Vertigo is frequently described as a consequence or side effect of defined entities such as cardiovascular, infectious, neurological and otological disease. Nevertheless, vertigo and dizziness are also discrete syndromes which are associated with co-morbidities. A major challenge is that nomenclature in vestibular research lacks uniform criteria for its classification and definition. Thus, "vertigo and dizziness" includes vertigo and dizziness as consequences of disease as well as disease entities such as benign paroxysmal positional vertigo (BPPV), phobic postural vertigo, central vestibular vertigo, psychogenic vertigo, Menière's disease, ocular motor disorders, and vestibular migraine. Vertigo is potentially disabling and has distinct impact on participation, psychosocial interaction and quality of life. However, data on health care costs and on burden of disease specific to vertiginous disease is scarce. Also, there is no consensus on which measures are the most appropriate, which aspects should be monitored, or which aspects are the most relevant to the patient. Also, existing measures have not been compared systematically as regarding their content validity.

To address these issues, Prof. Grill and her team at the Institute for Medical Information Processing, Biometrics and Epidemiology at Ludwig-Maximilians University München (LMU) initated a project to develop an ICF Core Set for vertigo. This project was conducted under the auspices of the Integrated Center for Research and Treatment of Vertigo, Balance and Ocular Motor Disorders (IFB-LMU), a centre sponsored by the German Federal Miinstry of Education and Research.

The preparatory phase of the project included the following preparatory studies:

• In a systematic literature review 133 different outcome measures that were most frequently used in assessing vertigo, nystagmus, DHI and in audiologic evaluation were identified in 67 papers using the ICF as a reference.
• A qualitative study (12 individual interviews of persons with vestibular and/or psychogenic disorder), aimed at identifying relevant aspects of functioning and contextual factors from the patient perspective was conducted.
• A worldwide internet-based survey gathered the opinion of 188 international experts from all over the world. This study represented the health professionals' perspective. 188 international experts identified by authorship, recommendation and membership with an average experience of 12 years in the area of vertigo were asked to fill out an online survey regarding the most relevant aspects of functioning in vertigo. These aspects were extracted and linked to the ICF. Experts were selected to represent the WHO world regions..
  A cross-sectional study collected data from 200 patients in the ambulatory care unit of the hospital of IFB, representing the clinical (epidemiological) perspective. The study yielded the prevalence of impairments, limitations, and restriction of various aspects of functioning as proposed by the ICF.

The results of these preparatory studies were presented at the international consensus conference, a multi-stage, iterative, decision-making and consensus process, that took place from 10-12 May 2012 in Seeon, Germany. During this consensus conference, 27 vertigo/vestibular disorders experts from 11 different countries worldwide (Australia, Germany, Italy, Netherlands, South Korea, Spain, Sweden, Switzerland, Luxembourg, UK and USA) decided to include 100 ICF categories in the Comprehensive ICF Core Sets and 29 ICF categories for teh Brief ICF Core Sets for vertigo.

Comprehenisve ICF Core Set for vertigo (download PDF)
Brief ICF Core Set for vertigo (download PDF)

For more information, feel free to contact Prof. Eva Grill (eva.grill@med.uni-muenchen.de) or the ICF Research Branch (Melissa.selb@paranet.ch).