Abstract
People with vestibular disorders report changes in symptoms based on their environment with many situations increasing their symptoms. The purpose of this paper was to utilize the International Classification of Functioning Disability and Health (ICF) from the World Health Organization (WHO) to describe common environmental triggers for dizziness in persons living with balance and vestibular disorders. A multi-centre cross-sectional study was conducted with four different centres on three different continents, including patients from the United States (Pittsburgh), Germany (Munich), Jordan (Amman) and Saudi Arabia (Riyadh). Subjects: Three hundred eighty one persons with vestibular disorders participated. Methods: A 9-item questionnaire (the Vestibular Environmental Scale) was developed from existing ICF items, which were compared to Dizziness Handicap Inventory (DHI) scores. Sixty-five percent of participants reported that “quick movements in the vicinity” increased symptoms, “crowds” at 45%, and “design of buildings, e.g. narrow hallways, stairs, elevators” at 42%. The “crowds” item was a good positive predictor of psychogenic vertigo (OR 1.8, 95% Confidence Interval 1.03–3.16), while “food” (OR 0.47, 95% Confidence Interval 0.17–1.29) and “light” (OR 0.41 95% Confidence Interval 0.23–0.75) were negative predictors of psychogenic vertigo. There also was a positive correlation between the number of triggers and DHI score (Spearman correlation coefficient 0.47, p < 0.0001). Sixty-eight percent of the subjects reported an increase in symptoms with between 1 and 4 environmental triggers. In our cross cultural sample, environmental triggers affect dizziness in persons living with balance and vestibular disorders. The use of items from the ICF of the WHO may help to promote cross cultural sharing of information in persons with dizziness.
The Vestibular Activities and Participation (VAP) scale was developed based on the International Classification of Functioning (ICF) from the World Health Organization (WHO) [2, 27]. Prior to the development of the VAP, there were no previous instruments that included exclusively activity and participation items according to the ICF for persons living with balance and vestibular disorders [3]. A recent Rasch analysis has shortened the VAP scale from 34 to 12 items [29].
Environmental triggers can provoke or make symptoms worse for persons living with vestibular disorders [6, 40]. Few disease-specific activity and participation ICF scales include environmental items [3, 28]. Patients living with balance and vestibular disorders often report that light, sound, and movement are factors that can make them worse, yet light, sound and movement are not included in the activity and participation section of the ICF [31].
At an international consensus conference, light, sound, and movement in the environment were reported to affect symptoms in persons living with balance and vestibular disorders [16]. Vestibular content experts agreed on items that were important across all ICF categories including environmental items within the ICF that could adversely affect persons living with balance and vestibular disorders [16].
The VAP has cross-cultural validity and has been translated from English into Arabic and German [29]. One of the goals of the WHO is to facilitate development of Core Sets and cross-validated questionnaires for research. The Vestibular Core Set has recently been published based on expert opinion [16]. The comprehensive ICF Core Set for vertigo, dizziness, and balance disorders included 40 activity and participation items, 29 from the environmental section of the ICF [16]. The remaining items were from body functions (25) and body structures (6) [16].
Based on a systematic review, patient interviews, and data collected from patients, it was reported that environmental items affect functioning of persons with vertigo, dizziness and balance disorders [16]. As questionnaires are only of value if they inform clinicians about important information to make clinical decisions, it appears that a questionnaire with only activity and participation items is not comprehensive for persons with balance and vestibular disorders. Therefore, the purpose of this study was to describe if people with vestibular and balance disorders report being affected by environmental factors as described in the ICF and identified as relevant by the international consensus group [16]. Specifically, we wanted to investigate if there is a disabling effect of environmental triggers in persons with vestibular and balance disorders.
Methods
Study design and sample
The study was a multi-center cross-sectional study with four different centers on three different continents, including patients from the United States (Pittsburgh), Germany (Munich), Jordan (Amman) and Saudi Arabia (Riyadh).
Individuals with vestibular disorders aged 18 and over who had adequate command of the language of the respective country and provided informed consent were included in the study. All subjects needed to be able to read and write English, Arabic, or German.Additionally, individuals were excluded if they were unable to complete the questionnaire because of cognitive barriers or if an acute medical condition was associated with dizziness and required immediate attention (e.g. acute myocardial infarction or stroke). Participants were asked to complete the environmental items and the Dizziness Handicap Inventory during their initial visit to the University of Pittsburgh Medical Centers Balance and Vestibular Clinic (USA), the outpatient dizziness clinic at the German Center for Vertigo and Balance Disorders at Ludwig-Maximilians-Universität in Munich (Germany), the Middle East Center for Hearing and Balance in Amman (Jordan), and the Audiology and Balance Unit at King Abdulaziz University Hospital in Riyadh (Saudi Arabia). The study was given ethical approval by the Institutional Review Boards of the respective institutions.
The environmental questionnaire that the patients completed is included in Table 1. The Arabic and the German versions of the chosen environmental items were forward and backward translated according to the WHO established criteria [30].
The Dizziness Handicap Inventory (DHI) [22] was completed by all participants. The DHI is a 25-item questionnaire that probes people about the disabling effects of dizziness. The score ranges from 0 to 100, with a higher score indicating greater disability. The DHI has been shown to be reliable and valid using the English, German and Arabic versions [5, 23].
Data analysis
The data are described using means, standard deviations, and percentages where appropriate. We used the Spearman correlation coefficient for correlations, and linear and loglinear regression models to examine the association of the number of environmental triggers with the DHI score and to examine the differential effects of culture and study site. All models were adjusted for age and sex. SAS V9.4 (Cary, NC, USA) was used for all analyses. All forms had to have at least 95% of the data to be included in the analysis.
Results
Three hundred eighty one persons with vestibular disorders seen at four sites [Pittsburgh, PA, USA (n = 101); Munich, Germany (n = 232); Amman, Jordan (n = 18); Riyadh, Saudi Arabia (n = 30)] completed the questionnaires (229 women; 152 men). One hundred seventy-seven subjects were classified by the physicians as having a peripheral disorder, 83 had a central diagnosis, 100 had a psychogenic disorder, and 21 were classified as “other”. Respondents endorsed all items but with very different frequencies (Table 2). The highest percentages of responses of triggering items were ”quick movements in the vicinity” (65%), “crowds” (45%), and “design of buildings, e.g. narrow hallways, stairs, elevators” (42%) and the lowest percentage of endorsed responses include “certain foods” (9%) and “opinions and attitudes of others (e.g. family members, colleagues, acquaintances, friends)” at 15%. The total number of items endorsed per person that increased their symptoms varied between 0 and 8 (Table 3), with the highest percentage at 2 items and the least with 3 people reporting symptoms with all 8 testitems.
Mean total DHI scores did not vary between the women and men (48 vs 42). Those with peripheral vestibular disorders had a mean DHI score of 44 (SD 21), those with central vestibular disorders has a DHI mean score of 55 (SD 22), and those with a psychogenic diagnoses had a mean score of 49(SD 22).
Comparisons were made between cultures. The persons from the Arabic countries combined reported a higher number of triggers on average while their Arabic DHI scores were not substantially higher (non-Arabic countries: mean score = 46, SD = 22, Arabic countries: mean score = 44, SD = 23). In addition, the “crowds” item was a good positive predictor of psychogenic vertigo (OR 1.8, 95% Confidence Interval 1.03–3.16), while “food” (OR 0.47, 95% Confidence Interval 0.17–1.29) and “light” (OR 0.41 95% Confidence Interval 0.23–0.75) were negative predictors. People were less likely to have psychogenic vertigo if food or light were reported as a trigger. There also was a positive correlation between the number of triggers and DHI score (Spearman correlation coefficient 0.47, p < 0.0001)
More than half of the patients reported one or more additional triggers that were not chosen from the ICF. The most frequent additional triggers were: stress or being hurried, fatigue or lack of sleep, lack of food or water, looking at screens such as TV or computers, going by car as a passenger, and change in the weather. Other, less frequently mentioned triggers were vibrations caused by an electric toothbrush or a hairdryer, repetitive patterns on the floor such as checkerboard patterns or open mesh floorings, department stores or supermarkets.
Discussion
In this multi-cultural sample of 381 persons with balance and vestibular disorders, environmental triggers appeared to increase their dizziness/balance problem. In persons with balance and vestibular disorders, the environmental section of the ICF appears to be of value in helping to identify factors that increase or trigger a person’s symptoms. Although only 3 persons reported becoming symptomatic with all 8 test items, 258 people (68% of the sample) reported an increase in symptoms with between 1 and 4 environmental triggers. Only 15% of the sample reported no increase in symptoms with any of the triggers. Others have reported that environmental triggers can either be facilitators or inhibitors to recovery [7, 16].
Visual vertigo is characterized by increased dizziness in dynamic and changing visual environments [9, 25]. Three of the most frequently endorsed items (building design, crowds, and quick movements in the vicinity) all relate to visually complex or moving environments, which is a well described problem in persons living with vestibular disorders [9, 40].
One item missing in the ICF that has been described as a problem for a subset of people living with vestibular disorders is a problem with heights [7, 8]. People with height intolerance, which has been noted in up to 28% of the population, [20] change their gait with visually provocative height exposure [38].
Dannenbaum et al. [14] recently developed a 9-item visual vertigo analogue scale. Walking in a supermarket and patterned floors are not included in the ICF but are included in Dannenbaum’s scale. Shopping in a store and patterned floors are common complaints of a subset of people with balance and vestibular disorders. Those with benign paroxysmal positional vertigo, labyrinthectomy, labyrinthine concussion and those with vestibular hypofunction were less symptomatic with the visual vertigo analogue scale than those with non-specific vestibulopathy [14]. Although exact percentages were not reported in Dannenbaum et al.’s work, a large percentage of their sample (n = 102) experienced symptoms above “0’ on their visual analogue scale on 2 or more items. Based on Dannenbaum’s work, it appears that possibly a subset of people with “non-specific vestibular disorders” experience an increase in symptoms with environmental stimuli. In our study, 85% of our subjects reported that they were more symptomatic with at least one of the environmental triggers included in our questionnaire.
Persons who poorly compensate after a vestibular disorder may have problems with environmental cues [13, 35]. Specific interventions have been devised to help people compensate for their sensitivity to environmental cues, most of which relate to repeated graded exposures to the offending visual, auditory, or aural stimuli [1, 41].
The correlation between the DHI and the ICF Vestibular Environmental scale was 0.47, whereas the correlation between the visual vertigo analogue scale and the DHI was r = 0.67, [14] suggesting that they measure similar constructs. Although it would be ideal to only utilize items from the ICF, Dannenbaum et al’s items of walking in a grocery store and patterned floors plus heights [7, 8] might add value to the ICF environmental items included in the present study.
Recently, investigators have suggested that some of the environmental items of the ICF are not clear based on cognitive interviews [26]. They divided all of the environmental items into 6 domains: access to information and technology, assistive technology, the social environment, services, systems and policies, economic quality of life, plus the built and natural environment [26]. Ongoing work is being done to help clarify items with the environmental section of the ICF so that it can be utilized across cultures [18, 26]. Most of the items suggested by the international group of vestibular experts plus intensive interviews of persons living with vestibular disorders cluster in the domain of the ICF currently called “natural environment and human-made changes in the environment”. It is clear from the present study and Dannenbaum et al.’s work [14] that the environment affects function in persons living with vestibular disorder.
Conclusion
There appear to be several key items from the environmental subsection of the ICF that are challenging for persons with vestibular and balance disorders. As the vestibular system is one of the body’s main sensory receptors, it is not surprising that environmental stimuli may increase or trigger their symptoms. The ICF Vestibular Environmental scale has promise in raising the attention of practitioners to these functional deficits in persons with balance and vestibular disorders and can be used across cultures.
Footnotes
Acknowledgments
The authors want to thank Anita Lieb, MS, Alaa Albishi, PT, MS, and Brooke Klatt, PT, MS, NCS, for helping to recruit and record the data in Pittsburgh, and Charlotte Selge, MD, and Antoanela Ciupe, MD, for support with data collection in Munich, and Mohammad Al-Masri, PhD, for referring patients in Amman. The project was financially supported by King Saud University, through Vice Deanship of Research Chairs, Rehabilitation Research Chair, the German Federal Ministry of Education and Research under the grant code 01 EO 0901, and the Department of Physical Therapy, University of Pittsburgh.