A comprehensive guide from a Vestibular Physiotherapist
Dizziness is one of the most common yet most misunderstood symptoms in medicine. It can mean spinning, swaying, lightheadedness, floating, rocking, tilting, visual disturbance, brain fog, or simply “I don’t feel right.”
One of the first questions patients ask is:
“Do I need an MRI?”
It’s a completely understandable question. MRI scans feel reassuring. They seem definitive. And when you’re dizzy, uncertain, and frightened — certainty is incredibly appealing.
But here’s the truth:
Most people with dizziness do not need an MRI.
And in some cases, getting one too early can actually increase anxiety, delay appropriate treatment, or lead to unnecessary further testing.
In this blog, we’ll unpack:
What dizziness really means
- The most common causes of dizziness
- When an MRI is necessary
- When it is not necessary
- The importance of seeing a Vestibular Physiotherapist
- The role of oculomotor testing and the Head Impulse Test
- Red flags that warrant urgent imaging
- How to advocate for the right care
Let’s start at the beginning.
Understanding Dizziness: Not All Dizziness Is the Same
Dizziness is not a diagnosis — it’s a symptom.
Broadly speaking, it can fall into categories:
- Vertigo – spinning sensation (you or the room moving)
- Disequilibrium – imbalance or unsteadiness
- Lightheadedness – feeling faint
- Rocking/swaying – internal motion without spinning
- Visual motion sensitivity
- Brain fog or derealisation-like symptoms
Each of these patterns points toward different causes.
And most of them do not originate from a brain tumour or structural brain disease — which is what most people fear when asking about MRI.
The Most Common Causes of Dizziness
Before talking about MRI, we need perspective.
The majority of dizziness seen in outpatient clinics is caused by:
- Benign Paroxysmal Positional Vertigo (BPPV)
- Vestibular migraine
- Vestibular neuritis
- Persistent Postural-Perceptual Dizziness (PPPD)
- Mal de Debarquement Syndrome (MdDS)
- Motorist Disorientation Syndrome
- Orthostatic intolerance
- Anxiety-related dizziness
- Post-concussion vestibular dysfunction
None of these require an MRI to diagnose in most cases.
They are clinical diagnoses — meaning they are diagnosed through:
- Careful history
- Eye movement testing
- Head impulse testing
- Balance assessment
- Positional testing
This is where a Vestibular Physiotherapist becomes crucial.
Why Clinical Examination Comes Before MRI
Modern medicine has drifted toward imaging first, examination second.
But in vestibular medicine, the opposite is true.
A detailed bedside examination often tells us more than a scan.
When you see a Vestibular Physiotherapist trained in vestibular disorders, they will assess:
1. Oculomotor Function
This includes:
- Smooth pursuit
- Saccades
- Gaze holding
- Skew deviation
- Convergence
- Nystagmus patterns on Dix-Hallpike Testing (BPPV testing)
These eye movement tests give us enormous insight into whether dizziness is likely:
- Peripheral (inner ear)
- Central (Brainstem/cerebellum)
- Migraine-related
- Functional/PPPD-related
Subtle abnormalities in eye movements can indicate central nervous system involvement long before imaging does.
2. Head Impulse Test (HIT)
The Head Impulse Test evaluates the Vestibulo-Ocular Reflex (VOR).
In simple terms:
Can your eyes stay fixed on a target while your head moves quickly?
If the reflex is deficient, the eyes make a corrective saccade.
A positive Head Impulse Test strongly suggests a peripheral vestibular lesion (e.g., vestibular neuritis).
Importantly:
A normal Head Impulse Test in someone with acute continuous vertigo raises concern for central causes.
This is part of what is known as the HINTS examination (Head Impulse, Nystagmus, Test of Skew) — which has been shown in research to be more sensitive than early MRI in detecting stroke in acute vestibular syndrome.
Let that sink in.
In early stroke (especially posterior circulation stroke), MRI can be falsely negative in the first 24–48 hours.
A skilled bedside examination may detect it sooner.
So When Should You Get an MRI?
There are specific situations where MRI is absolutely appropriate.
Let’s break them down.
1. Acute Continuous Vertigo with Central Red Flags
If someone presents with:
- Sudden severe continuous vertigo
- Inability to walk without support
- New neurological deficits (double vision, weakness, numbness, slurred speech)
- Direction-changing nystagmus
- Vertical nystagmus
- Normal Head Impulse Test
An MRI is indicated urgently to rule out:
- Posterior circulation stroke
- Cerebellar infarction
- Brainstem pathology
In these cases, imaging is not optional.
2. Progressive Neurological Symptoms
MRI is appropriate if dizziness is accompanied by:
- Progressive weakness
- New coordination difficulties
- Persistent unilateral facial numbness
- Progressive hearing loss (especially unilateral)
- Severe headache unlike previous migraines
- Signs of raised intracranial pressure
These features suggest possible structural pathology.
3. Unilateral Progressive Hearing Loss
MRI of the Internal Auditory Canals is indicated to rule out:
- Vestibular schwannoma (acoustic neuroma)
Especially if hearing loss is:
- Asymmetric
- Progressive
- Accompanied by unilateral tinnitus
4. Multiple Cranial Nerve Findings
If dizziness is accompanied by:
- Facial weakness
- Swallowing difficulty
- Hoarseness
- Double vision
Imaging is warranted.
5. New Onset Dizziness in High Stroke-Risk Patients
If someone has:
- Atrial fibrillation
- Recent cardiac procedure
- Significant vascular risk factors
- Sudden onset vertigo without positional triggers
MRI may be indicated.
When MRI Is Usually NOT Necessary
Let’s talk about the far more common scenarios.
BPPV
If dizziness is:
- Triggered by rolling in bed
- Triggered by looking up
- Brief (seconds)
- Associated with positional nystagmus on testing
This is classic BPPV.
MRI is not required.
Treatment: Canalith repositioning manoeuvres.
UNLESS the oculomotor signs are not classic of BPPV i.e. pure upbeating, pure downbeating, there is no vertigo during testing or a lack of response to respositioning manoeveres then an MRI of the posterior fossa may be warranted – a skilled Vestibular Physiotherapist can assess this.
Vestibular Neuritis
If there is:
- Sudden severe vertigo
- Nausea
- Positive Head Impulse Test
- Unidirectional horizontal nystagmus
- No neurological deficits
MRI is usually not necessary (unless atypical features exist).
Treatment: Vestibular rehabilitation.
Vestibular Migraine
If dizziness:
- Fluctuates
- Occurs with visual motion or sound sensitivity (i.e. photophobia or phonophobia)
- Associated with migraine history
- Has normal neurological examination
MRI is often unnecessary unless red flags exist.
PPPD (Persistent Postural-Perceptual Dizziness)
If dizziness:
- Is perceived as a rocking and swaying sensation or is Chronic (> 3 months)
- Worse in busy crowded environments
- Worse with visual motion
- Worse when upright
- Improves when lying down
- Normal neurological examination
MRI rarely changes management.
MdDS (Mal de Debarquement Syndrome)
If symptoms:
- Begin after boat/plane travel or other forms or transport (i.e train)
- Improve with passive motion (i.e. go away in motion in the car)
- Perceived as a persistent rocking sensation
MRI is typically normal.
The Anxiety Factor
One important truth:
MRI is often ordered for reassurance.
But sometimes reassurance backfires.
Incidental findings are common:
- White matter changes
- Small cysts
- Benign variants
- Non-specific hyperintensities
These can create more anxiety without explaining dizziness.
The key question should always be:
“Will this MRI change management?”
If the answer is no, we should reconsider.
The Power of Seeing a Vestibular Physiotherapist First
Before jumping to imaging, a structured vestibular assessment is invaluable.
A trained Vestibular Physiotherapist will:
- Take a detailed history
- Identify pattern recognition
- Perform positional testing
- Assess oculomotor signs
- Perform Head Impulse Testing
- Assess balance integration
- Screen for central red flags
- Determine if imaging is necessary
In many cases, we can:
- Diagnose the condition immediately
- Begin treatment the same day
- Avoid unnecessary scans
- Reduce fear
And importantly:
We know when to escalate.
Why MRI Can Miss Things
Many patients assume MRI is definitive.
But:
- Early posterior strokes can be missed
- Functional disorders won’t show
- Migraine won’t show
- PPPD won’t show
- BPPV won’t show
- Neuritis often won’t show
MRI is excellent for structural abnormalities.
But most dizziness is functional, physiological, or inner-ear based — not structural brain disease.
The Balance Between Over-Scanning and Under-Scanning
The goal isn’t to avoid MRI at all costs.
The goal is to:
- Use it appropriately
- Use it when it changes management
- Avoid unnecessary radiation (CT)
- Avoid incidental anxiety
Good medicine is pattern recognition + clinical reasoning.
Not reflex imaging.
Red Flags That Warrant Immediate Medical Attention
Seek urgent medical care if dizziness is accompanied by:
- Severe sudden headache (“worst ever”)
- Double vision
- Slurred speech
- Facial droop
- Limb weakness
- Inability to walk
- Chest pain
- Sudden hearing loss
These are not “wait and see” symptoms.
Questions to Ask Before Getting an MRI
If your doctor suggests imaging, consider asking:
- What are we ruling out?
- What red flags are present?
- Will the result change treatment?
- Is my neurological exam abnormal?
- Have I had a full vestibular assessment?
These are reasonable, empowered questions.
A Structured Approach to Dizziness
Here is the ideal pathway:
1. Detailed clinical history
2. Vestibular physiotherapy assessment
- Oculomotor testing
- Head Impulse Test
- Positional testing
- Balance testing
3. Identify likely diagnosis
4. Screen for red flags
5. MRI only if indicated
This approach is both evidence-based and patient-centred.
Final Thoughts
Dizziness is distressing.
It can make you feel:
- Unsafe
- Detached
- Frightened
- Out of control
It’s natural to want certainty.
But certainty does not always come from a scan.
Often it comes from:
- A skilled clinical assessment
- Clear explanation
- Pattern recognition
- Targeted treatment
An MRI is a powerful tool.
But it is not the first step in most cases of dizziness.
If you’re unsure whether you need imaging, the most appropriate first step is to see an Experienced Vestibular Physiotherapist trained in:
- Oculomotor examination
- Head Impulse Testing
- Positional assessment
- Central vs peripheral differentiation
Because sometimes, the answer isn’t inside the scanner.
It’s inside the eyes.
