Selective dorsal rhizotomy (SDR) is a treatment for lower-extremity spasticity in disorders such as cerebral palsy (CP). "Selective" refers to sectioning nerve rootlets with the most abnormal responses on electromyograph...Selective dorsal rhizotomy (SDR) is a treatment for lower-extremity spasticity in disorders such as cerebral palsy (CP). "Selective" refers to sectioning nerve rootlets with the most abnormal responses on electromyography (EMG) upon intraoperative stimulation. EMG abnormalities can be classified by waveform appearance or by degree of spread throughout lower extremity muscles. We examine the relationship between different EMG waveforms and grades of spread. Intraoperative SDR EMG records from November 2009 through December 2021 were analyzed for waveform types and degrees of spread. Irregular, incremental, multiphasic, sustained, and clonic waveform patterns were considered more abnormal. Decremental, squared decremental, and squared waveforms were less abnormal. Degrees of spread were graded 0-4+, 4+ signifying the most abnormal spread. Distribution of grades of spread was compared between waveform patterns using pairwise Cochran-Armitage tests with Holm-Bonferroni correction. We hypothesized that more abnormal EMG waveform patterns would correlate with higher grades of spread. Sixty-three patients were included, with an average age of 8 years. Most had cerebral palsy (86%, n = 54). The remainder had brain malformations (8%, n = 5) and other etiologies (6%, n = 4). Higher grades of spread significantly increased the likelihood of multiphasic, sustained, or clonic patterns, compared to decremental, irregular, and squared patterns (p < .05). Squared waveforms decreased with higher grades of spread relative to other patterns (p < .05). Different EMG waveform patterns are associated with varying grades of spread in SDR, suggesting that evaluating both waveform pattern and degree of spread together can be useful in guiding rootlet sectioning.
A 42-year-old female presented with acute onset of asymmetric lower extremity weakness, bilateral lower extremity areflexia and sensory loss, and urinary incontinence. Initial investigation with a spine MRI for a spinal...A 42-year-old female presented with acute onset of asymmetric lower extremity weakness, bilateral lower extremity areflexia and sensory loss, and urinary incontinence. Initial investigation with a spine MRI for a spinal cord process was negative, leading to further investigation with nerve conduction studies/electromyography (NCS/EMG). This revealed absent F waves bilaterally in the fibular nerves, and there was only one isolated F wave with decreased amplitude and increased latency in the left tibial nerve and had lack of heterogeneity in the right tibial nerve. Given the early presentation of her symptoms, this led to a working diagnosis of Guillain-Barré Syndrome, which was treated with plasmapheresis without improvement. After plasmapheresis, the diagnosis was revisited, and a repeat spine MRI revealed an extensive lower thoracic and lumbar spinal cord infarction. In this unique scenario, the properties and abnormalities of F waves are discussed and reviewed, along with the influence of acute central nervous system lesions on their configuration.
Brain-computer interface (BCI) is a term used to describe systems that translate biological information into commands that can control external devices such as computers, prosthetics, and other machinery. While BCI is us...Brain-computer interface (BCI) is a term used to describe systems that translate biological information into commands that can control external devices such as computers, prosthetics, and other machinery. While BCI is used in military applications, home control systems, and a wide array of entertainment, much of its modern interest and funding can be attributed to its utility in the medical community, where it has rapidly propelled advancements in the restoration or replacement of critical functions robbed from victims of disease, stroke, and traumatic injury. BCI devices can allow patients to move prosthetic limbs, operate devices such as wheelchairs or computers, and communicate through writing and speech-generating devices. In this article, we aim to provide an introductory summary of the historical context and modern growing utility of BCI, with specific interest in igniting the conversation of where and how the neurodiagnostics community and its associated parties can embrace and contribute to the world of BCI.
A craniotomy with cortical and subcortical mapping was planned for a 64-year-old male with a large right frontotemporal brain mass. Total intravenous anesthesia was performed, and 200 milligrams of succinylcholine was ad...A craniotomy with cortical and subcortical mapping was planned for a 64-year-old male with a large right frontotemporal brain mass. Total intravenous anesthesia was performed, and 200 milligrams of succinylcholine was administered at induction. A train of four prior to head pinning (52 minutes after succinylcholine administration) revealed zero of four twitches in the left hand and foot. The patient did not regain spontaneous breathing despite discontinuation of infusions and the surgeon canceled the case at 108 minutes from induction. The patient was safely extubated at 270 minutes. Pseudocholinesterase deficiency was suspected, and labs revealed that the patient was outside of the normal range for pseudocholinesterase enzyme at 698 units/L with a dibucaine inhibition number of 40. The patient's procedure was rescheduled 2 days later, and neuromuscular blockade was avoided. The procedure went ahead as planned with successful mapping and monitoring. This case highlights the effect of pseudocholinesterase deficiency on neuromonitoring and the importance of running train of four early on to detect neuromuscular junction issues in high-risk procedures. In this case, the surgeon was able to avoid pinning and positioning the patient and rescheduled the procedure so that motor mapping, direct cortical motor evoked potentials, and transcranial motor evoked potentials could be successfully performed.
Graphogenic, or writing epilepsy, is a rare type of reflex epilepsy (RE) in which seizures are provoked by the act of writing. RE is a condition that affects between 4% and 7% of all patients diagnosed with epilepsy. In...Graphogenic, or writing epilepsy, is a rare type of reflex epilepsy (RE) in which seizures are provoked by the act of writing. RE is a condition that affects between 4% and 7% of all patients diagnosed with epilepsy. In this case study, we provide a case report on a patient whose seizures were generated by the act of writing. We also present evidence that the cortical mechanisms by which writing-induced seizures occur are focal with possible secondary generalization.
Intraoperative neurophysiological monitoring (IONM) is instrumental in mitigating neurological deficits following cranial and spinal procedures. Despite extensive research on IONM's ability to recognize limb-malposition-...Intraoperative neurophysiological monitoring (IONM) is instrumental in mitigating neurological deficits following cranial and spinal procedures. Despite extensive research on IONM's ability to recognize limb-malposition-related issues, less attention has been given to other secondary neural injuries in cranial surgeries. A comprehensive multimodal neuromonitoring approach was employed during a left frontal craniotomy for tumor resection. The electronic medical record was reviewed in detail in order to describe the patient's clinical course. The patient, a 46-year-old female, underwent craniotomy for excision of a meningioma. Deteriorations in somatosensory evoked potential and transcranial motor evoked potential recordings identified both a mal-positioned limb as well as an infiltrated intravenous (IV) line in the arm contralateral to the surgical site. The IONM findings for the infiltrated IV were initially attributed to potential limb malposition until swelling and blistering of the limb were appreciated and investigated. The timely identification and management of the infiltrated IV and adjustment of limb positioning contributed to the patient's recovery, avoiding fasciotomy, with no postoperative neurological deficits. This case is the first published demonstration of the utility of IONM in detecting IV infiltration. This early recognition facilitated early intervention, saving the patient from a potential fasciotomy and enabling their recovery with no postoperative neurological deficits. The findings from this single case highlight the necessity for vigilant and dynamic application of IONM techniques to enhance patient safety and outcomes in neurosurgical procedures. Further research is needed to explore broader applications and further optimize the detection capabilities of IONM.
Epileptiform abnormalities that arise over the midline can sometimes be confused with normal sleep transients, such as vertex sharp waves, because of their location and their activation during sleep. However, epileptifor...Epileptiform abnormalities that arise over the midline can sometimes be confused with normal sleep transients, such as vertex sharp waves, because of their location and their activation during sleep. However, epileptiform transients can be distinguished from sleep architecture by their waveform and their occurrence during wakefulness. Here, we report a 24-year-old man with drug-resistant epilepsy whose seizures began with tonic posturing of the left leg before progressing to bilateral tonic-clonic activity. During presurgical scalp video-EEG monitoring, his interictal background showed focal spike-wave discharges maximal over the vertex (phase reversal at Cz), with a more-well-defined field over the right parasagittal region (C4/F4), that were present during both sleep and awake states. The discharges met the IFCN criteria for focal interictal epileptiform discharges (spiky morphology, duration shorter than background activity, asymmetric waveform, after-going slow wave, and physiologic distribution) and appeared to be distinct from the patient's vertex sharp waves. Prior to electroclinical seizures, these discharges would increase in prevalence and appear as repetitive spike-wave discharges. When distinguishing epileptiform from nonepileptiform transients, it is critical to consider both their morphology, especially the degree of background disruption and presence of an after-going slow wave, and their variability with state changes.
This paper reviews the evidence base for an in-hospital 12-month training program in neurodiagnostic technology utilizing two educational tracks: Electroencephalography (EEG) or Polysomnography (PSG), employing standardi...This paper reviews the evidence base for an in-hospital 12-month training program in neurodiagnostic technology utilizing two educational tracks: Electroencephalography (EEG) or Polysomnography (PSG), employing standardized didactic courses via the ASET - The Neurodiagnostic Society EEGCore Curriculum EEG 200-211 and the A-STEP online sleep self-study modules by the American Academy of Sleep Medicine (AASM). Specifically, we examine the purpose, strategy, and outcomes for the training program that was established in 2016 at Ann & Robert H. Lurie Children's Hospital of Chicago to support mission sustaining service lines. In addition, we report the results from a series of student course evaluations and an independent assessment of the program by ABRET Neurodiagnostic Credentialing and Accreditation through the application for programmatic recognition for EEG. Finally, we present a set of recommendations for organizations looking to develop a neurodiagnostic technology training program.
Recurrent laryngeal nerve (RLN) injury during neck surgery can cause significant morbidity related to vocal cord (VC) dysfunction. VC electromyography (EMG) is used to aid in the identification of the RLN and can reduce...Recurrent laryngeal nerve (RLN) injury during neck surgery can cause significant morbidity related to vocal cord (VC) dysfunction. VC electromyography (EMG) is used to aid in the identification of the RLN and can reduce the probability of inadvertent surgical injury. Errors in the placement of specialized EMG endotracheal tubes (ETT) can result in unreliable signals, false-negative responses, or no response when stimulating the RLN. We describe a novel educational protocol developed to optimize uniformity in the placement of ETTs to improve the reliability of RLN monitoring. An intraoperative neuromonitoring database was queried for all neck surgeries requiring RLN monitoring. Data points extracted for all cases requiring EMG monitoring for neck procedures. Free running and stimulated EMG were monitored and continuously recorded by a certified technologist. Alerts were compared between 2013-14 and 2015-18 using a two-sample test of proportions. Significant reductions in alerts were demonstrated after protocol implementation (7.5% pre-implementation to 2.1% post). Alerts were compared between 2013-14 (overall alert rate of 1.8%, pre-implementation period) and 2015-18 (overall alert rate of 2.8%, post-implementation period). Protocolization for placement of EMG-ETT improved accuracy in EMG monitoring. In the follow-up cohort of 1,080 patients, use of this protocol continued to reduce the rate of alerts related to ETT malposition, confirming the sustainability of this intervention through routine education. The risk of nerve injury is reduced when the rate of alerts is minimized. Scheduled or continuous protocol education of anesthesia personnel should continue to ensure compliance with protocol.
Entrapment neuropathy of the ulnar nerve at the elbow, the so-called cubital tunnel syndrome, is the second most frequent focal mononeuropathy after carpal tunnel syndrome in adults. Currently, there is a pressing need t...Entrapment neuropathy of the ulnar nerve at the elbow, the so-called cubital tunnel syndrome, is the second most frequent focal mononeuropathy after carpal tunnel syndrome in adults. Currently, there is a pressing need to identify cost-effective biomarkers and procedures capable of accurately detecting alterations in ulnar nerve structural and functional integrity. Established electrophysiological techniques, such as motor and sensory nerve conduction studies, along with needle electromyography of specific muscles, represent the gold standard for ulnar nerve electrodiagnosis. Concurrently, the introduction of neuromuscular ultrasound and its integration into electromyographic laboratories has significantly impacted structural diagnosis and the precise localization of ulnar nerve pathology over the past two decades. In this review, our objective is to summarize the current knowledge on both classical and advanced diagnostic methods utilized in clinical neurophysiology laboratories. We aim to provide a synthesis of modern electrodiagnostic and neurosonographic techniques, with a particular emphasis on easily attainable, clinically relevant parameters.
Although real-time event detection during video EEG recording is required to ensure patients' safety, it is limited by the technologists' availability. We sought to explore the efficiency of real-time event detection by...Although real-time event detection during video EEG recording is required to ensure patients' safety, it is limited by the technologists' availability. We sought to explore the efficiency of real-time event detection by the EEG technologists in a single tertiary academic center. We retrospectively reviewed events from continuous inpatient video EEGs (cEEGs) and epilepsy monitoring unit (EMU) recordings in January 2017, when real-time surveillance was only available during the night shift, and June 2017, when a dedicated neurodiagnostic EEG technologist was available for real-time monitoring during all shifts. The events were categorized into those detected immediately (eyes-on), later in the same shift (delayed) or identified on the subsequent shift (missed). Chi-square and Fisher's exact tests were used for statistical comparisons. In January 2017, there were 25 patients (117 days of monitoring) in the EMU and 54 inpatients (146 days of monitoring) on cEEG with 92 total events, (39% seizures). In June 2017, there were 30 patients (133 days of monitoring) in the EMU and 47 additional inpatients (80 days of monitoring) on cEEG with 110 total events, (39% seizures). The number of events identified in real time was low and did not significantly differ among shifts regardless of the availability of the monitoring technologist. Most events were identified at the time of subsequent EEG scanning by the EEG technologist. Partial staffing for continuous video EEG surveillance is insufficient to identify events in real time. EEG technologists are able to identify events during regular EEG scanning.
The distinct and specialized movements performed in different sports disciplines may significantly influence nerve performance, potentially affecting nerve responses and the overall function within the respective athleti...The distinct and specialized movements performed in different sports disciplines may significantly influence nerve performance, potentially affecting nerve responses and the overall function within the respective athletic activities. The purpose of this study is to find the effect of forearm supination and pronation across the elbow joint on ulnar and median nerve conduction velocity (NCV) in throwers, archers, and non-athletes. A total of 34 participants both male and females were recruited with a body mass index (BMI) between 18.5 and 24.9 kg/m. Nerve conduction study (NeuroStim NS2 EMG/NCV/EP System) was used for measuring ulnar and median NCV across the elbow joint at different angles with the forearm in supination and pronation. Repeated measure analysis of variance (RMANOVA) revealed that there are statistically significant differences in mean values of forearm positions, angles, nerves and groups (p < .05). This study illuminates distinctive NCV variations across diverse athletic groups during forearm supination and pronation movements. Pronation consistently exhibited faster ulnar NCV compared to the median nerve across throwers, archers, and non-athletes, while in supination specific joint positions revealed notable differences within sports groups and nerve function.
Intraoperative neurophysiological monitoring (IONM) is shown to be useful in surgeries when the nervous system is at risk. Its success in part relies upon proper setup of often dozens of electrodes correctly placed and s...Intraoperative neurophysiological monitoring (IONM) is shown to be useful in surgeries when the nervous system is at risk. Its success in part relies upon proper setup of often dozens of electrodes correctly placed and secured upon patients and inserted in specific stimulating and recording receptacles. Given the complicated setups and the demanding operating room environment, errors in setup are bound to occur. These have led to false negatives associated with new patient morbidities including, at times, paralysis. No studies quantify the prevalence of these types of setup errors. Approximately 800,000 operations annually utilize intraoperative neuromonitoring in the US alone, so even a small percentage of errors suggests clinical significance. In addition, these types of errors hinder the overall effectiveness of IONM and may result in lower reported sensitivities and lower cost-effectiveness of this important service. We sought to discover through a prospective study and verification through chart review the prevalence of "electrode-swap" errors (when recording and/or stimulating electrodes are incorrectly placed on the patient or in the IONM equipment during setup) across all procedures monitored. We found recording and/or stimulating electrode set up errors in 24 of 454 cases (5.3%). These data and examples of how errors were discovered intraoperatively are reported. We also offer techniques to help reduce this error rate. This study demonstrates a significant potential avoidable error in IONM diagnostic utility, patient outcome, and sensitivity/specificity of alert criteria. The value of identifying and correcting these errors is consequential, multifaceted, and far-reaching.