As health care providers we like to say that we provide evidence based treatment, but what is the evidence for the treatment we provide? What is the evidence for the vestibular therapy we provide? Specifically, how about the treatment we provide for vestibular hypofunction?
With being a busy clinician it can be a bit daunting trying to keep up with the latest research. Then, if we try to keep up with research we also have to realize that for every good piece of research there is research that is, well, not so good. So, how do we filter out the clinically relevant and strong evidence based research?
Fortunately, from time to time clinical practice guidelines come out and provide direction. Over the past few years there have been clinical practice guidelines for common conditions like BPPV and sports related concussion. The Barany Institute has also provided some great resources in the field of vestibular therapy.
Vestibular Hypofunction Clinical Practice Guidelines
Recently, associates from Key Clinical Skills forwarded me a copy of the Vestibular Rehabilitation For Peripheral Hypofunction: An Updated Clinical Practice Guideline (Dec 2021). This is exactly what I had been looking for as I often wonder if my treatment approach is up to date with the best evidence out there.
When you first look at the guidelines though it can be a, “Oh dear when will I have time to get through this document?” moment. This, like the other resources outlined above, though, are great resources that are well worth the time to go through.
Although it is recommended to read through the entire article, below is a summary for quick reference.
What Is Peripheral Vestibular Hypofunction?
According to the guidelines, a unilateral vestibular hypofunction (UVH) is a partial or complete loss of function of one of the peripheral vestibular sensory organs and/or vestibular nerves. Acute UVH is most commonly due to a vestibular neuritis, but may also be due to:
- Surgical transection,
- Ototoxic medication,
- Meniere’s Disease,
- Or other lesion of the vestibulocohlear nerve or labyrinth.
Spontaneous rebalancing of the resting firing rate of the tonic vestibular system results in reduction of the nystagmus and symptoms usually within 14 days. Now this does not mean that patients will be fully recovered in 14 days. Rather they will be feeling a lot better when not moving within the first 14 days.
Bilateral vestibular hypofunction (BVH) , on the other hand, is a partial or complete loss of function of both peripheral vestibular sensory organs and/or vestibular nerves. Causes for BVH include, but are not limited to:
- Ototoxic medication,
- Bilateral Meniere’s Disease,
- Neurodegenerative disorders,
- Infectious disease,
- Autoimmune diease,
- Genetic abnormalities,
- Vascular disease,
- And congenital causes.
Worth noting is that 20-51% of the time the cause is unknown.
What Was The Diagnostic Criteria For A Peripheral Vestibular Loss?
With the guidelines, a peripheral vestibular loss in the research reviewed was determined by laboratory testing of calorics, rotary chair, or video head impulse testing (vHIT). While clinically, we may not have these tests accessible there are several bedside clinical tests that used together can help rule in a vestibular hypofunction. These tests include looking for spontaneous & gaze evoked nystagmus, using the head shaking nystagmus test, head thrust test (aka head impulse test), and static vs dynamic visual acuity testing.
Defining Acute, Subacute & Chronic
For the sake of these guidelines:
Acute refers to the first 2 weeks after the onset of symptoms.
Subacute refers to after the acute stage to 3 months following the onset of symptoms.
Chronic refers to symptoms persisting past 3 months.
How to Interpret the Strength of a Recommendation?
When reading through the guidelines there are two main things to consider. One is the recommendation itself and the other, the strength of the recommendation. The following tables will help you determine the strength of the recommendations.
|GRADE||RECOMMENDATION||STRENGTH OF EVIDENCE|
|A||Strong evidence||A preponderance of level I and/or level II studies support the recommendation. This must include at least 1 level I study directly on the topic that supports the recommendation. Recommendation obligation: “should” or “should not.”|
|B||Moderate evidence||A single high-quality randomized controlled study or a preponderance of level II studies support the recommendation. Recommendation obligation: “may” or “may not.”|
|C||Weak evidence||A single level II study or the preponderance of level III and IV studies support the recommendation. Recommendation obligation: “may” or “may not.”|
|D||Expert opinion||Best practice based on the clinical experience of the guideline development team and guided by evidence, which may be conflicting. Recomendation obligation: “may consider.”|
|LEVEL OF EVIDENCE|
|I||Evidence obtained from high-quality (over 50% critical appraisal score and >80% follow-up, blinding, and appropriate randomization) randomized controlled trials.|
|II||Evidence obtained from high-quality cohort (>80% follow-up) study or lesser quality (<50% critical appraisal score or the study does not meet requirements for high quality) randomized controlled trials.|
|III||Evidence obtained from case-controlled study, lower-quality cohort study, or retrospective study.|
|IV||Evidence obtained from case series|
Summary of the Recommendations
The updated guidelines provide 11 action statements that are really recommendations:
- Clinicians should offer vestibular physical therapy (VPT) to individuals with acute or subacute unilateral vestibular hypofunction – strong evidence.
- Clinicians should offer VPT to individuals with chronic unilateral vestibular hypofunction – strong evidence.
- Clinicians should offer VPT to individuals with bilateral vestibular hypofunction – strong evidence.
- Clinicians should not offer saccadic or smooth pursuit exercises as specific exercises for gaze stability to individuals with unilateral or bilateral vestibular hypofunction – strong evidence.
- Clinicians may provide targeted exercise techniques to accomplish specific goals appropriate to address identified impairments, activity limitations, and participation restrictions – moderate strength.
- Clinicians may prescribe static and dynamic balance exercises: (1) for a minimum of 20 minutes daily for at least 4-6 weeks for individuals with chronic unilateral vestibular hypofunction – weak evidence. May prescribe static and dynamic balance exercises: (2) for individuals with acute/subacute vestibular hypofunction; however, no specific dose recommendations can be made at this time – expert opinion. And, (3) for 6-9 weeks for individuals with bilateral vestibular hypofunction – expert opinion.
- Clinicians may prescribe weekly clinic visits plus a home exercise program of gaze stabilization exercises including at a minimum: (1) 3 times per day for a total of at least 12 minutes daily for individuals with acute /subacute unilateral vestibular hypofunction – weak strength; (2) 3-5 times per day for a total of at least 20 minutes daily for 4-6 weeks for individuals with chronic unilateral vestibular hypofunction – weak strength; and (3) 3-5 times per day for a total of 20-40 minutes daily for approximately 5-7 weeks for individuals with bilateral vestibular hypofunction – weak strength.
- Clinicians should offer supervised vestibular physical therapy in individuals with unilateral or bilateral vestibular hypofunction – strong strength.
- Clinicians may use achievement of primary goals, resolution of symptoms, normalized balance and vestibular function, or plateau in progress as reasons for stopping therapy – moderate strength.
- Clinicians may evaluate factors that could modify rehabilitation outcomes – moderate to strong evidence.
- Clinicians should offer vestibular physical therapy to persons with peripheral vestibular hypofunction with the intention of improving quality of life – strong evidence.
A 4 minute video summary from several of the authors of the guidelines can be found at: https://links.lww.com/JNPT/A369
For further information about the:
- Health care burden of peripheral vestibular hypofunction,
- Aging and vestibular dysfunction,
- The specific research articles that were reviewed.
- The potential to help children who also have sensorineural hearing loss and the use of virtual reality check out the full article.
It is great to have groups such as the Academy of Neurologic Physical Therapy perform a literature review and provide guidelines. Looking through the guidelines we can be reassured of what we are doing well along with things we can tweak a bit to provide even better care.
These guidelines are also great to determine the direction of further research so we can continue to improve our understanding of peripheral vestibular hypofunction and how to best address it.
Looking forward to the update planned for 2026 and appreciate these current guidelines.
Further updates to the guidelines can be found at www.neuropt.org.