|Year : 2022 | Volume
| Issue : 1 | Page : 32-40
Persistent postural-perceptual dizziness: A multispecialty survey of clinician awareness and practices in Malaysia
Carren S Teh1, Salim Iffah1, Narayanan Prepageran2
1 Department of Otorhinolaryngology, Hospital Sungai Buloh, Sungai Buloh, Selangor, Malaysia
2 Department of Otorhinolaryngology, Faculty of Medicine, University of Malaya, Wilayah Persekutuan Kuala Lumpur, Malaysia
|Date of Submission||18-Oct-2021|
|Date of Decision||06-Dec-2021|
|Date of Acceptance||03-Jan-2022|
|Date of Web Publication||25-Apr-2022|
Dr. Carren S Teh
Department of Otorhinolaryngology, Hospital Sungai Buloh, Jalan Hospital, 47000 Sungai Buloh, Selangor
Source of Support: None, Conflict of Interest: None
Objectives: Persistent postural-perceptual dizziness (PPPD) is a chronic functional vestibular disorder which is also the most common cause of chronic dizziness. Effective treatment is dependent on the awareness of the provider's knowledge of PPPD and correct provision of treatment. This study was aimed to assess the awareness of PPPD and practice patterns among a diverse group of providers who care for patients with chronic dizziness in the outpatient clinics. Materials and Methods: A 12-question web-based survey was distributed to a cross-sectional convenience sample of medical providers from primary care including general practitioners, otorhinolaryngology (ORL) and internal medicine all over Malaysia. We analyzed the responses using multivariate logistic regression. Results: Of the 186 included responses, only 46.7% (85 respondents) replied they have heard of PPPD and 158 (84.9%) have actually encountered patients with symptoms describing PPPD. Those in primary care had less odds of having heard of PPPD (adjusted odds ratio [aOR] 0.37 confidence interval [CI] 0.18–0.76) nor treated patients with PPPD symptoms (aOR 0.18 CI 0.07–0.49) when compared to the General Medical and ORL providers. In terms of treatment of PPPD, gender, level of training, and practice setting predicted the provision of therapy. Conclusion: PPPD awareness is still lacking among our providers and the current practices reflect that the management of chronic dizziness is focused on ruling out systemic causes. Now is the time to invest in health communication strategies to improve the awareness and knowledge of managing chronic dizziness especially PPPD.
Keywords: Chronic dizziness, clinician awareness, functional disorder, persistent postural-perceptual dizziness
|How to cite this article:|
Teh CS, Iffah S, Prepageran N. Persistent postural-perceptual dizziness: A multispecialty survey of clinician awareness and practices in Malaysia. Indian J Otol 2022;28:32-40
|How to cite this URL:|
Teh CS, Iffah S, Prepageran N. Persistent postural-perceptual dizziness: A multispecialty survey of clinician awareness and practices in Malaysia. Indian J Otol [serial online] 2022 [cited 2022 May 26];28:32-40. Available from: https://www.indianjotol.org/text.asp?2022/28/1/32/343752
| Introduction|| |
Chronic dizziness is not a new ailment. As early as 1870, patients who feared leaving their homes to head out to the marketplace were diagnosed with agoraphobia. However, it has since been said that the fear of leaving the home may be due to chronic dizziness or imbalance which was made worse with the visual stimuli in a crowded market. Different names have since been given to describe the collective symptoms of dizziness, imbalance, non-spinning vertigo such as phobic postural vertigo, space-motion discomfort, visual vertigo, and chronic subjective dizziness.,,
In 2017, Barany Society consolidated existing data and presented the diagnostic criteria for persistent postural-perceptual dizziness (PPPD) [Table 1]. It basically translates to persistent nonvertiginous dizziness, unsteadiness, and nonspinning vertigo that is exacerbated by postural challenges and perceptual sensitivity to space-motion stimuli lasting for more than 3 months., PPPD is now recognized by the World Health Organization and has been included in the 11th Edition of the International Classification of Diseases.
|Table 1: Criteria for the diagnosis of persistent postural-perceptual dizziness (Staab et al., 2017)|
Click here to view
PPPD onset may occur after a vertiginous event such as Benign Positional Paroxysmal Vertigo (BPPV), panic attacks, concussion, or autonomic disorders.,,, Once acute vertigo fades, PPPD patients complain of dizziness described as feeling light-headed, floating, or head fullness with unsteadiness and feeling as if veering from side to side when walking. Symptoms persist for most days.
Categorized as a chronic functional vestibular disorder, PPPD is now the most common cause of chronic dizziness in the middle-aged with incidence peak between 30 and 50 years.,, Numerous studies have since shown that PPPD interferes in daily life as well as the way individuals experience their personal, social, and work life in the presence of chronic conditions.
The pathophysiologic process has been hypothesized that it may be due to a persistent shift in multi-sensory processing of space-motion information. In a normal healthy person, multiple sensory inputs from the vestibular, visual, and proprioception help a healthy person maintain balance. However, visual dependence occurs following a vestibular event in PPPD [Figure 1]. Alteration in postural control strategies such as stiffening of stance and gait to avoid falls then sets in. Those with anxiety-related personality traits of neuroticism and introversion poses as a risk factor and becomes a sustaining mechanism.,,,
|Figure 1: An acute dizzy attack will normally lead to an acute adaptation involving visual dependence with increased postural control and environmental vigilance. Overtime, they will achieve recovery through normal re-adaptation. However, those with anxiety-related personality traits may develop sustaining mechanisms which shifts multi-sensory processing of space-motion information resulting in maladaptation. Overvigilance and prolonged postural control then results in secondary effects such as dizziness, imbalance, neck stiffness, phobia and fatigue. These symptoms trigger the already heightened senses and perpetuate the sustaining mechanism leading to the vicious PPPD cycle. Exiting this cycle would require re-adaptation involving individualized treatment. Adapted from Dieterich and Staab 2017 and Popkirov et al. 2018|
Click here to view
PPPD is a diagnosis made by clinical history that fulfills the diagnostic criteria and is not a diagnosis of exclusion. Physical examination, clinical laboratory testing, vestibular evaluation, and diagnostic neuroimaging may be normal but should be tailored to the patient's history and is performed to rule out more sinister conditions. These include peripheral or central vestibular deficits, autonomic disorders, head injuries, cardiac pathology, or intracranial tumors. PPPD being a functional disorder may have findings which are characterized by the task dependency of symptoms such as postural performance. While patients show increased body sway during simple standing tasks, they typically improve during more difficult balance tasks or when distracted. For example, when a patient is asked to guess the number written on their back as they balanced, PPPD patients will show an improvement in sway.
Published papers show therapies which may be helpful are cognitive behavioral therapy (CBT), medications such as selective serotonin reuptake inhibitor (SSRI) or vestibular rehabilitation therapy (VRT) which are exercises to help with compensation and adaptation.,, However, effective treatment is dependent on the awareness of the provider's knowledge of PPPD and the correct provision of treatment. Delayed treatment will only perpetuate the functional disorder. This study aims to assess the awareness of PPPD and practice patterns among a diverse group of providers who care for outpatient patients with chronic dizziness.
| Materials and Methods|| |
A 12-question web-based survey [Table 1] was distributed to a cross-sectional convenience sample of medical providers across specialties treating patients with dizziness in Malaysia from September to October 2020 via the network of respective professions from the field of primary care, otorhinolaryngology (ORL), and internal medicine. Incomplete surveys or surveys from other medical fields were excluded from the study. This study received Medical Research Ethics Committee approval by the Malaysian National Medical Research Registry (NMRR-20-1742-55979 [IIR]).
Data collected were age, gender, medical field (primary care including general practitioners, ORL, and internal medicine), level of training (specialist or medical officer in training), practice setting (public, private, academic), years of experience, and whether the practitioner has heard of PPPD (to assess awareness). Subsequently, they were provided the symptoms of PPPD and were asked if they have encountered patients with those symptoms and how they would have managed those patients to study the practice patterns [Table 2].
Baseline demographics and characteristics were compared using the Chi-square test between participants from different fields. Chi-square tests with Yates correction were used to determine whether knowledge and management of care varied by specialty. To identify factors associated with knowledge and provision of care for chronic dizziness, multivariate logistic regression models were used to estimate adjusted odds ratios (aORs) with a 95% confidence interval (CI). P < 0.05 was deemed as significant.
| Results|| |
One hundred and ninety-seven surveys were received and 11 were rejected as there was either incomplete data or they did not fit the inclusion criteria. Of the 186 responses, there were predominantly females making up 63.4% (118) of the respondents [Table 3]. The ratio between those who were specialists in their field and who are still in training was almost 1:1. Majority worked in the public setting with 129 (69.4%) and more than 75% of the respondents frequently saw dizzy patients at least once a week.
Majority of the respondents were from the ORL field with 84 (45.2%) followed by Primary Care 61 (32.8%) and internal medicine 41 (22%). The only parameter which did not differ significantly was the years of experience in their field.
46.7% (85 respondents) replied they have heard of PPPD with 50 (59.5%) from ORL, 17 (41.5%) from general medicine and a mere 18 (29.5%) from primary care. When the symptoms of PPPD were provided, the total number of respondents who had encountered such patients almost doubled to 158 (84.9%) and majority had seen a patient with PPPD as frequently as once a day to at least once a week.
When comparing gender, age, level of training, years of experience, practice setting, and the different fields, there was a significant difference where actual PPPD encounters were significantly higher than the awareness [Table 4]. Providers aged >50 and who treated dizzy patients infrequently did not see have any significant difference.
|Table 4: Comparison of persistent postural-perceptual dizziness awareness and encounter with persistent postural-perceptual dizziness patients|
Click here to view
In multivariate models, the provider characteristics that were most often associated with the poorer awareness and actual encounters with PPPD were those practicing in the primary care of general practitioner clinics [Table 5]. Those in primary care had less odds of having heard of PPPD (aOR 0.37 CI 0.18–0.76) and had lesser chance of actually meeting a patient with PPPD symptoms (aOR 0.18 CI 0.07–0.49) when compared to the General Medical and ORL providers.
|Table 5: Multivariate analysis of persistent postural-perceptual dizziness awareness and encounter with persistent postural-perceptual dizziness patients|
Click here to view
When considering investigation modalities, the multivariate models showed the age of provider, years of experience, practice settings, and medical field predicted the different investigative methods [Table 6]. Those in primary care were more focused on ruling out cardiac causes such as blood pressure measurement (OR 2.59 (CI 1.20–5.60), order electrocardiography (ECG) (odds ratio [OR] 2.39, CI 1.21–4.73) and less likely to perform Dix-Hallpike (OR 0.35, CI 0.17–0.72), order a videonystagmography (VNG) (OR 0.05, CI 0.01–0.41), computerized tomography (CT) scan of the brain (OR 0.24, CI 0.10–0.60) or magnetic resonance imaging (MRI) scan of the brain (OR 0.16, CI 0.05–0.58).
|Table 6: Multivariate analysis of investigation preference in persistent postural-perceptual dizziness|
Click here to view
In terms of treatment of PPPD, gender, level of training, and practice setting predicted the provision of therapy [Table 7]. Male providers (OR 0.30, CI 0.14–0.68) were less likely to prescribe physiotherapy similarly to those who worked in the public setting (OR 0.28, CI 0.13–0.60). However, those who were not specialists were more likely to choose physiotherapy as a form of treatment (OR 3.05, CI 1.37–6.77). Those practicing in public settings were also less likely to prescribe vestibular sedatives (OR 0.39, CI 0.19–0.80).
|Table 7: Multivariate analysis of management preference in persistent postural-perceptual dizziness|
Click here to view
| Discussion|| |
Dizziness or vertigo is a burden to the patient as well as the health-care services. It has been reported that 69.8% of working adults had reduced their workload, 63.3% had lost working days, and 4.6% had changed and 5.7% had quit their jobs, due to vertigo symptoms. Patients would have had between one to four visits to the emergency services, primary care services, or specialist consultants before getting a diagnosis. Some may have had hospitalization ranging from 2–7 days. Hence, getting the right diagnosis to start the right treatment is crucial.
Clinician awareness and practices
This study was aimed to assess the awareness of PPPD and practice patterns among a diverse group of providers who care for patients with chronic dizziness and we focused on providers from ORL, general medicine and primary care. As PPPD is a relatively new diagnosis with its diagnostic criteria presented by the Barany society in 2017, it was expected that the new terminology is not be widely acknowledged. This was evident with less than half of the respondents having heard of PPPD but this did not mean the disorder was not prevalent as almost 85% of the respondents had treated patients with PPPD symptoms. Providers from primary care had the lowest percentage of having heard of PPPD (29.5%) as well as the lowest number of encounters with patients with PPPD (67.2%). Multivariate analysis also showed when compared to general medical and ORL, primary care had lower odds of hearing of PPPD or treating patients with PPPD symptoms. Based on the 2014 Malaysian National Medical Care Statistics for Primary Care, complaints of dizziness or vertigo in primary care had a rate of 1.5/100 encounters as compared to digestive complaints rated at 15.5/100 encounters or musculoskeletal complaints of 11.1/100 encounters. In fact, 72.3% of the patient load was managing noncommunicable diseases (NCD) such as hypertension, diabetes, and lipid disorder. The lower exposure rates to patient complaints of dizziness would explain the lower awareness of PPPD.
When comparing the level of awareness of PPPD and encountering PPPD patients, the difference was significant regardless of the field, gender of provider, level of training, years of experience or practice setting. Only those providers aged above 50 and had fewer exposure to patients with dizziness with only seeing one case every 6 months had no significant difference in the awareness and actual PPPD encounters. Here comes the importance of creating awareness among the clinicians as this will influence case detection, raise the profile of the disease, proper intervention will mean more effective treatment strategies for our patients. This was one of the intentions of the survey as it would trigger the awareness of PPPD among the respondents and at the end of the survey was a website link to provide details of PPPD to aid in disseminating more information.
The investigation pattern was also reflective of the practices by the different fields. As the major bulk of patients in the primary care clinics are those with NCD, a dizzy patient would more likely have the blood pressure (OR 2.58, CI 1.20–5.60) and ECG (OR 2.39, CI 1.21–4.73) examined as compared to a patient in Medical or ORL Clinic. Modalities which are costly or highly specialized are also less likely to be ordered from the public setting such as brain imaging or VNG.
Benign Paroxysmal Positional Vertigo (BPPV) is the most common vestibular cause for vertigo or dizziness. Dix Hallpike is simple, safe, and quick to complete, requires no specific equipment, and can be performed in any clinical setting, including in the community. It is unfortunate that the numbers show that the public setting is less likely to perform this compared to the private or academic setting. This could be due to the difference in patient load managed in the public which would limit consultation time. While there are no guidelines to what is considered the best consultation duration, a recent Malaysian study in 2017 showed an average consultation duration in a public outpatient clinic was 18.21 min and ranged between 2 and 75 min depending on the type of cases. Based on our experience, the average of 18 min is too short to diagnose in a patient with chronic dizziness.
Deriving a diagnosis in chronic dizziness
To derive the correct diagnosis, accurate history is of utmost importance. Most of the diagnoses have their distinct differences with its own management path and have been discussed thoroughly by Staab et al. 2007, Munchie et al. 2017 and Gan 2018 and will not be described in detail here but instead, the discussion here is to highlight the direction one should take when encountering a patient with dizziness, mainly those with chronic symptoms.
In the case of an acute vestibular syndrome where there is the sudden onset of acute, continuous vertigo lasting for more than 24 h, it could be due to vestibular neuritis (hearing spared), labyrinthitis (hearing affected), or something more urgent such as a posterior circulation stroke. To differentiate a benign peripheral cause from a stroke, HINTS examination (Head Impulse Nystagmus and Test of Skew) is a well-validated tool with a sensitivity of 94.6%–100%. If HINTS is suggestive of a stroke, the MRI of the brain and brainstem is indicated.
When approaching chronic dizziness, current symptoms are often focused but the history during the first onset of illness and the progression of symptoms can narrow down the diagnosis. There are three major patterns for chronic dizziness. The first group may present with multiple episodic vertigo. These symptoms may come spontaneously such as vestibular migraine, panic attacks, Meniere's disease, TIA, multiple sclerosis, cardiovascular pathology, or endocrine causes. Episodic events may also be triggered in cases of BPPV, perilymph fistula, or orthostatic hypotension. The second group may present with a single acute episode where the patient would recall a severe case of vertigo which may last up to days which then improve but has a lingering disequilibrium. In this group, going back into the history is particularly important as it could be the beginning of PPPD after a case of vestibular neuritis, panic attack, or BPPV. The third group may have a chronic, slowly progressively worsening imbalance or disequilibrium without any acute vertigo at any point. These are seen in bilateral vestibular deficits, central nervous system disorders such as ataxias, drug or toxin induced or in psychological causes such as anxiety and depression. History of syncope or feeling lightheaded especially after prolonged standing is a predictor of cardiac in origin.,,
It is helpful to dissect the secondary symptoms which have developed over the time from the offending pathology. Symptoms such as muscular pain, neck stiffness, eye strain, and fatigue especially at the end of the day which are due to visual dependence and postural control mechanism can sometimes create confusion in making the etiological diagnosis.,,, History of falls is also important as it is seen in patients with disequilibrium rather than in those with chronic dizziness.
While some diagnosis is heavily reliant on history such as in Meniere's Disease, vestibular migraine, and PPPD,,, clinical examination can help confirm the diagnosis such as in BPPV. Even if history is not suggestive of BPPV especially in the elderly, Dix-Hallpike should be performed. Blood pressure is also warranted to rule out undiagnosed hypertension or orthostatic hypotension, especially in the elderly on antihypertensive medications. Blood investigation is usually ordered if the history is vague and can help rule out anemia, hypothyroidism, diabetes or hypoglycemia. Tilt-bed test, ECG, or even a Holter monitor would be useful in those with symptoms suggestive of cardiac in origin. MRI brain is useful in cases where there is asymmetrical hearing loss, skew deviation, gaze-evoked nystagmus, or other focal neurological signs., Hearing tests and vestibular function tests may not be as easily available but can help narrow down the peripheral vestibular diagnoses by determining the site of the pathology which may be from the cochlear, semicircular canals, otolithic organs, or vestibular nerve. This may seem to be academic to delineate the pathology, but it will aid in customizing rehabilitation.,,
Where does PPPD standout in this sea of chronic dizziness diagnosis? PPPD has its distinct diagnostic criteria. Often in our clinic, PPPD patients have a palpable relief upon hearing that their symptoms were not imagined and instead identical to the diagnostic criteria. In fact, verification and explanation of their condition is a step towards treatment., While there is a significant lack of PPPD awareness among the Primary Care providers, it is good to note that vestibular sedatives were not prescribed rampantly which has no role in PPPD. Instead, treatment of PPPD should be individualized treatment involving VRT, CBT or medications such as SSRI if indicated.,,,,
Successful diagnosis and treatment depend on clinician awareness. Creating clinician awareness in PPPD or any disease is a multi-prong process. The eye cannot see what the mind does not know states the obvious importance of education. Vestibular medicine is a growing important field and should be incorporated in the medical school syllabus. We recommend following up with certified continuing medical education (CME) in all medical fields that may encounter patients with chronic dizziness to be updated with the latest development. Clinical peer consultation is also encouraged where it is possible and this is made easier with technology enabling consultation over the internet thus bringing down geographical barriers between the clinician and the subject matter experts. Instead of the classical teaching model of supervision, peer consultation is a model where here colleagues come together to seek support and consultation from each other. Peer consultation would be an ideal strategy as practice maintenance especially when the clinician has already had previous training. Training received should be by recognized boards with systematic courses. There are also online courses and certifications which are recognized internationally such as the International Vestibular Rehabilitation Certificate by the American Institute of Balance or International Online Vestibular Diploma by Audiology-Vestibular Science Academy. Patients are now Internet savvy and come for consultations with some amount of knowledge – although information may be incorrect. Hence, it is important that clinicians are aware and updated on the latest medical information especially those related to their field.
Limitations in this study were in the number of respondents among the general medical field is small compared to the ORL and primary care and may not reflect the true nature of the medical outpatient clinics. The survey was also distributed through a few networks and we were not able to track how many respondents had received it which in turn prevented the calculation of response rates. Another limitation was that we did not study the knowledge of PPPD but instead the awareness and was defined as “Knowing that something exists” and in no way reflects the clinician's knowledge of PPPD. At the current stage, seeing that the number of respondents who have heard of PPPD was so low, we anticipate that the knowledge scores would have also been low. We suggest once the PPPD information has been substantially disseminated and communicated, future studies can be conducted to include validated questionnaires to assess the knowledge of PPPD.
| Conclusion|| |
PPPD is a chronic functional vestibular disorder where effective treatment is dependent on the clinician's awareness. PPPD awareness is still lacking among our providers and the current practices reflect that the management of chronic dizziness is focused on ruling out systemic causes. Now is the time to invest in health communication strategies to improve the awareness and knowledge of managing chronic dizziness, especially PPPD.
We would like to thank Mrs. Izzah Syazwani Binti Ahmad for her guidance in the statistical analysis of this study.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
| References|| |
Staab JP, Eckhardt-Henn A, Horii A, Jacob R, Strupp M, Brandt T, et al.
Diagnostic criteria for persistent postural-perceptual dizziness (PPPD): Consensus document of the committee for the Classification of Vestibular Disorders of the Bárány Society. J Vestib Res 2017;27:191-208.
Staab JP, Ruckenstein MJ. Expanding the differential diagnosis of chronic dizziness. Arch Otolaryngol Head Neck Surg 2007;133:170-6.
Dieterich M, Staab JP. Functional dizziness: From phobic postural vertigo and chronic subjective dizziness to persistent postural-perceptual dizziness. Curr Opin Neurol 2017;30:107-13.
Popkirov S, Staab JP, Stone J. Persistent postural-perceptual dizziness (PPPD): A common, characteristic and treatable cause of chronic dizziness. Pract Neurol 2018;18:5-13.
Holle D, Schulte-Steinberg B, Wurthmann S, Naegel S, Ayzenberg I, Diener HC, et al
. Persistent postural-perceptual dizziness: A matter of higher, central dysfunction? PLoS One 2015;10:e0142468.
Powell G, Derry-Sumner H, Rajenderkumar D, Rushton SK, Sumner P. Persistent postural perceptual dizziness is on a spectrum in the general population. Neurology 2020;94:e1929-38.
Sezier AE, Saywell N, Terry G, Taylor D, Kayes N. Working-age adults' perspectives on living with persistent postural-perceptual dizziness: A qualitative exploratory study. BMJ Open 2019;9:e024326.
Dieterich M, Staab JP, Brandt T. Functional (psychogenic) dizziness. Handb Clin Neurol. Elsevier (Amsterdam) 2016;139:447-68. doi: 10.1016/B978-0-12-801772-2.00037-0. PMID: 27719862.
Huber J, Flanagin VL, Popp P, Zu Eulenburg P, Dieterich M. Network changes in patients with phobic postural vertigo. Brain Behav 2020;10:e01622.
Indovina I, Riccelli R, Chiarella G, Petrolo C, Augimeri A, Giofrè L, et al.
Role of the insula and vestibular system in patients with chronic subjective dizziness: An fMRI study using sound-evoked vestibular stimulation. Front Behav Neurosci 2015;9:334.
Popkirov S, Stone J, Holle-Lee D. Treatment of persistent postural-perceptual dizziness (PPPD) and related disorders. Curr Treat Options Neurol 2018;20:50.
Benecke H, Agus S, Kuessner D, Goodall G, Strupp M. The burden and impact of vertigo: Findings from the REVERT Patient Registry. Front Neurol 2013;4:136.
Sivasampu S, Wahab YF, Ong SM, Ismail SA, Goh PP, Jeyaindran S. National Medical Care Statistics Primary Care 2014. National Healthcare Statistics Initiative. Ministry of Health Malaysia; January, 2016.
Zühlke LJ, Engel ME. The importance of awareness and education in prevention and control of RHD. Glob Heart 2013;8:235-9.
Parker IG, Hartel G, Paratz J, Choy NL, Rahmann A. A systematic review of the reported proportions of diagnoses for dizziness and vertigo. Otol Neurotol 2019;40:6-15.
Male AJ, Ramdharry GM, Grant R, Davies RA, Beith ID. A survey of current management of Benign Paroxysmal Positional Vertigo (BPPV) by physiotherapists' interested in vestibular rehabilitation in the UK. Physiotherapy 2019;105:307-14.
Ahmad BA, Khairatul K, Farnaza A. An assessment of patient waiting and consultation time in a primary healthcare clinic. Malays Fam Physician 2017;12:14-21.
Muncie HL, Sirmans SM, James E. Dizziness: Approach to evaluation and management. Am Fam Physician 2017;95:154-62.
Gan GL. Dizziness update: A new approach and treatment based on timing and triggers. Arch Gen Intern Med 2018;2:17-22.
Hotson JR, Baloh RW. Acute vestibular syndrome. N Engl J Med 1998;339:680-5.
Choi JH, Oh EH, Park MG, Baik SK, Cho HJ, Choi SY, et al.
Early MRI-negative posterior circulation stroke presenting as acute dizziness. J Neurol 2018;265:2993-3000.
Bronstein AM, Lempert T, Seemungal BM. Chronic dizziness: A practical approach. Pract Neurol 2010;10:129-39.
Lempert T, Olesen J, Furman J, Waterston J, Seemungal B, Carey J, et al.
Vestibular migraine: Diagnostic criteria. J Vestib Res 2012;22:167-72.
Lopez-Escamez JA, Carey J, Chung WH, Goebel JA, Magnusson M, Mandalà M, et al.
Diagnostic criteria for Menière's disease. J Vestib Res 2015;25:1-7.
Fetter M. Assessing vestibular function: Which tests, when? J Neurol 2000;247:335-42.
Fife TD, Tusa RJ, Furman JM, Zee DS, Frohman E, Baloh RW, et al.
Assessment: Vestibular testing techniques in adults and children: Report of the Therapeutics and Technology Assessment Subcommittee of the American Academy of Neurology. Neurology 2000;55:1431-41.
Wuyts FL, Furman J, Vanspauwen R, Van de Heyning P. Vestibular function testing. Curr Opin Neurol 2007;20:19-24.
Yu YC, Xue H, Zhang YX, Zhou J. Cognitive behavior therapy as augmentation for sertraline in treating patients with persistent postural-perceptual dizziness. Biomed Res Int 2018;2018:8518631.
Bittar RS, Lins EM. Clinical characteristics of patients with persistent postural-perceptual dizziness. Braz J Otorhinolaryngol 2015;81:276-82.
Waltman SH, Frankel SA, Williston MA. Improving clinician self-awareness and increasing accurate representation of clinical competencies. Pract Innov 2016;1:178-88.
Trevethan R. Deconstructing and assessing knowledge and awareness in public health research. Front Public Health 2017;5:194.
[Table 1], [Table 2], [Table 3], [Table 4], [Table 5], [Table 6], [Table 7]