Vagal nerve stimulators (VNS) are indicated as a palliative treatment for medically refractory epilepsy. The vagus nerve may have a variable position within the carotid sheath and may be confused with a prominent ansa ce...Vagal nerve stimulators (VNS) are indicated as a palliative treatment for medically refractory epilepsy. The vagus nerve may have a variable position within the carotid sheath and may be confused with a prominent ansa cervicalis. The objective of this study was to describe an intraoperative neuromonitoring technique for VNS placement and provide stimulation thresholds that may aid in the creation of stimulation protocols. A retrospective study was performed assessing 40 patients undergoing intraoperative vocal cord monitoring during vagal nerve stimulator placement surgery. Endotracheal electrodes were utilized to record vocal cord activity at various surgical time points. The stimulation thresholds were tested at the time of opening of the carotid sheath (mean 0.35 mA [range 0.08-1.00]), after full and circumferential dissection of the vagus nerve (0.34 mA [0.10-0.90]), after tenting of the vagus nerve in preparation for placement of the electrode (0.22 mA [0.06-1.20]), and after electrode placement (0.26 mA [0.05-1.20]). The vagus nerve was identified in all patients; it was located behind the common carotid artery (CCA) in two patients, on top of the internal jugular vein (IJV) in one patient, and in the typical location between the CCA and IJV in the remainder of patients. The average size of the vagus nerve was 2.9 mm [1.5-5.0]. Intraoperative vagus nerve stimulation represents a safe adjunctive tool that can help localize the nerve, particularly in the setting of varying anatomy or hazardous dissections. It may help reduce the potential for vagal trunk damage or electrode misplacement and potentially improve clinical outcomes.
A misconception in the field of intraoperative neurophysiological monitoring (IONM) is that continuous, multi-nerve (four-limb), interleaved somatosensory evoked potential (SSEP) stimulation, while advantageous, is not u...A misconception in the field of intraoperative neurophysiological monitoring (IONM) is that continuous, multi-nerve (four-limb), interleaved somatosensory evoked potential (SSEP) stimulation, while advantageous, is not universally utilized due to variety of misunderstandings regarding this approach to SSEP stimulation. This article addresses the rationale for this misconception. We find that continuous, multi-nerve, interleaved SSEP stimulation is superior to all other stimulation paradigms in most operative scenarios, allowing the fastest acquisition of SSEPs at low stimulation repetition rates, which generate the highest amplitude cortical responses.
Spinal cord stimulation is used to treat patients with severe neuropathic pain and other forms of debilitating back pain. Spinal cord stimulators (SCS) can either be placed under sedation or general anesthesia (GA). This...Spinal cord stimulation is used to treat patients with severe neuropathic pain and other forms of debilitating back pain. Spinal cord stimulators (SCS) can either be placed under sedation or general anesthesia (GA). This study evaluated the utility of neurogenic evoked potentials in enabling multimodal spinal cord mapping (MSCM) for the placement of SCSs under GA. The goal of our MSCM paradigm, which integrated recordings from multiple antidromic and orthodromic generators, was to enable the use of precise neuromonitoring techniques, typically used for localizing the midline of the dorsal spinal cord in intramedullary tumor cases, for the safe placement of SCSs. Two distinct modalities were incorporated - orthodromic responses from the somatosensory cortex (Cp3-Cp4 cancellation) and antidromic stimulation via the SCS which resulted in compound nerve action potentials of the extremities. In addition, two incidental findings were made. First, our results suggest that previous investigations may have incorrectly identified compound muscle action potentials as compound nerve action potentials. Additionally, anti D-wave responses, that are theorized to be the equivalent of a D-wave, were observed. This manuscript describes the first use of MSCM, which will ultimately provide neurophysiologists more information during SCS implantation, enabling them to confirm midline placement more confidently. MSCM also allows the application of techniques typically used in spinal cord tumors, allowing the neurophysiologist to maintain proficiency with these techniques on more common procedures. The parallel collection of several sources of data will allow for future studies that better define which mapping methods are the most accurate.
Supplementary motor area (SMA) syndrome refers to varying degrees of transient hemiparesis and mutism following insult to the medial posterior frontal lobe. We describe a rare case of an isolated lower limb SMA deficit w...Supplementary motor area (SMA) syndrome refers to varying degrees of transient hemiparesis and mutism following insult to the medial posterior frontal lobe. We describe a rare case of an isolated lower limb SMA deficit with associated pre- and post-operative multimodality neurophysiological monitoring data. We review the literature on SMA somatotopy and the prognostic abilities of intraoperative motor evoked potentials in suspected SMA dysfunction. A 45-year-old male underwent staged resection of a complex parasagittal WHO grade II meningioma involving the posterior superior frontal gyrus bilaterally. Intraoperative neurophysiological monitoring with transcranial motor evoked potentials (TCMEP) and direct cortical motor evoked potentials (DCMEP) were used during both stages of resection. The patient developed an isolated left foot drop despite unchanged DCMEP and TCMEP data obtained during the first stage of the procedure. During the second stage of resection 3 days later, repeat neurophysiological monitoring confirmed intact corticospinal tracts. Deep peroneal somatosensory evoked potentials (SSEPs) revealed good morphology, appropriate latency and amplitudes during the second stage of resection. These results suggested a diagnosis of focal SMA dysfunction. Left foot drop persisted 7 days post-operatively. At one month follow up, the patient was neurologically intact with full strength noted in all muscle groups of the left lower extremity. An improved understanding of the somatotopic organization of the SMA with additional neuromonitoring data can allow neurosurgeons to better predict and understand perioperative SMA dysfunctions.
To evaluate the diagnostic yield of the first 8 hours of video-EEG (vEEG) monitoring in detecting Psychogenic Non-Epileptic Seizures (PNES) during the Epilepsy Monitoring Unit (EMU) admission. We performed a retrospectiv...To evaluate the diagnostic yield of the first 8 hours of video-EEG (vEEG) monitoring in detecting Psychogenic Non-Epileptic Seizures (PNES) during the Epilepsy Monitoring Unit (EMU) admission. We performed a retrospective chart review of patients ages ≥4 years who were admitted to the EMU between 2011 and 2018 (n = 616). We calculated the proportion of patients diagnosed with PNES within the first 8 hours of EEG recording and studied the associated risk factors for patients diagnosed with PNES and patients with epileptic seizures (ES). Out of the total 616 patients, 24% (149) patients had an EMU diagnosis of PNES. Of these, 44.3% had at least one typical event within the first 8 hours of vEEG monitoring. A higher incidence was seen within the pediatric subgroup (54.8% had an event within 8 hours). A diagnosis of chronic pain disorder was more common with PNES compared to ES (48.3% versus 16.5%, p < 0.001). A suspicion for PNES documented during an office visit was noted in a high proportion of patients (68.5%) who eventually had a PNES event during EMU. Our study suggests that in a well-selected group of patients (such as a high suspicion of PNES during a physician/neurology office visit), an outpatient 8-hour vEEG could open new avenues for a prompt diagnosis. This could especially be beneficial in hospital settings where there is either a lack of an EMU or a delay in admission to the EMU.
According to the World Health Organization, cardiovascular disease is the number one cause of death globally. Cardiac-related maladies are a common occurrence in emergency rooms across the United States. The most common...According to the World Health Organization, cardiovascular disease is the number one cause of death globally. Cardiac-related maladies are a common occurrence in emergency rooms across the United States. The most common symptoms of a myocardial infarction include pain or discomfort in the arms, left shoulder or elbows. Sometimes, what appears to be common, stereotypical symptoms could pose more than one diagnosis to a medical professional. This report describes the case of a 67-year-old male who presented to the emergency department with left arm numbness and syncopal episodes. He had a history of cardiac-related issues, which led to a concern for possible heart failure. Fortunately, an EEG was performed, revealing multiple right centroparietal dominant seizures.
Falls are a common adverse event (AE) in general hospital admissions and in the epilepsy monitoring unit (EMU) and can cause serious physical injury for patients; however, fall prevention policies widely vary between epi...Falls are a common adverse event (AE) in general hospital admissions and in the epilepsy monitoring unit (EMU) and can cause serious physical injury for patients; however, fall prevention policies widely vary between epilepsy centers. Patient safety, including minimizing AEs, such as falls, continue to be a major goal of quality improvement in the EMU. The bathroom area in an EMU is highly prone for falls due to the need for patient privacy. Syncope is a physiologic non-epileptic event with high prevalence in general population and is a potential cause for fall. It is also reported in people diagnosed with epilepsy. We report a case of vasovagal syncope (VVS) associated with injury in a young female during long-term video EEG recording in our EMU facility. We also briefly address concerns for identifying patients at risk for syncope and its prevention. A multidisciplinary team including EEG technologists can play a vital role in educating patients and caretakers about the risk factors of syncopal fall and its preventive measures.
Maple Syrup Urine Disease (MSUD) is a rare autosomal recessive disorder characterized by deficiency of branched-chain keto acid dehydrogenase complex, which is required to metabolize the three branched chain amino acids...Maple Syrup Urine Disease (MSUD) is a rare autosomal recessive disorder characterized by deficiency of branched-chain keto acid dehydrogenase complex, which is required to metabolize the three branched chain amino acids (BCAAs), leucine, isoleucine and valine. This metabolic dysfunction results in progressive encephalopathy manifesting with lethargy, vomiting, posturing and abnormal movements during the neonatal period in the classic form of the disease. If untreated, progressive brain damage causes coma, seizures and death usually within a few weeks. EEG is an essential investigation in a neonate with progressive encephalopathy and seizures. EEG abnormalities in neonatal encephalopathies due to inborn error of metabolism (IEM) are widely variable depending on the severity. Central comb-like rhythm is an EEG marker of neonatal MSUD in appropriate clinical context. This pattern should not be mistaken for epileptic abnormalities, sleep spindles or other similar nonspecific activities. We describe a patient with classic MSUD who presented with an EEG pattern of comb-like rhythm. Background abnormalities and epileptic discharges are common along comb-like rhythm in MSUD patients. EEG technologists and interpreters should be able to identify this pattern to support the early diagnosis and treatment of MSUD.
Ambulatory electroencephalogram (AEEG) can be a cost-effective and valuable alternative to in-patient long-term EEG monitoring. A potential benefit of AEEG is that it allows monitoring in the patient's unique home enviro...Ambulatory electroencephalogram (AEEG) can be a cost-effective and valuable alternative to in-patient long-term EEG monitoring. A potential benefit of AEEG is that it allows monitoring in the patient's unique home environment. While this can be more affordable and convenient for the patient, it can also present unique challenges for the reviewer. Unlike long-term monitoring in an epilepsy unit, the AEEG recording occurs in a less controlled environment and most often without immediate EEG technical assistance during the recording. As a result, unique EEG artifacts can occur with AEEG. Their recognition and correct interpretation are crucial for proper EEG analysis. This report presents a case of a patient who underwent a 72-hour AEEG to evaluate symptoms initially concerning for subclinical seizures. During the AEEG recording, the patient had a tactile encounter with an electric fence. This tactile event resulted in a unique, not previously reported, pattern clouding an otherwise normal study. By conducting a brief review of the most common non-physiologic environmental artifacts encountered in modern EEG monitoring, we aim to emphasize the importance of patient education to prevent artifactual pollution. This knowledge can facilitate planning and help avoid environmental influences that may create artifacts when recording in an uncontrolled setting.
Lance-Adams syndrome (LAS) was first described in 1963 by Lance and Adams, who cited four cases of posthypoxic action myoclonus. Since then, less than 150 cases have been reported world-wide. LAS differs from acute posth...Lance-Adams syndrome (LAS) was first described in 1963 by Lance and Adams, who cited four cases of posthypoxic action myoclonus. Since then, less than 150 cases have been reported world-wide. LAS differs from acute posthypoxic myoclonus, which usually occurs within twelve hours of the anoxic event, with the patient remaining in a deep coma with an extremely poor prognosis. Patients with LAS retain neurological function and develop myoclonus days or weeks after their hypoxic event. This report describes the case of a 64-year-old male who developed LAS following cardiac arrest. His progression from ICU to outpatient was followed through multiple electroencephalograms.