Aided by sophisticated imaging techniques and abetted by rapid information channels, modern physicians appear to be well-equipped for the accurate diagnosis of diseases and disorders. The human body, however, cannot be separated into isolated parts that can be immediately identified with specific conditions, and is instead comprised of numerous interacting systems that complicate the process of evaluation.
Due to such intricacy, the assessment of a particular disorder requires many diagnostic tests, some of which may cause the patient discomfort and fatigue. In an attempt to address the concern of how to diagnose vestibular disorders, a group of balance disorders that entail a prolonged evaluative process, a research team lead by Bryan Ward, M.D.—a resident in the Department of Otolaryngology-Head and Neck Surgery at the Johns Hopkins University School of Medicine—has recently presented findings that suggest the applicability of MRI magnetic fields to the disorders’ diagnostic process.
Originating from the disturbance of the inner ear, vestibular disorders are closely related to vision. The Hopkins researchers found that the MRI’s magnetic field causes involuntary eye movements due to the pull on the inner ear fluid, whose stability is critical to maintaining balance. In the first of two studies conducted utilizing the MRI machine, the investigators in Ward’s team placed nine patients, all of whom had balance problems, in an MRI machine and took videos of their eye movements. People with “one-sided” inner ear problems showed distinct eye motions, unlike their healthy counterparts who in an earlier investigation had been demonstrated to have normal side-to-side eye movements. Based on the affected ear, left or right, and the order, head or feet, in which they were placed into the machine, the afflicted patients underwent down-to-up eye motions or vice versa and showed patterns of unnaturally rapid eye movements.
In the second study, which was published on March 19 in the journal PLOS One, Ward’s team tested the effect of the magnetic field of the MRI machine on the inner ear systems of zebrafish, an ideal specimen for the study due to the resemblance of the animal’s vestibular system to that of human beings. In this specific investigation, 30 healthy zebrafish in an aquarium were placed under the influence of a strong 11.7 Tesla magnetic field. The majority of the fish, under the influence of magnetism, displayed a range of erratic behavior, such as flipping, rolling, or swimming faster than normal. They demonstrated normal swimming behavior only when they were placed outside of the MRI machine.
From this subsequent study, Ward’s team has noted the implications of the zebrafish as a useful medium through which to conduct drug trials and further investigation of the genetics involved in causing balance disorders. Moreover, as magnetic stimulation has been revealed in both studies to cause imbalances in the vestibular systems, the research suggests the significance of magnetic stimulation as a criterion in diagnosing balance disorders.
