The Cost of After-Hour Electroencephalography

Background and Objectives

High costs associated with after-hour electroencephalography (EEG) constitute a barrier for financially constrained hospitals to provide this neurodiagnostic procedure outside regular working hours. Our study aims to deepen our understanding of the cost elements involved in delivering EEG services during after-hours.

Methods

We accessed publicly available data sets and created a cost model depending on 3 most commonly seen staffing scenarios: (1) technologist on-site, (2) technologist on-call from home, and (3) a hybrid of the two.

Results

Cost of EEG depends on the volume of testing and the staffing plan. Within the various cost elements, labor cost of EEG technologists is the predominant expenditure, which varies across geographic regions and urban areas.

Discussion

We provide a model to explain why access to EEGs during after-hours has a substantial expense. This model provides a cost calculator tool (made available as part of this publication in eAppendix 1, links.lww.com/CPJ/A513) to estimate the cost of EEG platform based on site-specific staffing scenarios and annual volume.

Clinical Neurophysiology Fellowship Program Directors Survey on a Standardized Fellowship Match Process: A Call for Action

PURPOSE

To survey US Clinical Neurophysiology (CNP) fellowship program directors on the nature of CNP and related training programs, current recruitment cycle, and views for a standardized process.

METHODS

A 23-question electronic survey was sent to all 93 US Accreditation Council for Graduate Medical Education-accredited CNP fellowship program directors from December 2020 to January 2021.

RESULTS

The response rate was 60%. There was great variability in the number of CNP positions and CNP tracks offered. The following tracks were identified: 48% EEG dominant, 26% EMG dominant, 22% split equally between EEG and EMG, and 2% and 1% were neurophysiologic intraoperative monitoring and autonomic dominant, respectively. Of the responding institutions, 43% offered a second year of training options to CNP fellows, mainly in conjunction with Epilepsy fellowship, which was pursued by 25% of CNP fellows. Many programs indicated flexibility in their design between different CNP tracks or between CNP and other related training programs based on the available candidates. The median percentage of CNP fellowship positions filled over the last 5 years was 80%, and there was great variation in the recruitment timeline across institutions. Overall, 86% of program directors favored a universal timeline and 71% favored a formal match for CNP. The respondents were split between an independent CNP match (39%) and joining the initiatives of affiliate societies on a standardized process (61%).

CONCLUSIONS

There is significant heterogeneity in the makeup of the CNP fellowship programs and the recruitment process. The majority of CNP program directors are in favor of standardization of the recruitment process.

Epidural electrical stimulation of the cervical spinal cord opposes opioid-induced respiratory depression

Opioid overdose suppresses brainstem respiratory circuits, causes apnoea and may result in death. Epidural electrical stimulation (EES) at the cervical spinal cord facilitated motor activity in rodents and humans, and we hypothesized that EES of the cervical spinal cord could antagonize opioid-induced respiratory depression in humans. Eighteen patients requiring surgical access to the dorsal surface of the spinal cord between C2 and C7 received EES or sham stimulation for up to 90 s at 5 or 30 Hz during complete (OFF-State) or partial suppression (ON-State) of respiration induced by remifentanil. During the ON-State, 30 Hz EES at C4 and 5 Hz EES at C3/4 increased tidal volume and decreased the end-tidal carbon dioxide level compared to pre-stimulation control levels. EES of 5 Hz at C5 and C7 increased respiratory frequency compared to pre-stimulation control levels. In the OFF-State, 30 Hz cervical EES at C3/4 terminated apnoea and induced rhythmic breathing. In cadaveric tissue obtained from a brain bank, more neurons expressed both the neurokinin 1 receptor (NK1R) and somatostatin (SST) in the cervical spinal levels responsive to EES (C3/4, C6 and C7) compared to a region non-responsive to EES (C2). Thus, the capacity of cervical EES to oppose opioid depression of respiration may be mediated by NK1R+/SST+ neurons in the dorsal cervical spinal cord. This study provides proof of principle that cervical EES may provide a novel therapeutic approach to augment respiratory activity when the neural function of the central respiratory circuits is compromised by opioids or other pathological conditions. KEY POINTS: Epidural electrical stimulation (EES) using an implanted spinal cord stimulator (SCS) is an FDA-approved method to manage chronic pain. We tested the hypothesis that cervical EES facilitates respiration during administration of opioids in 18 human subjects who were treated with low-dose remifentanil that suppressed respiration (ON-State) or high-dose remifentanil that completely inhibited breathing (OFF-State) during the course of cervical surgery. Dorsal cervical EES of the spinal cord augmented the respiratory tidal volume or increased the respiratory frequency, and the response to EES varied as a function of the stimulation frequency (5 or 30 Hz) and the cervical level stimulated (C2-C7). Short, continuous cervical EES restored a cyclic breathing pattern (eupnoea) in the OFF-State, suggesting that cervical EES reversed the opioid-induced respiratory depression. These findings add to our understanding of respiratory pattern modulation and suggest a novel mechanism to oppose the respiratory depression caused by opioids.

Overview of intraoperative neuromonitoring

Intraoperative neuromonitoring (IONM) is used widely to reduce neurologic adverse postoperative outcomes. A variety of techniques are used. Initial techniques were used as far back as the 1930s, and the variety of methods expanded greatly since the 1980s. Many methods monitor baseline findings over time. Other methods test for neurologic function to identify nerves or eloquent cortex. Physicians trained in neurophysiology are key for interpretation of findings, supervision of staff, and making medical recommendations to the surgeon or anesthesiologist. Some neurophysiologists provide the services personally, and in other circumstances well-trained technologist staff help with the techniques. Much IONM is provided by the neurophysiology physician in the operating room, whereas in other cases, the physician may be on-line in real time from a remote site. When monitoring identifies changes, the IONM team must give a clear, timely, and compelling message to the surgeon and anesthesiologist.

Neurophysiology during epilepsy surgery

Intraoperative neuromonitoring (IONM) complements modern presurgical investigations by providing information about the epileptic focus as well as real-time identification of critical functional tissue and assessment of ongoing neural integrity during resective epilepsy surgery. This chapter summarizes current IONM methods for mapping the epileptic focus and for mapping and monitoring functionally important structures with direct brain stimulation and evoked potentials. These techniques include electrocorticography, computerized high-frequency oscillation mapping, single-pulse electric stimulation, cortical and subcortical motor evoked potentials, somatosensory evoked potentials, visual evoked potentials, and cortico-cortical evoked potentials. They may help to maximize epileptic tissue resection while avoiding permanent postoperative neurologic deficits.

Electroencephalography, electrocorticography, and cortical stimulation techniques

Electroencephalography (EEG) and electrocorticography (ECoG) are two important neurophysiologic techniques used in the operating room for monitoring and mapping electrical brain activity. In this chapter, we detail their principle, recording methodology, and address specifics of their interpretation in the intraoperative setting (e.g., effect of anesthetics), as well as their clinical applications in epilepsy and non-epilepsy surgeries. In addition, we address differences between scalp, surface, and deep cortical recordings that will help towards a more reliable interpretation of the significance of electrophysiologic parameters such as amplitude and morphology as well as in differentiation between abnormal and normal patterns of electrical brain activity. Electrical stimulation is used for intraoperative mapping of different cortical functions such as language, parietal, and motor. Stimulation paradigms used in clinical practice vary with regard to stimulation frequencies and probes being used. Parameters, such as the number of phases per pulse, pulse/phase duration, pulse frequency, organization, and polarity, define their characteristics, including their safety, propensity to trigger seizures, efficiency and reliability of stimulation, and the mapping thresholds. Specifically, in this chapter, we will address differences between monopolar and bipolar stimulation; anodal and cathodal polarity; monophasic and biphasic pulses; constant voltage, and constant current paradigms.

Monitoring scoliosis and other spinal deformity surgeries

Surgery to correct a spinal deformity incurs a risk of injury to the spinal cord and roots. Injuries include postoperative paraplegia. Surgery for cervical myelopathy also incurs risk for postoperative motor deficits, as well as nerve injury most commonly at the C5 root. Risks can be mitigated by monitoring the nervous system during surgery. Ideally, monitoring detects an impending injury in time to intervene and correct the impairment before it becomes permanent. Monitoring includes several modalities of testing. Somatosensory evoked potentials measure axonal conduction in the spinal cord posterior columns. This can be checked almost continuously during surgery. Motor evoked potentials measure conduction along the lateral corticospinal tracts. Because motor pathway stimulation often produces a patient movement on the table, these often are tested periodically rather than continuously. Electromyography observes for spontaneous discharges accompanying injuries, and is useful to assess misplacement of pedicle screws. Literature demonstrates the usefulness of these techniques, their association with reducing motor adverse outcomes, and the relative value of the techniques. Neurophysiologic monitoring for scoliosis, kyphosis, and cervical myelopathy surgery are addressed, along with background information about those conditions.

Neurocritical Care Coding for Neurologists

Coding specifies the work performed when providing patient care. Critical care services mostly use code 99291, and other codes specify additional time and procedures. Current Procedural Terminology defines critically ill as "a high probability of imminent or life-threatening deterioration in the patient's condition," a condition necessary for use of the critical care code. A patient may be critically ill for neurologic reasons even when stable from a cardiorespiratory status. Rules govern who can use these codes, whether they can be used by more than one physician, the locations where the code may be used, and what services are included and excluded. Physicians need to document the medical necessity of visits and nature of critical illness or high-risk medical decision making because auditors may not understand the nature of serious neurologic illness.

Spinal cord monitoring

Spinal cord surgery carries the risk of spinal cord or nerve root injury. Neurophysiologic monitoring decreases risk of injury by continuous assessment of spinal cord and nerve root function throughout surgery. Techniques include somatosensory evoked potentials (SEPs), transcranial electrical motor evoked potentials (MEPs), and electromyography (EMG). Baseline neurophysiologic data are obtained prior to incision. Real-time signal changes are identified in time to correct compromised neural function. Such monitoring improves postoperative neurologic functional outcomes. Challenges in neurophysiologic intraoperative monitoring (NIOM) include effects of anesthetics, neuromuscular blockade, hypotension, hypothermia, and preexisting neurological conditions, e.g., neuropathy or myelopathy. Technical factors causing poor quality data must be overcome in the electrically noisy operating room environment. Experienced monitoring teams understand tactics to obtain quality recordings and consider confounding variables before raising alarms when change occurs. Once an alert is raised, surgeons and anesthesiologists respond with a variety of actions, such as raising blood pressure or adjusting retractors. In experienced hands, NIOM significantly reduces postoperative neurological deficits, e.g., 60% reduction in risk of paraplegia and paraparesis. A technologist in the operating room sets up the NIOM procedure. An experienced clinical neurophysiologist supervises the case, either in the operating room or remotely on-line continuously in real time.

AR2, a novel automatic muscle artifact reduction software method for ictal EEG interpretation: Validation and comparison of performance with commercially available software

Objective: To develop a novel software method (AR2) for reducing muscle contamination of ictal scalp electroencephalogram (EEG), and validate this method on the basis of its performance in comparison to a commercially available software method (AR1) to accurately depict seizure-onset location. Methods: A blinded investigation used 23 EEG recordings of seizures from 8 patients. Each recording was uninterpretable with digital filtering because of muscle artifact and processed using AR1 and AR2 and reviewed by 26 EEG specialists. EEG readers assessed seizure-onset time, lateralization, and region, and specified confidence for each determination. The two methods were validated on the basis of the number of readers able to render assignments, confidence, the intra-class correlation (ICC), and agreement with other clinical findings. Results: Among the 23 seizures, two-thirds of the readers were able to delineate seizure-onset time in 10 of 23 using AR1, and 15 of 23 using AR2 (p<0.01). Fewer readers could lateralize seizure-onset (p<0.05). The confidence measures of the assignments were low (probable-unlikely), but increased using AR2 (p<0.05). The ICC for identifying the time of seizure-onset was 0.15 (95% confidence interval (CI), 0.11-0.18) using AR1 and 0.26 (95% CI 0.21-0.30) using AR2.  The EEG interpretations were often consistent with behavioral, neurophysiological, and neuro-radiological findings, with left sided assignments correct in 95.9% (CI 85.7-98.9%, n=4) of cases using AR2, and 91.9% (77.0-97.5%) (n=4) of cases using AR1. Conclusions: EEG artifact reduction methods for localizing seizure-onset does not result in high rates of interpretability, reader confidence, and inter-reader agreement. However, the assignments by groups of readers are often congruent with other clinical data. Utilization of the AR2 software method may improve the validity of ictal EEG artifact reduction.

Quantitative EEG in attention-deficit/hyperactivity disorder: A companion payment policy review for clinicians and payers

Quantitative EEG measurement of the scalp vertex theta/beta ratio (TBR) is marketed as a tool for use in the evaluation of patients who may have attention-deficit/hyperactivity disorder (ADHD). The American Academy of Neurology (AAN) recently assessed the literature about this tool. The assessment urged caution, considering that the TBR remains an investigational research tool at this time. This perspective comments further on that assessment and its rationale, and recommends a perspective for the clinician and payer.

Engaging Cervical Spinal Cord Networks to Reenable Volitional Control of Hand Function in Tetraplegic Patients

BACKGROUND

Paralysis of the upper limbs from spinal cord injury results in an enormous loss of independence in an individual's daily life. Meaningful improvement in hand function is rare after 1 year of tetraparesis. Therapeutic developments that result in even modest gains in hand volitional function will significantly affect the quality of life for patients afflicted with high cervical injury. The ability to neuromodulate the lumbosacral spinal circuitry via epidural stimulation in regaining postural function and volitional control of the legs has been recently shown. A key question is whether a similar neuromodulatory strategy can be used to improve volitional motor control of the upper limbs, that is, performance of motor tasks considered to be less "automatic" than posture and locomotion. In this study, the effects of cervical epidural stimulation on hand function are characterized in subjects with chronic cervical cord injury.

OBJECTIVE

Herein we show that epidural stimulation can be applied to the chronic injured human cervical spinal cord to promote volitional hand function.

METHODS AND RESULTS

Two subjects implanted with a cervical epidural electrode array demonstrated improved hand strength (approximately 3-fold) and volitional hand control in the presence of epidural stimulation.

CONCLUSIONS

The present data are sufficient to suggest that hand motor function in individuals with chronic tetraplegia can be improved with cervical cord neuromodulation and thus should be comprehensively explored as a possible clinical intervention.

Diagnostic Coding for Epilepsy

Accurate coding is an important function of neurologic practice. This contribution to Continuum is part of an ongoing series that presents helpful coding information along with examples related to the issue topic. Tips for diagnosis coding, Evaluation and Management coding, procedure coding, or a combination are presented, depending on which is most applicable to the subject area of the issue.

Practice advisory: The utility of EEG theta/beta power ratio in ADHD diagnosis: Report of the Guideline Development, Dissemination, and Implementation Subcommittee of the American Academy of Neurology

OBJECTIVE

To evaluate the evidence for EEG theta/beta power ratio for diagnosing, or helping to diagnose, attention-deficit/hyperactivity disorder (ADHD).

METHODS

We identified relevant studies and classified them using American Academy of Neurology criteria.

RESULTS

Two Class I studies assessing the ability of EEG theta/beta power ratio and EEG frontal beta power to identify patients with ADHD correctly identified 166 of 185 participants. Both studies evaluated theta/beta power ratio and frontal beta power in suspected ADHD or in syndromes typically included in an ADHD differential diagnosis. A bivariate model combining the diagnostic studies shows that the combination of EEG frontal beta power and theta/beta power ratio has relatively high sensitivity and specificity but is insufficiently accurate.

CONCLUSIONS

It is unknown whether a combination of standard clinical examination and EEG theta/beta power ratio increases diagnostic certainty of ADHD compared with clinical examination alone.

RECOMMENDATIONS

Level B: Clinicians should inform patients with suspected ADHD and their families that the combination of EEG theta/beta power ratio and frontal beta power should not replace a standard clinical evaluation. There is a risk for significant harm to patients from ADHD misdiagnosis because of the unacceptably high false-positive diagnostic rate of EEG theta/beta power ratio and frontal beta power. Level R: Clinicians should inform patients with suspected ADHD and their families that the EEG theta/beta power ratio should not be used to confirm an ADHD diagnosis or to support further testing after a clinical evaluation, unless such diagnostic assessments occur in a research setting.

Critical Care Coding for Neurologists

Accurate coding is an important function of neurologic practice. This contribution to Continuum is part of an ongoing series that presents helpful coding information along with examples related to the issue topic. Tips for diagnosis coding, Evaluation and Management coding, procedure coding, or a combination are presented, depending on which is most applicable to the subject area of the issue.

Chronic care management coding for neurologists

Chronic care management provides a way for neurologists to code for time spent by clinical office staff who coordinate services for patients with major chronic illnesses. Medicare allows payment for one such code; some third party payers accept 2 additional codes. When using these codes, the physician develops a Care Plan that organizes the patient's medical and psychosocial needs. Clinical office staff communicates among the patient's physicians, therapists, community services, the patient, family, and caregiver. The patient chooses only one physician whose office provides these coordination services. Rules include 24/7 access for urgent phone contact and use of an electronic health record system.

Does intraoperative neurophysiologic monitoring matter in noncomplex spine surgeries?

Objectives:

To determine associations between intraoperative neurophysiologic monitoring (IOM) for spinal decompressions and simple fusions with neurologic complications, length of stay, and hospitalization charges.

Methods:

Adult discharges in the Nationwide/National Inpatient Sample (NIS) (2007–2012) with spinal decompressions and simple spinal fusions were included. Revision surgeries, instrumentations, complicated approaches, and tumor- and trauma-related surgeries were excluded. Extracted data included patient demographics, medical comorbidities, primary spinal surgery type, and hospital characteristics. Bivariate and multiple regression analyses using NIS survey design variables correlated IOM use with neurologic complications, hospital charges, and length of stay.

Results:

IOM was reported in 4.9% of an estimated 1.1 million discharges in the weighted sample. Discharges reporting IOM were more often privately insured (61% vs 57%, p < 0.001) and had slightly more comorbidities (25% vs 24% with 3+ comorbidities, p = 0.01). Spinal fusions more often reported IOM than decompressions. The IOM group had fewer neurologic complications (0.8% vs 1.4% of controls) with no difference in length of stay (3.0 days for each group), but increased hospital charges (39% greater). Multiple regression adjustment showed significant associations of IOM with fewer neurologic complications (odds ratio 0.60, 95% confidence interval [CI] 0.47, 0.76, p < 0.001), while the estimated percentage of hospital charges was sizably diminished from the unadjusted analysis (IOM effect +9%, 95% CI +4%, +13%, p < 0.001), and length of stay was reduced (IOM effect −0.26 days, 95% CI −0.42, −0.11, p < 0.001).

Conclusions:

IOM was associated with better clinical outcomes and some increased hospital charges among discharges of simple spinal fusions and laminectomies in a large, multiyear, nationally representative dataset.

Continuous and routine EEG in intensive care: utilization and outcomes, United States 2005-2009

OBJECTIVES

To evaluate the effect of intensive care unit continuous EEG (cEEG) monitoring on inpatient mortality, hospital charges, and length of stay.

METHODS

A retrospective cross-sectional study was conducted using the Nationwide Inpatient Sample, a dataset representing 20% of inpatient discharges in nonfederal US hospitals. Adult discharge records reporting mechanical ventilation and EEG (routine EEG or cEEG) were included. cEEG was compared with routine EEG alone in association with the primary outcome of in-hospital mortality and secondary outcomes of total hospital charges and length of stay. Demographics, hospital characteristics, and medical comorbidity were used for multivariate adjustments of the primary and secondary outcomes.

RESULTS

A total of 40,945 patient discharges in the weighted sample met inclusion criteria, of which 5,949 had reported cEEG. Mechanically ventilated patients receiving cEEG were younger than routine EEG patients (56 vs 61 years; p < 0.001). There was no difference in the 2 groups in income or medical comorbidities. cEEG was significantly associated with lower in-hospital mortality in both univariate (odds ratio = 0.54, 95% confidence interval 0.45-0.64; p < 0.001) and multivariate (odds ratio = 0.63, 95% confidence interval 0.51-0.76; p < 0.001) analyses. There was no significant difference in costs or length of stay for patients who received cEEG relative to those receiving only routine EEG. Sensitivity analysis showed that adjusting for diagnosis-related groups (DRGs) for any neurologic diagnoses, DRGs for neurologic procedures, and specific DRGs for epilepsy/convulsions did not substantially alter the association of cEEG with reduced inpatient mortality.

CONCLUSIONS

cEEG is favorably associated with inpatient survival in mechanically ventilated patients, without adding significant charges to the hospital stay.

Changes in emergency department coverage for the neurologist

The role of the neurologist in the emergency department (ED) is constantly evolving and has become more diversified in recent times. This article gives an overview of different practice models that neurologists are employing to cover ED calls. A review of billing and coding for ED visits is also discussed.

Suboccipital craniotomy for Chiari I results in evoked potential conduction changes

BACKGROUND

Management of Chiari I is controversial, in part because there is no widely used quantitative measurement of decompression. It has been demonstrated that brainstem auditory evoked responses (BAER) and somatosensory evoked potentials (SSEP) have decreased conduction latencies after wide craniectomy. We analyzed these parameters in a suboccipital craniectomy/craniotomy procedure.

METHODS

Thirteen consecutive patients underwent suboccipital decompression for treatment of symptomatic Chiari I. Craniectomy was restricted to the inferior aspect of the nuchal line, and in most cases the bone flap was replaced. Neuronal conduction was monitored continuously with median nerve somatosensory evoked potentials (M-SEP), posterior tibial nerve somatosensory evoked potentials (T-SEP), BAER, or a combination. The M-SEP N20, T-SEP P37, and BAER V latencies were recorded at four milestones - preoperatively, following craniotomy, following durotomy, and following closure.

RESULTS

Five males and eight females, with average age of 9 years, were studied. Clinical improvement was noted in all 13 patients. M-SEP N20 latency decreased from a mean of 18.55 at baseline to 17.75 ms after craniotomy (P = 0.01); to 17.06 ms after durotomy (P = 0.01); and to 16.68 ms after closing (P = 0.02). T-SEP P37 latency did not change significantly. BAER V latency decreased from a mean of 6.25 ms at baseline to 6.14 ms after craniotomy (P = 0.04); to 5.98 ms after durotomy (P = 0.01); and to 5.95 ms after closing (P = 0.45).

CONCLUSION

Significant improvements in conduction followed both craniectomy and durotomy. Bone replacement did not affect these results.