Cognitive outcome in acute sporadic encephalitis

Use of antiviral drugs and incidence of Parkinson's disease in Taiwan

Patients infected with herpes zoster might be at risk for Parkinson's disease (PD). However, antiviral drugs may impede viral deoxyribonucleic acid (DNA) synthesis. This study aimed to determine whether the currently observed association between herpes zoster and PD is consistent with previous findings, and whether antiviral drug use is associated with PD. This retrospective cohort study used the Longitudinal Generation Tracking Database. We included patients aged 40 years and above and applied propensity score matching at 1:1 ratio for study comparability. PD risk was evaluated using Cox proportional hazards regression methods. A total of 234,730 people were analyzed. The adjusted hazard ratio (aHR) for PD in patients with herpes zoster was 1.05. Furthermore, the overall incidence of PD was lower in those treated with antiviral drugs than in the untreated ones (3.17 vs. 3.76 per 1,000 person-years); the aHR was 0.84. After stratifying for sex or age, a similar result was observed. In conclusion, herpes zoster may increase the risk of PD, particularly among females, but receiving antiviral treatment reduces the risk by 16%. Therefore, using antiviral drugs may help prevent PD. However, additional research is required to determine the underlying mechanism(s).

Vulnerability of the Hippocampus to Insults: Links to Blood-Brain Barrier Dysfunction

The hippocampus is a critical brain substrate for learning and memory; events that harm the hippocampus can seriously impair mental and behavioral functioning. Hippocampal pathophysiologies have been identified as potential causes and effects of a remarkably diverse array of medical diseases, psychological disorders, and environmental sources of damage. It may be that the hippocampus is more vulnerable than other brain areas to insults that are related to these conditions. One purpose of this review is to assess the vulnerability of the hippocampus to the most prevalent types of insults in multiple biomedical domains (i.e., neuroactive pathogens, neurotoxins, neurological conditions, trauma, aging, neurodegenerative disease, acquired brain injury, mental health conditions, endocrine disorders, developmental disabilities, nutrition) and to evaluate whether these insults affect the hippocampus first and more prominently compared to other brain loci. A second purpose is to consider the role of hippocampal blood-brain barrier (BBB) breakdown in either causing or worsening the harmful effects of each insult. Recent research suggests that the hippocampal BBB is more fragile compared to other brain areas and may also be more prone to the disruption of the transport mechanisms that act to maintain the internal milieu. Moreover, a compromised BBB could be a factor that is common to many different types of insults. Our analysis indicates that the hippocampus is more vulnerable to insults compared to other parts of the brain, and that developing interventions that protect the hippocampal BBB may help to prevent or ameliorate the harmful effects of many insults on memory and cognition.

Cognitive decline following acute viral infections: literature review and projections for post-COVID-19

Recently, much attention has been drawn to the importance of the impact of infectious disease on human cognition. Several theories have been proposed, to explain the cognitive decline following an infection as well as to understand better the pathogenesis of human dementia, especially Alzheimer's disease. This article aims to review the state of the art regarding the knowledge about the impact of acute viral infections on human cognition, laying a foundation to explore the possible cognitive decline followed coronavirus disease 2019 (COVID-19). To reach this goal, we conducted a narrative review systematizing six acute viral infections as well as the current knowledge about COVID-19 and its impact on human cognition. Recent findings suggest probable short- and long-term COVID-19 impacts in cognition, even in asymptomatic individuals, which could be accounted for by direct and indirect pathways to brain dysfunction. Understanding this scenario might help clinicians and health leaders to deal better with a wave of neuropsychiatric issues that may arise following COVID-19 pandemic as well as with other acute viral infections, to alleviate the cognitive sequelae of these infections around the world.

Antiviral therapy: Valacyclovir Treatment of Alzheimer's Disease (VALAD) Trial: protocol for a randomised, double-blind,placebo-controlled, treatment trial

INTRODUCTION

After infection, herpes simplex virus-1 (HSV1) becomes latent in the trigeminal ganglion and can enter the brain via retrograde axonal transport. Recurrent reactivation of HSV1 may lead to neurodegeneration and Alzheimer's disease (AD) pathology. HSV1 (oral herpes) and HSV2 (genital herpes) can trigger amyloid beta-protein (Aβ) aggregation and HSV1 DNA is common in amyloid plaques. Anti-HSV drugs reduce Aβ and phosphorylated tau accumulation in cell-culture models. Cognitive impairment is greater in patients with HSV seropositive, and antiviral drugs show robust efficacy against peripheral HSV infection. Recent studies of electronic health records databases demonstrate that HSV infections increase dementia risk, and that antiviral medication treatment reduces this risk. The generic antiviral drug valacyclovir was superior to placebo in improving memory in a schizophrenia pilot trial but has not been tested in AD.

METHODS AND ANALYSIS

In patients with mild AD who test positive for HSV1 or HSV2 serum antibodies, valacyclovir, repurposed as an anti-AD drug, will be compared with placebo (lactose pills) in 130 patients (65 valacyclovir and 65 placebo) in a randomised, double-blind, 78-week phase II proof-of-concept trial. Patients on valacyclovir, dose-titrated from 2 g to a targeted oral dose of 4 g daily, compared with placebo, are hypothesised to show smaller cognitive and functional decline, and, using 18F-Florbetapir positron emission tomography (PET) and 18F-MK-6240 PET imaging, to show less amyloid and tau accumulation, respectively. In the lumbar puncture subsample, cerebrospinal fluid acyclovir will be assayed to assess central nervous system valacyclovir penetration.

ETHICS AND DISSEMINATION

The trial is being overseen by the New York State Psychiatric Institute Institutional Review Board (protocol 7537), the National Institute on Ageing, and the Data Safety Monitoring Board. Written informed consent is obtained for all subjects. Results will be disseminated via publication, clinicaltrials.gov, media and conferences.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov identifier (NCT03282916) Pre-results.

Viral Hypothesis and Antiviral Treatment in Alzheimer's Disease

PURPOSE OF REVIEW

Viruses, particularly herpes simplex virus (HSV), may be a cause of Alzheimer's disease (AD). The evidence supporting the viral hypothesis suggests that antiviral treatment trials, which have not been conducted, are warranted.

RECENT FINDINGS

HSV1 (oral herpes) and HSV2 (genital herpes) can trigger amyloid aggregation, and their DNA is common in amyloid plaques. HSV1 reactivation is associated with tau hyperphosphorylation and possibly tau propagation. Anti-HSV drugs reduce Aβ and p-tau accumulation in infected mouse brains. Clinically, after the initial oral infection, herpes simplex virus-1 (HSV1) becomes latent in the trigeminal ganglion and recurrent reactivation may produce neuronal damage and AD pathology. Clinical studies show cognitive impairment in HSV seropositive patients, and antiviral drugs show strong efficacy against HSV. An antiviral treatment trial in AD is clearly warranted. A phase II treatment trial with valacyclovir, an anti-HSV drug, recently began with evaluation of clinical and biomarker outcomes.

The impact of Herpes simplex virus type 1 on cognitive impairments in young, healthy individuals - A historical prospective study

Herpes simplex virus (HSV) is a highly prevalent neurotropic virus. Although on the whole, chronic, latent or persistent infection is considered to be relatively benign, HSV infections can cause cognitive impairment during and after acute encephalitis. Some studies have documented cognitive impairment in exposed persons that is untraceable to encephalitis. Most studies have focused on these impairments in the mentally ill, mostly among individuals with schizophrenia, and only recently have studies begun to examine the impact of HSV infection on the cognition of healthy individuals. Subjects were a representative, random sample of 612 soldiers before active duty in the Israeli military (Israeli defense force - IDF), 62.2% HSV positive (n=381) and 38.8% HSV negative (n=231). Cognitive functioning and language abilities were compared between these groups, controlling for years of education, immigration status, and gender. Compared to soldiers who were sero-negative, soldiers who were sero-positive for HSV had significantly lower IQ scores (IQ=97.96, SD=15.19 vs IQ=103.23, SD=14.23; p≤0.001, effect size (ES)=0.2), and significantly lower Hebrew language scores (ES=0.1, p≤0.01). The results remained significant after removing subjects with mild depression, anxiety or personality disorders. Although we could not control for socio-economic status directly, our findings indicate that infection with HSV-1 is associated with reduced cognitive functioning in healthy individuals. This finding adds to the growing number of studies in the schizophrenia literature and indicates that many research findings seemingly characteristic of schizophrenia are related to the association between HSV exposure and cognitive functioning in general, and are not illness specific.

Exposure to herpes simplex virus type 1 and cognitive impairments in individuals with schizophrenia

Latent infection with neurotropic herpes viruses, such as herpes simplex virus, type 1 (HSV1), has been generally considered benign in most immunocompetent individuals except for rare cases of encephalitis. However, several recent studies have shown impaired cognitive functions among individuals with schizophrenia exposed to HSV1 compared with schizophrenia patients not exposed to HSV1. Such impairments are robust and are prominently observed in working memory, verbal memory, and executive functions. Brain regions that play a key role in the regulation of these domains have shown smaller volumes, along with correlation between these morphometric changes and cognitive impairments in schizophrenia. One study noted temporal decline in executive function and gray matter loss among HSV1-exposed first-episode antipsychotic-naïve schizophrenia patients. Furthermore, a proof-of-concept double-blind placebo-controlled trial indicated improvement in cognitive performance following supplemental anti-herpes-specific medication among HSV1 seropositive schizophrenia patients. Cross-sectional studies have also identified an association between HSV1 exposure and lesser degrees of cognitive impairment among healthy control individuals and patients with bipolar disorder. These studies fulfill several Bradford-Hill criteria, suggesting etiological links between HSV1 exposure and cognitive impairment. Exposure to other human herpes viruses such as cytomegalovirus and herpes simplex virus type 2 (HSV2) may also be associated with cognitive impairment, but the data are less consistent. These studies are reviewed critically and further lines of enquiry recommended. The results are important from a public health perspective, as HSV1 exposure is highly prevalent in many populations.

Additive effects of elevated C-reactive protein and exposure to Herpes Simplex Virus type 1 on cognitive impairment in individuals with schizophrenia

OBJECTIVES

We investigated the effect of elevated levels of C-reactive protein (CRP) and exposure to Herpes simplex virus type 1 (HSV-1) on the severity of cognitive impairment in individuals with schizophrenia.

METHODS

We measured the levels of CRP and of antibodies to HSV-1 in serum samples from 588 individuals with schizophrenia by enzyme immunoassay tests. Cognitive functioning was measured with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and psychiatric symptoms with the Positive and Negative Syndrome Scale (PANSS). The effects of HSV1 and CRP on cognitive functioning were analyzed with linear and logistic regression analyses adjusting for demographic and clinical variables.

RESULTS

The individuals with elevated CRP levels and HSV-1 seropositivity had lower RBANS cognitive scores. The strongest effect was found in individuals who had both serological evidence of HSV-1 exposure and elevated levels of CRP. These individuals had odds of 2.35 to have an RBANS Total score<=60 as compared to individuals who were HSV-1 seronegative and who did not have elevated levels of CRP (p=.002). The risks of decreased cognitive functioning associated with HSV-1 exposure and elevated levels of CRP were independent and additive. There was no effect of HSV-1 exposure and CRP levels on the severity of symptoms as measured by the PANSS (all p>.5).

CONCLUSIONS

Elevated levels of CRP and exposure to HSV-1 are associated with the severity of cognitive impairment in schizophrenia. These findings indicate that infection and inflammation may play a major role in the cognitive deficits associated with schizophrenia.

Long-term outcome of acute encephalitis of unknown aetiology in adults

Encephalitis is caused by a variety of conditions, including infections of the brain by a wide range of pathogens. A substantial number of cases of encephalitis defy all attempts at identifying a specific cause. Little is known about the long-term prognosis in patients with encephalitis of unknown aetiology, which complicates their management during the acute illness. To learn more about the prognosis of patients with encephalitis of unknown aetiology, patients in whom no aetiology could be identified were examined in a large, single-centre encephalitis cohort. In addition to analysing the clinical data of the acute illness, surviving patients were assessed by telephone interview a minimum of 2 years after the acute illness by applying a standardized test battery. Of the patients with encephalitis who qualified for inclusion (n = 203), 39 patients (19.2%) had encephalitis of unknown aetiology. The case fatality in these patients was 12.8%. Among the survivors, 53% suffered from various neurological sequelae, most often attention and sensory deficits. Among the features at presentation that were associated with adverse outcome were older age, increased C-reactive protein, coma and a high percentage of polymorphonuclear cells in the cerebrospinal fluid. In conclusion, the outcome in an unselected cohort of patients with encephalitis of unknown aetiology was marked by substantial case fatality and by long-term neurological deficits in approximately one-half of the surviving patients. Certain features on admission predicted an unfavourable outcome.

Serological evidence of exposure to Herpes Simplex Virus type 1 is associated with cognitive deficits in the CATIE schizophrenia sample

Cognitive impairment is a core feature of schizophrenia. Previous studies have indicated that exposure to neurotropic infectious agents such as Herpes Simplex Virus type 1 may contribute to cognitive deficits and neuroanatomical abnormalities in individuals with schizophrenia. We examined the association between exposure to neurotropic infectious agents and cognitive function in 1308 participants in the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) trial. This sample included all of the individuals in the CATIE trial for whom baseline blood samples were available. Cognition was evaluated at baseline by a test battery which yielded composite scores in the domains of processing speed, verbal memory, vigilance, reasoning, and working memory as well as a summary neurocognitive score. Solid phase immunoassay techniques were used to measure IgG class antibodies to Herpes Simplex Virus type 1 (HSV-1), Herpes Simplex Virus type 2 (HSV-2), Cytomegalovirus (CMV), and to Toxoplasma gondii (T gondii) in the sera of the study individuals. We found a significant association between the neurocognitive summary score and antibodies to HSV-1 but not to HSV-2, CMV, or T. gondii. There was also a significant association between HSV-1 exposure and the Verbal Memory, Vigilance, and Processing Speed composite scores. HSV-1 may modulate the neurocognitive function of individuals with schizophrenia through its ability to establish latency in the central nervous system and undergo periodic reactivation. A better understanding of the role of HSV-1 may lead to better methods of treatment for the cognitive impairments associated with schizophrenia.

Dementia following herpes zoster encephalitis

We studied the rare case of an older adult with dementia following herpes zoster encephalitis (HZE). This 71-year-old woman presented to us approximately 1 year following resolution of a rapid-onset episode of HZE, and subsequently underwent neuropsychological and neuroimaging examinations. Cognitive assessment revealed impairments in general cognitive functioning, verbal and nonverbal memory, executive functions, speed of information processing, attention/working memory, and motor skills. The patient's neuroimaging data, when compared to a demographically similar healthy control sample (n = 9), demonstrated moderate central and perisylvian brain volume loss, several subcortical lesions in the white matter, and resting state whole brain and hippocampal hypoperfusion. These findings highlight neuropsychological changes evident in a dementia syndrome of this type, and they suggest that early identification and treatment of HZE has implications for the preservation of long-term cognitive functioning.

Neuroanatomic and cognitive abnormalities related to herpes simplex virus type 1 in schizophrenia

Herpes simplex virus 1 (HSV-1) tends to replicate in the temporal cortex and can damage the limbic system. The presence of serum antibodies to HSV-1 is associated with cognitive impairment in adults with schizophrenia, suggesting that cerebral gray matter abnormalities might distinguish patient subgroups defined by HSV-1 exposure. We assessed 43 adult outpatients with schizophrenia. The assessment included clinical interviews, neurocognitive testing, anatomic brain magnetic resonance imaging and measures of serum IgG antibodies specific to herpes simplex viruses 1 and 2. We then compared 25 patients who tested positive for antibodies to HSV-1 with 15 who were seronegative for both HSV-1 and HSV-2. The seropositive patients performed significantly worse than the seronegative patients on four neuropsychological measures of psychomotor speed, executive functioning, and explicit verbal memory. Voxel-based morphometric analyses revealed that the same patients showed reduced gray matter volume in the anterior cingulate and areas of the cerebellum. Finally, performance on the test of psychomotor speed and executive functioning that showed the largest between- group effect size correlated with reduced gray matter volume in some of the same brain regions (cingulate and cerebellum) that distinguished the two HSV-1 subgroups. In these outpatients with schizophrenia, HSV-1 seropositivity and performance on a cognitive test that is highly sensitive to it co-localize to closely overlapping brain regions.

Neurocognitive and functional outcomes in persons recovering from West Nile virus illness

Long-term neurocognitive and functional impairments following West Nile virus (WNV) disease are poorly understood. We assessed quality-of-life indices and neurocognitive performance in a cohort of 54 persons recovering from one of three WNV disease syndromes (fever [WNF], meningitis [WNM], or encephalitis [WNE]) approximately 1.5 years following acute illness. We compared findings between the three syndromic groups; the study cohort and a demographically similar group of 55 controls from a study of chronic fatigue syndrome (CFS); and the study cohort and a 'normative' control population based on cognitive test data. Persistent symptoms, diminished quality of life, and functional impairment were reported by 50% of WNF patients, and 75% each of WNM and WNE patients. Overall, objective neurocognitive performance did not differ significantly between the three syndromic groups, or between the study cohort and the CFS controls or the normative controls. In some neurocognitive subtests, the study cohort scored below the 15th percentile when compared with normative control data. Most persons who returned to independent living following hospitalization for WNV illness had persistent subjective complaints, but had normal cognitive function. However, a minority displayed subtle neurocognitive deficits more than 18 months following acute disease.

Association between cognitive functioning, exposure to Herpes Simplex Virus type 1, and the COMT Val158Met genetic polymorphism in adults without a psychiatric disorder

Previous studies have documented that serologic evidence of infection with the neurotropic human herpesvirus Herpes Simplex Virus type 1 (HSV-1) is associated with increased levels of cognitive dysfunction in individuals with schizophrenia or bipolar disorder. The catechol-o-methyl transferase (COMT) Val158Met polymorphism has also been associated with cognitive dysfunction in individuals with psychiatric disorders as well as in some control populations. We examined whether these factors are independently associated with cognitive functioning in adults without a history of a psychiatric disorder. A total of 240 individuals were evaluated with the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and the Wisconsin Card Sorting Test (WCST). We measured IgG antibodies to HSV-1 by enzyme immunoassay and employed real time PCR to measure COMT Val158Met genotypes. Serological evidence of HSV-1 was significantly associated with a lower RBANS total score independent of demographic factors and the COMT Val158Met genotype. The strongest association between cognitive functioning and serological evidence of HSV-1 infection was with the domain of delayed memory. Serological evidence of HSV-1 infection was associated with an 18-fold increased odds of having a severe impairment in this domain. The Val/Val genotype of the COMT Val158Met polymorphism was also significantly associated with the RBANS total score and with a moderate decrease in the domain of attention. Infections with HSV-1 and the COMT Val158Val genotype are risk factors for cognitive deficits in non-elderly persons without a psychiatric disorder.

Postencephalitic amnesia with long term-working memory impairment: A case report

Herpes simplex virus encephalitis (HSVE) is an inflammation of the brain parenchyma caused by virus, leading to focal necrosis in medial temporal lobes, hippocampal complex and basal forebrain. Cognitively, HSVE is associated to many dysfunctions which vary according to the extent of the lesion. Episodic memory impairment is the most common sequelae following HSVE episodes, although others can occur. The aim of this case report was to describe the cognitive profile of a 42 year-old man who had extensive bilateral damage to the medial temporal lobe, insular bilateral and orbitofrontal cortices due to HSVE. Severe anterograde and retrograde amnesia, naming deficits, perseverative behaviors and confabulations were observed on neuropsychological assessment. We discussed the concept of long term-working memory based on this evaluation. These cognitive impairments corroborated HSVE previous findings in the literature.

Primary target cells of herpes simplex virus type 1 in the hippocampus

Herpes simplex virus type 1 (HSV-1) causes fatal and sporadic encephalitis in human. The encephalitis-survivors frequently suffer from symptoms of memory deficits. It remains unclear how HSV-1 induces tissue damages in memory formation-associated brain tissues such as the hippocampus. In this study, we examined HSV-1 infection in the hippocampus using a rat HSV-1 infection model. We found profound pathological changes in the hippocampus and large numbers of HSV-1 antigen-positive cells in the dentate gyrus (DG) subfield of HSV-1-infected rats. To understand the precise mechanism of HSV-1-induced tissue damages in the hippocampus, we employed rat organotypic hippocampal slice cultures (OHC) as an in vitro HSV-1 infection model. In OHC, HSV-1 infection predominated in neuronal cells and the infected neuronal cells were severely damaged. Longitudinal analysis indicated that granule cells in DG subfield were extremely vulnerable to HSV-1 infection among neuronal cells in the hippocampus. Since DG granule cells play a crucial role in memory formation, disruption of these cells may be a primary step leading to memory deficits.

Neuropsychologic outcomes in children with neonatal herpes encephalitis

Neonatal herpes simplex virus infection with involvement of the central nervous system is a serious disease with high morbidity, even with acyclovir therapy. The disability includes cerebral palsy and different aspects of cognitive dysfunction which are of utmost importance for the child's future habilitation. We conducted a descriptive cohort study to define neuropsychologic outcomes and determine the relationship between neonatal neuroimaging and neuropsychologic outcomes. Among 267,690 children born in the Stockholm area over 12 years (1989-2000), 14 were diagnosed with neonatal herpes including central nervous system involvement. Nine children were neuropsychologically evaluated. Neonatal herpes virus infection had an even greater impact on cognitive function, speech ability, and attention deficit than anticipated. Relapse leading to deterioration was demonstrated in one child. Social skills were influenced to a lesser degree. Neurodevelopmental outcomes of the children were not well-correlated with extent of cerebral damage as visualized by computed tomography at 7-28 days after onset of signs. Neuropsychologic assessment is essential in the habilitation of the child, and a prerequisite for the evaluation of new treatments and for the assessment of deterioration of cerebral function related to relapses.

Risk factors for postencephalitic epilepsy in children: a hospital-based study in Taiwan

To identify clinical, neurophysiological and neuroradiological features in acute encephalitis with predictive value for postencephalitic epilepsy (PEE) in children, a retrospective cohort study by following up 0-17-year-old children with the diagnosis of acute encephalitis was done. Total 330 children were enrolled. Of these, 54 (16.4%) developed epilepsy with a mean follow-up period of 6+/-4.6 years, and 79.6% had the diagnosis of epilepsy within six months after encephalitis. Significant risk factors for PEE include the presence of recurrent seizures, status epilepticus, severe disturbance of consciousness, the existence of focal neurological sign, and the presence of neurological deterioration during hospitalization. Patients with abnormal electroencephalogram, including focal (P<0.05), or profound cerebral dysfunction (P<0.001), and focal cortical abnormalities in neuroimaging (P<0.01), also have higher incidence of epilepsy. Furthermore, children with refractory status epilepticus at presentation also significantly increased the possibility of intractable PEE (P<0.01). We concluded that PEE is not a rare complication of acute encephalitis. Children with refractory status epilepticus or poor control of seizures are more likely to have intractable PEE.

Modulation of microglia and CD8(+) T cell activation during the development of stress-induced herpes simplex virus type-1 encephalitis

The central nervous system (CNS) has been shown to be vulnerable to a variety of insults in animals exposed to glucocorticoids. For example, psychological stress, a known inducer of glucocorticoid production, enhances the susceptibility of mice to herpes simplex virus type-1 (HSV-1) infection and results in the development of HSV-1 encephalitis (HSE). To determine the immune mechanisms by which stress promotes the development of HSE, we examined the role of the glucocorticoid receptor (GR) and the N-methyl-d-aspartate (NMDA) receptor in the development of HSE. Our findings demonstrate that blockade of either the GR or the NMDA receptor enhances survival following HSV-1 infection in stressed mice to levels similar to non-stressed mice. Subsequent studies determined the effect of GR and NMDA receptor blockade on immune function by specifically examining both microglia and CD8(+) T cell activation. Stress inhibited the expression of MHC class I by microglia and other brain-derived antigen presenting cells (CD45(hi)) independent of either the glucocorticoid receptor or the NMDA receptor, suggesting that stress-induced suppression of MHC class I expression in the brain does not affect survival during HSE. Blockade of the NMDA receptor, however, diminished HSV-1-induced increases in class I expression by CD45(hi) cells, suggesting that blockade of the NMDA receptor may limit CNS inflammation. Also, while CD8(+) T cell activation and function in the brain were not affected by stress, the number of CD8(+) T cells in the superficial cervical lymph nodes (SCLN) was decreased in stressed mice via GR-mediated mechanisms. These findings indicate that stress-induced hypocellularity is mediated by the GR while NMDA receptor activation is responsible for enhancing CNS inflammation. The combined effects of GR-mediated hypocellularity of the SCLN and NMDA receptor-mediated CNS inflammation during stress promote the development of HSE.

Neuropsychological and psychiatric profiles in acute encephalitis in adults

Acute encephalitis is an inflammation of brain tissue that can result from activity in the central nervous system (CNS) of a number of viruses. Although the neurological and psychiatric effects of encephalitis in the acute phase of the illness are well-known (Caroff, Mann, Gliatto, Sullivan, & Campbell, 2001), larger scale studies of the pattern of neuropsychological and psychiatric impairment following recovery from the acute inflammatory phase are less apparent. This paper reports the results of neuropsychological testing with a range of standardised cognitive measures in a case series of long-term post-acute participants. Psychiatric abnormality is examined using the SCL-90-R self-report scale of distress (Derogatis, 1983). We also examined the role of emerging insight in the aetiology of depression in this population. Two clusters of cognitive dysfunction were observed, one group of primarily herpes simplex cases showing a severe generalised deficit across a number of cognitive domains and a second cluster showing a variety of more isolated disorders of executive function. Abnormally high levels of distress were reported by participants, with depression, obsessive-compulsive symptoms, interpersonal sensitivity and phobic anxiety most significantly increased. Depression was found to be least severe in those with most accurate insight into their problems. Examining the correlations between cognitive and psychiatric test results demonstrates a relationship between depression and interpersonal anxiety and specific cognitive measures. Obsessive-compulsive behaviour and phobic anxiety, however, appear to exist independently of the assessed cognitive deficits.

Pre- and post-encephalitic neuropsychological profile of a 7-year-old girl

Our understanding of the neuropsychological effects of encephalitis has largely come from studies in which the level of premorbid functioning is estimated. Moreover, data on the neuropsychological effects of encephalitogenic pathogens other than the herpes simplex virus (HSV) are scant. We present the case of a 7-year-old girl who had intellectual and language assessment seven months prior to the onset of non-HSV encephalitis (possible aetiology: Mycoplasma pneumoniae), and again post-encephalitis. MRI post-illness demonstrated basal frontal, temporal and (limited) parietal damage. Details of speech, psychological and neuropsychological assessments were also documented. Pervasive changes were apparent in the domains of personality, behaviour, emotionality, attention, executive function, speech, language and memory. The patient's profile appears to differ most from that seen following typical HSV encephalitis with respect to marked executive and attentional difficulties. Her deficits appear to reflect both her acute basal brain injury and more diffuse insult, probably caused by postinfectious encephalitis.

Long-term clinical and neuropsychological outcomes of West Nile virus infection

BACKGROUND

Since its introduction in 1999, West Nile virus has rapidly become the most common arboviral infection in North America. Little is known about the long-term clinical sequelae of West Nile virus infection.

METHODS

A total of 49 patients with laboratory-confirmed West Nile virus infection were identified through state-based surveillance. Stratification for disease severity was based on hospitalization during the infection episode. Assessment occurred a mean of 13 months after diagnosis. Medical records were reviewed, and a complete neurologic examination was performed. Standardized surveys for quality of life, functional ability, fatigue, and depression were performed for all subjects. An extensive battery of neuropsychological tests was performed to assess cognitive function.

RESULTS

Self-reported fatigue, memory problems, extremity weakness, word-finding difficulty, and headache were common complaints. Standardized survey data confirmed an overall sense of poor physical health, fatigue, depression, and moderate-to-severe disability in 24 (49%), 24 (49%), 12 (24%), and 4 (8%) patients, respectively. New tremor was seen or reported for 10 (20%) of the patients. Neuropsychological testing showed abnormalities of motor skills, attention, and executive functions. Univariate analysis of multiple risk factors did not identify any predictors of adverse outcomes.

CONCLUSIONS

Multiple somatic complaints, tremor, and abnormalities in motor skills and executive functions are common long-term problems among patients who have had West Nile virus infection. Patients with milder illness are just as likely as patients with more-severe illness to experience adverse outcomes.

Induction of UGT1A6 isoform by inflammatory conditions in rat astrocytes

Alteration of drug metabolism under diseased conditions is of clinical importance. We have investigated the effects of inflammatory conditions on phase II drug-metabolizing enzyme activity in rat cultured astrocytes. Lipopolysaccharide (LPS) treatment was used to promote inflammatory conditions. Thus, we reported that LPS initiates an inflammatory response, which is mediated by pro-inflammatory mediators and free radical generation. An increase in astrocyte glucuronidation activity was observed after a 48-h LPS treatment. This increase in glucuronidation activity was associated with an up-regulation of the UGT1A6 isoform mRNA level as shown by RT-PCR and gene reporter assay. Moreover, this endotoxin-induced increase in UGT1A6 expression level was blocked by actinomycin D and cycloheximide, indicating the requirement for RNA and protein synthesis. The UGT1A6 expression enhancement could be prevented by anti-inflammatory drugs (dexamethasone and NS398) or nitric oxide synthase inhibitors (L-NAME and L-NMMA). Moreover, gel shift assay revealed increased activator protein-1 (AP-1) binding activity after LPS treatment. We propose, based on the data presented, that the action of LPS to induce UGT1A6 isoform up-regulation may be mediated by pro-inflammatory mediator accumulation, and AP-1 binding activity increase.

Relative preservation of 'animate' knowledge in an atypical presentation of herpes simplex virus encephalitis

A comprehensive battery of neuropsychological tests designed to assess primary cognitive functions, including language and semantic memory, was given to MG, a patient with confirmed herpes simplex virus encephalitis. MG's initial jargon aphasia resolved over time to leave her with a mild phonological impairment. She had a very mild amnesia that was worse for verbal material and a category-specific impairment of semantic memory. This latter impairment resulted in a significant anomia that was worse for manmade/artefact items than for animate kinds. Her naming difficulties were associated with a mild impairment in comprehension that was not specific to category or feature type. MRI revealed a strongly asymmetric and atypical distribution of pathology in MG with the disease affecting the left medial temporal lobe, temporal pole, left frontotemporal and temporoparietal regions.

Infection with herpes simplex virus type 1 is associated with cognitive deficits in bipolar disorder

BACKGROUND

In a previous investigation, we found an association between reduced cognitive functioning and the prevalence of antibodies to herpes simplex virus type 1 in individuals with schizophrenia. The current study was undertaken to determine if this association also occurs in individuals with bipolar disorder.

METHODS

Cognitive functioning and serologic evidence of infection with potentially neurotropic herpesviruses were measured in 117 individuals with bipolar disorder and in 100 individuals without a history of psychiatric disorder. Cognitive functioning was evaluated with the Repeatable Battery for the Assessment of Neuropsychological Status. For each patient, serologic evidence of infection was ascertained by the measurement of serum immunoglobulin G class antibodies with specificities for six potentially neurotropic human herpesviruses. The association between serologic evidence of herpesvirus infection and cognitive functioning was analyzed by univariate analyses, as well as multivariate analyses that included demographic and clinical factors associated with cognitive functioning.

RESULTS

Serologic evidence of infection with herpes simplex virus type 1 was an independent predictor of decreased cognitive functioning in the individuals with bipolar disorder (F = 20.5, p <.0001). Discriminant function analysis indicated that most of the difference in cognitive functioning between individuals who were antibody positive and antibody negative for herpes simplex virus type 1 could be attributed to immediate verbal memory (F = 12.07, p <.001). There was no significant association between cognitive functioning and the other human herpesviruses. No association between antibodies to herpesviruses and cognitive functioning was found in the control individuals without a history of psychiatric disorder.

CONCLUSIONS

Serologic evidence of herpes simplex virus type 1 infection is associated with cognitive impairment in individuals with bipolar disorder.

Impact of viral and bacterial burden on cognitive impairment in elderly persons with cardiovascular diseases

BACKGROUND AND PURPOSE

Inflammation and infectious etiology have been implicated in the pathogenesis of dementia. We sought to investigate whether the seropositivity of common infections was associated with cognitive function.

METHODS

Viral burden (seropositivity for herpes simplex virus type 1 [HSV-1], herpes simplex virus type 2 [HSV-2], or cytomegalovirus [CMV]) and bacterial burden (Chlamydia pneumoniae and Mycoplasma pneumoniae) were related to cognitive status and its impairment among 383 home-dwelling elderly with cardiovascular diseases (mean age, 80 years). The Mini-Mental State Examination (MMSE) and its changes and the Clinical Dementia Rating (CDR) were used to define cognitive impairment.

RESULTS

At baseline, 0 to 1, 2, and 3 positive titers toward viruses were found in 48 (12.5%), 229 (59.8%), and 106 individuals (27.7%), respectively. MMSE points decreased with increasing viral burden (P=0.03). At baseline, 58 individuals (15.1%) had cognitive impairment, which after adjustments was significantly associated with seropositivity for 3 viruses (hazard ratio, 2.5; 95% CI, 1.3 to 4.7). MMSE score decreased in 150 (43% of 348) during 12-month follow-up. After adjustment for MMSE score at baseline and with 0 to 1 seropositivities as reference (1.0), the hazard ratios were 1.8 (95% CI, 0.9 to 3.6) and 2.3 (95% CI, 1.1 to 5.0) for 2 and 3 seropositivities, respectively. The prevalence of possible or definite dementia according to CDR also increased with viral burden. No significant associations were observed between bacterial burden and cognition.

CONCLUSIONS

Viral pathogen burden of HSV and CMV was associated with cognitive impairment in home-dwelling elderly persons with cardiovascular diseases. The results need to be tested in larger databases, but they may offer a preventable cause of cognitive decline.