Neurophysiology

Electromyography (EMG) is a diagnostic test that measures the electrical activity of muscles and the nerves controlling them. EMGs are essential for diagnosing a wide range of neuromuscular conditions, such as muscular dystrophy, amyotrophic lateral sclerosis (ALS), myasthenia gravis, and peripheral neuropathy. The procedure involves inserting small, sterile needle electrodes into the muscles to record electrical signals during rest and contraction.

Uses of EMG:

• Identifies the severity and location of neuromuscular diseases.
• Tracks the progression of disorders like muscular dystrophy.
• Helps diagnose nerve injuries or compressions, aiding in surgical planning.
• Monitors the effectiveness of treatments for neuromuscular conditions.

Components of EMG:

1. Needle EMG – Involves inserting needle electrodes into the muscle to measure electrical activity.
2. Nerve Conduction Studies (NCS) – Measures how well electrical signals move through peripheral nerves.

An Electroencephalogram (EEG) records the electrical activity of the brain and is primarily used to diagnose and monitor neurological conditions, such as epilepsy and seizures. EEGs can also help evaluate cognitive function, brain responses to stimuli, and sleep disorders. During the test, small electrodes are placed on the scalp using a conductive paste to record brain wave patterns.

Uses of EEG:

• Diagnoses epilepsy and other seizure disorders.
• Monitors treatment effectiveness for epilepsy.
• Evaluates cognitive and brain functions.
• Assesses brain activity in conditions like memory loss and sleep disorders.

Preparation for an EEG:

• No special preparation is required.
• Hair should be clean and free of styling products.
• Continue taking prescribed medications unless advised otherwise.
• The procedure involves placing 25 electrodes on the scalp and shoulders to record brain and heart activity.

Why do I need an EEG? EEGs are commonly used for patients experiencing seizures or blackouts, but they also help investigate other neurological symptoms.

Is an EEG painful or uncomfortable? No, EEGs are painless. Electrodes are attached using a water-soluble paste, and the test is not invasive.

How should I prepare for the EEG? Simply ensure your hair is clean and free of styling products. Take your medications as usual.

How long does an EEG take? The EEG takes approximately one hour, with the recording itself lasting about 20-30 minutes.

When will I receive the results? The results will be sent to your referring clinician within one week after the EEG.

Nerve Conduction Studies (NCS) assess the function and health of peripheral nerves by measuring the speed and strength of electrical signals. The test is vital for diagnosing conditions like carpal tunnel syndrome, diabetic neuropathy, Guillain-Barré syndrome, and radiculopathy. During the test, small electrical impulses are applied to the skin to stimulate the nerves, and the responses are measured.

Uses of NCS:

Diagnoses peripheral nerve disorders and entrapment syndromes.
Identifies the severity and location of nerve injuries or compressions.
Evaluates the health and function of nerves in cases of neuropathy.

Procedure:

Small electrical impulses are applied to the skin to stimulate the nerves.
In some cases, EMG may be performed alongside NCS to assess muscle function.
Most patients find the test tolerable, although some discomfort may occur temporarily.

Is NCS painful? The electrical impulses may cause a tingling sensation, but the test is generally well tolerated. Any discomfort is temporary.

Do I need to stop taking medication before NCS? You can continue taking your medications as usual unless advised otherwise by your doctor.

Can I drive after the test? Yes, NCS does not impair your ability to drive or perform daily activities.