per day for 2-5 days. Treatment outcomes were measured by subjective and objective data. Patients were required to rate the intensity of symptoms before and after each treatment session. They were also required to complete an MdDS symptom specific questionnaire on the first day before treatment and on the last day after treatment. Objective testing consisted of postural control and balance using a Wii balance board. These measurements were collected before, after, and in between each treatment session.
The results of the treatment protocol indicate 66% improvement. There was no substantial difference between the MT-MdDS group and the SO-MdDS group. Successful outcomes were measured by subjective reports of decreased symptoms, improvement in function, and improvement in quality of life. In addition, subjects demonstrated decreased sway and increased stability. It is important to note that the most improvement occurred during the protocol upon three consecutive treatment days. This study demonstrates that although MdDS is tricky to understand and treat, viable treatment options exist. A key factor is to identify appropriate individuals early in order to decrease the number of healthcare providers they see and treatments they receive.
Reference
Article review by Denise Schneider, DPT, FAAOMPT