From the Guidelines
Significance of Electroneuronography (ENoG) and Facial Electromyography (EMG)
For patients with facial weakness or paralysis, Electroneuronography (ENoG) and facial Electromyography (EMG) are crucial diagnostic tools to assess the severity of nerve damage and predict recovery 1.
- ENoG measures the electrical activity of the nerve, while facial EMG evaluates the muscle's response to nerve stimulation.
- It is recommended to perform ENoG within 3-14 days after onset of symptoms to determine the degree of nerve degeneration, and facial EMG after 14 days to assess muscle recovery 1.
- These tests can help guide treatment decisions, such as the use of corticosteroids, which may be prescribed to reduce nerve swelling and promote recovery.
- The results of electrodiagnostic testing, including ENoG and EMG, can provide meaningful prognostic information, alerting the physician and patient to a heightened likelihood of incomplete recovery 1.
- In patients with complete facial paralysis, ENoG testing can predict the likelihood of recovery, with a response amplitude of less than 10% of the normal side indicating a higher risk of incomplete recovery 1.
From the Research
Significance of Electroneuronography (ENoG) and Facial Electromyography (EMG)
- ENoG is a valuable tool for predicting recovery in patients with facial palsy, as it reflects the percentage of degenerated facial nerve fibers and can provide an accurate prognosis 2, 3, 4.
- Facial EMG can assist in diagnosis, assess the lesion severity, and aid in decision making, particularly in cases of acute facial palsy 5, 3, 6.
- ENoG and EMG can be used together to evaluate the extent of facial nerve degeneration and predict the likelihood of recovery 3.
- The results of ENoG and EMG should be interpreted in conjunction with other clinical evaluations, such as the facial muscle grading system, to provide a comprehensive assessment of facial palsy 2, 5.
Clinical Applications
- ENoG and EMG can be used to diagnose and monitor facial palsy, including Bell's palsy and traumatic facial paralysis 5, 3, 6.
- These tests can help identify patients who may benefit from surgical decompression, particularly those with severe degeneration of the facial nerve 3.
- ENoG and EMG can also be used to evaluate the effectiveness of treatment and predict long-term outcomes in patients with facial palsy 2, 3.
Methodology and Interpretation
- ENoG can be performed using different techniques, including nasolabial fold (NLF) and nasalis muscle (NM) methods, which have been shown to be highly correlated and reliable 3, 4.
- EMG can be used to evaluate the presence or absence of muscle unit potentials (MUPs), which can indicate the severity of facial nerve degeneration 3.
- The results of ENoG and EMG should be interpreted by experienced clinicians, taking into account the patient's clinical history and other diagnostic findings 2, 5.