Impaired Vigilance Research Articles

Reaction time and sustained attention in schizophrenia and its genetic predisposition

Sustained attention is affected by schizophrenia. The simplest form of Continuous Performance Test (CPT-X) is a purer test of vigilance than more demanding variants but widely thought too insensitive to detect abnormalities in those with genetic predisposition to schizophrenia. We used a 7-minute CPT to compare 61 patients diagnosed with schizophrenia, 45 of their never-psychotic relatives, and 47 control subjects. We found a significant impairment in stimulus discrimination in both patients ( p = 0.001) and their relatives ( p = 0.006). There was no difference in stimulus discrimination between relatives of patients with impaired and unimpaired stimulus discrimination. Relatives of patients with unimpaired stimulus discrimination were still inferior to controls ( p = 0.02). Reactions slowed in all groups equally as the test progressed. Patients showed increased mean reaction time ( p < 0.0001) and interquartile range ( p = 0.003). Relatives showed slower reaction times ( p = 0.01) but normal interquartile range. Groups did not differ in respect of individuals' fastest reaction times. We conclude that genetic predisposition to schizophrenia reduces performance even during a task placing minimal cognitive load on working memory and perceptual processing, suggesting impaired vigilance. Increased reaction time in the disease and its predisposition appear to be due to changes in response distribution rather than by a limitation of maximum speed. Our results raise the possibility of separating the cognitive components of vigilance, working memory and perceptual processing tapped by more demanding variants of the CPT, and draw attention to the need for consideration of dynamic neurocognitive processes in schizophrenia.

IN VIVO OBSERVATION OF MESENTERIC LEUKOCYTE-ENDOTHELIAL INTERACTIONS AFTER CECAL LIGATION/PUNCTURE AND SURGICAL SEPSIS SOURCE CONTROL

Cecal ligation and puncture (CLP) has been used as a useful model for the induction of polymicrobial sepsis. Necrotic tissue resection and peritoneal lavage (REL) are the surgical procedures for controlling perforated appendicitis. The aim of this study was to evaluate leukocyte-endothelial interactions in the rat mesentery in vivo after CLP and REL. Thirty-seven male Wistar rats (250-300 g) underwent laparotomy and were randomly assigned to the following groups: 1) SHAM; 2) CLP: animals submitted to CLP, 3) CLP+REL: animals submitted to CLP and REL. Mesenteric leukocyte-endothelial interactions were studied by intravital microscopy assessed once in each animal (3-5 postcapillary venules, 15-25 microm diameter) 24 hours after intervention. Follow-up was performed in all animals; this included analysis of glycemia, lactate, hematocrit, white blood cell count as well as a functional score that was the sum of scoring on the following parameters: alertness, mobility, piloerection, diarrhea, encrusted eyes, and dirty nose and tail. None of the animals showed significant changes in body weight (265 +/- 20 g) or in hematocrit levels (46% +/- 2%) during the experimental protocol. Compared to SHAM animals, CLP animals showed an increased number of rolling (2x), adherent, and migrating leukocytes (7x) in the mesenteric microcirculation, an increase in blood glucose (136 +/- 8 mg/dL), lactate (3.58 +/- 0.94 mmol/L), white cell count (23,570 +/- 4,991 cells/mm(3)) and functional alterations (score 11 +/- 1), characterized by impaired alertness and mobility, and presence of piloerection, diarrhea, encrusted eyes, and dirty nose and tail. The REL procedure normalized the number of rolling, adherent, and migrated leukocytes in the mesentery; glycemia; lactate; and white blood cell count. The REL procedure also improved the functional score (7 +/- 1). Local and systemic inflammation was induced by CLP, while REL completely overcame the inflammatory process.

ACUTE INCREASE IN BLOOD UREA NITROGEN CAUSED BY ENTERIC NUTRITION

ACUTE INCREASE IN BLOOD UREA NITROGEN CAUSED BY ENTERIC NUTRITION

The Visual Scoring of Sleep in Adults

The 1968 Rechtschaffen and Kales (R & K) sleep scoring manual was published 15 years after REM sleep was discovered. Advances in the ensuing 28 years warranted a re-look at visual scoring of sleep stages. This paper describes the work of the AASM Visual Scoring Task Force, including methodology, a literature review and the rationale behind the new rules. Reliability studies of R & K scoring were reviewed; reliability was low for stage one and moderate for slow wave sleep. Evidence indicated that K complexes and slow waves are expressed maximal frontally, spindles centrally and alpha rhythm over the occipital region. Three derivations of EEG, two of electro-oculography, and one of chin EMG were recommended. Scoring by 30-second epochs was retained. New terminology for sleep stages was proposed. Attenuation of alpha rhythm was determined to be the most valid electrophysiological marker of sleep onset. Alternative measures were proposed for non-alpha generating subjects. K complexes associated with arousals were determined to be insufficient alone to define the new stage N2. No evidence was found to justify dividing slow wave sleep into two stages. No reasons were found to alter the current slow wave amplitude criteria at any age. The phenomena of REM sleep were defined. The rules for defining onset and termination of REM sleep periods were simplified. Movement time was eliminated and major body movements defined. Studies are needed to test the reliability of the new rules. Future advances in technology may require modification of these rules with time.

Predictors of pneumonia in acute stroke patients admitted to a neurological intensive care unit

To determine independent clinical predictors of stroke-associated pneumonia (SAP) that are available in all patients on day of hospital admission. We studied 236 patients with acute ischemic stroke admitted to the neurological intensive care unit at our university hospital. Risk factors of SAP and of non-responsivity of early-onset pneumonia (EOP; onset within 72 hours after admission) to initial antibacterial treatment were analyzed. Incidence of SAP was 22%. The following independent risk factors were found to predict SAP with 76% (EOP: 90%) sensitivity and 88% specificity: dysphagia (RR, 9.92; 95% CI, 5.28-18.7), National Institute of Health Stroke Scale > or = 10 (RR, 6.57; CI, 3.36-12.9), non-lacunar basal-ganglia infarction (RR, 3.10; CI, 1.17-5.62), and any other infection present on admission (RR, 3.78; CI, 2.45-5.83). Excluding the patients with other infections on admission, the same independent risk factors (except infection) were found. Further, but not independent risk factors were: combined brainstem and cerebellar infarction, infarction affecting more than 66% of middle cerebral artery territory, hemispheric infarction exceeding middle cerebral artery territory, impaired vigilance, mechanical ventilation, age > or = 73 years, current malignoma, and cardioembolic stroke, whereas patients with lacunar infarctions had significantly lower risk. In contrast to previous reports, no impact of male gender or diabetes was found. Initial vomiting, especially if associated with impaired vigilance, predicted antibacterial treatment non-responsivity of EOP. In nonresponders exclusively fungal pathogens were identified. Increased risk of pneumonia in acute stroke patients can be sufficiently predicted by a small set of clinical risk factors.

Correlation of cognition and FDG-PET findings in early multiple sclerosis

Introduction: Patients with multiple sclerosis (MS), disease history of 11.5 years, an expanded disability status scale (EDSS) up to 6.0 and an involvement of verbal and/or spatial and long-term memory showed a bilateral reduction of glucose metabolism in the cingulate gyrus, thalamus, associative occipital cortex and cerebellum. To our knowledge no similar studies in early stages of MS are reported. Therefore we stressed the question of possible correlation of quality of life, objective cognitive impairment and FDG-PET findings in newly diagnosed definite MS according to McDonald criteria. Methods: In 11 patients (f=4, m=7, mean age: 35 years (CI 25–42), IQ 112 (CI 97–118)) with newly diagnosed definite MS and minor disability (mean EDSS=1.0) neuropsychological testing (VLMT, d2, Benton, TMT) and quality of life measurement (MSQOL-54) were done and correlated with age and education matched healthy group (mean age 33 years (CI 25–38), IQ 112 (100–124)). Additionally all patients were investigated by a FDG-PET. Results: Cognitive impairment reported by patients (MSQOL-54) was correlated with impairment of alertness, processing speed and concentration measured by neuropsychological testing (p<0.05). The FDG-PET analysis showed an increased metabolism of glucose at Brodmann-area 7, 18, 19, 21, and a decrease of glucose metabolism at the thalamus and cerebellum in these patients compared to a age-related healthy group. Discussion: In patients with newly diagnosed MS a increased glucose metabolism in cortical areas associated with secondary visual alertness processing could be demonstrate in contrast to prior findings in long-term MS. We suppose unconscious reactions of the MS patients lead to hyperactivity within the visual cortical regions to equalize the impairment of verbal memory and alertness. In correlation to patients with long-term history of MS reduction of glucose metabolism was found at the thalamus und cerebellum. According to previous studies the significant relationship between reduction of glucose metabolism at the cerebellum and memory scanning speed suggests that functional damage in the posterior fossa may contribute to slowed cognitive processing.

Time-on-task Impairment of Psychomotor Vigilance Is Affected by Mild Skin Warming and Changes With Aging and Insomnia

To investigate the effect of mild manipulations of core and skin temperature on psychomotor vigilance (PVT) in young adults, elderly, and elderly insomniacs. 432 PVTs were obtained during a 2-day semi-constant routine protocol, while differentially manipulating core and skin temperatures within a comfortable thermoneutral range. Sleep laboratory of the Netherlands Institute for Neuroscience. Groups of 8 sex-matched young adults (27.0 +/- 2.4 years, mean +/- s.e.m.), elderly (65.8 +/- 2.8 years), and insomniacs (59.1 +/-1.9 years). During the 7-minute PVTs, response speed typically declined with increasing time-on-task. Proximal skin warming by only +/- 0.6 degrees C accelerated this decline by 67% (P = 0.05) in young adults and by 50% (P < 0.05) in elderly subjects. In elderly insomniacs, proximal warming slowed down the mean response speed already from the onset of the task (3% level drop, P < 0.001). Response speed tended to decrease with age (P < 0.10), reaching significance only in elderly insomniacs (P < 0.05). Speed decrements occurred mostly towards the end of the time-on-task in young adults; earlier and more gradually in elderly without sleep complaints; and very early and in a pronounced fashion in insomniacs. Interestingly, the worsening by warming followed the time pattern already present within each group. The results are compatible with the hypothesis that the endogenous circadian variation of skin temperature could modulate vigilance regulating brain areas and thus contribute to the circadian rhythm in vigilance. Minute-by-minute PVT analyses revealed effects of age and insomnia not previously disclosed in studies applying time-point aggregation. Our data indicate that "age-related cognitive slowing" may result, in part, from age-related sleep problems.

199 Vigilance and cognitive impairment in children with OSAS

199 Vigilance and cognitive impairment in children with OSAS

197 Vigilance and cognitive impairment in adults with OSAS

Although the effects of infectious diseases on sleep and sleepiness have been known for thousands of years, it is only within the past 20 years that there has been a systematic study of changes on sleep following infection or microbial product-induced cytokine production, primarily in animals. In humans, the first few studies focused on the circadian pattern of the cytokines and showed that proinflammatory cytokines peak during nocturnal sleep. Since 1997, there has been a focus on the potential role of proinflammatory cytokines in sleep loss and sleep disorders, such as sleep apnea and narcolepsy. IL-6 and TNFa appear to be elevated in patients with sleep apnea and narcolepsy and have been postulated to be mediators of excessive daytime sleepiness and fatigue. Also, it has been shown that cytokines are elevated in obese vs. normal-weight subjects and contribute to their frequent complaints of sleepiness and fatigue. Cytokines are produced by fat tissue and more so by visceral fat, which may explain why obesity per se is an independent risk factor for excessive daytime sleepiness. In addition, it has been shown that cytokines are elevated in conditions that their primary pathogenetic mechanism is insulin resistance, i.e., women with PCOS, and that they contribute both to their sleep pathology (increased prevalence of sleep apnea and sleepiness) as well as to the underlying pathogenetic mechanism of obesity and insulin resistance. In healthy, normal-sleeping humans, cytokines are elevated after total or partial sleep loss, suggesting a role in the mediation of experimentally induced sleepiness also. Interestingly, interventions to reduce or neutralize cytokines in humans are associated with improved alertness and performance. For example, a mid-afternoon nap following sleep deprivation improved sleepiness and performance and decreased IL-6 peripheral levels. Also, the use of a TNFa antagonist in obese patients with sleep apnea was associated with a marked decrease in sleepiness and a significant though slight improvement of sleep apnea. These studies collectively suggest that proinflammatory cytokines play a key role in sleep pathology, i.e., sleep apnea, sleepiness, and in health problems frequently associated with sleep disorders/ sleep loss, i.e., cardiovascular events, obesity, and metabolic syndrome. Future research in this area may lead to novel and more effective treatments for disorders that plague a large percentage of the population.

Comparing Symptoms of Delirium in Adults and Children

Delirium is presumed to be the same syndrome in all ages. Comparing pediatric and adult studies, the authors found many of the same symptoms reported, but often at significantly different rates. Sleep-wake disturbance, fluctuating symptoms, impaired attention, irritability, agitation, affective lability, and confusion were more often noted in children; impaired memory, depressed mood, speech disturbance, delusions, and paranoia, more often in adults; impaired alertness, apathy, anxiety, disorientation, and hallucination occurrence were similar. These may represent true differences in the presentation of delirium across the life-cycle, or may be attributable to inconsistent methodologies. Prospective studies are needed to resolve this question.

Characterizing Impaired Functional Alertness From Diphenhydramine in the Elderly With Performance and Neurophysiologic Measures

Psychometric task performance measures can be highly sensitive to manipulations that impair functional alertness in young adults; such measures have been shown to be less sensitive to reduced alertness in older adults. The purpose of this study is to determine whether neurophysiologic measures can aid in the detection and characterization of impairments in functional alertness in the elderly. Double-blind, placebo-controlled, counter-balanced, crossover study. Research laboratory. Twelve healthy older adults (62-75 years of age). Diphenhydramine, 50 mg. Behavioral performance and electroencephalogram measures were obtained while participants completed spatial working memory and word recognition episodic memory tasks in a baseline interval before drug ingestion and in 4 hourly test intervals following drug ingestion. Relative to placebo, diphenhydramine had marginal effects on task performance yet was effective in reducing alertness, as evidenced by subjective ratings and objective neurophysiologic (electroencephalogram) markers. Diphenhydramine significantly reduced the amplitude of alertness-sensitive event-related potentials recorded during working memory task performance, including the N160 and P300. It also affected neurophysiologic processes underlying episodic memory, as evidenced by a reduction in the difference in event-related potentials between old and new words in the word recognition task. Discriminant analyses incorporating neurophysiologic measures showed that the time course of the central effects of diphenhydramine in older subjects was similar to that previously observed in young adults. These results demonstrate that diphenhydramine has adverse neurocognitive effects in elderly individuals and highlights the utility of incorporating direct measures of brain function into assessments of functional alertness.

A Brief Afternoon Nap Following Nocturnal Sleep Restriction: Which Nap Duration is Most Recuperative?

The purposes of this study were to compare the benefits of different length naps relative to no nap and to analyze the electroencephalographic elements that may account for the benefits. A repeated-measures design included 5 experimental conditions: a no-nap control and naps of precisely 5, 10, 20, and 30 minutes of sleep. Nocturnal sleep restricted to about 5 hours in participants' homes was followed by afternoon naps at 3:00 PM and 3 hours of postnap testing conducted in a controlled laboratory environment. Twenty-four healthy, young adults who were good sleepers and not regular nappers. The 5-minute nap produced few benefits in comparison with the no-nap control. The 10-minute nap produced immediate improvements in all outcome measures (including sleep latency, subjective sleepiness, fatigue, vigor, and cognitive performance), with some of these benefits maintained for as long as 155 minutes. The 20-minute nap was associated with improvements emerging 35 minutes after napping and lasting up to 125 minutes after napping. The 30-minute nap produced a period of impaired alertness and performance immediately after napping, indicative of sleep inertia, followed by improvements lasting up to 155 minutes after the nap. These findings suggest that the 10-minute nap was overall the most effective afternoon nap duration of the nap lengths examined in this study. The implications from these results also suggest a need to consider a process occurring in the first 10 minutes of sleep that may account for the benefits associated with brief naps.

Allergy medication in Japanese volunteers: treatment effect of single doses on nocturnal sleep architecture and next day residual effects

ABSTRACTObjectives: To evaluate the acute effects of two histamine H1-receptor antagonists on nocturnal sleep architecture and on next day cognitive function and psychomotor performance.Methods: This was a single-site, randomized, double-blind, 3-way crossover study, comparing the effects of a single dose of chlorpheniramine (6 mg), fexofenadine (120 mg) and placebo in 18 healthy (male and female) Japanese volunteers aged 20–55 years. Volunteers were resident for 3 days and each period was separated by a minimum 5‐day washout period. The three treatments were administered at 23.00 h. Overnight sleep was measured from 23.00 h to 07.00 h using polysomnography. Residual effects were studied at 07.00 h and 9.00 h the next morning, with the latency to sleep (sleep latency test) measured at 09.30 h.Results: Compared with placebo, chlorpheniramine increased the latencies to sleep onset and rapid eye movement (REM) sleep ( p ≤ 0.05 for both), and reduced the duration of REM sleep ( p ≤ 0.01), but this was not observed with fexofenadine. As far as residual effects the next morning were concerned there were decrements in performance with chlorpheniramine, but not with fexofenadine. Chlorpheniramine 6 mg impaired divided attention ( p < 0.001), vigilance ( p < 0.05), working memory ( p < 0.0001) and sensori-motor performance ( p < 0.01), and the latency to daytime sleep was reduced ( p < 0.0001). Six adverse events possibly related to study medication were reported during the study, three of which were related to placebo, two to fexofenadine and one to chlorpheniramine.Conclusion: These findings suggest that a single nocturnal dose of fexofenadine has advantages over the first-generation antihistamine chlorpheniramine, being free of disruption of night-time sleep and detrimental effects on cognitive performance the next day. It is likely that this advantage will remain with chronic ingestion, but this would need to be confirmed.

Sleepiness is not the inverse of alertness: evidence from four sleep disorder patient groups

The constructs "sleepiness" and "alertness" are often assumed to be reciprocal states of consciousness. This distinction is of increasing concern in relation to psychomotor performance tasks such as driving. We developed two separate subjective scales of alertness to complement existing sleepiness scales. Subjective sleepiness and alertness were compared in four groups of sleep-disordered patients. In a 175-patient cohort [25 narcoleptics and 50 each with sleep apnea, insomnia and periodic leg movement disorder (PLMD)], the Epworth Sleepiness Scale (ESS) was used to measure sleepiness while the Toronto Hospital Alertness Test (THAT) and ZOGIM Alertness Scale (ZOGIM-A) were used to measure alertness. Significant differences existed for sleepiness scores, with narcoleptics scoring highest on the ESS, followed by sleep apnea, with similar ESS scores for insomnia and PLMD. By contrast, alertness scores on both the THAT and ZOGIM-A did not differ significantly between the four groups. Sleepiness scores show a correlation of close to nil to alertness scores for the combined sleep disorder patient cohort, with the exception of insomnia patients, where a modest but significant inverse relationship was noted between sleepiness and alertness. Subjective states of impaired alertness and excessive sleepiness are independent constructs in the evaluation of sleep-disordered patients. The specific primary sleep disorder diagnosis may play a relevant role in mitigating this interrelationship.

The MSLT/MWT Should be Used for the Assessment of Workplace Safety

Increased awareness of the role of sleepiness as a contributing or causative factor in workplace accidents and driving fatalities has resulted in a new role for sleep specialists. Some regulatory agencies including the Federal Aviation Association (FAA), and the Federal Motor Carriers Safety Association (FMCSA), have looked to the sleep specialist to evaluate the safety of returning an individual to their workplace after the transportation employee has been diagnosed and treated for sleep disorders. This has placed an incredible responsibility on the sleep specialist. While the sleep specialist may not want to embrace this responsibility, it is clearly within the realm of sleep medicine and there is no other group of professionals better equipped to make such decisions. The American Academy of Sleep Medicine (AASM) recognizes this role for sleep specialist and has stated in its Practice Parameters that “the sleep clinician is responsible for assessing response to treatment, and making clinical decisions that affect individual and public safety.” 1 (p114) To aid the sleep clinician in the decision process, there are both objective and subjective measures available. However, given the implications of releasing an individual to return to an occupation with a high safety risk, the focus has been on objective testing rather than just subjective reports which are prone to bias and manipulation. The two objective tests available for evaluation of sleepiness and alertness are the Multiple Sleep Latency Test (MSLT) and the Maintenance of Wakefulness Test (MWT), respectively. They have been used for decades in the evaluation of medications, diagnosis of sleep disorders, and in evaluation of response to treatment for patients with sleep disorders. In response to the increasing awareness of the dangers of impaired alertness on personal and public safety in the workplace especially in high risk occupations, the use of these tests has expanded to include the assessment of workplace safety. In particular, the MWT has become the logical test to use in the evaluation of patients with sleep disorders associated with daytime sleepiness and other individuals who have been identified as posing a potential risk in the workplace due to impaired alertness. With new research demonstrating the usefulness and validity of the MWT in the assessment of safety, the MWT should now be a routine part of any evaluation of individuals for workplace safety. Reliability and Validity of the MSLT and MWT An important aspect of the MSLT and MWT is that they are de facto gold standards with demonstrated validity. The MSLT has been shown to be a reliable and valid measure of sleepiness. Its validity is based on numerous studies that show decreased latencies following sleep deprivation, 2 sleep fragmentation, 3-5 and use of hypnotic medications. 6,7 In addition, increased latencies have been demonstrated following extended sleep 2 and the use of stimulant medication. 8-11 The MSLT has also been shown to have a high test-retest reliability of 0.97 in normal subjects which is not affected by test intervals or level of sleepiness. 12 Based on these and numerous other studies, the Practice Parameters state that “the MSLT is a validated objective measure of the ability or tendency to fall asleep.” 1 (p115)

Effects of Short-Term CPAP Withdrawal on Neurobehavioral Performance in Patients With Obstructive Sleep Apnea

Changes in sleep parameters and neurobehavioral functioning were systematically investigated after an acute (1 night) and short-term (7 nights) period of withdrawal from continuous positive airway pressure (CPAP) treatment and 1 subsequent night of CPAP reintroduction in patients with obstructive sleep apnea. Repeated-measurement within-subject design. Sleep laboratory, university teaching hospital. Twenty participants receiving optimal CPAP therapy for > or = 12 months. CPAP withdrawal. Polysomnograms were performed on Night 0 (with CPAP), Night 1 and Night 7 (without CPAP) and Night 8_R (with CPAP). Acute CPAP withdrawal resulted in the recurrence of sleep-disordered breathing with sleep disruption, hypoxemia, and increased subjective sleepiness. Short-term CPAP withdrawal exacerbated hypoxemia, increased subjective and objective sleepiness and poor mood ratings. Neurobehavioral functioning assessed using the Psychomotor Vigilance Task was impaired following Night 7 and associated with hypoxemia and changes in morning levels of tumor necrosis factor-alpha. However, other neurobehavioral measures were not affected. Autonomic arousals measured via respiratory-related reductions in finger blood volume by peripheral arterial tonometry decreased from Night 1 to Night 7. On Night 8_R, reintroduction of CPAP treatment eliminated most airway obstruction, maintained oxygenation, and reversed daytime sleepiness and some vigilance decrements. Despite recurrence of sleep-disordered breathing with increased sleepiness and impaired vigilance, most neurobehavioral variables were unaffected by CPAP withdrawal. The reduction in vigilance appeared to be associated with worsened hypoxemia and changed levels of tumor necrosis factor-alpha. Resumption of CPAP treatment had immediate benefits on sleep consolidation and subjective sleepiness.

Effects of methylphenidate on multiple components of attention in children with attention deficit hyperactivity disorder

Methylphenidate (MPH) has been shown to be effective in the treatment of attention deficits in children with attention deficit hyperactivity disorder (ADHD). Although a variety of studies have been performed, there is little available information as to which components of attentional functioning are disturbed in ADHD. The aim of the present study was to monitor the effect of MPH on various measures of attention in children with ADHD. In a double-blind, placebo-controlled, crossover study, the attentional functioning of 58 children diagnosed with ADHD without psychiatric comorbidity was examined. Assessment of attention was performed on their usual MPH treatment and following withdrawal of the drug. Furthermore, the attentional performance of 58 healthy children was assessed. The test battery consisted of reaction time tasks, including measures of alertness, vigilance, divided attention, flexibility, and aspects of selective attention such as focused attention, inhibition, and integration of sensory information. In comparison to the test performance of healthy children, children with ADHD displayed impairments of vigilance, divided attention, flexibility, and aspects of selective attention including focused attention, inhibition, and integration of sensory information. Statistical comparison of attentional functioning of children with ADHD on and off MPH treatment revealed that the medication resulted in an improved task accuracy regarding vigilance, divided attention, inhibition, focused attention, integration of sensory information, and flexibility. The present findings indicate that various aspects of attention are markedly impaired in children with ADHD. Treatment with MPH was accompanied by improvements in attention functions of small to moderate sizes. Although MPH-induced improvements were observed in a broad range of attention measures, children with ADHD who were on MPH treatment nevertheless displayed serious deficits in a number of components of attention.

Correlation of cognition and FDG-PET findings in early multiple sclerosis

Introduction: Patients with multiple sclerosis (MS), disease history of 11.5 years, an expanded disability status scale (EDSS) up to 6.0 and an involvement of verbal and/or spatial and long-term memory showed a bilateral reduction of glucose metabolism in the cingulate gyrus, thalamus, associative occipital cortex and cerebellum. To our knowledge no similar studies in early stages of MS are reported. Therefore we stressed the question of possible correlation of quality of life, objective cognitive impairment and FDG-PET findings in newly diagnosed definite MS according to McDonald criteria. Methods: In 11 patients (f=4, m=7, mean age: 35 years (CI 25–42), IQ 112 (CI 97–118)) with newly diagnosed definite MS and minor disability (mean EDSS=1.0) neuropsychological testing (VLMT, d2, Benton, TMT) and quality of life measurement (MSQOL-54) were done and correlated with age and education matched healthy group (mean age 33 years (CI 25–38), IQ 112 (100–124)). Additionally all patients were investigated by a FDG-PET. Results: Cognitive impairment reported by patients (MSQOL-54) was correlated with impairment of alertness, processing speed and concentration measured by neuropsychological testing (p<0.05). The FDG-PET analysis showed an increased metabolism of glucose at Brodmann-area 7, 18, 19, 21, and a decrease of glucose metabolism at the thalamus and cerebellum in these patients compared to a age-related healthy group. Discussion: In patients with newly diagnosed MS a increased glucose metabolism in cortical areas associated with secondary visual alertness processing could be demonstrate in contrast to prior findings in long-term MS. We suppose unconscious reactions of the MS patients lead to hyperactivity within the visual cortical regions to equalize the impairment of verbal memory and alertness. In correlation to patients with long-term history of MS reduction of glucose metabolism was found at the thalamus und cerebellum. According to previous studies the significant relationship between reduction of glucose metabolism at the cerebellum and memory scanning speed suggests that functional damage in the posterior fossa may contribute to slowed cognitive processing.

The Effect of Recent Stimulant Use on Sustained Attention in HIV-Infected Adults

Evidence suggests that stimulant use may exacerbate the deleterious cognitive effects of HIV, and that it has similar neuropathological consequences. In the current study, we examined the effect of recent stimulant use on sustained attention in adults infected with HIV. The sample consisted of 23 non-drug users and 17 stimulant users (cocaine and/or methamphetamine), all who were HIV-positive. Drug use was determined via urine toxicology. Sustained attention was assessed with the Conners' Continuous Performance Task – second edition (CPT-II). Groups were compared on overall performance variables, as well as patterns of performance across time. Compared to the non-drug users, stimulant users showed a gradual increase in reaction time variability and omission errors. Stimulant users' scores indicated impaired vigilance relative to an age and gender-matched normative sample. The groups were equivalent on other measures of attention, global neuropsychological functioning, mood, and demographic variables. The results indicate that recent stimulant use among HIV-infected adults adversely affects sustained attention.

Neuropsychological sequelae of bacterial and viral meningitis

Survivors of meningitis often complain about neurological and neuropsychological consequences. In this study, the extent of these sequelae was quantified and correlated to MRI findings. Neurological, neuropsychological and neuroradiological examinations were performed with adult patients younger than 70 years, 1-12 years after recovery from bacterial meningitis (BM; n = 59), or from viral meningitis (VM; n = 59). Patients with other potential causes for neuropsychological deficits (e.g. alcoholism) were carefully excluded. Patients were compared to 30 healthy subjects adjusted for age, gender and length of school education. With the exception of attention functions, both patient groups showed more frequently pathological results than the control group for all domains examined. Applying an overall cognitive sum score, patients after BM did not differ significantly in their performance from patients after VM. Separate analyses of various cognitive domains, however, revealed a higher rate of persistent disturbances in short-term and working memory after BM than after VM. Moreover, patients after BM exhibited greater impairment of executive functions. Associative learning of verbal material was also reduced. These deficits could not be ascribed to impaired alertness functions or decreased motivation in BM patients. Applying a logistic regression model, the neuropsychological outcome was related to the neurological outcome. Patients with a Glasgow Outcome Scale (GOS) of <5 had more frequently impaired test results for non-verbal learning and memory. GOS was also correlated with performance in executive functions. Brain volume was lower and ventricular volume was higher in the bacterial than in the VM group, and cerebral volume and the amount of white matter lesions of patients after BM were negatively correlated with short-term and working memory. In conclusion, patients after both BM and VM with favourable outcome showed affected learning and memory functions. More patients after BM than after VM displayed pathological short-term and working memory. BM resulted in poorer performance in executive functions, language, short-term memory and verbal learning/memory tests. As a result of neurological and neuropsychological sequelae, BM with a GOS > or = 4 led to decreased activities of daily living but only a minority of patients were disabled in a way that social functions were affected. The extent of neuropsychological sequelae of BM might have been overestimated in earlier studies which often had not been controlled for comorbidity factors such as alcoholism.