Whole genome sequencing and phylogenetic analysis of SARS-CoV-2 strains isolated during the COVID-19 pandemic in Nigeria.

Objectives: The emergence and spread of SARS-CoV-2 have stimulated ongoing research into the virus transmission dynamics, circulating variants, and potential mutations. This study was conducted to understand the genomic dynamics of the epidemic in Nigeria. Design: Whole genome sequencing was conducted on SARS-CoV-2 samples collected during the first and second outbreaks using the Oxford Nanopore MinION sequencing platform. Phylogenetic analysis was conducted, and genomes were grouped into different pangolin lineages. Results: The study revealed four circulating SARS-CoV-2 variants. The Alpha (B.1.1.7) variant was the most prevalent (32.7%), followed by Beta (B.1 B.1.1, L.3, and B.1.1.318) (30.8%), Eta (B.1.525) (28.9%), and Delta (B.1.617, AY.1, AY.109, and AY.36) (7.7%). Phylogenetic analysis revealed three clusters with four Nextstrain clades (20I, 20B, 21D, and 21J). The Alpha lineages (B.1.1.7) clustered with references from Italy. The Beta lineages (Clade 20B) (B.11, B.11318, and L3) and sub-lineage B.11 were distinct. Sub-lineage B.11318 is clustered with references from the USA, whereas sub-lineage L3 is clustered with references from Russia, the Philippines, Australia, and Japan. The 21D and 21J, belonging to two Pango lineages, Eta (B.1525) and Delta (B.1.617 and AY.109), showed high genetic similarity. Conclusion: The phylogenetic relatedness of the lineages suggests multiple virus introduction, which could be a source of more virulent, locally adapted variants.

Rotational thromboelastometry parameters as predicting factors for bleeding in immune thrombocytopenic purpura.

OBJECTIVE/BACKGROUND: Patients with immune thrombocytopenic purpura (ITP) often present with a severe reduction in platelet counts and suffer from an increased risk of bleeding. However, platelet counts do not accurately predict bleeding risk in these patients. METHODS: We thereby conducted a case series prospective study to compare the ability to predict hemorrhage in ITP patients between platelet counts and various rotational thromboelastometry (ROTEM) parameters. RESULTS: The inclusion criteria for patients diagnosed with acute, persistent, and chronic ITP were platelet counts of <30 × 109/L and no clinically significant bleeding (grade ≥ 2 according to the WHO Bleeding Scale) at the beginning of the study. After 24 hours of follow-up, of the 45 enrolled patients, 14 (31.1%) experienced clinically significant bleeding. The mean platelet counts of patients with and without clinically significant bleeding were not statistically different (p = .09). However, the mean EXTEM maximum clot firmness (MCF), EXTEM A10, EXTEM area under the curve (AUC), and platelet maximum clot elasticity (MCE) values of the two groups were statistically different (p < .05). There was also a significant difference in IPF values between these two groups (p < .05.) CONCLUSION: Results obtained from this preliminary study demonstrate that ROTEM parameters might be useful in predicting factors for hemorrhage in ITP patients. Future studies with a larger sample size is warranted to confirm our findings, which will allow prompt and effective bleeding management in ITP patients.

Suspected heparin-induced thrombocytopenia in a COVID-19 patient on extracorporeal membrane oxygenation support: a case report.

BACKGROUND: Extracorporeal membrane oxygenation (ECMO) support can be life-saving in critically ill COVID-19 patients. However, there are many complications associated with this procedure, including Heparin-induced thrombocytopenia (HIT.) Despite its rarity in ECMO cases, HIT can lead to devastating consequences and is difficult to manage. CASE PRESENTATION: In this report, we present a case of a COVID-19 patient on ECMO support who was diagnosed with HIT and required intensive treatment. Initially, HIT was only suspected due to newly-developed thrombocytopenia and oxygenator dysfunction, with thrombi observed later. Regarding his treatment, since there was no recommended replacement to heparin available to us at the time of diagnosis, we decided to use rivaroxaban temporarily. No adverse events were recorded during that period. The patient was able to make a full recovery. CONCLUSION: HIT may jeopardize patient's care during ECMO. As COVID-19 may bring about a surge in the number of patients requiring ECMO support, we need consented guidance to optimize treatment in this specific situation.

Barriers and facilitators to implementation of epilepsy self-management programs: a systematic review using qualitative evidence synthesis methods.

BACKGROUND: Epilepsy affects nearly 50 million people worldwide. Self-management is critical for individuals with epilepsy in order to maintain optimal physical, cognitive, and emotional health. Implementing and adopting a self-management program requires considering many factors at the person, program, and systems levels. We conducted a systematic review of qualitative and mixed-methods studies to identify facilitators and barriers that impact implementation and adoption of self-management programs for adults with epilepsy. METHODS: We used established systematic review methodologies for qualitative and mixed-methods studies. We included studies addressing facilitators (i.e., factors that aided) or barriers (i.e., factors that impeded) to implementation and adoption of self-management interventions for adults with epilepsy. We conducted a narrative thematic synthesis to identify facilitators and barriers. RESULTS: The literature search identified 2700 citations; 13 studies met eligibility criteria. Our synthesis identified five themes that categorize facilitators and barriers to successful implementation epilepsy self-management: (1) relevance, intervention content that facilitates acquisition of self-management skills; (2) personalization, intervention components that account for the individual's social, physical, and environmental characteristics; (3) intervention components, components and dosing of the intervention; (4) technology considerations, considerations that account for individual's use, familiarity with, and ownership of technology; and (5) clinician interventionist, role and preparation of the individual who leads intervention. We identified facilitators in 11 of the 13 studies and barriers in 11 of the 13 studies and classified these by social-ecological level (i.e., patient/caregiver, program, site/system). CONCLUSION: Identification of facilitators and barriers at multiple levels provides insight into disease-specific factors that influence implementation and adoption of self-management programs for individuals with epilepsy. Our findings indicate that involving individuals with epilepsy and their caregivers in intervention development, and then tailoring intervention content during the intervention, can help ensure the content is relevant to intervention participants. Our findings also indicate the role of the clinician (i.e., the individual who provides self-management education) is important to intervention implementation, and key issues with clinicians were identified as barriers and opportunities for improvement. Overall, our findings have practical value for those seeking to implement and adopt self-management interventions for epilepsy and other chronic illnesses. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration number is CRD42018098604.

Development of a highly sensitive magneto-enzyme lateral flow immunoassay for dengue NS1 detection.

BACKGROUND: Dengue infection represents a global health issue of growing importance. Dengue non-structural protein 1 (NS1) plays a central role in the early detection of the disease. The most common method for NS1 detection is testing by lateral flow immunoassays (LFIAs) with varying sensitivity. In this study, we present a highly sensitive magneto-enzyme LFIA for prompt diagnosis of dengue. METHODS: We have demonstrated the development of a magneto-enzyme LFIA combining super-paramagnetic nanoparticles as labels and Biotin-Streptavidin signal amplification strategy to detect dengue NS1. Factors affecting the test performance including antibody pair, super-paramagnetic nanoparticle size, nitrocellulose membrane type, amounts of detection and capture antibodies, and amounts of Streptavidin-polyHRP were optimized. Analytical sensitivity and cross-reactivity were determined. Clinical performance of the novel assay was evaluated using a panel of 120 clinical sera. RESULTS: This newly developed assay could detect NS1 of all four serotypes of dengue virus (DENV). The limit of detection (LOD) was found to be as low as 0.25 ng ml-1 for DENV-1 and DENV-3, 0.1 ng ml-1 for DENV-2, and 1.0 ng ml-1 for DENV-4. The LOD for DENV-2 was a 50-fold improvement over the best values previously reported. There was an absence of cross-reactivity with Zika NS1, Hepatitis B virus, Hepatitis C virus, and Japanese encephalitis virus. The sensitivity and specificity of the novel assay were 100% when tested on clinical samples. CONCLUSIONS: We have successfully developed a magneto-enzyme LFIA, allowing rapid and highly sensitive detection of dengue NS1, which is essential for proper management of patients infected with DENV.

Self-management of Epilepsy: A Systematic Review.

Background: Although self-management is recommended for persons with epilepsy, its optimal strategies and effects are uncertain. Purpose: To evaluate the components and efficacy of self-management interventions in the treatment of epilepsy in community-dwelling persons. Data Sources: English-language searches of MEDLINE, Cochrane Central Register of Controlled Trials, PsycINFO, and CINAHL in April 2018; the MEDLINE search was updated in March 2019. Study Selection: Randomized and nonrandomized comparative studies of self-management interventions for adults with epilepsy. Data Extraction: An investigator assessed study characteristics; intervention details, including 6 components of self-management; and outcomes, which were verified by a second reviewer. Risk of bias (ROB) was assessed independently by 2 investigators. Data Synthesis: 13 randomized and 2 nonrandomized studies (2514 patients) evaluated self-management interventions. Interventions were delivered primarily in group settings, used a median of 4 components, and followed 2 general strategies: 1 based on education and the other on psychosocial therapy. Education-based approaches improved self-management behaviors (standardized mean difference, 0.52 [95% CI, 0.0 to 1.04]), and psychosocial therapy-based approaches improved quality of life (mean difference, 6.64 [CI, 2.51 to 10.77]). Overall, self-management interventions did not reduce seizure rates, but 1 educational intervention decreased a composite of seizures, emergency department visits, and hospitalizations. Limitation: High ROB in most studies, incomplete intervention descriptions, and studies limited to English-language publications. Conclusion: There is limited evidence that self-management strategies modestly improve some patient outcomes that are important to persons with epilepsy. Overall, self-management research in epilepsy is limited by the range of interventions tested, the small number of studies using self-monitoring technology, and uncertainty about components and strategies associated with benefit. Primary Funding Source: U.S. Department of Veterans Affairs. (PROSPERO: CRD42018098604).

Implementation of an established algorithm and modifications for the identification of epilepsy patients in the veterans health administration.

Identification of epilepsy patients from administrative data in large managed healthcare organizations is a challenging task. The objectives of this report are to describe the implementation of an established algorithm and different modifications for the estimation of epilepsy prevalence in the Veterans Health Administration (VHA). For the prevalence estimation during a given time period patients prescribed anti-epileptic drugs and having seizure diagnoses on clinical encounters were identified. In contrast to the established algorithm, which required inclusion of diagnoses data from the time period of interest only, variants were tested by considering diagnoses data beyond prevalence period for improving sensitivity. One variant excluded data from diagnostic EEG and LTM clinics to improve specificity. Another modification also required documentation of seizures on the problem list (electronic list of patients' established diagnoses). Of the variants tested, the one excluding information from diagnostic clinics and extending time beyond base period of interest for clinical encounters was determined to be superior. It can be inferred that the number of patients receiving care for epilepsy in the VHA ranges between 74,000 and 87,000. In the wake of the recent implementation of ICD-10 codes in the VHA, minor tweaks are needed for future prevalence estimation due to significant efforts presented. This review is not only beneficial for researchers interested in VHA related data but can also be helpful for managed healthcare organizations involved in epilepsy care aiming at accurate identification of patients from large administrative databases.

Diagnostic Accuracy of Electrographic Seizure Detection by Neurophysiologists and Non-Neurophysiologists in the Adult ICU Using a Panel of Quantitative EEG Trends.

PURPOSE: To evaluate the sensitivity and specificity of a panel of quantitative EEG (qEEG) trends for seizure detection in adult intensive care unit (ICU) patients when reviewed by neurophysiologists and non-neurophysiologists. METHODS: One hour qEEG panels (n = 180) were collected retrospectively from 45 ICU patients and were distributed to 5 neurophysiologists, 7 EEG technologists, and 5 Neuroscience ICU nurses for evaluation of seizures. Each panel consisted of the following qEEG tools, displayed separately for left and right hemisphere electrodes: rhythmicity spectrogram (rhythmic run detection and display; Persyst Inc), color density spectral array, EEG asymmetry index, and amplitude integrated EEG. The reviewers did not have access to the raw EEG data. RESULTS: For the reviewer's ability to detect the presence of seizures on qEEG panels when compared with the gold standard of independent raw EEG review, the sensitivities and specificities are as follows: neurophysiologists 0.87 and 0.61, EEG technologists 0.80 and 0.80, and Neuroscience ICU nurses 0.87 and 0.61, respectively. There was no statistical difference among the three groups regarding sensitivity. CONCLUSIONS: Quantitative EEG display panels are a promising tool to aid detection of seizures by non-neurophysiologists as well as by neurophysiologists. However, even when used as a panel, qEEG trends do not appear to be adequate as the sole method for reviewing continuous EEG data.

Characteristics of Veterans diagnosed with seizures within Veterans Health Administration.

The purpose of this report is to describe the demographics of Veterans diagnosed with seizures and taking antiepileptic drugs (AEDs) within the Veterans Health Administration (VHA) during fiscal year (FY) 2011 (October 1, 2010, to September 30, 2011), particularly with regard to comorbid traumatic brain injury (TBI) and posttraumatic stress disorder (PTSD). Information collected included age; sex; Operation Iraqi Freedom/Operation Enduring Freedom/Operation New Dawn (OIF/OEF/OND) status; and relevant encounter diagnosis codes for seizures, TBI, and PTSD. During FY11, 87,377 Veterans with seizures on AEDs were managed within the VHA. Prevalence was 15.5 per 1,000, and annual incidence was 148.2 per 100,000. The percentages of comorbid TBI and PTSD were 15.8% and 24.1%, respectively. For OIF/OEF/OND Veterans, these percentages increased to 52.6% and 70.4%, respectively. PTSD and TBI are risk factors for both epilepsy and psychogenic nonepileptic seizures. Within the VHA, many Veterans experiencing seizures cannot be successfully treated with AEDs. The VHA Epilepsy Centers of Excellence promotes a multidisciplinary approach to increase and improve access to both epilepsy and mental health specialists for the care of epileptic and nonepileptic seizures.

Quality of life comparing dor and toupet after heller myotomy for achalasia.

BACKGROUND: Laparoscopic Heller cardiomyotomy (LHC) is standard therapy for achalasia. Traditionally, an antireflux procedure has accompanied the myotomy. This study was undertaken to compare quality-of-life outcomes between patients undergoing myotomy with Toupet versus Dor fundoplication. In addition, we investigated overall patient satisfaction after LHC in the treatment of achalasia. METHODS: One hundred thirty-five patients who underwent LHC over a 13-year period were identified for inclusion. Symptoms queried included dysphagia, heartburn, and bloating using the Gastroesophageal Reflux Disease-Health-Related Quality of Life Scale and a second published scale for the assessment of gastroesophageal reflux disease and dysphagia symptoms. The patients' overall satisfaction after surgery was also rated. Data were compared on the basis of type of fundoplication. Symptom scores were analyzed using chi-square tests and Fisher's exact tests. RESULTS: Sixty-three patients completed the survey (47%). There were no perioperative deaths or reoperations. The mean length of stay was 2.8 days. The mean operative time for LHC with Toupet fundoplication was 137.3±30.91 minutes and for LHC with Dor fundoplication was 111.5±32.44 minutes (P=.006). There was no difference with respect to the incidence or severity of postoperative heartburn, dysphagia, or bloating. Overall satisfaction with Toupet fundoplication was 87.5% and with Dor fundoplication was 93.8% (P>.999). CONCLUSIONS: LHC with either Toupet or Dor fundoplication gave excellent patient satisfaction. Postoperative symptoms of heartburn and dysphagia were equivalent when comparing LHC with either antireflux procedure. Dor and Toupet fundoplication were found to have equivalent outcomes in the short term. We prefer Dor to Toupet fundoplication because of its decreased need for extensive dissection and better mucosal protection.

Measuring postoperative recovery: what are clinically meaningful differences?

BACKGROUND: Surgical innovations are introduced to improve "recovery," a complex construct often operationalized by the use of patient-reported outcomes. The minimal clinically important difference (MCID) is the smallest change in an outcome sufficiently important to influence management and is crucial for designing and interpreting comparative effectiveness trials. Our objective was to generate MCID estimates for three postoperative recovery metrics. METHODS: Prospectively collected data on two cohorts of 281 and 130 adult patients undergoing abdominal surgery were analyzed. At each of three visits, patients had completed the 36-Item Short Form Survey from the RAND Medical Outcomes Study (SF-36) and either Community Healthy Activities Model Program for Seniors (CHAMPS) or the 6-minute walk test (6MWT). The MCID was estimated with an anchor-based approach with random effects linear regression models. Patients' rating of their own health was used to predict SF-36 domain, CHAMPS, and 6MWT scores. Results are reported as MCID (95% confidence interval). RESULTS: On the SF-36 domains analyzed, MCIDs were consistently smaller for patients rating their health as "excellent" or "very good" (from 8 [6-9] to 15 [12-18]) compared with those for patients rating their health as "fair" or "poor" (from 15 [12-19] to 32 [28-36]). For CHAMPS, the MCID was 8 kcal/kg/week (7-9), and for the 6MWT, 14 meters (9-18). CONCLUSION: Plausible MCIDs and ranges around each estimate are provided. These values should be considered when planning and interpreting abdominal surgery clinical trials where patient-reported outcomes are assessed.

Short-stay surgery: what really happens after discharge?

BACKGROUND: Although duration of hospital stay commonly is used as a surrogate outcome for surgical recovery, it is not applicable in the setting of short-stay surgery (<24 hours). The objective of our study was to describe the trajectory of recovery after short-stay abdominal surgery by using measures of physical activity and health-related quality of life (HRQL) and identify predictors of prolonged, postdischarge recovery. METHODS: Patients undergoing short-stay abdominal surgery were evaluated preoperatively and at 3 weeks and 2 months postoperatively. Physical activity was assessed with a validated questionnaire (Community Health Activities Model Program for Seniors, ie, CHAMPS) in which patients report physical activity for the previous week; responses estimate total weekly caloric expenditure (kcal/kg/wk). The Medical Outcomes Study 36-Item Short-Form Health survey (SF-36) was used to assess HRQL. Multivariate logistic regression was performed to determine which variables were predictive of recovery to baseline physical activity levels. RESULTS: A total of 132 patients (71% male, 53 [15] years) participated; 91% were discharged on the day of surgery. The most common procedures were open inguinal herniorrhaphy (40%) and laparoscopic cholecystectomy (30%). As a group, total, self-reported physical activity and most domains of HRQL were recovered to or greater than baseline at 3 weeks postoperatively and were above baseline levels at 2 months (P < .01). Patients who were older, had a complication, low baseline physical HRQL, or greater baseline physical activity were less likely to be recovered to their preoperative levels of physical activity at 3 weeks. At 2 months, 33% remained below preoperative levels; only high baseline physical activity was an important predictor of prolonged recovery. CONCLUSION: Despite uniformly early discharge, a substantial proportion of patients (∼33%) had suboptimal recovery 2 months after short-stay surgery. Measures of physical activity and HRQOL provide complementary information and reflect the variability in trajectories of recovery after surgery.

A comparative study of three-year weight loss and outcomes after laparoscopic gastric bypass in patients with "yellow light" psychological clearance.

The relationship between psychological factors and bariatric surgical outcomes is unclear. While some psychological contraindications to bariatric surgery are described, there is no consensus on preoperative psychological evaluation or on factors that can predict bariatric outcomes. Our aim was to determine whether full or reserved psychological clearance predicts early weight loss or compliance with follow-up. We found no clinically significant differences in short-term weight loss outcomes or in attendance at scheduled follow-up visits between patients receiving full or "green light" clearance versus "yellow light" clearance, meaning clearance with recommendations for ongoing therapy. Further research may identify psychological predictors of success following bariatric surgery and help optimize preoperative evaluation practices.

Revisional weight loss surgery after failed laparoscopic gastric banding: an institutional experience.

BACKGROUND: Increasing experience with laparoscopic adjustable gastric banding (LAGB) has demonstrated a high rate of complications and inadequate weight loss. Laparoscopic Roux-en-Y gastric bypass (LRYGB) and laparoscopic sleeve gastrectomy (LSG) have been reported to be safe and effective in selected patients. The purpose of our study was to evaluate the incidence and outcomes of revisional weight loss surgery (RWLS) after laparoscopic gastric banding at our institution. METHODS: From June 2006 to February 2013, all patients who underwent LAGB and those who required revision were retrospectively analyzed. All procedures were performed by two surgeons with extensive experience in bariatric surgery. Parametric data are presented as mean ± SD; nonparametric data are presented as median and interquartile range (IQR). RESULTS: During the study period, 256 patients underwent LAGB. A total of 111 patients (43 %) required reoperation. Sixty-one patients (56 women, age = 43.7 ± 12 years) with a BMI of 45.4 ± 6 kg/m(2) successfully underwent RWLS (53 RYGB, 8 LSG). Indications for RWLS included dysphagia (40 patients, 63 %), inadequate weight loss (17 patients, 27 %), GERD (2 patients, 3 %), gastric prolapse (2 patients, 3 %), and needle phobia (1 patient, 2 %). Two required conversion to an open RYGB due to extensive adhesions. RWLS was undertaken approximately 36.3 [25-45] months after LAGB. Removal of the gastric band and the RWLS were performed in 15 patients with an interval of 3 [1.5-7] months between procedures. Median operative time was 165 [142-184] min. Median hospital length of stay was 2 [2-3] days. Early complications occurred in 11 patients (18 %), including 4 anastomotic leaks. Twelve patients (20 %) presented with late complications requiring intervention. There was one death. At a median follow-up of 12.4 months, excess weight loss was 47.5 ± 27 %, and 48 % of patients achieved a BMI < 33. CONCLUSION: LAGB is associated with a high incidence of reoperation. Reoperative weight loss surgery can be performed in selected patients with a higher rate of complications than primary surgery. Good short-term weight loss outcomes can be achieved.

Does the teddy bear sign predict psychogenic nonepileptic seizures?

This study evaluated whether adults and older teenagers who bring toy stuffed animals to an epilepsy monitoring unit (EMU), i.e., the "teddy bear sign," were more likely to be diagnosed to have psychogenic nonepileptic seizures (PNES) than to have epilepsy. We prospectively evaluated 335 patients, aged 15 years and older, admitted to our EMU over a 19-month period, assessing age at seizure onset, duration of seizures, gender, seizure diagnosis, presence of intellectual disabilities, presence of psychiatric illness, and possession of a toy stuffed animal in the EMU. Among all ages, patients who brought toy stuffed animals were not more likely to have PNES or both PNES and epilepsy than to have epilepsy alone. For those 18 and over, there was a significant difference but only after adjusting for all other patient characteristics, and absolute differences were small. Patients 18 and older with stuffed animals had a 3.21 (95% confidence interval = 1.58, 8.90) times greater odds of being diagnosed to have PNES or both PNES and epilepsy than to have epilepsy alone after adjusting for other patient characteristics (p = 0.022). We conclude that patient possession of toy stuffed animals in the EMU is not a reliable sign of PNES.

Staged hepatectomy for bilobar colorectal hepatic metastases.

OBJECTIVES: This study describes the management of patients with bilobar colorectal liver metastases (CRLM). METHODS: A retrospective collection of data on all patients with CRLM who were considered for staged resection (n= 85) from January 2003 to January 2011 was performed. Patients who underwent one hepatic resection were considered to have had a failed staged resection (FSR), whereas those who underwent a second or third hepatic resection to produce a cure were considered to have had a successful staged resection (SSR). Survival was calculated from the date of diagnosis of liver metastases. Complete follow-up and dates of death were obtained from the Government of Quebec population database. RESULTS: Median survival was 46 months (range: 30-62 months) in the SSR group and 22 months (range: 19-29 months) in the FSR group. Rates of 5-year survival were 42% and 4% in the SSR and FSR groups, respectively. Fifteen of the 19 patients who remained alive at the last follow-up date belonged to the SSR group. CONCLUSIONS: In patients in whom staged resection for bilobar CRLM is feasible, surgery would appear to offer benefit.

Component structure of event-related fMRI responses in the different neurovascular compartments.

In most functional magnetic resonance imaging (fMRI) studies, brain activity is localized by observing changes in the blood oxygenation level-dependent (BOLD) signal that are believed to arise from capillaries, venules and veins in and around the active neuronal population. However, the contribution from veins can be relatively far downstream from active neurons, thereby limiting the ability of BOLD imaging methods to precisely pinpoint neural generators. Hemodynamic measures based on apparent diffusion coefficients (ADCs) have recently been used to identify more upstream functional blood flow changes in the capillaries, arterioles and arteries. In particular, we recently showed that, due to the complementary vascular sensitivities of ADC and BOLD signals, the voxels conjointly activated by both measures may identify the capillary networks of the active neuronal areas. In this study, we first used simultaneously acquired ADC and BOLD functional imaging signals to identify brain voxels activated by ADC only, by both ADC and BOLD and by BOLD only, thereby delineating voxels relatively dominated by the arterial, capillary, and draining venous neurovascular compartments, respectively. We then examined the event-related fMRI BOLD responses in each of these delineated neurovascular compartments, hypothesizing that their event-related responses would show different temporal componentries. In the regions activated by both the BOLD and ADC contrasts, but not in the BOLD-only areas, we observed an initial transient signal reduction (an initial dip), consistent with the local production of deoxyhemoglobin by the active neuronal population. In addition, the BOLD-ADC overlap areas and the BOLD-only areas showed a clear poststimulus undershoot, whereas the compartment activated by only ADC did not show this component. These results indicate that using ADC contrast in conjunction with BOLD imaging can help delineate the various neurovascular compartments, improve the localization of active neural populations, and provide insight into the physiological mechanisms underlying the hemodynamic signals.