Appeal type: Medical necessity
Decision: Overturned

Diagnosis: Neuromuscular Disorder-Seizures.
Treatment: Diagnostic Testing - 4.5 Hours of Neuropsychological Testing for Surgery.

The health plan denied the 4.5 Hours of Neuropsychological Testing for Surgery.  The health plan decision was overturned.

This patient is an adult male with a history of medically refractory focal epilepsy. He is currently being evaluated for potential epilepsy surgery. He has had an extensive pre-surgical workup thus far. His electroencephalograms (EEGs) have captured seizures arising from the left temporal lobe. Brain magnetic resonance imaging (MRI) scan showed a lesion in the left temporal lobe concerning for a focal cortical dysplasia or a low-grade neoplasm. Fludeoxyglucose (FDG) positron emission tomography (PET) scan showed hypometabolism in the left temporal lobe. Neuropsychological testing is not lateralizing to either hemisphere. Functional MRI showed left hemisphere language dominance. The treating physician has requested for a Wada test (The Wada test can help epilepsy doctors evaluate how important each side of the brain is with respect to language and memory functions) and a neuropsychological testing along with Wada for further evaluation of his language and memory functions.

The requested health service is medically necessary for this patient.

Presurgical evaluation for refractory epilepsy is a complex process requiring multidisciplinary input from neurosurgeons, neurophysiologists, radiologists, psychiatrists, and clinical neuropsychologists. A series of diagnostic tests are performed, and the information obtained provides insight into the epileptic processes, the cerebral organization of cognitive skills and the safety of resection. This is relevant in the context of epilepsy surgery because it is important to preserve the functional regions of the brain during the removal of the epileptogenic cortex, especially those eloquent areas responsible for language and memory. The decision to perform surgery is thus a balance of achieving seizure control, the projected risk of inducing unacceptable cognitive and neurological deficit from surgery.

The Wada test, also known as the intracarotid amobarbital test, is considered a pertinent tool in in the preoperative evaluation for cerebral language dominance in epilepsy surgery. It is typically indicated for the assessment of language dominance and memory capacity in patients planned for the resection of temporal lobe structures. The patient undergoes a baseline evaluation to determine to assess for language and memory functions before administration of an anesthetic agent. The patient is then injected with anesthetic agent and each hemispheric function is assessed separately. To test various components of language, the patient is presented with tasks, such as naming objects, reading and repeating sentences. Additionally, memory is assessed by showing a series of items for subsequent recall.

While functional MRI has been replacing Wada test in most clinical situations, it is still considered a potentially useful test in presurgical evaluation of selected patients for epilepsy surgery, especially those with dominant temporal lobe epilepsy. Given this patient's previous neuropsychological testing has been non-lateralizing, use of a Wada test and neuropsychological evaluation during Wada test would be considered medically necessary and standard of care.

Per guidelines from International League Against Epilepsy, "Whilst functional neuroimaging is proving to be at least equal to and possibly better than the Wada test in lateralizing language function, both structural and functional imaging play important complementary roles in screening for amnesic risk in adults."