Vertigo is diagnosed primarily through a careful history and a set of bedside physical exams, not through blood tests or brain scans. In most cases, a doctor can identify the cause by asking two key questions: how long do your episodes last, and what triggers them? These answers, combined with specific eye-movement tests, point toward a diagnosis more reliably than imaging in the early stages.
Why Timing and Triggers Matter Most
The single most useful diagnostic framework for vertigo follows a simple logic: timing, triggers, and targeted examination. How your dizziness behaves over time and what sets it off narrows the list of possible causes before any test is performed.
Timing means onset, duration, and pattern. Episodes lasting seconds to under a minute suggest a positional problem in the inner ear. Episodes lasting 20 minutes to 12 hours point toward Ménière’s disease. Vertigo that arrives suddenly and persists for days without letting up suggests vestibular neuritis or, less commonly, stroke. Your doctor will also want to know whether symptoms come and go or whether this is one continuous episode.
Triggers are equally telling. If turning your head in bed or looking up sets off a spinning sensation, that’s a positional trigger characteristic of BPPV (benign paroxysmal positional vertigo). If episodes seem to happen spontaneously with no clear trigger, the diagnostic path shifts toward Ménière’s disease, vestibular migraine, or a central nervous system cause.
The Bedside Eye Exam
Your eyes reveal what’s happening in your inner ear and brainstem. During vertigo, involuntary eye movements called nystagmus occur, and the direction, speed, and behavior of those movements tell a trained clinician whether the problem is peripheral (inner ear) or central (brain).
A key distinction: nystagmus that fades when you focus your gaze on a fixed point suggests an inner ear problem. Nystagmus that persists regardless of visual fixation, or that changes direction when you look in different directions, raises concern for a central cause like stroke or a brain lesion.
For patients presenting with sudden, continuous vertigo and at least one stroke risk factor, many emergency departments use a three-part bedside exam called HINTS. It checks head impulse response, nystagmus direction, and whether the eyes are vertically misaligned (skew deviation). In the original validation study, this exam was 100% sensitive and 96% specific for identifying stroke, actually outperforming early MRI, which catches only about 80% of strokes in the first 24 hours. Adding a check for new hearing loss on one side pushes the sensitivity to roughly 99%.
How BPPV Is Diagnosed
BPPV is the most common cause of vertigo, and it has its own specific diagnostic test: the Dix-Hallpike maneuver. You sit on an exam table, and the clinician quickly moves you from sitting to lying flat with your head turned 45 degrees to one side and extended slightly over the edge. If tiny calcium crystals have drifted into the wrong part of your inner ear’s semicircular canal, this position will provoke a brief burst of vertigo and characteristic eye movements.
A positive test for posterior canal BPPV (the most common type) shows nystagmus that beats upward and rotates, typically starting 2 to 5 seconds after the position change and lasting less than one minute. With repeated testing, the response tends to weaken, a feature called fatigability. These specific characteristics separate BPPV from more concerning causes.
Not all BPPV affects the posterior canal. Horizontal canal BPPV is diagnosed using a different maneuver: the supine roll test, where the clinician turns your head side to side while you lie flat. This produces horizontal nystagmus and correctly identifies the affected ear in over 95% of cases with one variant and about 75% with another. Anterior canal BPPV, the rarest type, is identified by a head-hanging test that produces downward-beating nystagmus.
Diagnosing Ménière’s Disease
Ménière’s disease has no single definitive test. Diagnosis is clinical, meaning it’s based on a pattern of symptoms rather than a scan or lab result. The current criteria require episodic vertigo lasting between 20 minutes and 12 hours, documented low- to mid-frequency hearing loss on one side (confirmed by a hearing test), and fluctuating ear symptoms like fullness, ringing, or muffled hearing in the affected ear.
A “probable” diagnosis applies when someone has episodic dizziness with fluctuating ear symptoms but hasn’t yet met the full criteria. The hearing loss can come and go early in the disease, which sometimes makes it difficult to catch on a single audiogram.
Vestibular Migraine
Vestibular migraine is one of the most underdiagnosed causes of recurrent vertigo. Diagnosis requires at least five episodes of vestibular symptoms (spinning, rocking, or a sense of motion), where at least half of those episodes occur alongside migraine features: a one-sided, pulsating headache of moderate to severe intensity, sensitivity to light and sound, or a visual aura. You don’t need to have a headache during every episode, which is partly why it’s so often missed. Many people experience the vertigo without any head pain at all during a given attack.
Vestibular Neuritis and Labyrinthitis
Both conditions involve inflammation of the inner ear’s nerve pathways and produce sudden, severe vertigo lasting days. The clinical difference between them is straightforward: vestibular neuritis causes vertigo without hearing changes, while labyrinthitis also affects hearing, producing hearing loss or tinnitus on the affected side. Both are typically diagnosed based on history and bedside examination rather than imaging, unless there’s concern about stroke.
When Imaging Is Needed
Most vertigo does not require a brain scan. Imaging becomes important when specific red flags suggest the cause could be in the brain rather than the inner ear. According to Johns Hopkins Medicine, the situations that support ordering an MRI or CT include:
- Neurological deficits beyond dizziness, such as double vision, slurred speech, difficulty swallowing, facial numbness, or weakness on one side of the body
- Strong stroke risk factors like high blood pressure, diabetes, atrial fibrillation, or a history of vascular disease
- Progressive, asymmetric hearing loss that could indicate a growth on the hearing nerve
- Asymmetric findings on coordination testing, suggesting a cerebellar problem
- Vertigo with no clear peripheral cause after a thorough exam
An important caveat: the absence of neurological symptoms does not completely rule out a central cause. But their presence is a strong signal that further investigation is needed.
Specialized Vestibular Testing
When bedside exams don’t provide a clear answer, or when symptoms recur without explanation, your doctor may refer you for formal vestibular function testing. The most common is videonystagmography (VNG), which uses infrared goggles to precisely track your eye movements during a series of tasks.
VNG testing typically includes several components. Saccade testing checks how quickly and accurately your eyes jump between targets. Smooth pursuit testing measures how well your eyes follow a moving object. Positional testing looks for nystagmus in different head and body positions. The caloric test, often the most uncomfortable part, involves running warm and then cool air or water into each ear canal to stimulate the inner ear individually. A difference of more than 25% in response strength between the two sides indicates a weakness on the weaker side.
VNG doesn’t usually give a single diagnosis on its own. Instead, it maps where the problem is and how well your vestibular system is compensating. Combined with your symptoms and history, it helps confirm or rule out conditions including BPPV, vestibular neuritis, Ménière’s disease, vestibular migraine, superior canal dehiscence, acoustic neuroma, and central vestibular disorders.
What to Expect at Your Appointment
If you’re seeing a doctor about vertigo for the first time, come prepared with specific details: how long each episode lasts, what you’re doing when it starts, whether it happens with position changes, and any accompanying symptoms like hearing changes, headache, or nausea. These details matter more than you might expect. A 30-second episode triggered by rolling over in bed tells a completely different diagnostic story than a 4-hour episode that starts spontaneously with ear pressure.
Your doctor will likely check your eye movements, test your balance, perform positional maneuvers, and assess basic neurological function. For many people, especially those with classic BPPV, a diagnosis and even treatment can happen in a single visit. For more complex or recurrent cases, you may be referred to an otolaryngologist (ENT) or a neurologist with vestibular expertise for further testing.