Neurologists use a wide range of tests to evaluate how your brain, spinal cord, and nerves are functioning. Some are as simple as following a light with your eyes during an office visit. Others involve imaging, electrical recordings, or fluid analysis that can take hours. The specific tests you’ll encounter depend on your symptoms, but most people see a neurologist for headaches, numbness, dizziness, memory problems, or seizures.
The Neurological Exam
Almost every visit to a neurologist starts with a physical neurological exam. This is a hands-on evaluation that typically lasts 30 minutes to an hour, depending on your symptoms. No special preparation is needed. Your neurologist will test your reflexes, coordination, balance, muscle strength, sensation, and eye movements. They’ll ask you to walk in a straight line, touch your nose with your finger, or push against their hands. These seemingly simple tasks reveal a lot about which parts of your nervous system are working normally and which aren’t.
The results of this exam guide everything that comes next. If your reflexes on one side are abnormally brisk, your neurologist might order brain imaging. If your grip strength is weak or your feet are numb, nerve conduction testing could be the next step. Think of the neurological exam as a roadmap that tells your doctor which deeper tests are worth pursuing.
Brain and Spinal Cord Imaging
MRI and CT scans are the two main imaging tools neurologists rely on, and each has distinct strengths.
A CT scan is fast, often completed in minutes, which makes it the go-to choice in emergencies like head trauma, stroke, or sudden severe headaches. It’s also less expensive than MRI and works well for patients with pacemakers, metal implants, or severe claustrophobia. CT is particularly good at detecting bleeding, skull fractures, and calcifications.
MRI is the preferred scan for most non-emergency neurological workups. It produces far more detailed images of soft tissue, making it superior for spotting tumors, inflammation, nerve damage, and the characteristic lesions of multiple sclerosis. MRI doesn’t use radiation, so it’s the safer option for children or anyone who needs repeated scans over time. The tradeoff is that MRI takes longer (often 30 to 60 minutes), is louder, and requires you to lie still inside a narrow tube. Some scans use a contrast dye injected into a vein to make certain structures stand out more clearly. MRI contrast agents carry a smaller risk of allergic reactions compared to CT contrast.
Your neurologist may also order specialized MRI sequences. MR angiography maps blood vessels in the brain. Functional MRI tracks blood flow changes during specific tasks, which can help with surgical planning. Diffusion-weighted MRI is highly sensitive to early stroke damage.
EEG: Recording Brain Waves
An electroencephalogram, or EEG, measures electrical activity in the brain by placing small electrodes on the scalp. It’s one of the primary tests for diagnosing epilepsy and other seizure disorders. Beyond seizures, an EEG can also help evaluate encephalopathy (a broad term for brain dysfunction from various causes), sleep conditions, and the effects of brain injuries or tumors.
A routine EEG takes about 30 to 60 minutes. You’ll be asked to avoid caffeine beforehand and may need to skip hair products like gel or hairspray, since they can interfere with electrode contact. During the test, you’ll sit or lie down while a technician records your brain’s electrical patterns at rest, during deep breathing, and while looking at a flashing light. These provocations can trigger abnormal brain wave patterns that wouldn’t show up otherwise.
In some cases, a routine EEG doesn’t capture enough. Your neurologist might then order a prolonged or continuous EEG, where you wear the electrodes for several days, sometimes in a hospital monitoring unit. Recording over a longer period dramatically increases the chance of catching seizure activity as it happens.
EMG and Nerve Conduction Studies
When the problem seems to involve peripheral nerves or muscles rather than the brain itself, neurologists turn to electromyography (EMG) and nerve conduction studies. These are often done together in the same appointment.
A nerve conduction study measures how fast and how strongly electrical signals travel through your nerves. Small electrodes are placed on the skin, and brief electrical pulses stimulate the nerve at different points. The speed of the response, called conduction velocity, tells your neurologist whether a nerve is damaged, compressed, or functioning normally. Carpal tunnel syndrome, for example, shows up as slowed conduction through the wrist.
The EMG portion uses a thin needle electrode inserted into specific muscles to record their electrical signals at rest and during contraction. Healthy muscles are electrically quiet at rest. If the needle picks up spontaneous electrical activity in a resting muscle, that’s a sign of nerve damage or a muscle disorder. Together, these two tests help diagnose conditions like pinched nerves, neuropathy, ALS, and muscular dystrophy. The needle portion can be uncomfortable, but each muscle is tested for only a few seconds.
Lumbar Puncture
A lumbar puncture, commonly called a spinal tap, collects a small sample of cerebrospinal fluid from the lower back. This fluid surrounds and cushions your brain and spinal cord, so analyzing it provides a direct window into what’s happening in your central nervous system.
Lab technicians check the fluid’s appearance first. Healthy spinal fluid is clear and colorless. Orange, yellow, or pink tinting suggests bleeding. Beyond appearance, the fluid is tested for protein levels, glucose, white blood cell counts, and the presence of bacteria, viruses, or abnormal antibodies. These markers help diagnose serious infections like meningitis and encephalitis, inflammatory conditions like multiple sclerosis and Guillain-Barré syndrome, certain cancers that have spread to the nervous system, bleeding around the brain, and even some forms of dementia including Alzheimer’s disease.
The procedure itself takes about 30 to 45 minutes. You’ll curl up on your side or sit hunched forward while a needle is inserted between two vertebrae in the lower back. Local anesthetic numbs the area first. The most common side effect is a headache afterward, which usually resolves within a day or two, especially if you rest and stay hydrated.
Neuropsychological Testing
When the concern is cognitive rather than physical, such as memory loss, difficulty concentrating, or personality changes, a neurologist may refer you for neuropsychological testing. This is a detailed assessment of how well different brain functions are working, and it typically takes several hours to complete.
The evaluation covers multiple cognitive domains through a series of paper-and-pencil tasks, verbal questions, and computer-based exercises. These include attention and concentration (your ability to focus and sustain focus), processing speed (how quickly you take in and respond to information), executive functioning (planning, problem-solving, impulse control, and mental flexibility), learning and memory (taking in new information and recalling it later), language (understanding speech, naming objects, following instructions, and written expression), visuospatial skills (perceiving and mentally manipulating shapes and spatial relationships), and fine motor skills like dexterity and reaction time.
Your results are compared against norms for your age and education level. This testing is especially valuable for distinguishing normal age-related cognitive changes from early dementia, identifying the specific effects of a brain injury, or tracking how a known condition is progressing over time.
Sleep Studies
Polysomnography, the formal name for an overnight sleep study, is used when a neurologist suspects a sleep disorder is behind your symptoms. During the study, you sleep overnight in a lab while sensors track your brain waves, eye movements, heart rate, breathing pattern, blood oxygen level, body position, and limb movements.
Brain wave and eye movement data reveal your sleep stages and whether you’re cycling through them normally. Drops in blood oxygen paired with pauses in breathing point toward sleep apnea. Frequent leg movements during sleep can indicate periodic limb movement disorder. Acting out dreams, sometimes violently, may signal REM sleep behavior disorder, which in some people is an early marker of neurological conditions like Parkinson’s disease.
Balance and Vestibular Testing
Dizziness is one of the most common reasons people see a neurologist, and videonystagmography (VNG) is a key test for sorting out its cause. VNG measures involuntary eye movements called nystagmus, which are closely linked to your inner ear balance system.
During the test, you sit in a dark room wearing goggles with a built-in camera that tracks your eyes. The test has three main parts. In ocular testing, you follow moving lights with your eyes while keeping your head still. In positional testing, a provider moves your head and body into specific positions to see if certain orientations trigger abnormal eye movements. In caloric testing, warm and then cool water or air is introduced into each ear separately. The temperature change should trigger a predictable eye movement response, and comparing the two ears reveals whether one side’s balance system is weaker than the other.
VNG can help diagnose benign paroxysmal positional vertigo (BPPV), Ménière’s disease, vestibular neuritis, labyrinthitis, and acoustic neuromas. It’s also useful for distinguishing inner ear problems from neurological causes of dizziness, which require very different treatment approaches.
Blood Work and Genetic Testing
Neurologists frequently order blood tests, though these happen at a regular lab rather than in the neurology office. Blood work can reveal vitamin deficiencies (especially B12, which causes nerve damage when low), thyroid dysfunction, inflammatory markers, autoimmune antibodies, and infection. For conditions like neuropathy, blood tests often identify the underlying cause more efficiently than nerve-specific tests alone.
Genetic testing has become increasingly relevant in neurology. If your neurologist suspects a hereditary condition like Huntington’s disease, certain forms of ALS, or hereditary neuropathies, a blood or saliva sample can be sent for DNA analysis. These results can confirm a diagnosis, guide treatment decisions, and inform family planning discussions.