Tuesday, September 29, 2020

The Plastic Brain and 20/20/30

Brain imaging results and function do not always correlate with one another.  For instance, I will never forget working with a four year old many years ago.  He did not want to lie down because he was dizzy.  He demonstrated typical BPPV nystagmus, but I knew this was not likely for his age.  His positional vertigo went away in about three to four days.  He went on to have fevers and periods of ataxia that would resolve.  His speech and cognition would sometimes seem sluggish and delayed.  After months of testing, he was found to have a very rare spinal cord and brain tumor that affected his cerebral spinal fluid.  He was eventually diagnosed with a low grade glioma that is classified as a juvenile pilocytic astrocytoma. He had two cystic tumors removed- one from the cerebellum and one from the spine.  

We realized that he was amazing at compensating.  His brain was phenomenally plastic.   Imaging would reveal significant hydrocephalus with his tumors.  However, through our time in trying to figure out what was wrong, his symptoms would improve and he would “return to normal.”  We realized that his brain would compensate.  His tumors and hydrocephalus developed slowly enough that his brain would adapt.

While imaging can sometimes reveal a problem that our body can adapt to hide, sometimes our body can reveal a problem that imaging is not sensitive enough to find.  This occurs with acute brainstem strokes.  When it comes to brainstem strokes, remember 20/20/30.

I had a 45 year old gentleman who had been to the ED because of vertigo.  His CT was normal and he was told he had BPPV and referred to me.  I saw him five days later.  He described his spells as untriggered and lasting 15-30 minutes.  Spells seemed to be about two to three days apart meaning he could go a few days with no dizziness at all.  While he sat in my exam room, he said, “here it comes.”   He proceeded to have an attack of spinning and vomiting.  As I looked in his eyes, I noted direction changing nystagmus.  Since this was central sign and his history was not at all consistent with BPPV, I sent him to the ED where he progressed to have a cerebellar stroke.  He was having TIAs that the CT scans were not sensitive enough to find.  

What occurred to this gentleman was not uncommon.  20% of strokes occur in the cerebellum/brainstem and only have isolated vertigo as symptoms 20% of the time.  As a result, these kinds of strokes are missed about 30% of the time(1).   One major reason is that CT scans have 16% sensitivity (2) and diffusion weighted imaging-magnetic resonance imaging performed within 24 hours from symptom onset miss about 20% of acute posterior fossa infarctions(3).  The good news is that there is an alternative and we can help these individuals find help faster using the HINTS+ battery of  bedside tests.  A positive HINTS+ test exam of a client in Acute Vestibular Syndrome (Head impulse normal bilaterally, central appearing direction changing nystagmus, a skew deviation, and new hearing loss), is reported to suggest central pathology and have 99.9% sensitivity and 97% specificity in detecting posterior circulation infarcts(4).  I will never forget 20/20/30.


  1. Venhovens J, Meulstee J, Verhagen WI. Acute vestibular syndrome: a critical review and diagnostic algorithm concerning the clinical differentiation of peripheral versus central aetiologies in the emergency department. J Neurol. 2016;263(11):2151-2157.
  2. 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(11):3504-3510.
  3. Newman-Toker DE. Missed stroke in acute vertigo and dizziness: It is time for action, not debate. Ann Neurol. 2016;79(1):27-31.
  4. Newman-Toker DE, Kerber KA, Hsieh YH, et al. HINTS outperforms ABCD2 to screen for stroke in acute continuous vertigo and dizziness. Acad Emerg Med. 2013;20(10):986-996.

Sunday, September 6, 2020

Diagnostic Imaging and VNGs in the Dizzy World

I am currently taking a class on diagnostic imaging.  I am going to post my hypothetical response to a patient for our discussion group here, but before I do, I want to underscore the value of a few key elements.  

#1.  When it comes to diagnosing dizziness, I want to emphasize the big three.  When it comes to helping clients figure out why they are dizzy, I always say "The Big Three is Key."  The big three are triggers, timing, and nystagmus.  Add in whether or not hearing loss is present, and we are really moving in the right direction for helping confirm the cause of dizziness.  Never underestimate the value of a high quality thorough history and bedside exam.  Also, if a client is having spells that are not present at the time of the clinical visit, have them video their eyes during an attack!  So much valuable information can be gained by doing so!  

Here is a link to the American College of Radiology's recommendations regarding when to order imaging for people who have sudden onset of dizziness and/or hearing loss.  https://acsearch.acr.org/docs/69488/Narrative/

#2.  "Normal" VNGs completed on individuals who are asymptomatic only provide insight regarding performance of the inner ear and brain at the time the VNG was performed.  Using a cell phone to record eye movements during spells should be encouraged when VNG results do not provide answers regarding why a client is dizzy.  Caution should be exercised before telling clients they have no inner ear or brain problems simply because the VNG was "normal" in the absence of symptoms.

#3.  Abnormal results on MRIs may or may not have meaning.  Please see my hypothetical response below addressed to an individual with low back pain:

You are seeing a 49 yo patient with a 4 week history of low back pain and they are very upset because their physician did not order an MRI.  Outline a potential response to this patient.  Can you imagine a scenario where the patient's frustration is justified?


I understand your concern for wanting an MRI.  However, according to the American College of Radiology guidelines, an MRI is not warranted right now because you have no red flags.  If you had a traumatic onset, a history of spinal surgery, osteoporosis, a history of cancer, suspicion of cancer, infection,  weakness or changes in your bowel/bladder, your Physician would probably be more likely to order an MRI and your frustration would certainly warrant a phone call from myself to your Physician.  These recommendations are based upon studies of thousands of different individuals combined with collaboration of experts with years of experience.  Also, please consider a study done in 2015.  The study was done on 1211 asymptomatic subjects.  87.5% had significant disc bulging, but no symptoms!(1).  Another study on 67 individuals found about ⅓ of asymptomatic individuals to have abnormal findings (2).  These individuals were surveyed over a seven year period and the abnormal findings were unable to predict which individuals would develop pain (3).  What matters most is our clinical findings at this time.   For now, I believe we can help your back pain with therapy.    

1.    Nakashima H, Yukawa Y, Suda K, Yamagata M, Ueta T, Kato F. Abnormal findings on magnetic resonance images of the cervical spines in 1211 asymptomatic subjects. Spine (Phila Pa 1976). 2015;40(6):392-398.

2.    Boden SD, Davis DO, Dina TS, Patronas NJ, Wiesel SW. Abnormal magnetic-resonance scans of the lumbar spine in asymptomatic subjects. A prospective investigation. J Bone Joint Surg Am 1990;72:403- 8

3.    Borenstein DG, O'Mara JW, Jr., Boden SD, Lauerman WC, Jacobson A, Platenberg C et al. The value of magnetic resonance imaging of the lumbar spine to predict low-back pain in asymptomatic subjects : a seven-year follow-up study. J Bone Joint Surg Am 2001;83-A:1306-11.


Thursday, September 3, 2020

Finding Answers Sometimes Takes Time...Especially if We Forget Our Roots

Reading the articles this week and watching the videos for class have reminded me of a very meaningful discussion I had with a referring ENT who had been practicing medicine 50 years.  During our conversation, I asked him what had changed the most during his time since his practice began in the 1950s.  He shared two major patterns he had identified. 

First, he stated that MRIs and CT scans had created a belief in our culture that many people could and should be diagnosed very quickly.  He explained that many people do not understand that finding a diagnosis to their problem sometimes takes time for the symptoms and disease to evolve.  He stated MRIs and CT scans had created unrealistic expectations from our patients and had also changed practice patterns of many healthcare providers.  Interestingly, Chou et al shared how these expectations can sometimes cause lack of trust in their healthcare providers if imaging is not performed. (1)  

Another great lesson my ENT friend shared is that many healthcare providers had lost the art of taking a strong history and performing a thorough bedside exam.  He stated some providers had placed too much confidence in imaging.  He stated that too many were ordering special tests instead of listening to their patients and holding true to the roots of medicine.  He explained that many had abandoned a thorough bedside exam in exchange for referring patients for more expensive testing.  

I have reflected on his observations many times over the years.  My heart breaks when I hear my clients detail the months of extensive tests and referrals they have endured.  In the context of back pain, Chou et al claim that, “routine imaging does not seem to improve clinical outcomes and exposes patients to unnecessary harms.  Imaging can lead to additional tests, follow-up, and referrals and may result in an invasive procedure of limited or questionable benefit.” (1)   

At times, I have found the dizzy world to be similar.   Many patients demand CT scans or MRIs.  They spend weeks, months, and even years going from test to test and specialist to specialist.  I have patients with dizziness spend thousands of dollars on CT scans, MRIs, VNGs, etc.  They see specialist after specialist and take months to find answers regarding why they are dizzy.  By the time they see me, they are so frustrated and have lost hope.  They lack hope in healthcare and they lack hope they will improve. In addition, they may often be in the vicious cycle of dizziness that involves avoidance, disuse, and fear that makes their problems worse.   I believe we, as passionate and knowledgeable healthcare providers, can change this paradigm through teamwork.  

Teams of healthcare providers sharing the same high quality education about the reason for symptoms followed by ways to address those symptoms and improve quality of life helps greatly.  My best results are obtained when the referring Physician and I are speaking the same language regarding the diagnosis and plan to improve.  Physicians who prepare patients for success by completing a thorough history and exam followed by a confident referral my way has lead to great outcomes.  I am often able to complete basic bedside tests and a highly sensitive/specific history that helps.  Spending time with the patient and learning how to speak their language provides them with the aha moment they are seeking.  I can often see the stress relieved from their shoulders as explanations are given through providing high quality dizziness neuroscience education.  

It is not  unreasonable for our patients to expect a quick and accurate diagnosis.  However, somehow we have to shift their confidence away from machine based diagnostics toward trusting the expertise of their healthcare provider(s).   Machine based results are often misleading.  For instance, “most lumbar imaging abnormalities are common in persons without low back pain and are only loosely associated with back symptoms.” (1)  

The bottom line is that people want to know why they are in pain or why they are dizzy.   People in general love machines and they trust those kinds of results.  However, these machines are often not able to provide the proper answers our clients seek.   We have to use our bedside exam skills, research articles available, and take the time required to provide high quality education in a way they can understand, believe, and then change their lives by changing their perspective.

1. Chou R, Qaseem A, Owens DK, Shekelle P; Clinical Guidelines Committee of the American College of Physicians. Diagnostic imaging for low back pain: advice for high-value health care from the American College of Physicians [published correction appears in Ann Intern Med. 2012 Jan 3;156(1 Pt 1):71]. Ann Intern Med. 2011;154(3):181-189.