What does it involve?
Facial EMG is a neurophysiological assessment that evaluates the function of the facial nerve, the trigeminal nerve, and the muscles of the face, neck, and tongue. Performing this examination requires specialised expertise that goes beyond conventional electromyography of the limbs. Few centres offer it in routine practice. At IENA Neurophysiologie, it is an integral part of our neuromuscular assessment services.
How is the examination performed?
Facial EMG consists of three complementary components, carried out according to the clinical indication.
Nerve conduction studies involve electrically stimulating the facial nerve along its path in front of the ear, and recording the response of the facial muscles. This measures the speed and amplitude of conduction along the nerve. The trigeminal nerve can also be partially evaluated in this context. Repetitive nerve stimulation of both the facial and trigeminal nerves allows for the assessment of potential neuromuscular junction disorders.
The blink reflex study explores the trigemino-facial loop: electrical stimulation of the trigeminal nerve (at the eyebrow) triggers a blink reflex, which is recorded in the orbicularis oculi muscles on both sides. This reflex utilizes complex neurological pathways passing through the brainstem, making it a valuable tool for localising neurological impairments at this level.
Needle electromyography is used to examine the electrical activity of the muscles of the face, neck, and tongue at rest and during voluntary contraction. It detects signs of denervation or myopathy.
A facial EMG can be combined with a limb EMG when the suspected pathology affects the wider peripheral nervous system or neuromuscular system.
In which cases is it prescribed?
Peripheral facial palsy
This is the most common indication. Facial EMG provides both diagnostic value — confirming facial nerve involvement and localising the site — and prognostic value. Performed after the 10th day following the onset of palsy, it allows for the assessment of axonal damage and helps estimate the chances of recovery: the presence or absence of denervation potentials and the degree of reinnervation are key prognostic factors to guide patient management.
Myasthenia gravis
Myasthenia gravis is a neuromuscular junction disorder that frequently affects the ocular and facial muscles. Investigating the facial muscles, in combination with repetitive stimulation, contributes to the electrophysiological diagnosis of this condition.
Swallowing and phonation disorders
Difficulty swallowing or speaking may reflect impairment of the motor cranial nerves or the muscles of the tongue and pharynx. Electromyography of the tongue and cervical muscles helps to objectify and characterise this impairment.
Amyotrophic Lateral Sclerosis (ALS)
In the evaluation of ALS, investigating the muscles of the tongue and face is essential to look for signs of lower motor neuron involvement in the bulbar region, in addition to limb EMG.
Autoimmune neuropathies
Certain inflammatory neuropathies (such as Guillain-Barré syndrome, antibody-mediated neuropathies, etc.) can affect the cranial nerves, including the facial and trigeminal nerves. Facial EMG helps document and quantify this involvement.
Ptosis and oculomotor muscle pathologies
Ptosis (drooping eyelid) may result from myasthenia gravis, myopathy, or nerve damage. Facial EMG, combined with repetitive stimulation if necessary, plays a key role in the diagnostic workup.
Myopathies
In myopathies affecting the orofacial area, electromyography of the facial and tongue muscles helps document direct muscle involvement and guides the search for the underlying cause.
The specific value of the blink reflex
The blink reflex deserves special mention. By exploring the trigemino-facial loop, which passes through the pons and medulla oblongata, it can detect abnormalities in the brainstem — area inaccessible to conventional limb EMG. It is useful in the assessment of demyelinating lesions (such as multiple sclerosis), brainstem compression, trigeminal neuropathies, and certain autoimmune neuropathies. Whether it is normal or abnormal, symmetric or asymmetric, it precisely guides the localisation of the neurological lesion.
Practical details
Facial EMG is a medical examination performed by prescription only. It is prescribed by a neurologist, an ENT specialist, a physical rehabilitation specialist, or a general practitioner. No special preparation is required. A detailed report is provided immediately after the procedure.
Summary
Facial EMG assesses the facial nerve, the trigeminal nerve, the blink reflex, and the muscles of the face, neck, and tongue
It is a highly specialised examination, rarely performed outside dedicated neurophysiology centres — it is available at IENA Neurophysiologie Paris 16th
It holds diagnostic and prognostic value in facial palsy, provided it is performed after the 10th day of the onset
It contributes to the evaluation of myasthenia gravis, swallowing disorders, ALS, autoimmune neuropathies, ptosis, and myopathies
The blink reflex allows for the exploration of the brainstem, complementing conventional EMG
The test requires a prescription and can be combined with a limb EMG
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Book an appointment for a facial EMG in Paris at IENA Neurophysiologie
By telephone on +33 (0)1 89 74 47 69 or via Doctolib
EMG in Paris: procedure, fees, and appointments
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