Neurophysiological studies may be reimbursed individually whether performed independently or in conjunction with each other.

However, if a provider reports any neurophysiological studies (92586, 92589, 95812, 95813, 95816, 95819, 95822, 95827, 95925, 95926, 95927, 95928, 95929, 95930, 95950, 95951, 95954, 95956) in addition to comprehensive evoked response audiometry (92585), the charges should be combined and processed under code 92585 (e.g., 92585 + 92589 = 92585)

Magnetoencephalography and Magnetic Source Imaging
Magnetoencephalogaphy (MEG) (95965, 95966, 95967) and Magnetic Source Imaging (MSI) (S8035) are eligible for use in the presurgical evaluation of certain patients with medically refractory epilepsy.*  This includes:

• non-lesional superficial cortical epilepsy
• lesional epilepsy within or adjacent to the eloquent cortex, 
• epilepsy associated with large structural lesions, 
• ongoing or recurrent seizure activity following previous resections for epilepsy, and
• cases where the seizure focus has not been detected or well localized by traditional methods.

*Medically refractory epilepsy refers to the failure of adequate trials of different classes of FDA approved antiepilepsy medications to control seizure activity, when taken in appropriate doses and carefully monitored for effectiveness and patient compliance.

Intraoperative Neurophysiology Monitoring
Intraoperative neurophysiology monitoring should be reported under procedure code 95920, regardless of the specific monitoring performed (e.g., brainstem auditory evoked response, somatosensory evoked potentials, etc.) If any of the testing codes for neurophysiological monitoring which are addressed below in the "Description" area of this policy are reported in conjunction with 95920, the services should be combined and processed under 95920 (e.g., 95925 + 95920 = 95920).

Intraoperative neurophysiology monitoring is an eligible service when it is performed by an eligible professional provider for any of the following indications:

• Acoustic neuroma
• Anterior cervical corpectomy
• Carotid endarterectomy
• Cerebral vascular aneurysms
• Cervical or thoracic myelopathy
• Dorsal rhizotomy
• Exploration of peripheral nerve neuroma
• Fracture of the spine
• Hemifacial spasm, 7th nerve decompression operation
• Herniated nucleus pulposus with spinal cord compression and wedge graft surgery following anterior cervical discectomy
• Leg lengthening procedure
• Most spinal instrumentation procedures
• Scoliosis
• Spinal arteriovenous malformation
• Spinal cord trauma
• Spinal stenosis
• Spondylolisthesis
• Spondylosis
• Syringomyelia
• Tethered cord
• Thoracic disc disease
• Trigeminal neuralgia, 5th nerve decompression operation
• Tumor of the CNS or peripheral NS
• Unstable spine

Individual consideration may be given for indications other than those above.  The physician must be performing the service in real time.  The physician may be in the O.R. suite or at a remote site with the monitoring performed via digital transmission or closed circuit television.  When digital transmission or closed circuit television is used, there must be the ability for continuous or immediate contact with the operating surgeon to ensure that information about the patient's status can be immediately communicated.

Description

Neurophysiological studies is a generic term for objective tests performed via sophisticated electronic equipment to detect various neurological dysfunctions. They include the following studies:

• Electroencephalography (EEG) - 95812-95813, 95816-95822, 95827, 95950, 95951, 95954, 95956
• Evoked response audiometry (ERA) - 92585, 92586
• Visual evoked potential (VEP) - 95930
• Central auditory testing - 92589
• Somatosensory evoked potential (SEP) testing -95925, 95926, 95927
• Central motor evoked potential study (transcranial motor stimulation) - 95928, 95929 

(The above codes represent testing performed in a nonoperative setting.)

NOTE: Evoked response audiometry (92585, 92586) can also be reported as:

• Brain stem auditory evoked response (BAER)
• Electrophysiological response audiometry
• Electrical response audiometry
• Evoked potential audiometry
• Low or high level biophysical EEG

Magnetoencephalography
Magnetoencephalography (MEG) measures neurological activity of the brain using magnetic fields. It is used for fundamental study of the brain, and for clinical studies and assessment of patients with specific neurological disorders. MEG is a noninvasive functional imaging technique in which the weak magnetic forces associated with the electrical activity of the brain are recorded externally on the scalp. Using mathematical modeling, the recorded data are then analyzed to provide an estimated location of the electrical activity. This information can be superimposed on an anatomic image of the brain, typically an MRI, to produce a functional/anatomic image of the brain, referred to as magnetic source imaging (MSI)

MEG and MSI have been found to be useful in the anatomical localization of areas of seizure focus and epileptogenic lesions of the brain, and in predicting outcomes in surgical resections for intractable temporal lobe epilepsy and brain lesions.

The primary advantage of MSI is that while the conductivity and thus measurement of electrical activity as recorded by the EEG is altered by surrounding brain structures, the magnetic fields are not. Therefore, MSI permits a high resolution functional/anatomic image.  This allows precise localization of epileptiform activity and anatomical identification of causative lesions.

Intraoperative Neurophysiology Monitoring
Intraoperative neurophysiology monitoring is used to identify complications to the nervous system during certain surgical procedures. Evoked responses are constantly monitored for changes which could imply damage to the nervous system. The intent of this monitoring is to alert the surgeon so that he may possibly alter the surgical procedure to avoid permanent neurological damage.

NOTE:

This policy is designed to address medical guidelines that are appropriate for the majority of individuals with a particular disease, illness, or condition. Each person's unique clinical circumstances may warrant individual consideration, based on review of applicable medical records.

This medical policy may not apply to FEP.  Medical policy is not an authorization, certification, explanation of benefits or a contract.  Benefits are determined by the Federal Employee Program.

PRN References

03/1994, Intraoperative neurophysiology testing, coding for
03/1995, Intraoperative neurophysiology monitoring, codes and reimbursement for
06/2005, Blue Shield covers real time on-site and remote-location intraoperative neurophysiological monitoring
08/2007, Magnetoencephalography (MEG) and Magnetic Source Imaging (MSI) now eligible

Epilepsy Surgery, Resection Volume and MSI Localization in Lesional Frontal Lobe Epilepsy, Elsevier Ireland, Ltd., 08/2003

Magnetoencephalography (MEG) Predicts Focal Epileptogenicity in Cavarnomas, The Journal of Neurology, Neurosurgery and Psychiatry, 2004

Does Magnetoencephalography Add to Scalp Video-EEG as a Diagnostic Tool in Epilepsy Surgery? Neurology, Volume 62, 03/2004

Magnetoencephalography Source Localization and Surgical Outcome in Temporal Lobe Epilepsy, Elsevier Ireland, Ltd, 06/2004

Application of Magnetoencephalography in Epilepsy Patients with Widespread Spike or Slow-wave Activity, Epilepsia, Volume 46, Number 8, 2005

Detection of Epileptiform Activity by Human Interpreters: Blinded Comparison Between Electroencephalography and Magnetoencephalography, Epilepsia, Volume 46, Number 1, 2005

Dynamic Statistical Parametric Mapping for Analyzing the Magnetoencephalographic Epileptiform Activity in Patients with Epilepsy, Journal of Child Neurology, Volume 20, 04/2005

Toward the Substitution of Invasive Electroencephalography in Epilepsy Surgery, The Journal of Clinical Neurophysiology, Volume 22, Number 4, 08/2005

Magnetic Source Imaging Localizes Epileptogenic Zone in Children with Tuberous Sclerosis Complex, Neurology, Volume 66, 04/2006

Reliability of Language Mapping with Magnetic Source Imaging in Epilepsy Surgery Candidates, Elsevier Ireland, Ltd, 04/2006

Magnetoencephalography/Magnetic Source Imaging, MPRM, Policy 6.01.21, 12/12/2006