Testing of putative antiseizure drugs in a preclinical Dravet syndrome zebrafish model

Dravet syndrome (DS) is a severe genetic epilepsy primarily caused by de novo mutations in a voltage-activated sodium channel gene (SCN1A). Patients face life-threatening seizures that are largely resistant to available anti-seizure medications (ASM). Preclinical DS animal models are a valuable tool to identify candidate ASMs for these patients. Among these, scn1lab mutant zebrafish exhibiting spontaneous seizure-like activity are particularly amenable to large-scale drug screening. Prior screening in a scn1lab mutant zebrafish line generated using N-ethyl-N-nitrosourea (ENU) identified valproate, stiripentol, and fenfluramine e.g., Federal Drug Administration (FDA) approved drugs with clinical application in the DS population. Successful phenotypic screening in scn1lab mutant zebrafish consists of two stages: (i) a locomotion-based assay measuring high-velocity convulsive swim behavior and (ii) an electrophysiology-based assay, using in vivo local field potential (LFP) recordings, to quantify electrographic seizure-like events. Using this strategy more than 3000 drug candidates have been screened in scn1lab zebrafish mutants. Here, we curated a list of nine additional anti-seizure drug candidates recently identified in preclinical models: 1-EBIO, AA43279, chlorzoxazone, donepezil, lisuride, mifepristone, pargyline, soticlestat and vorinostat. First-stage locomotion-based assays in scn1lab mutant zebrafish identified only 1-EBIO, chlorzoxazone and lisuride. However, second-stage LFP recording assays did not show significant suppression of spontaneous electrographic seizure activity for any of the nine anti-seizure drug candidates. Surprisingly, soticlestat induced frank electrographic seizure-like discharges in wild-type control zebrafish. Taken together, our results failed to replicate clear anti-seizure efficacy for these drug candidates highlighting a necessity for strict scientific standards in preclinical identification of ASMs.

The effects of aneurysmal subarachnoid hemorrhage on cerebral vessel diameter and flow velocity

BACKGROUND

Transcranial Doppler flow velocity is used to monitor for cerebral vasospasm following aneurysmal subarachnoid hemorrhage. Generally, blood flow velocities appear inversely related to the square of vessel diameter representing local fluid dynamics. However, studies of flow velocity-diameter relationships are few, and may identify vessels for which diameter changes are better correlated with Doppler velocity. We therefore studied a large retrospective cohort with concurrent transcranial Doppler velocities and angiographic vessel diameters.

METHODS

This is a single-site, retrospective, cohort study of adult patients with aneurysmal subarachnoid hemorrhage, approved by the UT Southwestern Medical Center Institutional Review Board. Study inclusion required transcranial Doppler measurements within </= 24 hours of vessel imaging. Vessels assessed were: bilateral anterior, middle, posterior cerebral arteries; internal carotid siphons; vertebral arteries; and basilar artery. Flow velocity-diameter relationships were constructed and fitted with a simple inverse power function. A greater influence of local fluid dynamics is suggested as power factors approach two.

RESULTS

98 patients were included. Velocity-diameter relationships are curvilinear, and well fit by a simple inverse power function. Middle cerebral arteries showed the highest power factors (>1.1, R²>0.9). Furthermore, velocity and diameter changed (P<0.033) consistent with the signature time course of cerebral vasospasm.

CONCLUSIONS

These results suggest that middle cerebral artery velocity-diameter relationships are most influenced by local fluid dynamics, which supports these vessels as preferred endpoints in Doppler detection of cerebral vasospasm. Other vessels showed less influence of local fluid dynamics, pointing to greater role of factors outside the local vessel segment in determining flow velocity.

Endoscopic Endonasal versus Transcranial Optic Canal Decompression: A Morphometric, Cadaveric Study

Introduction Decompression of the optic nerve within the optic canal is indicated for compressive visual decline. The two most common approaches utilized for optic canal decompression are a medial approach with an endoscopic endonasal approach and a lateral approach with a craniotomy. Our study is a cadaveric anatomical study comparing the length and circumference of the orbit decompressed via an endoscopic endonasal approach versus a frontotemporal craniotomy.

Methods Five cadaveric specimens were utilized. Predissection computed tomography (CT) scans were performed on each specimen. On each specimen, a standard frontotemporal craniotomy with anterior clinoidectomy and superolateral orbital decompression was performed on one side and an endoscopic endonasal approach with medial wall decompression was performed on the contralateral side. Post-dissection CT scans were performed. An independent radiologist provided measurements of the length (mm) and circumference (degrees) of optic canal decompression bilaterally.

Results The mean length of optic canal decompression for open and endoscopic approach was 13 mm (range 12–15 mm) and 12.4 mm (range 10–16 mm), respectively. The mean circumference of decompression for open and endoscopic approaches was 252.8 degrees (range 205–280 degrees) and 124.6 degrees (range 100–163 degrees), respectively.

Conclusion The endoscopic endonasal and the transcranial approaches provide a similar length of optic canal decompression, but the transcranial approach leads to greater circumferential decompression. The endoscopic endonasal approach has the benefit of being minimally invasive, though. Ultimately, the surgical approach decision should be based on the location of the pathology and the surgeon's comfort.

Retrieval of an Intracranially Migrated Dental Injection Needle Through the Foramen Ovale: 2-Dimensional Operative Video

Dental injection needle migration is a rare complication of orthodontal procedures. When these needles fracture, they typically dislodge into the cervical space or the facial musculature. Migration into the cranial vault is difficult because of the obstacle created by the skull base. We report a rare case of intracranial migration of an anesthetic injection needle through the foramen ovale. A 59-yr-old man underwent the extraction of a right maxillary molar. The distal end of a 25-gauge injection needle broke into his pterygoid musculature, causing him pain while chewing. Vascular imaging obtained after a computed tomography scan of his face showed that the needle had migrated, potentially because of his efforts of mastication, and had traversed the foramen ovale into the middle cranial fossa. The patient started experiencing intermittent right facial numbness, likely due to compression or injury to the right trigeminal nerve. Our oral and maxillofacial colleagues did not believe that the needle could be retrieved from its facial end. The patient elected to undergo the recovery of the needle through a craniotomy given the fact that the object was contaminated and because he was becoming increasingly symptomatic. A right pterional craniotomy was planned. Extradural dissection was performed until the dura going into the foramen ovale was revealed. We could feel the metallic needle under the dural sheath of the trigeminal nerve. The dura was opened sharply directly over the needle. We then proceeded to mobilize the needle into the face, and then pulled it out completely through the craniotomy to avoid injury to the temporal lobe. The patient recovered well and was asymptomatic at the time of discharge. This case report was written in compliance with our institutional ethical review board. Institutional review board (IRB) approval and patient consent were waived in light of the retrospective and deidentified nature of the data presented in accordance with the University of Texas Southwestern (UTSW) IRB.

0220 Sleep Deprivation Increases Self-Reported But Not Behavioral Avoidance

Introduction

A common form of emotion regulation is avoidance, in which attention toward negative stimuli results in avoiding (Elliot, 2006). Dysfunctional avoidance is linked to negative outcomes in various forms of psychopathology (Kashdan, Barrios, Forsyth, & Steger, 2006). Sleep challenges have been identified as a mechanism in numerous mental health disorders (Kryger, Roth, & Dement, 2017). These two mechanisms may be related. We hypothesized sleep deprived individuals would demonstrate more avoidance compared to baseline and a sleep as usual group as indexed by lower scores on a behavioral approach task (BAT) and more self-reported avoidance.

Methods

Fifty-two undergraduates (mean age: 18.87, white: 45, female: 35) without mental health disorders, sleep apnea symptoms, or use of medications that may impact sleep or wakefulness were recruited. Participants completed a Cognitive-Behavioral Avoidance Scale (CBAS modified) in which all questions were modified to elucidate present moment avoidance (ex. I would avoid attending social activities) and a BAT in which they were presented with a bedpan made to look and smell dirty. They were asked to complete seven hierarchical levels of engagement ex. (1) touching it with a tissue, (7) touching it with both hands then touching your face. The task ended when a participant declined to complete a step or they completed all seven. They were randomly assigned to 26 hours of sleep deprivation or sleep as usual. Students completed the CBAS modified and the BAT the next morning.

Results

After conducting a mixed ANOVA, there were no significant differences between or within groups in BAT steps completed. There were significant increases in self-reported behavioral social (p &lt; .001) and nonsocial (p &lt; .001), and cognitive nonsocial (p = .006), and social (p = .031) avoidance in the sleep deprivation group.

Conclusion

The study demonstrated a discrepancy between behavioral and self-report avoidance, suggesting a response bias after sleep loss. This investigation illuminates the effects of sleep loss on the transdiagnostic mechanism, avoidance. Note, there are no psychometric data for the modified CBAS. Future work should examine social forms of behavioral avoidance.

Support

This study was conducted using the University of Arkansas SONA system.

Dual-Energy X-Ray Absorptiometry vs Computed Tomography: Comparison of Bone Mineral Density Measurements in Predicting Postoperative Spinal Fusion Outcomes

INTRODUCTION

Diminished bone mineral density (BMD) places patients at increased risk for complications from lumbar fusion procedures. Dual-energy X-Ray absorptiometry (DEXA) scanners have been used as the gold standard in measuring BMD. More recently, various studies have suggested that Hounsfield unit measurements from computed tomography (CT) scans may be more accurate.

METHODS

After obtaining IRB approval, we retrospectively reviewed all patients aged 18 and older who underwent lumbar fusion procedures between 01/01/2010 and 12/31/2016 at our institution. We used linear regression to assess for a correlation between CT Hounsfield units and DEXA t scores. Student's t-test was used to compare CT Hounsfield units, lumbar spine t score and hip t scores for patients with and without pseudoarthrosis as well as those with and without hardware failure.

RESULTS

A total of 167 patients with lumbar fusion procedures met inclusion criteria. Ages ranged 24 to 88 yr old with a mean of 64. Using linear regression there was no correlation between CT Hounsfield units and Dexa T scores. There was no difference between the groups with respect to CT Hounsfield units or DEXA T scores when comparing patients with and without pseudoarthrosis and when comparing patients with or without hardware failure.

CONCLUSION

Diminished BMD is an important factor to consider when contemplating lumbar spine fusion procedures as this has been associated with increased risk of hardware failure or pseudoarthrosis. Traditionally DEXA scans and more recently CT Hounsfield units have used to screen patients for decreased BMD, however, in this relatively large retrospective series we found that neither correlate well with complications from lumbar spine fusion procedures. CT and DEXA scans may not be as reliable as once thought in assessing BMD.

Delayed treatment of ruptured brain AVMs: is it ok to wait?

OBJECTIVE Despite a hemorrhagic presentation, many patients with arteriovenous malformations (AVMs) do not require emergency resection. The timing of definitive management is not standardized in the cerebrovascular community. This study was designed to evaluate the safety of delaying AVM treatment in clinically stable patients with a new hemorrhagic presentation. The authors examined the rate of rehemorrhage or neurological decline in a cohort of patients with ruptured brain AVMs during a period of time posthemorrhage. METHODS Patients presenting to the authors' institution from January 2000 to December 2015 with ruptured brain AVMs treated at least 4 weeks posthemorrhage were included in this analysis. Exclusion criteria were ruptured AVMs that required emergency surgery involving resection of the AVM, prior treatment of AVM at another institution, or treatment of lesions within 4 weeks for other reasons (subacute surgery). The primary outcome measure was time from initial hemorrhage to treatment failure (defined as rehemorrhage or neurological decline as a direct result of the AVM). Patient-days were calculated from the day of initial rupture until the day AVM treatment was initiated or treatment failed. RESULTS Of 102 ruptured AVMs in 102 patients meeting inclusion criteria, 7 (6.9%) failed the treatment paradigm. Six patients (5.8%) had a new hemorrhage within a median of 248 days (interquartile range 33-1364 days). The total "at risk" period was 18,740 patient-days, yielding a rehemorrhage rate of 11.5% per patient-year, or 0.96% per patient-month. Twelve (11.8%) of 102 patients were found to have an associated aneurysm. In this group there was a single (8.3%) new hemorrhage during a total at-risk period of 263 patient-days until the aneurysm was secured, yielding a rehemorrhage risk of 11.4% per patient-month. CONCLUSIONS It is the authors' practice to rehabilitate patients after brain AVM rupture with a plan for elective treatment of the AVM. The present data are useful in that the findings quantify the risk of the authors' treatment strategy. These findings indicate that delaying intervention for at least 4 weeks after the initial hemorrhage subjects the patient to a low (< 1%) risk of rehemorrhage. The authors modified the treatment paradigm when a high-risk feature, such as an associated intracranial aneurysm, was identified.

Rare DNA variants in the brain-derived neurotrophic factor gene increase risk for attention-deficit hyperactivity disorder: a next-generation sequencing study

Attention-deficit hyperactivity disorder (ADHD) is a prevalent and highly heritable disorder of childhood with negative lifetime outcomes. Although candidate gene and genome-wide association studies have identified promising common variant signals, these explain only a fraction of the heritability of ADHD. The observation that rare structural variants confer substantial risk to psychiatric disorders suggests that rare variants might explain a portion of the missing heritability for ADHD. Here we believe we performed the first large-scale next-generation targeted sequencing study of ADHD in 152 child and adolescent cases and 188 controls across an a priori set of 117 genes. A multi-marker gene-level analysis of rare (<1% frequency) single-nucleotide variants (SNVs) revealed that the gene encoding brain-derived neurotrophic factor (BDNF) was associated with ADHD at Bonferroni corrected levels. Sanger sequencing confirmed the existence of all novel rare BDNF variants. Our results implicate BDNF as a genetic risk factor for ADHD, potentially by virtue of its critical role in neurodevelopment and synaptic plasticity.

Evaluation of fluoroscopic cases qualifying as potential fluoroscopic sentinel events

RATIONALE AND OBJECTIVES

To address the risk of radiation injury during interventional procedures, the Joint Commission has defined prolonged fluoroscopy resulting in a cumulative skin dose of 15 Gy or more to a single field as a reviewable sentinel event. The goal of this work is to present a system for identifying potential fluoroscopic sentinel events (FSE) and describing common case characteristics.

MATERIALS AND METHODS

Criteria based on fluoroscopic time (FT) > 150 minutes and reference air kerma (RAK) > 6 Gy were used to identify potential sentinel events. Case information including procedure type, number of procedures, and radiation dose parameters was recorded. Peak skin dose (PSD) was calculated by a medical physicist. Values were compared between procedure types and the relationship between FT, RAK, and PSD was evaluated.

RESULTS

Between 2008 and 2011, 183 events exceeding the investigation criteria were identified in three interventional categories: cardiology (54%), neuroradiology (31%), and vascular (16%). The average number of procedures/patient was 1.7 ± 0.1, with the majority (59.6%) having undergone only one procedure. Most cases could be identified using the RAK criterion alone (96.7%). Based on the PSD/RAK ratio, a threshold RAK of 7.5 Gy would effectively identify all cases that would exceed 15 Gy in PSD.

CONCLUSION

Radiation delivered during interventional cases can place patients at risk of cutaneous radiation injury and potential sentinel events. Using appropriate thresholds to determine which cases require detailed investigation allows efficient utilization of department resources for identifying sentinel events.

Generation of antibody- and B cell-deficient pigs by targeted disruption of the J-region gene segment of the heavy chain locus

A poly(A)-trap gene targeting strategy was used to disrupt the single functional heavy chain (HC) joining region (J_H) of swine in primary fibroblasts. Genetically modified piglets were then generated via somatic cell nuclear transfer (SCNT) and bred to yield litters comprising J_H wild-type littermate (+/+), J_H heterozygous knockout (±) and J_H homozygous knockout (−/−) piglets in the expected Mendelian ratio of 1:2:1. There are only two other targeted loci previously published in swine, and this is the first successful poly(A)-trap strategy ever published in a livestock species. In either blood or secondary lymphoid tissues, flow cytometry, RT-PCR and ELISA detected no circulating IgM⁺ B cells, and no transcription or secretion of immunoglobulin (Ig) isotypes, respectively in J_H −/− pigs. Histochemical and immunohistochemical (IHC) studies failed to detect lymph node (LN) follicles or CD79α⁺ B cells, respectively in J_H −/− pigs. T cell receptor (TCR)_β transcription and T cells were detected in J_H −/− pigs. When reared conventionally, J_H −/− pigs succumbed to bacterial infections after weaning. These antibody (Ab)- and B cell-deficient pigs have significant value as models for both veterinary and human research to discriminate cellular and humoral protective immunity to infectious agents. Thus, these pigs may aid in vaccine development for infectious agents such as the pandemic porcine reproductive and respiratory syndrome virus (PRRSV) and H1N1 swine flu. These pigs are also a first significant step towards generating a pig that expresses fully human, antigen-specific polyclonal Ab to target numerous incurable infectious diseases with high unmet clinical need.

Targeted disruption of the porcine immunoglobulin kappa light chain locus

Inactivation of the endogenous pig immunoglobulin (Ig) loci, and replacement with their human counterparts, would produce animals that could alleviate both the supply and specificity issues of therapeutic human polyclonal antibodies (PAbs). Platform genetics are being developed in pigs that have all endogenous Ig loci inactivated and replaced by human counterparts, in order to address this unmet clinical need. This report describes the deletion of the porcine kappa (κ) light chain constant (Cκ) region in pig primary fetal fibroblasts (PPFFs) using gene targeting technology, and the generation of live animals from these cells via somatic cell nuclear transfer (SCNT) cloning. There are only two other targeted loci previously published in swine, and this is the first report of a targeted disruption of an Ig light chain locus in a livestock species. Pigs with one targeted Cκ allele (heterozygous knockout or ±) were bred together to generate Cκ homozygous knockout (-/-) animals. Peripheral blood mononuclear cells (PBMCs) and mesenteric lymph nodes (MLNs) from Cκ -/- pigs were devoid of κ-containing Igs. Furthermore, there was an increase in lambda (λ) light chain expression when compared to that of wild-type littermates (Cκ +/+). Targeted inactivation of the Ig heavy chain locus has also been achieved and work is underway to inactivate the pig lambda light chain locus.

The association of visuospatial working memory with dysthymic disorder in pre-pubertal children

BACKGROUND

Visuospatial working memory (VSWM) deficits have not been investigated specifically in children with dysthymic disorder (DD), although they are associated with impairments in attention that commonly occur in DD. This study investigates VSWM impairment in children with DD.

METHOD

A cross-sectional study of VSWM in 6- to 12-year-old children with medication-naive DD (n=26) compared to an age-, gender- and 'performance IQ' (PIQ)-matched healthy control group (n=28) was completed.

RESULTS

The DD group demonstrated impairment in VSWM, including impairment in the spatial span and strategy components of VSWM. Furthermore, the VSWM impairment remained after controlling for spatial span. Inattentive symptoms were significantly associated with the VSWM impairment.

CONCLUSIONS

This study of children with DD found deficits in performance on VSWM tasks, suggesting that fronto-striatal-parietal neural networks that underlie processes of attention and the executive component of VSWM are dysfunctional in children with DD. These findings further our understanding of DD and suggest more specific interventions that might improve functioning.

Right parietal dysfunction in children with attention deficit hyperactivity disorder, combined type: a functional MRI study

Attention deficit hyperactivity disorder, combined type (ADHD-CT) is associated with spatial working memory deficits. These deficits are known to be subserved by dysfunction of neural circuits involving right prefrontal, striatal and parietal brain regions. This study determines whether decreased right prefrontal, striatal and parietal activation with a mental rotation task shown in adolescents with ADHD-CT is also evident in children with ADHD-CT. A cross-sectional study of 12 pre-pubertal, right-handed, 8-12-year-old boys with ADHD-CT and 12 pre-pubertal, right-handed, performance IQ-matched, 8-12-year-old healthy boys, recruited from local primary schools, was completed. Participants underwent functional magnetic resonance imaging while performing a mental rotation task that requires spatial working memory. The two groups did not differ in their accuracy or response times for the mental rotation task. The ADHD-CT group showed significantly less activation in right parieto-occipital areas (cuneus and precuneus, BA 19), the right inferior parietal lobe (BA 40) and the right caudate nucleus. Our findings with a child cohort confirm previous reports of right striatal-parietal dysfunction in adolescents with ADHD-CT. This dysfunction suggests a widespread maturational deficit that may be developmental stage independent.

Visuospatial memory deficits in adolescent onset schizophrenia

Visuospatial memory encoding deficits have been reported in adults with schizophrenia, while adolescents with schizophrenia have not been specifically investigated with visuospatial memory encoding and retrieval paradigms. A cross sectional study of delayed matching-to-sample performance in 19 right handed, male, anti-psychotic medication naïve adolescents with undifferentiated schizophrenia and 28 age, gender, IQ and handedness matched healthy participants was completed. The adolescent-onset schizophrenia group demonstrated significant impairment in visuospatial memory, independent of the degree of delay, consistent with an encoding impairment. The impaired encoding phase of visuospatial memory in the adolescent-onset schizophrenia group is consistent with findings in adult onset schizophrenia samples, suggesting a developmental stage-independent deficit.

Patient Radiation Doses from Adult and Pediatric CT

OBJECTIVE

The purpose of our study was to determine typical organ doses, and the corresponding effective doses, to adult and pediatric patients undergoing a single CT examination.

MATERIALS AND METHODS

Heads, chests, and abdomens of patients ranging from neonates to oversized adults (120 kg) were modeled as uniform cylinders of water. Monte Carlo dosimetry data were used to obtain average doses in the directly irradiated region. Dosimetry data were used to compute the total energy imparted, which was converted into the corresponding effective dose using patient-size-dependent effective-dose-per-unit-energy-imparted coefficients. Representative patient doses were obtained for scanning protocols that take into account the size of the patient being scanned by typical MDCT scanners.

RESULTS

Relative to CT scanners from the early 1990s, present-day MDCT scanners result in doses that are approximately 1.5 and approximately 1.7 higher per unit mAs in head and body phantoms, respectively. Organ absorbed doses in head CT scans increase from approximately 30 mGy in newborns to approximately 40 mGy in adults. Patients weighing less than approximately 20 kg receive body organ absorbed doses of approximately 7 mGy, which is a factor of 2 less than for normal-sized (70-kg) adults. Adult head CT effective doses are approximately 0.9 mSv, four times less than those for the neonate. Effective doses for neonates undergoing body CT are approximately 2.5 mSv, whereas those for normal-sized adults are approximately 3.5 mSv.

CONCLUSION

Representative organ absorbed doses in CT are substantially lower than threshold doses for the induction of deterministic effects, and effective doses are comparable to annual doses from natural background radiation.

Visuospatial working memory deficits in adolescent onset schizophrenia

This study determines that visuospatial working memory (VSWM) deficits are evident in adolescent-onset schizophrenia, while the spatial strategy and spatial span components of VSWM are spared. These findings imply that frontal-striatal-parietal neural networks are dysfunctional in adolescent-onset schizophrenia, while mid-dorsolateral and ventrolateral PFC functions remain intact: the current conceptualisation of schizophrenia as a progressive neurodevelopmental disorder is consistent with these results.

An investigation of visuospatial memory impairment in children with attention deficit hyperactivity disorder (ADHD), combined type

BACKGROUND

Memory impairment is not considered a core cognitive feature of attention deficit hyperactivity disorder, combined type (ADHD-CT), although it is associated with impairments in attentional and executive functions. This study investigates visuospatial memory impairment, in particular encoding and retrieval aspects, in children with ADHD-CT who are stimulant-medication naive and medicated with stimulant medication.

METHOD

A cross-sectional study of visuospatial memory in 6- to 12-year-old children with stimulant-medication-naive ADHD-CT (n = 62) and medicated ADHD-CT (n = 58) compared to an age- and gender-matched healthy control group (n = 39) was completed.

RESULTS

Both medication-naive and medicated ADHD-CT groups demonstrated subtle yet significant impairment in visuospatial memory. The memory impairment was delay-independent, which, along with other factors, suggest dysfunction of the encoding rather than retrieval phase of visuospatial memory.

CONCLUSIONS

Careful study of large ADHD-CT samples does detect deficits in a visuospatial memory task, but these reflect attentional deficits rather than being specifically due to dysfunction of the medial temporal lobe explicit memory system. Children with ADHD-CT may benefit from cognitive and behavioural strategies focused on improving encoding of relevant information rather than retrieval strategies.

Fronto-parietal activation in attention-deficit hyperactivity disorder, combined type: functional magnetic resonance imaging study

A functional magnetic resonance imaging mental rotation paradigm was used to investigate the patterns of activation of fronto-parietal brain areas in male adolescents with attention-deficit hyperactivity disorder, combined type (ADHD-CT) compared with age-, gender-, handedness- and performance IQ-matched healthy controls. The ADHD-CT group had (a) decreased activation of the 'action-attentional' system (including Brodmann's areas (BA) 46, 39, 40) and the superior parietal (BA 7) and middle frontal (BA10) areas and (b) increased activation of the posterior midline attentional system. These different neuroactivation patterns indicate widespread frontal, striatal and parietal dysfunction in adolescents with ADHD-CT.

Contextual abnormalities of saccadic inhibition in children with attention deficit hyperactivity disorder

Abnormalities of executive function are observed consistently in children with attention-deficit hyperactivity disorder (ADHD), and it is hypothesised that these arise because of disruption to a behavioural inhibition system. Executive and inhibitory functions were compared between unmedicated and medicated children with ADHD (combined type), age-matched healthy children and healthy adults. Executive functions were measured using a test of spatial working memory shown previously to be sensitive to ADHD and to stimulant medication. Inhibitory functions were measured using an ocular motor paradigm that required individuals to use task context to control the release of fixation. Context was set according to the probability that a target would appear at either of the two locations. In one block, targets appeared on 80% of trials. In the other block, targets appeared on 20% of trials. The ability to control the release of fixation was inferred from the fixation offset effect (FOE), or the difference in saccade latency when the current fixation is offset 200 ms prior to the onset of the saccade target (gap condition), compared with when there is no offset (overlap condition). Although the healthy children made more errors on the spatial working memory task than the healthy adults, there was no difference between the two groups in their ability to control fixation using context. Both showed a larger FOE when target probability was low. As expected, the unmedicated ADHD group made more errors on the spatial working memory test than the healthy children, although spatial working memory performance was normal in the medicated ADHD group. However, both the unmedicated and medicated ADHD groups were unable to modulate the FOE according to context, and this was due to their inability to voluntarily inhibit saccades when there was a low target probability. These data suggest that the context-based modulation of fixation release is not controlled by the same systems that control executive function. Furthermore, deficits in executive function and inhibitory control appear independent in children with ADHD.

Abnormal executive function in attention deficit hyperactivity disorder: the effect of stimulant medication and age on spatial working memory

OBJECTIVE

This study sought to examine the factors associated with spatial working memory and the use of strategies to impairments in spatial working memory in children with attention deficit hyperactivity disorder (ADHD). The developmental trajectories for spatial working memory in medicated and medication naïve children with ADHD were investigated. In addition, the effect of psychostimulant medication on deficits in spatial working memory was examined.

METHOD

A cross-sectional study compared performance between 21 psychostimulant medicated children with ADHD, 27 medication naïve children with ADHD and 26 matched control subjects on computerized tests of spatial memory and spatial working memory.

RESULTS

Compared with the controls, performance in medication naïve children with ADHD was significantly worse on the spatial working memory task. There was no difference in performance between the medicated children with ADHD and the control subjects on this same task, despite the ongoing symptoms of ADHD in the former group. The pattern of normal and abnormal performance in the ADHD groups was age-independent.

CONCLUSIONS

Deficits in executive functions related to spatial working memory do occur in children with ADHD, although the magnitude of these deficits is not related to the child's age or the level of ADHD symptoms. These deficits were not present in the current sample of children who were receiving psychostimulant medication.

Executive function and attention deficit hyperactivity disorder: stimulant medication and better executive function performance in children

BACKGROUND

Executive function deficits have been reported repeatedly in children with Attention Deficit Hyperactivity Disorder (ADHD). Stimulant medication has been shown to be effective in improving cognitive performance on most executive function tasks, but neuropsychological tests of executive function in this population have yielded inconsistent results. Methodological limitations may explain these inconsistencies. This study aimed to measure executive function in medicated and non-medicated children with ADHD by using a computerized battery, the Cambridge Neuropsychological Test Automated Battery (CANTAB), which is sensitive to executive function deficits in older patients with frontostriatal neurological impairments.

METHODS

Executive function was assessed in 30 children with ADHD: 15 were stimulant medication naive and 15 were treated with stimulant medication. These two groups were compared to 15 age, sex and IQ matched controls.

RESULTS

The unmedicated children with ADHD displayed specific cognitive impairments on executive function tasks of spatial short-term memory, spatial working memory, set-shifting ability and planning ability. Impairments were also seen on spatial recognition memory and delayed matching to sample, while pattern recognition memory remained intact. The medicated children with ADHD were not impaired on any of the above executive function tasks except for deficits in spatial recognition memory.

CONCLUSIONS

ADHD is associated with deficits in executive function. Stimulant medication is associated with better executive function performance. Prospective follow-up studies are required to examine these effects.

Restructuring clinical time to professionalize the RN-BSN student

The needs of the RN-BSN student are unique. If the RN-BSN student is to be successful in a degree completion program, it is important that the program be designed with the needs of the student in mind. It is important that the program be tailored to the needs of the student who may already possess expertise in nursing. This will enhance the likelihood that the student will stay in the program and that learning will occur.

Oral and systemic effects of prolonged minocycline therapy

The following case report shows the unfortunate side effects of minocycline therapy used in the management of facial acne. All three features of discoloration affecting the skin, bone and dentition were found. A 46-year-old patient presented with adult onset discoloration of the dentition following prolonged minocycline therapy. In addition, oral and cutaneous pigmentation were noted. Unfortunately, the undesirable cosmetic appearance of facial acne was exchanged for permanent discoloration of the dentition. When considering prolonged minocycline therapy, patients would benefit from dialogue between the medical and dental practitioners, so that the risk of this potential side effect can be assessed in a more informed way.

Irritability in work relationships

Irritability is a word that is not commonly found in management textbooks. However, it is a phenomenon that the manager may frequently encounter and should be understood if correct intervention is to occur. This paper explores the phenomenon of irritability as it relates to emotions, behavior, and physiology, in order to provide information for the manager to use in recognizing, understanding, and detecting irritability in one's self, peers, boss, or employees.

Motivating the paraprofessional in long-term care

Motivating the paraprofessional employee in the long-term care setting is one of the biggest challenges facing health care supervisors. Unlike their counterparts in industry, whose work may produce tangible results and rewards, long-term care professionals often must face patients who show little or no change over time. Supervisors must have understanding and knowledge of motivational techniques that will involve and challenge paraprofessionals.

Strategies to Assist Students to be Successful the Next Time Around on the NCLEX-RN

Not passing the NCLEX is traumatic for both the graduate and the nursing program's faculty and dean. The faculty need to look at the program and make some strengthening changes such as higher admission requirements, more time in some clinical course, or increased use of NLN tests for specialty areas. Additionally, a supportive faculty member needs to assist the graduate who has not passed to make an individualized plan for succeeding the second time. A variety of ways to assist the graduate in studying, that have been found useful at the author's school of nursing, have been suggested.