Vertigo and dizziness: challenges for epidemiological research

Introduction Vertigo and dizziness are among the most common chief complaints when patients seek medical advice and affect a considerable part of adults of working age. With a high lifetime prevalence and high burden of disease, vertigo and dizziness can be severely disabling symptoms because of their high impact on daily life. Although most vestibular disorders are manageable they are often underand misdiagnosed in primary care. Epidemiological data on vertigo and dizziness is scarce and inconsistent. Challenges that make epidemiological research difficult include case definition and diagnostic algorithms, data collection procedures and standardization of routine data. Vertigo and dizziness as symptoms are difficult to describe and to standardize. With very few exceptions, vertigo has been regarded in epidemiological studies as a symptom or consequence of some other underlying disease of cardiovascular or neurological origin and has hardly been the focus of epidemiological research. Epidemiological data also vary depending on data collection procedures, study design Vertigo and dizziness: challenges for epidemiological research E Grill1,2*, M Müller1,2, T Brandt2,4, K Jahn2,3 and sample. In epidemiological studies, detailed diagnostic work-ups of vestibular and non-vestibular causes of vertigo may be impossible. Nevertheless, representative studies could include simple and noninvasive bedside tests to verify diagnoses and give deeper insight into determinants and distribution of vestibular disorders. With the growing number of dedicated dizziness units at hospitals, a systematic approach to data collection in clinical cohorts is needed. This also requires a common classification of disorders. The aim of this review was to discuss the challenges for epidemiological research in vertigo and dizziness. Conclusion Successfully transferring terminology, procedures, diagnostic algorithms and therapy options from a specialized clinical setting to the primary care setting is necessary if such knowledge is to be of any practical utility for the health system. Costs, benefits, effectiveness and potential harm of this implementation must be shown. Introduction Vertigo and dizziness belong to the most common chief complaints when patients seek medical advice1. However, vertigo as well as dizziness are symptoms present in a wide variety of disorders. Despite the frequency of these symptoms, there is a lack of epidemiological data for the following reasons: (1) in contrast to headache, lumbago or dyspnoea, patients have problems to describe their complaints; (2) disorders presenting with vertigo and dizziness fall in different medical subspecialties (e.g. general practice, otorhinolarngology, neurology, psychiatry, ophthalmology, cardiology); (3) diagnostic categories are not established across medicine; and (4) most syndromes are not represented in international classification systems (e.g. ICD-10). Vertigo can be either a reaction to stimulus, e.g. following unaccustomed head movements as in a carrousel or on a ship, or the result of a discrepancy between visual and vestibular information, e.g. in a moving car or on an exposed mountain ridge. The most frequent cause of pathologic vertigo is an impairment of the vestibular system. Three semicircular canals and the otolithic apparatus in the bony labyrinth of the inner ear provide information about the position of head in space. The eighth cranial nerve carries this information to the vestibular nuclei in the brainstem. Pathways to the spinal cord support postural stability. Closed connections to the eye muscles via the vestibularocular reflex (VOR) ensure stable images on the retina during head movements. Vertigo can be of peripheral origin, i.e. a problem of the labyrinth or the vestibular nerve, or of central origin, as a consequence of a lesion of the cerebellum or brain stem. Further, psychogenic vertigo can develop following organic vestibular disorders, or might develop as a comorbid condition of phobia or panic attacks2. The visual and the somatosensory systems contribute to postural stability. Impaired sensory functions or impaired interaction between sensory systems can cause vertigo and dizziness. Patients may describe their complaints as light-headedness, *Corresponding author Email: [email protected] 1 Institute for Medical Information Processing, Biometrics and Epidemiology, Ludwig-Maximilians-Universität-München, Munich, Germany 2 German Center for Vertigo and Balance Disorders, Ludwig-Maximilians-UniversitätMünchen, Munich, Germany 3 Department of Neurology, Ludwig-Maximilians-UniversitätMünchen, Munich, Germany 4 Institute for Clinical Neuroscience, LudwigMaximilians-UniversitätMünchen, Munich, Germany