Scientific Study

Current Research

VeDA partners with the Journal of Vestibular Research and Barany Society to keep you up-to-date on the latest research in vestibular medicine.

Science Leads to Answers

Want to keep up-to-date on current research into the diagnosis and treatment of vestibular disorders? Search the National Institutes of Health Library of Medicine database. 

Following are summaries of select research papers.

*VeDA partners with the Journal of Vestibular Research to give a platform to the latest developments in vestibular research.Journal of Vestibular Research

Dizziness in Patients with Cognitive Impairment

This paper attempted to determine the effect of dizziness on cognitive function. The paper made the assumption that cognitive decline correlates to the increased perception of dizziness. The result was that cognitive decline could exist without dizziness, but the presence of dizziness increased the cognitive impairment if they coexisted in the same person. The study also confirmed that postural instability is an important determinant of dizziness. This is not a new thought, as patients will often use the word “dizzy” when referring to postural stability.

Source: Lee, Ho-Won, Lim, Yong-Hyun, and Kim, Sung-Hee. ‘Dizziness in Patients with Cognitive Impairment’. 1 Jan. 2020 : 17 – 23.

Summary written by Dr. Dennis Fitzgerald

Characteristics of Assessment and Treatment in Benign Paroxysmal Positional Vertigo (BPPV)

This article explains the results of a study performed in a physiotherapy clinic in Australia intended to explore the incidence of BPPV and its varied forms of presentation, evaluation and treatment. The observational study included 314 patients with BPPV, specifically involving the posterior semicircular canal (PC) or horizontal semicircular canal (HC). The diagnostic maneuvers used were the Dix-Hallpike (DHP) and the Supine roll test (SRT) respectively.

In a significant majority of the patients it took one or two canalith repositioning maneuvers (CRMs) to effectively treat PC BPPV (91%), and HC BPPV (88%). More than two CRMs were required to effectively treat patients with bilateral PC BPPV, multiple canal involvement, or canal conversions.

Patients who had nystagmus and vertiginous symptoms during the Epley Maneuver (EM) and those who did not have nystagmus and vertiginous symptoms during the EM had similar treatment outcomes. Of note, 19% of patients experienced down-beating nystagmus (DBN) and vertigo after the first or even the second EM.

As a result of this observational study of 314 patients, three arguments were put forth:

  • Firstly, it was posited that repeatedly testing and treating for BPPV within the same clinic session can be considered safe and effective, and need not increase the risk for canal conversion.
  • Secondly, the presence of vertigo and nystagmus throughout the EM need not necessarily be indicative of successful treatment.
  • Thirdly, the risk of an otolithic crisis following CRM is not lessened and therefore clinicians need to be ever mindful of the risk of falls, and prepared to prevent the occurrence of falls in patients especially immediately following CRM.

Other protocols followed during this observational study include the adherence to the clinical practice guidelines for BPPV. Therefore, patients were not given post-treatment precautions.

The financial and personal time benefits to the patient and the public are considerable with the implementation of repeated CRMs within the same session. An additional benefit of this practice is that the efficacy of the treatment is known within the same session. The benefits and advantages of repeated CRMs over consecutive sessions is greater than supposed risks.

Source: Power, Laura, Murray, Katherine, and Szmulewicz, David J. ‘Characteristics of Assessment and Treatment in Benign Paroxysmal Positional Vertigo (BPPV)’. 1 Jan. 2020 : 55 – 62.

Summary prepared by: Mona Fazzina, PT, DPT, Certificate in Vestibular Rehabilitation, 2020, Board Certified Clinical Specialist in Geriatric Physical Therapy (GCS),  Certified Exercise Expert for Aging Adults (CEEAA)

Effects of long-term vestibular rehabilitation with vibrotactile sensory augmentation for people with unilateral vestibular disorders

Coordination of the body involves the prioritizing of sensory systems depending on the movement the person is doing. The brain needs vision, touch, joint movement, inner ear (vestibular) information, sound (and sometimes smell) to control the body smoothly. When someone has a vestibular disorder, the brain’s ability to prioritize the senses is affected, and it is not able to use the inner ear/vestibular input effectively. The purpose of vestibular rehabilitation is to help the brain to re-learn how to prioritize the sensory systems, and compensate for any loses.This study indicated that vibration stimulation on the lower back may enhance traditional vestibular rehabilitation, encouraging the body to reorganize which sensory systems it uses at what time.This study included a group of eight people with vestibular disorders on one side of the body (unilateral). A neurologist evaluated and diagnosed them. They all performed vestibular rehabilitation balance training for six weeks. The treatment for one group (the experimental group) also included sensory stimulation involving a customized, vibrating device attached to their lower back with a belt. The sensors in the device detected when the person was shifting his/her torso and provided the vibration then. A physical therapist who did not know which participants received the sensory stimulation performed several tests to determine whether the vibrational sensory stimulation was making a difference.The results were measured with body sway, standing dynamic gait tests, and surveys specific to vestibular disorders. They were tested one month and six months after the treatment had ended as well.All participant improved, but the group with the sensory stimulation performed better. Furthermore, they maintained their abilities six months after the treatment had ended.This study is encouraging because it may enable people suffering from unilateral vestibular disorders to make further and or more complete recovery. There are other types of sensory stimulation that may be used to improve vestibular rehabilitation, namely auditory, visual, and electro-tactile combinations. They will need to be tested in future studies.

Source: Bao, Tian et al. Journal of Vestibular Research, vol. 29, no. 6, pp. 323-334, 2019. DOI: 10.3233/VES-190683Summary written by Jennifer A. Robbins, MPT

Estimating loss of canal function in the video head impulse test (vHIT)

Historically, the caloric test has been the most common clinical method for evaluating vestibular function. The caloric test has a number of limitations and sometimes causes unpleasant symptoms for patients suffering from dizziness.

In the past 10 years or so the video head impulse test (vHIT) has gained popularity for evaluating vestibular abnormalities. vHIT can test parts of the vestibular system, namely the vertical semicircular canals, that are not tested in the caloric test. So far, vHIT is not considered a replacement for the caloric test, and in most clinics the two tests are used in conjunction with each other for a broader evaluation of the vestibular pathway. In a somewhat oversimplified analogy with the hearing evaluation, one can describe the caloric test and vHIT as testing two different sound frequencies in the audiogram.

Unlike with the caloric test, the extent of semicircular canal dysfunction was not readily available from vHIT. This paper uses a computer simulation of the vestibular pathways to determine a simple formula that can relate the loss of canal function to the measured parameters of vHIT. This can also help in clarifying the relationship between vHIT and other vestibular tests, including the caloric test.

Source:  Barin, Kamran, Journal: Journal of Vestibular Research, vol. 29, no. 6, pp. 295-307, 2019. DOI: 10.3233/VES-190688

Third Window Syndrome: Surgical Management of Cochlea-Facial Nerve Dehiscence

Ninety years ago, Tullio described the physiologic outcomes of creating a third mobile window in the semicircular canals of pigeons. Since that time, many locations of third mobile windows have been described; however, the sound-induced dizziness and/or nystagmus has been memorialized by the eponym ‘Tullio phenomenon.’ Clinically, the most thoroughly characterized third mobile window is superior semicircular canal dehiscence (SSCD). Over the years, many other sites of a mobile third window have been reported (15 to date). They all produce, to varying degrees, the spectrum of symptoms and findings seen in third window syndrome (TWS).

This communication is the first assessment of outcomes after surgical repair of cochlea-facial nerve dehiscence (CFD) in a series of patients. Pre- and postoperative quantitative measurement of validated survey instruments, symptoms, diagnostic findings and anonymous video descriptions of symptoms in a cohort of 16 patients with CFD and TWS symptoms were systematically studied.

Overall there was a marked and clinically significant improvement in Dizziness Handicap Inventory (DHI), Headache Impact Test (HIT-6) and TWS symptoms postoperatively for the CFD cohort who had round window reinforcement (RWR) surgery. A statistically significant reduction in cVEMP thresholds was observed in patients with radiographic evidence of CFD. Surgical management with RWR in patients with CFD was associated with improved symptoms and outcomes measures. There was no statistically significant change of hearing in the patients with CFD who underwent RWR. It was emphasized that radiographic CFD is not in itself an indication for surgery and that the most important factor in decision-making should be in the context of clinical symptoms and other diagnostic findings. There are 3 important presenting symptoms and physical findings that are critical when identifying a TWS, including CFD: 1) sound-induced dizziness; 2) hearing internal sounds; and 3) hearing or feeling low frequency tuning forks in an involved ear when applied to a patient’s knee or elbow. Another important observation in the study was that multiple sites of dehiscence in temporal bones with TWS occur and this finding is important to consider when faced with recurrent or incompletely resolved TWS symptoms after plugging a SSCD.

Source: Wackym, P. Ashley, et. al. Front. Neurol., 13 December 2019

Adult neurogenesis promotes balance recovery after vestibular loss

When the vestibule in our inner ear is damaged, information about the position or movement of our body in space is altered or missing. This situation is serious since our brain can no longer provide the motor responses necessary to maintain our balance. The major risk is of course the fall. To prevent this, our brain has an extraordinary ability to adapt called “vestibular compensation”. This fascinating neurobiological process allows our brain to use information from other sensory sensors, such as those of vision or posture, to detect the movements of our body in its environment. To achieve this, it is necessary to reshape our brain connectivity, a bit like old telephone terminals. This is a complex process that involves a mosaic of structural rearrangements, among which the birth of new neurons plays a central role. In the review published in Progress in Neurobiology, we describe how the adult brain produces new neurons to restore balance after vestibular loss. This discovery can be considered as the best example so far of causal reparative role of adult neurogenesis.
Authors: Christian Chabbert & Brahim Tighilet
Source: Progress in Neurobiology, 2019