Cost-utility analysis of magnetoencephalography used to inform intracranial electrode placement in patients with drug resistant epilepsy: a model based analysis.

OBJECTIVES: We estimated the cost-effectiveness of adding magnetoencephalography to a standard assessment for epilepsy surgery consisting of neuropsychology, magnetic resonance imagining, scalp electroencephalography, video electroencephalography and intracranial electroencephalography, in the capacity of informing intracranial electroencephalography electrode placement. METHODS: We used Microsoft Excel (2007) to construct a decision model. Discounted costs and quality adjusted life years are aggregated to calculate incremental cost-effectiveness ratios. Sensitivity analyses are conducted to assess robustness of findings. RESULTS: Our base case analysis yielded a result of $14 300 per quality adjusted life year gained. A total of 82.7% of probabilistic sensitivity analysis iterations resulted in incremental cost-effectiveness ratios below $100 000 in 2014 Canadian dollars. CONCLUSIONS: Our findings demonstrate that the inclusion of Magnetoencephalography in the assessment for epilepsy surgery in the capacity of informing intracranial electroencephalography electrode placement is likely not cost saving but does represent a reasonable allocation of resources from a value for money perspective.

Diagnostic evaluation in patients with intractable epilepsy and normal findings on MRI: a decision analysis and cost-effectiveness study.

BACKGROUND AND PURPOSE: Patients with focal intractable epilepsy and normal MR imaging findings frequently undergo further diagnostic tests to localize the epileptogenic zone. The aim of this study was to determine the cost-effective diagnostic strategy that will identify the epileptogenic zone in patients with suspected focal intractable epilepsy and normal MR imaging findings by using decision analysis. MATERIALS AND METHODS: A Markov decision model was constructed by using sensitivities and specificities of test strategies, seizure outcomes following surgical and medical treatment, cost, utilities, probabilities, and standardized mortality ratios. We compared 6 diagnostic test strategies: PET, ictal SPECT, and MEG individually; and combinations of PET+SPECT, PET+MEG, and SPECT+MEG. The outcomes measured were health care costs, QALY, and ICER. One-way and probabilistic sensitivity analyses were conducted to adjust for uncertainties in model parameters. RESULTS: The preferred strategies were PET+MEG and SPECT. The health care cost of the baseline strategy (PET+MEG) was $95,612 with 16.30 QALY gained. SPECT cost $97,479 with 16.45 QALY gained and an ICER of $12,934/QALY gained compared with those in PET+MEG. One-way sensitivity analyses showed that the decisions of the model were sensitive to variations in sensitivity and specificity of the test strategies. Probabilistic sensitivity analysis showed that when the willingness to pay was <$10,000, PET+MEG was the favored strategy, but the favored strategy changed to SPECT when the willingness to pay was >$10,000. CONCLUSIONS: PET+MEG and SPECT were the preferred strategies in the base case. The choice of test was dependent on the sensitivity and specificity of test strategies and willingness to pay. Further study with a larger sample size is needed to obtain better estimates of sensitivity and specificity of diagnostic tests.

Magnetoencephalography: an investigational tool or a routine clinical technique?

Magnetoencephalography (MEG) is a relatively novel noninvasive technique, with a much shorter history than EEG, that conveys neurophysiological information complementary to that provided by EEG, with high temporal and spatial resolution. Despite its a priori, highly competitive profile, the role of MEG in the clinical setting is still controversial. We briefly review the major obstacles MEG faces in becoming a routine clinical test and the different strategies needed to bypass them. The high cost and complexity associated with MEG equipment are powerful hindrances to wide acceptance of this relatively new technique in clinical practice. The most straightforward advantage is based on the relative facility of MEG recordings in the process of source localization, which also carries some degree of uncertainty, thus partly explaining why the development of clinical applications of MEG has been so slow. Obviously, a decrease in the cost and the elaboration of semiautomatic protocols that could reduce the complexity of the studies and favor the development of consensual strategies, as well as a major effort on the part of clinicians to identify clinical issues where MEG could be decisive, would be most welcome.

Towards optimal recording and analysis of the mismatch negativity.

In this paper, the conceptual and practical issues related to the measurement of mismatch negativity (MMN) are discussed from the viewpoint of cost-efficiency. First, various criteria for efficiency or optimality of measurements are described, including reliability and signal-to-noise ratio. Then a critical look is taken at some currently used concepts and data analysis methods. Practical guidelines for the measurement and analysis of MMN are given, complementing the earlier reviews on the subject. Finally, reliability studies on MMN are critically reviewed.

Spike and slow wave localization by magnetoencephalography.

At institutions where MEG is available, it is now considered a standard part of the diagnostic workup of most patients with epilepsy. Available data indicate that interictal MEG can be an effective tool for localization of the epileptic irritative zone, and in some cases it can even indicate the seizure onset site. Both spike and ALFMA examinations are clinically viable because of the availability of large-array systems. The current cost of acquiring MEG technology is high (greater than 2 million dollars), but recent technical developments should soon yield more cost-effective systems. It is anticipated that the increasing applicability of this technology to conditions beyond epilepsy (e.g., head trauma, ischemic disease, dementia, and psychiatric dysfunction) will soon render MEG a critical element in the general armamentarium of diagnostic procedures available to epileptologists, radiologists, neurologists, neurosurgeons, and psychiatrists.

Applications of magnetic source imaging to presurgical brain mapping.

This article highlights the patient benefits of noninvasive presurgical mapping using magnetic source imaging, discusses magnetic source imaging in terms of its practical implementation and current limitations in mapping the human cerebral cortex, and illustrates the use of magnetic source imaging in ongoing clinical studies. An overview of preliminary research studies that have attempted to evaluate the accuracy and cost-effectiveness of magnetic source imaging in presurgical mapping is also provided.