The VERTIGO RECORDING GOGGLES are a unique system designed to allow a patient the opportunity to use their smart phone in a setting remote from a clinical environment to record their eye movements during an attack of disequilibrium or vertigo. This important data, if collected properly, may allow a physician to better identify why the patient has these episodes of “dizziness”. Video recordings from the goggles may be uploaded to the DizzyDoctor website where additional data about eye tracking and head position stability can be presented along with the sequence of video recordings. The DizzyDoctor system provides a unique opportunity for the patient and physician to view the data and hopefully come to a quicker diagnosis and more focused plan of care.
The goggles were designed by Dr. Ian Purcell after decades of working with vertigo patients. The most difficult component to managing a “dizzy” patient was seeing the patient during a vertiginous event. As Dr. Purcell was only located in San Diego, California, he had limited access to patients outside of the area. Most of his patients continually had brief or prolonged episodes of vertigo away from the clinic and were often symptom free or normal at the time they presented for evaluation in the clinic. This prolonged and confused an accurate diagnostic process. For years, Dr. Purcell and his Otolaryngology (ENT) colleagues discussed the need for remote diagnosis access for their patients. After eight years of research and design, the VRG unit was created.
“This is very exciting for the world of ENT and Neurology because now we can actually
collect important video oculography data on patients when they are briefly symptomatic
and inaccessible to the clinic. Now we can accurately and systematically look at some
of their data and better decide whether their attacks of ‘dizziness’ were from BPPV,
Meniere’s disease, migraine, or some cardiogenic/cardiovascular cause. The best part
is the patient can utilize their smart phone, which is something everyone has access to”.
- Ian Purcell, M.D., Ph.D.
The goggles are designed to be an inexpensive, high-tech way to utilize a readily available smart phone to obtain accurate eye movement recordings at the time a patient is dizzy. The goggle unit has a LED illumination system as well as special focusing lenses to obtain a high resolution video recording of the patient’s eye. The DizzyDoctor App uses the iPhone's internal gyroscope and verbal commands to accurately direct the patient to the proper head positions in three-dimensional space before they are allowed to record their eye movements. The DizzyDoctor App also uses the iPhone’s 6 axis gyroscope to collect head movement data during the recording session to verify the patient’s head was held relatively still while saving eye movement data. This is very important because normal rhythmic eye movements and vestibular ocular reflexes that are generated when the patient moves their head may accidently be interpreted as abnormal if this data set was not also presented to the interpreting physician.
The patient is often given the VRG unit by their physician and told to download the DizzyDoctor application onto their iPhone. At the time they are experiencing a “dizzy” attack, they may clip their iPhone into the goggle unit and begin recording their data. “The nice thing is the patient can be traveling in Paris, France and obtain a video recording data set below the Eiffel tower on a park bench if needed” says Dr. Purcell.
To find out more about the DizzyDoctor System or the Vertigo Recording Goggles, click on the following link:
There is growing evidence that the etiology of acute vertiginous syndrome is often misdiagnosed(9-13) in many patients and that many clinicians are seeking better guidelines to aid them in their diagnosis(14-15). A common trend in differentiating between all of these disorders is the evaluation of eye movements or patterns of nystagmus. Nystagmus is defined as the repetitive and rhythmic oscillation of the eyes and can be vertical, horizontal, torsional, oblique, or any combination of these movements(28). Research has shown that stimulatory testing such as the Dix-Hallpike positional test is crucial in the evaluation of dizziness because it can reproduce the patient’s symptoms and elicit nystagmus patterns necessary for diagnosis(16-17). Other tests utilized at the bedside in a clinical setting include the head impulse test, ocular tilt reaction (including head tile, ocular torsion, and skew deviation), and tests of balance function(6).
In an emergency department setting, further imaging studies may be ordered to rule out stroke. However, there are multiple factors and studies that suggest bedside examination is superior to brain imaging in determining the diagnosis of an acute episode of vertigo(6). A study by Chalela et al. suggests the sensitivity of computed tomography scans in identifying stroke is as low as 26%(18). A second study estimated the sensitivity of CT scans for acute infarction of the posterior fossa to be even lower at 16%(24). While magnetic resonance imaging is more sensitive that computed tomography, sensitivity is lowest within 24 hours of onset (the most crucial clinical time period)(6). Sensitivity may even be lower in MR imaging for lesions involving the brainstem or cerebellum(18-20). Within the first 48 hours of symptom onset, initial diffusion-weighted MR imaging may reveal false negative results(19,20,25) in 12-20% of stroke patients(21-22). Results such as these can be detrimental to a patient and even fatal in some cases. It is important for a physician to also rely on the physical and bedside examination for his/her diagnosis.
One of the main examination findings a clinician will be evaluating for during his/her physical examination is nystagmus. Both positional and spontaneous nystagmus patterns are informative clues to the patient’s diagnosis(23). When looking at spontaneous nystagmus, it is important to evaluate the direction and effect of gaze on the intensity or direction of the nystagmus(6). In other cases, gaze-evoked nystagmus (GEN), or nystagmus that is developed when the eyes are in the most eccentric positions, may also be evaluated(6). Bedside maneuvers can induce nystagmus or modulate pre-existing spontaneous nystagmus(6), which is essential in revealing any underlying vestibular dysfunction(26-27). The Dix-Hallpike maneuver, utilized in the DizzyDoctor System, is one such bedside maneuver that allows for the evaluation of nystagmus patterns.
Each vestibular disorder may display a unique set of nystagmus patterns. The recognition of these types of nystagmus patterns is crucial to obtain the correct diagnosis of the patient’s vertigo/dizziness. The DizzyDoctor System will allow a vertiginous or dizzy patient to obtain recordings of their eye movements during a vertiginous event, remote from a clinical environment. These recordings may later be analyzing by a licensed physician to determine a proper diagnosis. By allowing the patient to obtain a recording while they are symptomatic, the DizzyDoctor System catches and records the nystagmus patterns while they are most prominent or severe. While the DizzyDoctor System was primarily designed for the diagnosis of BPPV, an accurate and well-versed knowledge of the different nystagmus patterns commonly seen in peripheral or central vestibulopathies may further aid a clinician’s diagnostic process.
Benign paroxysmal positional vertigo (BPPV) is a common vestibular disorder caused by dislodged otoconia or otoliths in the semicircular canals of the inner ear. Otoconia are microscopic calcium carbonate particles that originate from the macule of the utricle(40). They are normally attached to strategically placed hair cell sensors in the maculae and they deflect those hair cells towards gravity in a linear fashion. Occasionally, these otoliths or “crystals” become dislodged by either idiopathic or disease processes and can migrate into the semicircular canals of the labyrinth. Gravitational movements of these otoconia within the semicircular canals cause positional related vertigo and other associated symptoms of nausea, vomiting, pallor, and sweating(40). During the episode of vertigo, there is often an objectively observed pathological eye movement called nystagmus(40). Certain nystagmus patterns are indicative of the otolith debris in different areas of the semicircular canals.
During the Dix-Hallpike positional maneuvers, the DizzyDoctor System allows for accurate oculography recordings of nystagmus. There are many published studies detailing the different types of nystagmus patterns that may present depending on which semicircular canal is affected. 60-90% of all BPPV cases are caused by loose otoliths within a posterior semicircular canal(39), making it the most common form of BPPV(6). Other studies report posterior semicircular canal BPPV occurring in as many as 85-95% of cases(38). According to the clinical practice guidelines set by Bhattacharyya et al., diagnosis of posterior semicircular canal BPPV is made when a patient 1) reports symptoms of vertigo provoked by changes in head position relative to gravity and 2) when, on physical examination, characteristic nystagmus is provoked by the Dix-Hallpike maneuver(30). In posterior canal BPPV (PC-BPPV), an upbeating and ipsiversive torsional nystagmus (top poles of the eye beating toward the downward ear) should be evoked(36,37). This is a result of the otolith debris and endolymph flowing away from the cupula, therefore deflecting the cupula in an excitatory ampullofugal direction(6). When the patient sits up from the Dix-Hallpike supine position, the direction of the nystagmus will be reversed; leading to a compensatory downbeat and contraversive torsional nystagmus(6).
The DizzyDoctor System obtains eye movement recordings in both the supine and recumbent sitting position in order to assess both positional and compensatory nystagmus patterns. It is a unique system that allows a symptomatic patient to obtain eye movement data away from a clinical environment. BPPV episodes are brief, lasting only seconds, and brought on by head movements(38,40). Because BPPV episodes are so short-lived and usually occur without warning, it is often difficulty for physicians to obtain a diagnosis for their patients. By the time the patient presents to the emergency department or clinic for evaluation, their symptoms may have resolved or nystagmus may not be present during the Dix-Hallpike maneuver due to repositioning of the loose otoliths over time. Therefore, it is useful for the patient to obtain eye movement recordings in the Dix-Hallpike positions as soon as they experience a vertiginous event. The DizzyDoctor System allows for a patient to obtain these recordings in any location. The patient may subsequently present their data to the clinician to aid in a more efficient and accurate diagnosis.
6. Jung, Ileok, and Ji-Soo Kim. "Approach to dizziness in the emergency department." Clinical and Experimental Emergency Medicine 2.2 (2015): 75-88.
9. Kerber KA, Brown DL, Lisabeth LD, et al. Stroke among patients with dizziness, vertigo, and imbalance in the emergency department: a population-based study. Stroke 2006;37:2484-
10. Savitz SI, Caplan LR, Edlow JA. Pitfalls in the diagnosis of cerebellar infarction. Acad Emerg Med 2007;14:63-8.
11. Newman-Toker DE, Robinson KA, Edlow JA. Frontline misdiagnosis of cerebrovascular events in the era of modern neuro -imaging: a systematic review [abstract]. Abstracts of the 133rd Annual Meeting of the American Neurological Association. Ann Neurol 2008;64(Suppl 12):S17-8.
12. Newman-Toker DE, Camargo CA Jr, Hsieh YH, et al. Disconnect between charted vestibular diagnoses and emergency department management decisions: a cross-sectional analysis from a nationally representative sample. Acad Emerg Med 2009; 16:970-7.
13. Kim AS, Fullerton HJ, Johnston SC. Risk of vascular events in emergency department patients discharged home with diagnosis of dizziness or vertigo. Ann Emerg Med. 2011;57:34-41.
14. Stanton VA, Hsieh YH, Camargo CA Jr, et al. Overreliance on symptom quality in diagnosing dizziness: results of a multicenter survey of emergency physicians. Mayo Clin Proc 2007; 82: 1319-28.
15. Eagles D, Stiell IG, Clement CM, et al. International survey of emergency physicians’ priorities for clinical decision rules. Acad Emerg Med 2008;15:177-82.
16. Newman-Toker DE, Camargo CA Jr. “Cardiogenic vertigo” — true vertigo as the presenting manifestation of primary cardiac-disease. Nat Clin Pract Neurol 2006;2:167-72.
17. Baloh RW. Dizziness: neurological emergencies. Neurol Clin 1998;16:305-21.
18. Chalela JA, Kidwell CS, Nentwich LM, et al. Magnetic resonance imaging and computed tomography in emergency assessment of patients with suspected acute stroke: a prospective comparison. Lancet 2007;369:293-8.
19. Newman-Toker DE, Kattah JC, Alvernia JE, Wang DZ. Normal head impulse test differentiates acute cerebellar strokes from vestibular neuritis. Neurology 2008;70:2378-85.
20. Oppenheim C, Stanescu R, Dormont D, et al. False-negative diffusion-weighted MR findings in acute ischemic stroke. AJNR Am J Neuroradiol 2000;21:1434-40.
21. Kattah JC, Talkad AV, Wang DZ, Hsieh YH, Newman-Toker DE. HINTS to diagnose stroke in the acute vestibular syndrome: three-step bedside oculomotor examination more sensitive than early MRI diffusion-weighted imaging. Stroke 2009;40: 3504-10.
22.Tarnutzer AA, Berkowitz AL, Robinson KA, Hsieh YH, Newman-Toker DE. Does my dizzy patient have a stroke? A systematic review of bedside diagnosis in acute vestibular syndrome. CMAJ 2011;183:E571-92.
23. Serra A, Leigh RJ. Diagnostic value of nystagmus: spontaneous and induced ocular oscillations. J Neurol Neurosurg Psychiatry 2002;73:615-8.
24. Edlow JA, Newman-Toker DE, Savitz SI. Diagnosis and initial management of cerebellar infarction. Lancet Neurol. 2008;7:951–964.
26. Huh YE, Kim JS. Bedside evaluation of dizzy patients. J Clin Neurol 2013;9:203-13.
27.Choi KD, Oh SY, Kim HJ, Koo JW, Cho BM, Kim JS. Recovery of vestibular imbalances after vestibular neuritis. Laryngoscope 2007;117:1307-12.
30. Bhattacharyya, MD, Neil, Reginald F. Baugh, MD, Laura Orvidas, MD, David Barrs, MD, Leo J. Bronston, DC, MAppSc, Stephen Cass, MD, MPH, Ara A. Chalian, MD, Alan L. Desmond, AuD, Jerry M. Earll, MD, Terry D. Fife, MD, Drew C. Fuller, MD, MPH, James O. Judge, MD, Nancy R. Mann, MD, Richard M. Rosenfeld, MD, MPH, Linda T. Schuring, MSN, RN, Robert W. P. Steiner, MD. PhD, Susan L. Whitney, PhD, and Jenissa Haidari, MPH. "Clinical practice guideline: Benign paroxysmal positional vertigo." Otolaryngology-Head and Neck Surgery 139 (2008): 47-81.
36. Cambi J, Astore S, Mandala M, Trabalzini F, Nuti D. Natural course of positional down-beating nystagmus of peripheral origin. J Neurol 2013;260:1489-96.
37. Kim JS, Zee DS. Clinical practice. Benign paroxysmal positional vertigo. N Engl J Med 2014;370:1138-47.
38. Chan, Yvonne. "Differential diagnosis of dizziness." Current Opinion in Otolaryngology & Head and Neck Surgery 17 (2009): 200-03.
39. Froehling DA, Silverstein MD, Mohr DN, Beatty CW, Offord KP, Ballard DJ. Benign positional vertigo: incidence and prognosis in a population-based study in Olmsted County, Minnesota. Mayo Clin Proc. 1991;66:596-601
40. Fife MD, Terry D. "Benign paroxysmal positional vertigo." Seminars in Neurology 27.5 (2009): 500-08.
HOW IT WORKS
The Vertigo Recording Goggles (VRG) are a non-invasive, portable battery operated, miniaturized remote diagnostic system for home use or remote from clinic use. The unit connects to the user's personal smartphone and uses the smartphone's camera to record eye movements while the smartphone's internal gyroscope tracks and records the user’s relative head position and head movement in three-dimensional space. The camera and gyroscope are controlled by the DizzyDoctor App, which utilizes voice commands to guide the user through a pre-programmed series of head movement routines performed in standard well-known nystagmus analysis, e.g. Dix-Hallpike test or Supine Positional test. All raw data gathered by the App can be directly viewed on the user’s smart phone and is also simultaneously uploaded to the DizzyDoctor website for processing and viewing at a later date. In either case, the data may be reshown to the user’s physician or healthcare practitioner for analysis and interpretation. The Physician or Health Care Practitioner can log into their “Physician Portal” on the DizzyDoctor website and may view and analyze their patient's eye movements there.
First you must sign up and create a patient account on the DizzyDoctor website or DizzyDoctor iPhone App. The iPhone App can be downloaded from the Apple App Store.
During an episode of dizziness or vertigo, attach your iPhone to the Vertigo Recording Goggles and begin a Step-by-Step recording. The DizzyDoctor iPhone Application will then verbally instruct you through the Dix-Hallpike testing positions. A picture diagram will also be available to help guide you through each position. You may also obtain an Instant recording, which will recording 10 seconds of eye movement data in any position.
*PLEASE NOTE* For safety reasons, all testing is to be performed with the assistance of a family member or friend
The following pictures depict the proper Dix-Hallpike Positions:
THE RECORDING PROCESS
1. Neutral Starting Position
2. Dix-Hallpike Supine Right
3. Neutral Sitting Position #1
4. Dix-Hallpike Supine Left
5. Neutral Sitting Position #1
Advanced testing can be performed to include supine positional testing as pictured below:
6. Supine Head Center
7. Supine Head Right
8. Supine Head Left
REVIEWING YOUR VIDEOS
Once you have completed a video recording session, you may review your videos in the iPhone App or on the DizzyDoctor website through your patient portal account. In the DizzyDoctor iPhone App, you can first view the raw footage of your eye movements to ensure that a good recording was obtained. Once satisfied with your recordings, it can then be processed for a small fee.
Processed videos use state-of-the-art eye tracking technology to produce nystagmograph data (depicted below). Not only are eye movements being tracked, but head position is also recording and depicted graphically for physician interpretation. Processed video's provide your Physician with valuable information that can aid them in their diagnostic process. To learn more about the types of nystagmus pattern that may be seen in an eye movement recording, visit the BPPV Education Page. Once processed, your eye movement recordings can be reviewed by your Physician at your next follow up appointment.