Samah G. Abdel Baki

Minocycline Synergizes with N-Acetylcysteine and Improves Cognition and Memory Following Traumatic Brain Injury in Rats

Background There are no drugs presently available to treat traumatic brain injury (TBI). A variety of single drugs have failed clinical trials suggesting a role for drug combinations. Drug combinations acting synergistically often provide the greatest combination of potency and safety. The drugs examined (minocycline (MINO), N-acetylcysteine (NAC), simvastatin, cyclosporine A, and progesterone) had FDA-approval for uses other than TBI and limited brain injury in experimental TBI models. Methodology/Principal Findings Drugs were dosed one hour after injury using the controlled cortical impact (CCI) TBI model in adult rats. One week later, drugs were tested for efficacy and drug combinations tested for synergy on a hierarchy of behavioral tests that included active place avoidance testing. As monotherapy, only MINO improved acquisition of the massed version of active place avoidance that required memory lasting less than two hours. MINO-treated animals, however, were impaired during the spaced version of the same avoidance task that required 24-hour memory retention. Co-administration of NAC with MINO synergistically improved spaced learning. Examination of brain histology 2 weeks after injury suggested that MINO plus NAC preserved white, but not grey matter, since lesion volume was unaffected, yet myelin loss was attenuated. When dosed 3 hours before injury, MINO plus NAC as single drugs had no effect on interleukin-1 formation; together they synergistically lowered interleukin-1 levels. This effect on interleukin-1 was not observed when the drugs were dosed one hour after injury. Conclusions/Significance These observations suggest a potentially valuable role for MINO plus NAC to treat TBI.

Minocycline plus N-acetylcysteine synergize to modulate inflammation and prevent cognitive and memory deficits in a rat model of mild traumatic brain injury

Traumatic brain injury (TBI) differs in severity from severe to mild. This study examined whether a combination of the drugs minocycline (MINO) plus N-acetylcysteine (NAC) produces behavioral and histological improvements in a mild version of the controlled cortical impact model of TBI (mCCI). Following mCCI, rats acquired an active place avoidance task by learning the location of a stationary shock zone on a rotating arena. Rats acquired this task with a training protocol using a 10-minute intertrial interval. Mildly injured rats had an apparent deficit in long-term memory since they did not acquire the task when the intertrial interval was increased to 24 h. Mildly injured rats also had an apparent deficit in set shifting since, after successfully learning one shock zone location they did not learn the location of a second shock zone. MINO plus NAC synergistically limited these behavioral deficits in long-term memory and set shifting. mCCI also produced neuroinflammation at the impact site and at distal white matter tracts including the corpus callosum. At the impact site, MINO plus NAC attenuated CD68-expressing phagocytic microglia without altering neutrophil infiltration or astrocyte activation. The drugs had no effect on astrocyte activation in the corpus callosum or hippocampus. In the corpus callosum, MINO plus NAC decreased CD68 expression yet increased overall microglial activation as measured by Iba-1. MINO plus NAC acted synergistically to increase Iba-1 expression since MINO alone suppressed expression and NAC alone had no effect. Despite the known anti-inflammatory actions of the individual drugs, MINO plus NAC appeared to modulate, rather than suppress neuroinflammation. This modulation of neuroinflammation may underlie the synergistic improvement in memory and set-shifting by the drug combination after mCCI.

A hierarchy of neurobehavioral tasks discriminates between mild and moderate brain injury in rats

Behavioral analysis commonly assesses cognitive deficits in rodents following traumatic brain injury (TBI). We examined rats that received sham, mild or moderate injury in the controlled cortical impact model of TBI. The rats were tested in a novel hierarchy of four behavioral tasks with increasing cognitive demand. All three groups had similar performance on the first two phases of training: open field exploration and passive place avoidance using a stationary shock zone on a non-rotating arena. The similar performance on the first two tasks suggested comparable sensory, motor skills and contextual memory in all three groups. In phase three, rats were tested on active place avoidance, their ability to avoid a stationary shock zone on the rotating arena. Control and mildly-injured rats learned this task within four ten-minute trials while moderately-injured animals were impaired. Moderately-injured animals were also impaired if tested 3 weeks after injury. One day after phase three, sham- and mildly-injured animals were tested on a phase four conflict active avoidance task with the shock zone shifted 180 degrees from its phase three location and mildly-injured animals were impaired. The speed in which the animals complete the four phases of testing as well as the ability to discriminate between differing injury severity suggests that this set of neurobehavioral tasks will be useful to understand cognitive deficits underlying TBI as well as a useful screening method for therapeutic drugs.

Folate deficiency in rat pups during weaning causes learning and memory deficits

Folate is essential for fetal development, and its deficiency during gestation causes behavioural deficits in the offspring. The present study investigated its influence during weaning on brain function in the pups of rats that were put on a folate-deficient (FD) diet on postnatal day (PND) 1. Systemic folate deficiency in pups on the FD diet (n 15) was evident from the dramatically lower hepatic folate concentrations (median 23·7, range 8·1-48·4 ng/mg protein) and higher homocysteine concentrations (median 27·7, range 14·7-45·5 pmol/mg protein), respectively, compared with those of pups on the normal diet (ND; n 9) (median 114·5, range 64·5-158·5 ng/mg protein and median 15·5, range 11·6-18·9 pmol/mg protein) on PND 23. Brain folate concentrations although low were similar in pups on the FD diet (median 10·5, range 5·5-24·5 ng/mg protein) and ND (median 11·1, range 7·1-24·2 ng/mg protein). There was a high accumulation of homocysteine in the brain of FD pups, mostly in the hippocampus (median 58·1, range 40·8-99·7 pmol/mg protein) and cerebellum (median 69·1, range 50·8-126·6 pmol/mg protein), indicating metabolic folate deficiency despite normal brain folate concentrations. Developmental deficits or autistic traits were more frequent in the FD group than in the ND group and repetitive self-grooming occurred, on average, three times (range 1-8) v. once (range 0-3) during 5 min, respectively. Long-term memory or spatial learning and set-shifting deficits affected 12 to 62% of rats in the FD group compared with none in the ND group. Post-weaning folic acid supplementation did not correct these deficits. These observations indicate that folate deficiency during weaning affects postnatal development even when gestational folate supply is normal.

Prevalence of non-convulsive seizure and other electroencephalographic abnormalities in ED patients with altered mental status.

UNLABELLED Four to ten percent of patients evaluated in emergency departments (ED) present with altered mental status (AMS). The prevalence of non-convulsive seizure (NCS) and other electroencephalographic (EEG) abnormalities in this population is unknown. OBJECTIVES To identify the prevalence of NCS and other EEG abnormalities in ED patients with AMS. METHODS A prospective observational study at 2 urban ED. Inclusion: patients ≥13 years old with AMS. Exclusion: An easily correctable cause of AMS (e.g. hypoglycemia). A 30-minute standard 21-electrode EEG was performed on each subject upon presentation. OUTCOME prevalence of EEG abnormalities interpreted by a board-certified epileptologist. EEGs were later reviewed by 2 blinded epileptologists. Inter-rater agreement (IRA) of the blinded EEG interpretations is summarized with κ. A multiple logistic regression model was constructed to identify variables that could predict the outcome. RESULTS Two hundred fifty-nine patients were enrolled (median age: 60, 54% female). Overall, 202/259 of EEGs were interpreted as abnormal (78%, 95% confidence interval [CI], 73-83%). The most common abnormality was background slowing (58%, 95% CI, 52-68%) indicating underlying encephalopathy. NCS (including non-convulsive status epilepticus [NCSE]) was detected in 5% (95% CI, 3-8%) of patients. The regression analysis predicting EEG abnormality showed a highly significant effect of age (P < .001, adjusted odds ratio 1.66 [95% CI, 1.36-2.02] per 10-year age increment). IRA for EEG interpretations was modest (κ: 0.45, 95% CI, 0.36-0.54). CONCLUSIONS The prevalence of EEG abnormalities in ED patients with undifferentiated AMS is significant. ED physicians should consider EEG in the evaluation of patients with AMS and a high suspicion of NCS/NCSE.

Nonconvulsive seizures in patients presenting with altered mental status: An evidence-based review

Definitive diagnosis of nonconvulsive seizures (NCS) can be made only by electroencephalography, and delay in diagnosis can increase morbidity, resource utilization, and length of hospitalization. We performed an evidence-based literature review to estimate the prevalence of NCS in patients with altered mental status (AMS) of unknown cause. PUBMED, EMBASE, the Cochrane Library, and other resources were searched for studies that included AMS and seizure as topics. The resulting 276 articles were screened for predetermined inclusion and exclusion criteria, leaving 5 studies enrolling 478 patients for review. The prevalence of NCS in patients with AMS ranged from 8 to 30% (overall prevalence of 21.5%, 95% CI: 18-25%), suggesting that the prevalence of NCS is sufficiently high to consider routine use of urgent electroencephalography in such patients. However, methodological weaknesses limit the generalizability of the results. A large, prospective study enrolling and screening for NCS in all patients who present with acute AMS is needed.

Technical and clinical analysis of microEEG: a miniature wireless EEG device designed to record high-quality EEG in the emergency department

BackgroundWe describe and characterize the performance of microEEG compared to that of a commercially available and widely used clinical EEG machine. microEEG is a portable, battery-operated, wireless EEG device, developed by Bio-Signal Group to overcome the obstacles to routine use of EEG in emergency departments (EDs).MethodsThe microEEG was used to obtain EEGs from healthy volunteers in the EEG laboratory and ED. The standard system was used to obtain EEGs from healthy volunteers in the EEG laboratory, and studies recorded from patients in the ED or ICU were also used for comparison. In one experiment, a signal splitter was used to record simultaneous microEEG and standard EEG from the same electrodes.ResultsEEG signal analysis techniques indicated good agreement between microEEG and the standard system in 66 EEGs recorded in the EEG laboratory and the ED. In the simultaneous recording the microEEG and standard system signals differed only in a smaller amount of 60 Hz noise in the microEEG signal. In a blinded review by a board-certified clinical neurophysiologist, differences in technical quality or interpretability were insignificant between standard recordings in the EEG laboratory and microEEG recordings from standard or electrode cap electrodes in the ED or EEG laboratory. The microEEG data recording characteristics such as analog-to-digital conversion resolution (16 bits), input impedance (>100MΩ), and common-mode rejection ratio (85 dB) are similar to those of commercially available systems, although the microEEG is many times smaller (88 g and 9.4 × 4.4 × 3.8 cm).ConclusionsOur results suggest that the technical qualities of microEEG are non-inferior to a standard commercially available EEG recording device. EEG in the ED is an unmet medical need due to space and time constraints, high levels of ambient electrical noise, and the cost of 24/7 EEG technologist availability. This study suggests that using microEEG with an electrode cap that can be applied easily and quickly can surmount these obstacles without compromising technical quality.

The new wave: time to bring EEG to the emergency department

Emergency electroencephalography (EEG) is indicated in the diagnosis and management of non-convulsive status epilepticus (NCSE) underlying an alteration in the level of consciousness. NCSE is a frequent, treatable, and under-diagnosed entity that can result in neurological injury. This justifies the need for EEG availability in the emergency department (ED). There is now emerging evidence for the potential benefits of EEG monitoring in various acute conditions commonly encountered in the ED, including convulsive status after treatment, breakthrough seizures in chronic epilepsy patients who are otherwise controlled, acute head trauma, and pseudo seizures. However, attempts to allow for routine EEG monitoring in the ED face numerous obstacles. The main hurdles to an optimized use of EEG in the ED are lack of space, the high cost of EEG machines, difficulty of finding time, as well as the expertise needed to apply electrodes, use the machines, and interpret the recordings. We reviewed the necessity for EEGs in the ED, and to meet the need, we envision a product that is comprised of an inexpensive single-use kit used to wirelessly collect and send EEG data to a local and/or remote neurologist and obtain an interpretation for managing an ED patient.

Effect of microEEG on clinical management and outcomes of emergency department patients with altered mental status: a randomized controlled trial.

OBJECTIVES Altered mental status (AMS) is a common presentation in the emergency department (ED). A previous study revealed 78% electroencephalogram (EEG) abnormalities, including nonconvulsive seizure (NCS; 5%), in ED patients with AMS. The objective of this study was to assess the impact of EEG on clinical management and outcomes of ED patients with AMS. METHODS This was a randomized controlled trial at two urban teaching hospitals. Adult patients (≥18 years old) with AMS were included. Excluded patients had immediately correctable AMS (e.g., hypoglycemia) or were admitted before enrollment. Patients were randomized to routine care (control) or routine care plus EEG (intervention). Research assistants used a scalp electrode set with a miniature, wireless EEG device (microEEG) to record standard 30-minute EEGs at presentation, and results were reported to the ED attending physician by an off-site epileptologist within 30 minutes. Primary outcomes included changes in ED management (differential diagnosis, diagnostic work-up, and treatment plan from enrollment to disposition) as determined by surveying the treating physicians. Secondary outcomes were length of ED and hospital stay, intensive care unit (ICU) requirement, and in-hospital mortality. RESULTS A total of 149 patients were enrolled (76 control and 73 intervention). Patients in the two groups were comparable at baseline. EEG in the intervention group revealed abnormal findings in 93% (95% confidence interval [CI] = 85% to 97%), including NCS in 5% (95% CI = 2% to 13%). Using microEEG was associated with change in diagnostic work-up in 49% (95% CI = 38% to 60%) of cases and therapeutic plan in 42% (95% CI = 31% to 53%) of cases immediately after the release of EEG results. Changes in probabilities of differential diagnoses and the secondary outcomes were not statistically significant between the groups. CONCLUSIONS An EEG can be obtained in the ED with minimal resources and can affect clinical management of AMS patients.

Electroencephalographic findings in consecutive emergency department patients with altered mental status: a preliminary report.

Electroencephalography (EEG) can help narrow the differential diagnosis of altered mental status (AMS) and is necessary to diagnose nonconvulsive seizure (NCS). The objective of this prospective observational study is to identify the prevalence of EEG abnormalities in emergency department patients with AMS. Patients of at least 13 years of age with AMS were enrolled, whereas those with an easily identifiable cause (e.g. hypoglycemia) underlying their AMS were excluded. Easily identifiable cause of AMS (e.g. hypoglycemia). A 30-min EEG with the standard 19 electrodes was performed on each patient. Descriptive statistics (%, 95% confidence interval) are used to report EEG findings of the first 50 enrolled patients. Thirty-five EEGs (70%, 57–81%) were abnormal. The most common abnormality was slowing of background activities (46%, 33–60%), reflecting an underlying encephalopathy. NCS was diagnosed in three (6%, 1–17%), including one patient in nonconvulsive status epilepticus. Nine patients (18%, 10–31%) had interictal epileptiform abnormalities, indicating an increased risk of spontaneous seizure. Patients presenting to the emergency department with AMS have a high prevalence of EEG abnormalities, including NCS.