Tatum, William O.

Purpose: These American Clinical Neurophysiology Society technical standards suggest best practices for electrical stimulation mapping (ESM) with subdural and stereotactic depth electrodes for seizure induction and mapping of brain function. Methods: A working group was convened from American Clinical Neurophysiology Society membership with expertise in ESM. PubMed searches were performed to identify pertinent peer-reviewed literature. Recurrent meetings reviewed progress, built consensus by discussion, and developed evidence-based recommendations to the extent possible. Recommendations: Stimulators used for ESM should have sufficient dynamic range, ability to interrupt a stimulus train, and ictal disrupt mechanism(s). Charge density should be calculated for the specific electrodes and ESM settings, the maximum safe limits being 52 to 57 μC/cm 2 /phase for subdural electrodes and not established for stereotactic depth electrodes. Subdural ESM for functional mapping is typically performed at 50-Hz pulse frequency, 200- to 300-µs pulse width, 2- to 8-s train duration, and 1- to 20-mA current strength. Stereo ESM is commonly performed using 2 different pulse frequencies: 1 Hz (300–500 µs pulse width, train duration up to 30 s, and often a constant current of 3–5 mA), and 50 Hz (100–500 µs pulse width, train duration 2-8 s, and 0.5–10 mA current intensity). Conclusions: This guideline provides technical standards for the performance of ESM, which will likely evolve over time with advances in technology and additional evidence (also see Graphical Abstract).

Summary: The development of clinical practice guidelines is an evolving field. In response to the need for consistent, evidence-based medical practice, the American Clinical Neurophysiology Society identified the need to update the Society's guideline development process. The American Clinical Neurophysiology Society Guidelines Committee created an action plan with the goal of improving transparency and rigor for future guidelines and bringing existing guidelines to current standards. This article provides an overview of the new American Clinical Neurophysiology Society standards for the creation of clinical guidance documents, including clinical guidelines, technical standards, and consensus statements. This process is rooted in the importance of clinical guidance documents and their significance in the context of current behests for updated standards for practicing clinical neurophysiology. The need and rationale for updating the guideline development process from its prior state were described. The updated American Clinical Neurophysiology Society categories for clinical guidance and recommendations were defined and compared. Finally, the new process is summarized, focusing on methodologies, authorship, and conflicts of interest.

AbstractObjectiveNeuromodulation is a viable option for patients with drug‐resistant epilepsies. We reviewed the management of patients with two deep brain neurostimulators. In addition, patients implanted with a device targeting the centromedian‐parafascicular (CM‐Pf) nuclear complex supplements this report to provide an illustrative case to implantation and programming a patient with three active devices.MethodsA narrative review using PubMed and Embase identified patients with drug‐resistant epilepsy implanted with more than one neurostimulator was performed. Combinations of vagus nerve stimulation (VNS), deep brain stimulation (DBS), and responsive neurostimulation (RNS) were identified. We provide a background of a newly reported case of an adult with a triple implant eventually responding to CM‐Pf DBS as the third implant following suboptimal benefit from VNS and RNS.ResultsIn review of the literature, dual‐device therapy is increasing in reports of use with combinations of VNS, RNS, and DBS to treat patients with drug‐resistant epilepsy. We review dual‐device implants with thalamic DBS device combinations, functional neural networks, and programming patients with dual devices. CM‐Pf is a new target for DBS and has shown a variable response in focal epilepsy. We report the unique case of 28‐year‐old male with drug‐resistant focal epilepsy who experienced a 75% seizure reduction with CM‐Pf DBS as his third device after suboptimal responses to VNS and RNS. After 9 months, he also experienced seizure freedom from recurrent focal to bilateral tonic–clonic seizures. No medical or surgical complications or safety issues were encountered.ConclusionWe demonstrate safety and feasibility in an adult combining active VNS, RNS, and CM‐Pf DBS. Patients with dual‐device therapy who experience a suboptimal response to initial device use at optimized settings should not be considered a neuromodulation “failure.” Strategies to combine devices require a working knowledge of brain networks.

Abstract In the case of suspicion of nonconvulsive status epilepticus (NCSE), reactivity on electroencephalograms (EEGs) can provide valuable diagnostic information. Reactivity refers to responses to auditory or somatosensory stimulation, with changes in amplitude and frequency of background activity. Because of self‐perpetuating processes and the failure of self‐terminating mechanisms, status epilepticus is unlikely to cease when patients spontaneously move, and it cannot typically be stopped by external stimulation (i.e., auditory and tactile stimuli). The defining EEG characteristic of absence status epilepticus is the presence of bilateral, synchronous, symmetric, rhythmic paroxysmal activity that shows little or no reactivity to sensory stimulation. On the other hand, in metabolic/toxic or multifactorial encephalopathies, triphasic waves (TWs) are influenced by the level of vigilance. TWs may be transiently abolished when patients increase their level of alertness from a drowsy/lethargic state to a state of wakefulness. This reactivity is only observed when patients can be aroused by a somatosensory or auditory stimulus. This reactivity tends to disappear with increasing severity of the disease and in comatose patients. In patients without preexisting developmental and epileptic encephalopathy, this pattern of stimulus‐induced wakefulness with transient improvement of the EEG is a major criterion in determining that the EEG patterns are not ictal. This criterion of reactivity on EEGs, beyond the classical clinical/EEG criteria of NCSE (Salzburg criteria), should now be systematically added.