Pediatric Intraoperative Neurophysiologic Mapping and Monitoring in Brain Surgery.

SUMMARY: Similar to adults, children undergoing brain surgery can significantly benefit from intraoperative neurophysiologic mapping and monitoring. Although young brains present the advantage of increased plasticity, during procedures in close proximity to eloquent regions, the risk of irreversible neurological compromise remains and can be lowered further by these techniques. More so, pathologies specific to the pediatric population, such as neurodevelopmental lesions, often result in medically refractory epilepsy. Thus, their successful surgical treatment also relies on accurate demarcation and resection of the epileptogenic zone, processes in which intraoperative electrocorticography is often employed. However, stemming from the development and maturation of the central and peripheral nervous systems as the child grows, intraoperative neurophysiologic testing in this population poses methodologic and interpretative challenges even to experienced clinical neurophysiologists. For example, it is difficult to perform awake craniotomies and language testing in the majority of pediatric patients. In addition, children may be more prone to intraoperative seizures and exhibit afterdischarges more frequently during functional mapping using electrical cortical stimulation because of high stimulation thresholds needed to depolarize immature cortex. Moreover, choice of anesthetic regimen and doses may be different in pediatric patients, as is the effect of these drugs on immature brain; these factors add additional complexity in terms of interpretation and analysis of neurophysiologic recordings. Below, we are describing the modalities commonly used during intraoperative neurophysiologic testing in pediatric brain surgery, with emphasis on age-specific clinical indications, methodology, and challenges.

Manipulating solid-state spin concentration through charge transport.

Solid-state defects are attractive platforms for quantum sensing and simulation, e.g., in exploring many-body physics and quantum hydrodynamics. However, many interesting properties can be revealed only upon changes in the density of defects, which instead is usually fixed in material systems. Increasing the interaction strength by creating denser defect ensembles also brings more decoherence. Ideally one would like to control the spin concentration at will while keeping fixed decoherence effects. Here, we show that by exploiting charge transport, we can take some steps in this direction, while at the same time characterizing charge transport and its capture by defects. By exploiting the cycling process of ionization and recombination of NV centers in diamond, we pump electrons from the valence band to the conduction band. These charges are then transported to modulate the spin concentration by changing the charge state of material defects. By developing a wide-field imaging setup integrated with a fast single photon detector array, we achieve a direct and efficient characterization of the charge redistribution process by measuring the complete spectrum of the spin bath with micrometer-scale spatial resolution. We demonstrate a two-fold concentration increase of the dominant spin defects while keeping the T2 of the NV center relatively unchanged, which also provides a potential experimental demonstration of the suppression of spin flip-flops via hyperfine interactions. Our work paves the way to studying many-body dynamics with temporally and spatially tunable interaction strengths in hybrid charge-spin systems.

Epilepsy Surgery Outcome of Traumatic Intradiploic Meningoencephalocele: A Case Report and Literature Review.

We highlight an under-recognized epileptic pathology in a 56-year-old left-handed female with progressive right facial numbness and weekly focal seizures characterized by episodic aphasia. She was found to have a left frontoparietal intradiploic meningoencephalocele (IDME). Her only epilepsy risk factor was minor head trauma 10 years prior to presentation. She underwent craniotomy for encephalocele resection and mesh cranioplasty without residual neurological deficits and excellent seizure outcome: at 3-year follow-up, she was still seizure-free since surgery, except for an isolated breakthrough seizure at 7 postoperative months when she discontinued her preoperative regimen of Lacosamide monotherapy. Traumatic IDME is a rare condition and rarely presents with seizures. Symptoms may arise up to decades following minor head trauma and are progressive in nature. The likely definitive treatment is cranioplasty and dural repair with or without resecting the protruding parenchyma.

Early Detection of Cerebral Herniation by Continuous Electroencephalography and Quantitative Analysis.

Continuous electroencephalography (cEEG) and quantitative analysis of EEG (qEEG) are used in various circumstances such as detecting seizures, identifying acute or delayed cerebral ischemia, monitoring sedative therapy, or assessing prognosis. The authors report 2 cases: (1) Case #1 was a patient with unilateral cerebral edema and uncal herniation with asymmetric cEEG and qEEG changes detected an hour before clinical examination changes were noted and (2) Case #2 was a patient with diffuse cerebral edema and trans-tentorial herniation with symmetric cEEG and qEEG changes detected an hour before clinical examination changes were noted. These cases demonstrate the ability of cEEG and qEEG in early detection of different types of cerebral herniation. qEEG can be utilized by intensive care unit (ICU) staff not trained in EEG interpretation as a surveillance method to detect cerebral herniation, which may provide an opportunity for early intervention in high-risk patients.

Characterization of Postanoxic Tonic Eyelid Opening: A Poorly Recognized Prognostic Sign.

BACKGROUND: Postanoxic myoclonus is a known poor prognostic sign, and other postanoxic spontaneous movements have been reported but poorly described. We aim to describe the electroclinical phenomenon of postanoxic eyelid openings in context of its possible prognostic value. METHODS: We collected clinical data on postcardiac arrest patients with suspicious eyelid movements noted on continuous EEG monitoring. The eyelid movements captured on the video were correlated with the EEG findings and final clinical outcome. Neuroimaging data were reviewed when available. We also conducted a thorough literature review on this topic. RESULTS: A total of 10 patients (5 females) with average age of 56.1 (±14.4) years were included. The mean cardiopulmonary resuscitation duration was 18.9 (±11.3) minutes. Postanoxic eyelid-opening movements occurred at variable intervals (0.5-570 seconds) in each individual. Close examination of eyelid opening (available in 6 patients) revealed them to be tonic movements, lasting an average of 3 (±0.8) seconds and always succeeded the onset of burst of EEG activity in a burst-suppression background. This is a transient phenomenon, lasting a median duration of 30 (interquartile range 7.75-36) hours. MRI findings in 3 patients demonstrated diffuse cortical ischemic injury with relative sparing of the brainstem. All patients died within 2-7 days following cardiac arrest. CONCLUSIONS: Contrary to previous descriptions, the postanoxic tonic eyelid openings (PATEO) are repetitive but nonperiodic, nonmyoclonic movements. Their close and specific temporal correlation with the burst of EEG activity suggests that this could be considered an ictal phenomenon requiring an intact midbrain based on MRI findings.

Long-term electro-clinical profile of sudden cardiac arrest survivors.

OBJECTIVE: Recent research has explored the use of continuous EEG (cEEG) monitoring for prognostication of spontaneous cardiac arrest (SCA). However, there is limited literature on the long-term (post-hospital discharge) electrographic findings among SCA survivors and their clinical correlates. Our study aims to fill this critical knowledge gap. METHODS: We retrospectively used our EEG database to identify adults (≥18 years) with SCA history who underwent an outpatient laboratory-based EEG between 01/01/2011 and 12/31/2018. After electronic medical records (EMR) review, patients with epilepsy history and unclear/poorly documented SCA history were excluded. Outpatient EEGs were reviewed by authors. Acute EEG findings were extracted from the EEG database and EMR. In addition, we extracted data on acute and long-term neuroimaging findings (CT/MRI), post-SCA seizures, and anti-seizure medications (ASM) status. Descriptive analysis and Fisher's exact test were performed. RESULTS: We included 32 SCA survivors (50% women; mean age = 52.1 ± 13.6 years) in the study. During a median clinical follow-up of 28.2 months, 3 patients suffered only clinical seizures, 3 only chronic post-hypoxic myoclonus, and 5 had both [11 (34.4%) in total]. Interictal epileptiform discharges (IEDs) were noted in one-third of the patients, which localized to vertex and frontocentral regions in all but one patient. Five (15.6%) of them did not suffer a clinical seizure despite the presence of EAs. Patients who developed epilepsy were significantly more likely to have abnormal neuroimaging findings [10/11 (90.9%)] during the follow-up compared to the rest of the patients [OR = 25 (95% CI 2.6->100, P = .002)]. Half of the study cohort was taking ASM at the last follow-up. SIGNIFICANCE: Our small study reveals a signature location of IEDs in SCA survivors. Neuroimaging abnormalities seem to be a better indicator of epilepsy development, while EEG may reveal markers of potential epileptogenicity in the absence of clinical seizures. Future, larger studies are needed to confirm our findings.

Factors Associated With Postoperative Confusion and Prolonged Hospital Stay Following Deep Brain Stimulation Surgery for Parkinson Disease.

BACKGROUND: Several patient and disease characteristics are thought to influence DBS outcomes; however, most previous studies have focused on long-term outcomes with only a few addressing immediate postoperative course. OBJECTIVE: To evaluate predictors of immediate outcomes (postoperative confusion and length of postoperative hospitalization) following deep brain stimulation surgery (DBS) in Parkinson disease (PD) patients. METHODS: We conducted a retrospective study of PD patients who underwent DBS at our institution from 2006 to 2011. We computed the proportion of patients with postoperative confusion and those with postoperative hospitalization longer than 2 d. To look for associations, Fisher's exact tests were used for categorical predictors and logistic regression for continuous predictors. RESULTS: We identified 130 patients [71% male, mean age: 63 ± 9.1, mean PD duration: 10.7 ± 5.1]. There were 7 cases of postoperative confusion and 19 of prolonged postoperative hospitalization. Of the 48 patients with tremors, none had postoperative confusion, whereas 10.1% of patients without tremors had confusion (P = .0425). Also, 10.2% of patients with preoperative falls/balance-dysfunction had postoperative confusion, whereas only 1.6% of patients without falls/balance-dysfunction had postoperative confusion (P = .0575). For every one-unit increase in score on the preoperative on-UPDRS III/MDS-UPDRS III score, the odds of having postoperative confusion increased by 10% (P = .0420). The following factors were noninfluential: age, disease duration, dyskinesia, gait freezing, preoperative levodopa-equivalent dose, number of intraoperative microelectrode passes, and laterality/side of surgery. CONCLUSION: Absence of tremors and higher preoperative UPDRS III predicted postoperative confusion after DBS in PD patients. Clinicians' awareness of these predictors can guide their decision making regarding patient selection and surgical planning.

Predictors of Functional and Quality of Life Outcomes following Deep Brain Stimulation Surgery in Parkinson's Disease Patients: Disease, Patient, and Surgical Factors.

OBJECTIVE: The primary objective was to evaluate predictors of quality of life (QOL) and functional outcomes following deep brain stimulation (DBS) in Parkinson's disease (PD) patients. The secondary objective was to identify predictors of global improvement. METHODS: PD patients who underwent DBS at our Center from 2006 to 2011 were evaluated by chart review and email/phone survey. Postoperative UPDRS II and EQ-5D were analyzed using simple linear regression adjusting for preoperative score. For global outcomes, we utilized the Patient Global Impression of Change Scale (PGIS) and the Clinician Global Impression of Change Scale (CGIS). RESULTS: There were 130 patients in the dataset. Preoperative and postoperative UPDRS II and EQ-5D were available for 45 patients, PGIS for 67 patients, and CGIS for 116 patients. Patients with falls/postural instability had 6-month functional scores and 1-year QOL scores that were significantly worse than patients without falls/postural instability. For every 1-point increase in preoperative UPDRS III and for every 1-unit increase in body mass index (BMI), the 6-month functional scores significantly worsened. Patients with tremors, without dyskinesia, and without gait-freezing were more likely to have "much" or "very much" improved CGIS. CONCLUSIONS: Presence of postural instability, high BMI, and worse baseline motor scores were the greatest predictors of poorer functional and QOL outcomes after DBS.

Socioeconomic Status May Impact Functional Outcome of Deep Brain Stimulation Surgery in Parkinson's Disease.

OBJECTIVES: To investigate the association between socioeconomic status and deep brain stimulation (DBS) outcomes in Parkinson's disease (PD). MATERIALS AND METHODS: We analyzed a cohort of PD patients who underwent DBS from 2007 to 2011, who had Clinical Global Impression Scale-Improvement subscale (CGI-I) scores at approximately one year postsurgery. We also analyzed a subgroup of patients who had pre and postoperative Movement Disorders Society-Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part II (functional subscale) and European Quality of Life Scale (EQ5D) scores. We performed regression analyses to determine the association between their median household income and their improvement in the MDS-UPDRS Part II, EQ-5D, and CGI-I post-DBS surgery. RESULTS: We analyzed 125 PD patients with CGI-I at one year post-DBS, including a subset of 43 patients who had pre- and post-DBS MDS-UPDRS Part II and EQ5D scores at 6 and 12 months. Median income was not significantly associated with the one-year CGI-I, the six-month MDS-UPDRS II, and the six-month and one-year EQ5D score. However, after adjusting for preoperative MDS-UPDRS II score, for every $10,000 increase in household median income, there was a 2.15-point improvement on the MDS-UPDRS II score after one year (95% confidence interval = -3.63 to -0.66, p = 0.0060). CONCLUSIONS: PD patients with higher household incomes had better functional improvement at one year. However, this did not necessarily translate to better quality of life or overall clinical improvement when compared with PD patients with lower household incomes. The influence of household income on DBS and other advanced therapies for PD will need further investigation.

Impact of mild cognitive impairment on outcome following deep brain stimulation surgery for Parkinson's disease.

INTRODUCTION: Unlike dementia, the effect of mild cognitive impairment (MCI) on outcomes after deep brain stimulation (DBS) in Parkinson's disease (PD) is less clear. We aimed to examine the effect of MCI on short- and long-term DBS outcomes. METHODS: To study the effect of MCI type, cognitive domains (attention, language, visuospatial, memory, executive function), and Dementia Rating Scale (DRS) score on immediate postoperative outcomes (postoperative confusion, hospitalization days), PD patients who underwent DBS at our Center from 2006 to 2011 were analyzed. To determine cognitive predictors of intermediate (6-month) and long-term (1-year) post-operative outcomes, the changes in functional and quality-of-life (QOL) scores were analyzed in a smaller group with available preoperative health status measures. RESULTS: We identified 130 patients [71% male, mean age: 63 ± 9.1, mean PD duration: 10.7 ± 5.1]. At preoperative assessment, 60% of patients had multiple-domain MCI, 21% had single-domain MCI, and 19% had normal cognition. MCI presence and type as well as DRS performance did not affect immediate outcomes. Attention impairment predicted longer postoperative hospitalization (P = 0.0015) and showed a trend towards occurrence of postoperative confusion (P = 0.089). For intermediate and long-term outcomes we identified 56 patients [73.2% male, mean age: 61.3 ± 9.6, mean PD duration: 10.6 ± 4.7]. Visuospatial impairment showed a trend towards less improvement in 6-month functional score (P = 0.0652), and 1-year QOL score (P = 0.0517). CONCLUSION: The presence of MCI did not affect DBS outcomes. However, the types of impaired domains were more detrimental. Detailed cognitive testing can help stratify low- and high-risk patients based on their pattern of cognitive dysfunction.

Tolerability of propofol in Wada testing.

OBJECTIVE: To assess the tolerability of propofol (PF) in Wada test in an Arab population with temporal lobe epilepsy (TLE). METHODS: This observational study with consecutive sampling took place in King Fahad Medical City, Riyadh, Saudi Arabia. Nine consecutive patients with mean (± SD) age of 26 (± 5.8) years, 6 males and 3 females, underwent Wada test between January 2009 and December 2012. Six of them had left TLE, and 3 had right TLE. Each patient received 10 mg of PF in the internal carotid artery (ICA). Right hemispheric injection was followed by left hemisphere injection after 30 minutes. During the procedure, EEG monitoring showed changes within 5-18 seconds of injection as hemispheric delta slowing. Neuropsychological tests were carried out for localization of memory and language. RESULTS: We were able to lateralize speech dominance in 8 patients and memory dominance in 6 patients. Peri-procedural complications included transient euphoria (n=1), transient spasm of ICA (n=1), eye pain (n=1), facial pain (n=1), and generalized tremulousness (n=2). None of the patients exhibited a symptomatic drop in blood pressure. CONCLUSION: We found that PF is well tolerable for the Wada test, with minimally significant complications, although blood pressure should be closely monitored.