The difference between EEG, EMG and nerve conduction studies
When these tests are usually requested
How private appointments work in Spain (referrals, timings, reports)
What to expect on the day, prep tips and typical duration
What is neurophysiology?
Clinical neurophysiology looks at how your brain, nerves and muscles are functioning. Instead of images like an MRI, these tests measure electrical activity. The three most common are:
EEG (electroencephalogram) - records brain-wave activity via small sensors on the scalp. Often used to investigate blackouts, seizures, epilepsy, sleep problems or cognitive symptoms.
NCS (nerve conduction studies) - checks how fast and well signals travel along a nerve. Useful for suspected carpal tunnel, ulnar neuropathy, sciatica/radiculopathy and generalised neuropathy.
EMG (electromyography) - a very fine needle records the electrical activity inside a muscle. Helps diagnose myopathy, motor neuron disorders, or neuromuscular junction problems (e.g. myasthenia).
When are these tests requested?
Repeated blackouts, suspected seizures or epilepsy (EEG ± sleep-deprived or prolonged monitoring).
Numbness, tingling, pain or weakness in an arm/leg suggesting trapped nerves or peripheral neuropathy (NCS/EMG).
Unexplained muscle weakness, cramping or fatigue where a myopathy is suspected (EMG).
Follow-up or treatment monitoring for known neurological conditions.
How appointments work in private care
Referral: Most centres ask for a GP or neurologist referral. With Sanitas, your Digital GP can refer you to a partnered unit.
Scheduling: Routine EEG/NCS slots are often available within days in larger cities; EMG may take longer due to specialist time.
On the day: Paperwork, consent and brief history; the test is performed by a neurophysiology technician and reported by a specialist physician.
Reports: A written report is usually available within 24–72 hours and can be shared with your referring doctor through the clinic portal.
Prep tips
For EEG, come with clean, dry hair (no products). Bring a list of medicines (especially anti-seizure or psychotropic drugs). For EMG/NCS, wear loose sleeves/trousers; avoid heavy moisturisers on the day.
Typical durations and comfort
EEG: 20–40 minutes for a routine study; up to a few hours for prolonged or sleep-deprived EEG.
NCS: 20–45 minutes depending on how many nerves are tested. You’ll feel brief, low-level electrical taps.
EMG: 20–40 minutes. Uses a very fine sterile needle; mild, short-lived discomfort is common.
Will insurance cover these tests?
Yes. When medically necessary and requested by a specialist, neurophysiology tests (EEG, EMG, NCS) are typically included across all Sanitas plans — both with and without copayments — subject to policy terms and authorisation where required.
Frequently asked questions
Do I need a referral for EEG/EMG/NCS?
Most centres ask for a GP or neurologist referral. With Sanitas, your Digital GP can refer you directly to an in-network neurophysiology unit.
Are these tests painful?
EEG is painless. Nerve conduction studies feel like brief, mild electrical taps. EMG uses a fine needle and can be uncomfortable for a few seconds in each muscle tested.
How soon will I get results?
Many centres provide a written report within 24–72 hours. Your referring doctor will discuss the findings and next steps.
Will my plan cover repeat tests or second opinions?
Plans usually cover medically necessary repeat tests and second opinions in-network, according to policy terms and any authorisation process.
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