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BACKGROUND: E2027 is a novel, highly selective and potent inhibitor of phosphodiesterase9 (PDE9) being evaluated as a treatment for dementia with Lewy bodies. METHODS: Phase 1, randomized, double-blind, single ascending dose (SAD, n=96) and multiple ascending dose (MAD, n=68) studies evaluated E2027 doses (5 to 1200 mg) in healthy subjects. The impact of age, race (Japanese/non-Japanese), and food on pharmacokinetics (PK)/pharmacodynamics were evaluated. Serial cerebrospinal fluid (CSF) samples were collected to assess the target engagement. RESULTS: E2027 PK profiles were biphasic (elimination half-life: ~30 hours. Approximately 3-fold accumulation was observed following multiple once-daily dosing. E2027 single doses of 50 to 400 mg resulted in mean maximum increases in CSF cyclic guanosine monophosphate ranging from 293% to 461% within 5.37 to 12.9 hours after dose administration to assess target engagement. Dose-response modelling of steady-state predose CSF cyclic guanosine monophosphate concentrations showed ≥200% increase from baseline is maintained with doses of ≥50 mg QD. The most common adverse events with E2027 were post-LP syndrome and back pain. PK profiles were similar between Japanese and non-Japanese. Higher exposure observed in fed versus fasted state was not considered clinically significant. PK exposure was higher in elderly subjects. CONCLUSIONS: S.E2027 was well-tolerated following single and multiple administration. E2027 achieved maximal and sustained target engagement at 50 mg QD, the dose selected for the phase 2 clinical trial.
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Doença por Corpos de Lewy , Inibidores de Fosfodiesterase , Idoso , Área Sob a Curva , Ensaios Clínicos Fase II como Assunto , Relação Dose-Resposta a Droga , Método Duplo-Cego , Guanosina Monofosfato , Voluntários Saudáveis , Humanos , Doença por Corpos de Lewy/tratamento farmacológico , Inibidores de Fosfodiesterase/uso terapêutico , Diester Fosfórico HidrolasesRESUMO
BACKGROUND: E2027 is a novel, highly selective and potent inhibitor of phosphodiesterase 9 in development for dementia with Lewy bodies. Cardiac safety assessments for emerging agents are essential to avoid drug-induced QT interval prolongation, which may predispose individuals to potentially fatal ventricular arrhythmias. To evaluate the cardiac safety of E2027 and to inform dose selection for the phase 2 study of E2027 in dementia with Lewy bodies, we evaluated concentration-response modeling of pooled electrocardiogram data. PATIENTS AND METHODS: A post hoc concentration-QTc analysis evaluated potential QT effects using data from 2 randomized, double-blind studies in healthy subjects: a single ascending dose (SAD) study and a multiple ascending dose (MAD) study. Daily E2027 doses ranged from 5 to 1200 mg. RESULTS: A linear mixed-effects model was used to establish the relationship between plasma concentrations of E2027 and change from the baseline of QTcF (ΔQTcF). A significant but shallow relationship was observed in the estimated slope of the concentration-ΔQTcF: 0.002 ms/ng/mL (90% confidence interval: 0.0007-0.0031) with a small, nonsignificant treatment effect-specific intercept of -0.6 ms. Based on this pooled concentration-QTc analysis, an effect on the QTcF interval >10 ms can be excluded up to E2027 plasma concentrations of â¼3579 ng/mL, corresponding to a dose at least 4-fold larger than the 50 mg phase 2 dose. CONCLUSION: This pooled post hoc analysis evaluating cardiac safety of E2027 demonstrated that clinically concerning QTcF prolongation and related cardiac complications are highly unlikely with proposed E2027 doses planned for phase 2.
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Doença por Corpos de Lewy , Síndrome do QT Longo , Inibidores de Fosfodiesterase , Relação Dose-Resposta a Droga , Método Duplo-Cego , Eletrocardiografia , Humanos , Doença por Corpos de Lewy/tratamento farmacológico , Síndrome do QT Longo/induzido quimicamente , Inibidores de Fosfodiesterase/efeitos adversos , Ensaios Clínicos Controlados Aleatórios como AssuntoRESUMO
In 2019, the Lewy Body Dementia Association formed an Industry Advisory Council to bring together a collaborative group of stakeholders with the goal of accelerating clinical research into Lewy body dementia treatments. At the second annual meeting of the Industry Advisory Council, held virtually on June 18, 2020, the key members presented ongoing and planned efforts toward the council's goals. The meeting also featured a discussion about the effects of the COVID-19 pandemic on Lewy body dementia clinical research, lessons learned from that experience, and how those lessons can be applied to the design and conduct of future clinical trials. This report provides a brief summary of the meeting proceedings with a focus on efforts to improve and adapt future Lewy body dementia clinical research.
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COVID-19 , Doença por Corpos de Lewy , Humanos , Doença por Corpos de Lewy/epidemiologia , Pandemias , SARS-CoV-2RESUMO
BACKGROUND: Lecanemab (BAN2401), an IgG1 monoclonal antibody, preferentially targets soluble aggregated amyloid beta (Aß), with activity across oligomers, protofibrils, and insoluble fibrils. BAN2401-G000-201, a randomized double-blind clinical trial, utilized a Bayesian design with response-adaptive randomization to assess 3 doses across 2 regimens of lecanemab versus placebo in early Alzheimer's disease, mild cognitive impairment due to Alzheimer's disease (AD) and mild AD dementia. METHODS: BAN2401-G000-201 aimed to establish the effective dose 90% (ED90), defined as the simplest dose that achieves ≥90% of the maximum treatment effect. The primary endpoint was Bayesian analysis of 12-month clinical change on the Alzheimer's Disease Composite Score (ADCOMS) for the ED90 dose, which required an 80% probability of ≥25% clinical reduction in decline versus placebo. Key secondary endpoints included 18-month Bayesian and frequentist analyses of brain amyloid reduction using positron emission tomography; clinical decline on ADCOMS, Clinical Dementia Rating-Sum-of-Boxes (CDR-SB), and Alzheimer's Disease Assessment Scale-Cognitive Subscale (ADAS-Cog14); changes in CSF core biomarkers; and total hippocampal volume (HV) using volumetric magnetic resonance imaging. RESULTS: A total of 854 randomized subjects were treated (lecanemab, 609; placebo, 245). At 12 months, the 10-mg/kg biweekly ED90 dose showed a 64% probability to be better than placebo by 25% on ADCOMS, which missed the 80% threshold for the primary outcome. At 18 months, 10-mg/kg biweekly lecanemab reduced brain amyloid (-0.306 SUVr units) while showing a drug-placebo difference in favor of active treatment by 27% and 30% on ADCOMS, 56% and 47% on ADAS-Cog14, and 33% and 26% on CDR-SB versus placebo according to Bayesian and frequentist analyses, respectively. CSF biomarkers were supportive of a treatment effect. Lecanemab was well-tolerated with 9.9% incidence of amyloid-related imaging abnormalities-edema/effusion at 10 mg/kg biweekly. CONCLUSIONS: BAN2401-G000-201 did not meet the 12-month primary endpoint. However, prespecified 18-month Bayesian and frequentist analyses demonstrated reduction in brain amyloid accompanied by a consistent reduction of clinical decline across several clinical and biomarker endpoints. A phase 3 study (Clarity AD) in early Alzheimer's disease is underway. TRIAL REGISTRATION: Clinical Trials.gov NCT01767311 .
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Doença de Alzheimer , Peptídeos beta-Amiloides , Doença de Alzheimer/complicações , Doença de Alzheimer/diagnóstico por imagem , Doença de Alzheimer/tratamento farmacológico , Teorema de Bayes , Encéfalo , Método Duplo-Cego , HumanosRESUMO
The authors wish to correct their afï¬liations in this paper [1] as follows:[...].
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BACKGROUND: Several monoclonal antibodies for the treatment of Alzheimer's disease (AD) have been in development over the last decade. BAN2401 is a monoclonal antibody that selectively binds soluble amyloid ß (Aß) protofibrils. METHODS: Here we describe the first clinical study with BAN2401. Safety and tolerability were investigated in mild to moderate AD. A study design was used with staggered parallel single and multiple ascending doses, from 0.1 mg/kg as a single dose to 10 mg/kg biweekly for four months. The presence of amyloid related imaging abnormalities (ARIA, E for edema, H for hemorrhage) was assessed with magnetic resonance imaging (MRI). Cerebrospinal fluid (CSF) and plasma samples were analyzed to investigate pharmacokinetics (PK) and effects on biomarkers. RESULTS: The incidence of ARIA-E/H on MRI was comparable to that of placebo. BAN2401 exposure was approximately dose proportional, with a serum terminal elimination half-life of ~7 days. Only a slight increase of plasma Aß(1-40) was observed but there were no measurable effects of BAN2401 on CSF biomarkers. On the basis of these findings Phase 2b efficacy study has been initiated in early AD. CONCLUSIONS: BAN2401 was well-tolerated across all doses. The PK profile has guided us for selecting dose and dose regimens in the ongoing phase 2b study. There was no clear guidance for an effective dose based on biomarkers. TRIAL REGISTRATION NUMBER: NCT01230853 ClinicalTrials.gov Registered October 27, 2010.
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Doença de Alzheimer/tratamento farmacológico , Peptídeos beta-Amiloides/imunologia , Anticorpos Monoclonais Humanizados/efeitos adversos , Anticorpos Monoclonais Humanizados/uso terapêutico , Idoso , Doença de Alzheimer/sangue , Doença de Alzheimer/imunologia , Peptídeos beta-Amiloides/sangue , Anticorpos Monoclonais Humanizados/farmacocinética , Biomarcadores/sangue , Encéfalo/efeitos dos fármacos , Encéfalo/patologia , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Humanos , Masculino , Fragmentos de Peptídeos/sangueRESUMO
Alzheimer's disease is characterized by redistribution of the tau protein pool from soluble to aggregated states. Aggregation forms proteolytically stable core polymers restricted to the repeat domain, and this binding interaction has prion-like properties. We have compared the binding properties of tau and tubulin in vitro using a system in which we can measure binding affinities for proteins alternated between solid and aqueous phases. The study reveals that a phase-shifted repeat domain fragment from the Paired Helical Filament core contains all that is required for high affinity tau-tau binding. Unlike tau-tubulin binding, tau-tau binding shows concentration-dependent enhancement in both phase directions due to an avidity effect which permits one molecule to bind to many as the concentration in the opposite phase increases. Phosphorylation of tau inhibits tau-tau binding and tau-tubulin binding to equivalent extents. Tau-tau binding is favoured over tau-tubulin binding by factors in the range 19-41-fold, irrespective of phosphorylation status. A critical requirement for tau to become aggregation-competent is prior binding to a solid-phase substrate, which induces a conformational change in the repeat domain permitting high-affinity binding to occur even if tau is phosphorylated. The endogenous species enabling this nucleation event to occur in vivo remains to be identified. The findings of the study suggest that development of disease-modifying drugs for tauopathies should not target phosphorylation, but rather should target inhibitors of tau-tau binding or inhibitors of the binding interaction with as yet unidentified endogenous polyanionic substrates required to nucleate tau assembly.
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Doença de Alzheimer/patologia , Proteínas tau/metabolismo , Doença de Alzheimer/metabolismo , Humanos , Cinética , Fosforilação , Ligação Proteica , Domínios Proteicos , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Tubulina (Proteína)/química , Tubulina (Proteína)/metabolismo , Água/química , Proteínas tau/química , Proteínas tau/genéticaRESUMO
BACKGROUND: Although numerous epidemiological studies on appendicitis have been conducted worldwide, only a few studies have paid attention to the effect of socioeconomic status on appendicitis, particularly studies focusing on the low-income population (LIP). METHODS: We analyzed the epidemiological features of appendicitis in Taiwan using data from the National Health Insurance Research Database from 2003 to 2011. All cases diagnosed as appendicitis were enrolled. RESULTS: Between 2003 and 2011, 2,916 patients from the LIP and 209,206 patients from the normal population (NP) were diagnosed with appendicitis. Our finding revealed that the ratios of comorbidities, complicated appendicitis, and readmissions in LIP patients were slightly higher than those of NP patients. LIP patients were more likely to live in suburban and rural areas, and hence a higher proportion of them were hospitalized in a district or regional hospital compared with NP patients. The crucially finding was that the overall incidence ratios of appendicitis, acute appendicitis, and perforated appendicitis in the LIP were substantially higher than those in the NP (36.25%, 35.33%, and 37.28%, respectively). The mean LOS in LIP patients was longer than that of NP patients. The overall case-fatality ratio of appendectomy in the LIP was higher when compared with the NP (0.41% versus 0.12%, p < 0.05). We also observed that appendicitis was occurred frequently in male patients, with a higher incidence for those aged 15-29 years in both the LIP and NP. The incidences of incidental appendectomy showed a decreasing trend in both the LIP and NP. Finally, a valuable discovery was that the total hospital cost was comparable between the laparoscopic appendectomy (LA) and open appendectomy (OA) (1,178 ± 13 USD versus 1,191 ± 19 USD, p < 0.05) in LIP patients because they saved more hospitalization costs than NP patients when the previous one chose the LA. CONCLUSION: This study confirmed that a lower socioeconomic status has significantly negative impact on the occurrence and treatment of appendicitis and appendectomy. In terms of hospital costs and LOS, LIP patients benefit more from the LA approach than they do from the OA approach in the treatment of appendicitis.
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Apendicectomia/estatística & dados numéricos , Apendicite/epidemiologia , Apendicite/cirurgia , Pobreza/estatística & dados numéricos , Centros Médicos Acadêmicos/estatística & dados numéricos , Adolescente , Adulto , Fatores Etários , Idoso , Apendicectomia/economia , Apendicectomia/mortalidade , Apendicite/complicações , Criança , Pré-Escolar , Comorbidade , Feminino , Custos Hospitalares/estatística & dados numéricos , Hospitais de Distrito/estatística & dados numéricos , Humanos , Incidência , Lactente , Recém-Nascido , Laparoscopia/economia , Tempo de Internação/estatística & dados numéricos , Masculino , Pessoa de Meia-Idade , Readmissão do Paciente/estatística & dados numéricos , População Rural/estatística & dados numéricos , Fatores Sexuais , População Suburbana/estatística & dados numéricos , Taiwan/epidemiologia , População Urbana/estatística & dados numéricos , Adulto JovemRESUMO
OBJECTIVES: Preclinical studies have demonstrated involvement of p38 mitogen-activated protein kinase signaling pathways in the development of persistent pain after peripheral nerve injury. A double-blind, randomized, placebo-controlled study was undertaken to evaluate the analgesic efficacy of losmapimod (GW856553), a novel p38α/ß inhibitor, in patients with chronic neuropathic pain due to lumbosacral radiculopathy. MATERIALS AND METHODS: A total of 144 patients with at least moderate baseline pain intensity (average daily score of ≥4 on an 11-point pain intensity numeric rating scale) were randomized to receive losmapimod, 7.5 mg bid orally or placebo. All patients underwent a blinded placebo run-in period for 7 days before receiving losmapimod/placebo for 28 days. Efficacy and safety evaluations were undertaken weekly. RESULTS: The adjusted mean treatment difference for the change from baseline to week 4 in numeric rating scale was -0.36 U (95% confidence interval, -0.84, 0.13; P=0.149) in favor of losmapimod over placebo; this was not considered clinically meaningful. Statistically significant differences in favor of losmapimod were observed, however, for several secondary endpoints of emotional, physical, and social functioning: Oswestry Disability Index; Profile of Mood States total score; Short-Form 36 Health Survey physical functioning, bodily pain, general health, role emotional, social functioning, and vitality domains; and Short-Form 36 physical, and mental components. There were no unexpected findings related to safety or tolerability following treatment with losmapimod. DISCUSSION: Losmapimod could not be differentiated from placebo in terms of analgesia. The lack of response could reflect insufficient losmapimod levels in the spinal cord or differences between lumbosacral radiculopathy and animal models of neuropathic pain.
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Analgésicos/uso terapêutico , Ciclopropanos/uso terapêutico , Neuralgia/tratamento farmacológico , Piridinas/uso terapêutico , Resultado do Tratamento , Adolescente , Adulto , Idoso , Método Duplo-Cego , Europa (Continente) , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Neuralgia/etiologia , Medição da Dor , Exame Físico , Radiculopatia/complicações , Adulto JovemRESUMO
Resting fluctuations in the blood oxygenation level-dependent signal have attracted considerable interest for their sensitivity to pathological brain processes. However, these analyses are susceptible to confound by nonneural physiological factors such as vasculature, breathing, and head movement which is a concern when investigating elderly or pathological groups. Here, we used simultaneous electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) (EEG/fMRI) to constrain the analysis of resting state networks (RSNs) and identify aging differences. Four of 26 RSNs showed fMRI and EEG/fMRI group differences; anterior default-mode network, left frontal-parietal network, bilateral middle frontal, and postcentral gyri. Seven RSNs showed only EEG/fMRI differences suggesting the combination of these 2 methods might be more sensitive to age-related neural changes than fMRI alone. Five RSNs showed only fMRI differences and might reflect nonneural group differences. Activity within some EEG/fMRI RSNs was better explained by neuropsychological measures (Mini Mental State Examination and Stroop) than age. These results support previous studies suggesting that age-related changes in specific RSNs are neural in origin, and show that changes in some RSNs relate better to elderly cognition than age.
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Envelhecimento/patologia , Envelhecimento/fisiologia , Encéfalo/fisiologia , Eletroencefalografia , Imageamento por Ressonância Magnética , Descanso/fisiologia , Adolescente , Adulto , Idoso , Encéfalo/anatomia & histologia , Encéfalo/patologia , Cognição/fisiologia , Feminino , Humanos , Masculino , Rede Nervosa/anatomia & histologia , Rede Nervosa/patologia , Rede Nervosa/fisiologia , Testes Neuropsicológicos , Adulto JovemRESUMO
BACKGROUND: The histamine H3 receptor plays a critical role in the negative neuromodulation of neurotransmitters involved in cognitive function. H3 receptor antagonists/inverse agonists have been shown to exert pro-cognitive effects in pre-clinical models. GSK239512 is a potent and selective H3 receptor antagonist developed for the treatment of cognitive dysfunction in neurodegenerative disorders. In this study we examined the safety, tolerability, pharmacokinetics and pro-cognitive effects of GSK239512 (oral) in patients with mild to moderate Alzheimer's disease using ascending dose titration regimens. METHODS: The study was conducted in two parts. Part A was a single-blind, placebo run-in, flexible dose titration over 9 days in two cohorts, each consisting of two patients. Part B was a double-blind, randomised, placebo controlled, parallel group, which investigated 3 flexible dose titration regimens over 4 weeks in 3 cohorts, each consisting of eight patients. RESULTS: Overall, the 5/10/20/40 µg and 10/20/40/80 µg regimens were well-tolerated. The regimen of 20/40/80/150 µg showed the poorest tolerability likely due to the higher starting dose. There were no clinically significant abnormalities in haematology, clinical chemistry, urinalysis parameters and cardiovascular parameters. GSK239512 had positive effects on tasks of attention and memory with effect sizes between 0.56 and 1.37. CONCLUSIONS: GSK239512 displayed asatisfactory level of tolerability in patients with Alzheimer's disease with evidence for positive effects on attention and memory. The findings suggest that a titration regimen with a starting dose of 5-10 µg and a maximum dose of 80 µg is likely to be a well-tolerated and potentially efficacious regimen for future clinical trials in patients with Alzheimer's disease. These findings await replication in a larger study.
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Doença de Alzheimer/tratamento farmacológico , Atenção/efeitos dos fármacos , Benzazepinas/administração & dosagem , Antagonistas dos Receptores Histamínicos H3/administração & dosagem , Memória/efeitos dos fármacos , Idoso , Idoso de 80 Anos ou mais , Benzazepinas/efeitos adversos , Benzazepinas/farmacocinética , Relação Dose-Resposta a Droga , Método Duplo-Cego , Feminino , Antagonistas dos Receptores Histamínicos H3/efeitos adversos , Antagonistas dos Receptores Histamínicos H3/farmacocinética , Humanos , Masculino , Método Simples-CegoRESUMO
Age-related declines in memory may be due in part to changes in the complexity of neural activity in the aging brain. Electrophysiological entropy provides an accessible measure of the complexity of ongoing neural activity. In the current study, we calculated the permutation entropy of the electroencephalogram (EEG) during encoding of relevant (to be learned) and irrelevant (to be ignored) stimuli by younger adults, older adults, and older cognitively declined adults. EEG entropy was differentially sensitive to task requirements across groups, with younger and older controls exhibiting greater control of encoding-related activity than older declined participants. Task sensitivity of frontal EEG during encoding predicted later retrieval, in line with previous evidence that cognitive decline is associated with reduced ability to self-initiate encoding-related processes.
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Envelhecimento , Eletroencefalografia , Lobo Frontal/fisiologia , Memória/fisiologia , Idoso , Humanos , Dinâmica não Linear , Adulto JovemRESUMO
The current study examined electrophysiological entropy in younger adults, older adults, and older cognitively declined adults across four experimental conditions - eyes closed, eyes open, and during both encoding and recognition of words in a memory task. We hypothesised reduced entropy in older declined adults relative to both older controls and younger adults, with the largest group differences in entropy expected during the encoding and recognition phases of the experiment. We also hypothesised greater hemispheric asymmetry in younger adults compared with older controls and older declined adults. Results revealed significant increases in entropy from eyes closed to eyes open to task. Young adults showed higher entropy in the right relative to the left hemisphere in the temporal lobe and higher entropy in the left relative to the right hemisphere in the parietal lobe. Old cognitively declined adults showed no significant differences between right and left hemisphere entropy. There was a trend whereby older declined adults showed lower entropy than older controls in the frontal lobe, this difference being largest in the left hemisphere during the encoding phase of the experiment. Results indicate that measures of entropy are sensitive to information processing demands and that higher cognitive performance may not be a simple function of entropy level, but rather a combination of level and range, or differentiated range of entropy states across the brain.
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Envelhecimento , Córtex Cerebral/fisiopatologia , Transtornos Cognitivos/fisiopatologia , Entropia , Idoso , Análise de Variância , Estudos de Casos e Controles , Eletroencefalografia , Olho , Feminino , Lateralidade Funcional , Humanos , Masculino , Testes Neuropsicológicos , Reconhecimento Psicológico , Aprendizagem Verbal , Vocabulário , Adulto JovemRESUMO
One of the most reliable psychophysiological markers of aging is a linear decrease in the amplitude of the P300 potential, accompanied by a more frontal topographical orientation, but the precise neural origins of these differences have yet to be explored. We acquired simultaneous electroencephalogram (EEG)/functional magnetic resonance imaging (fMRI) recordings from 14 older and 15 younger adults who performed a 3-stimulus visual oddball task designed to elicit P3a and P3b components. As in previous reports, older adults had significantly reduced P3a/P3b amplitudes over parietal electrodes but larger amplitudes over frontal scalp with no between-group differences in accuracy or reaction time. Electroencephalogram/functional magnetic resonance imaging fusion revealed that the P3a age effects were driven by increased activation of left inferior frontal and cingulate cortex and decreased activation of inferior parietal cortex in the older group. P3b differences were driven by increased activation of left temporal regions, right hippocampus, and right dorsolateral prefrontal cortex in the older group. Our results support the proposal that the age-related P300 anterior shift arises from an increased reliance on prefrontal structures to support target and distractor processing.
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Envelhecimento/fisiologia , Eletroencefalografia/métodos , Potenciais Evocados P300/fisiologia , Imageamento por Ressonância Magnética/métodos , Adolescente , Adulto , Idoso , Córtex Cerebral/fisiologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Desempenho Psicomotor/fisiologia , Tempo de Reação/fisiologia , Adulto JovemRESUMO
The current study examined the EEG of young, old and old declined adults performing a visual paired associate task. In order to examine the effects of encoding context and stimulus repetition, target pairs were presented on either detailed or white backgrounds and were repeatedly presented during both early and late phases of encoding. Results indicated an increase in P300 amplitude in the right parietal cortex from early to late stages of encoding in older declined adults, whereas both younger adults and older controls showed a reduction in P300 amplitude in this same area from early to late phase encoding. In the right hemisphere, stimuli encoded with a white background had larger P300 amplitudes than stimuli presented with a detailed background; however, in the left hemisphere, in the later stages of encoding, stimuli presented with a detailed background had larger amplitudes than stimuli presented with a white background. Behaviourally, there was better memory for congruent stimuli reinstated with a detailed background, but this finding was for older controls only. During recognition, there was a general trend for congruent stimuli to elicit a larger amplitude response than incongruent stimuli, suggesting a distinct effect of context reinstatement on underlying patterns of physiological responding. However, behavioural data suggest that older declined adults showed no memory benefits associated with context reinstatement. When compared with older declined adults, younger adults had larger P100 amplitude responses to stimuli presented during recognition, and overall, younger adults had faster recognition reaction times than older control and older declined adults. Further analysis of repetition effects and context-based hemispheric asymmetry may prove informative in identifying declining memory performance in the elderly, potentially before it becomes manifested behaviourally.
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Envelhecimento/fisiologia , Aprendizagem por Associação/fisiologia , Transtornos Cognitivos/fisiopatologia , Potenciais Evocados/fisiologia , Transtornos da Memória/fisiopatologia , Reconhecimento Visual de Modelos/fisiologia , Idoso , Envelhecimento/psicologia , Transtornos Cognitivos/diagnóstico , Transtornos Cognitivos/psicologia , Diagnóstico Precoce , Humanos , Transtornos da Memória/diagnóstico , Transtornos da Memória/psicologia , Adulto JovemRESUMO
BACKGROUND: Restless legs syndrome (RLS) is a common neurological disorder the pathophysiology of which is incompletely understood. Four studies have examined structural differences between the brains of RLS patients and healthy controls, using voxel-based morphometry (VBM). All 4 studies have provided different results. METHODS: Optimized VBM was used to search for structural differences in gray matter density. Sixteen RLS patients naïve to dopaminergic drugs and 16 age- and sex-matched controls received structural T1-weighted MR scans. Structural data were analyzed using FSL-VBM. RESULTS: No difference in gray matter density was detected between the two groups (voxel-wise significance: no significant voxels at P= .89 (whole brain Family Wise Error (FWE) corrected); no significant voxels at P < .05 (whole brain False Discovery Rate (FDR) corrected; smallest achievable FDR threshold .99). CONCLUSION/DISCUSSION: The present study did not replicate (confirm) previous findings of structural brain changes in RLS, but instead supported the findings of a recent study showing a lack of gray matter alteration in an elderly RLS population. More specifically, the results do not support neuronal loss as an underlying disease mechanism in RLS. Potential limitations in the application of VBM are also discussed.
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Encéfalo/patologia , Interpretação de Imagem Assistida por Computador/métodos , Imageamento Tridimensional/métodos , Imageamento por Ressonância Magnética/métodos , Neurônios/patologia , Síndrome das Pernas Inquietas/patologia , Estudos de Casos e Controles , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reprodutibilidade dos Testes , Sensibilidade e EspecificidadeRESUMO
Rising life expectancies coupled with an increasing awareness of age-related cognitive decline have led to the unwarranted use of psychopharmaceuticals, including acetylcholinesterase inhibitors (AChEIs), by significant numbers of healthy older individuals. This trend has developed despite very limited data regarding the effectiveness of such drugs on non-clinical groups and recent work indicates that AChEIs can have negative cognitive effects in healthy populations. For the first time, we use a combination of EEG and simultaneous EEG/fMRI to examine the effects of a commonly prescribed AChEI (donepezil) on cognition in healthy older participants. The short- and long-term impact of donepezil was assessed using two double-blind, placebo-controlled trials. In both cases, we utilised cognitive (paired associates learning (CPAL)) and electrophysiological measures (resting EEG power) that have demonstrated high-sensitivity to age-related cognitive decline. Experiment 1 tested the effects of 5 mg/per day dosage on cognitive and EEG markers at 6-hour, 2-week and 4-week follow-ups. In experiment 2, the same markers were further scrutinised using simultaneous EEG/fMRI after a single 5 mg dose. Experiment 1 found significant negative effects of donepezil on CPAL and resting Alpha and Beta band power. Experiment 2 replicated these results and found additional drug-related increases in the Delta band. EEG/fMRI analyses revealed that these oscillatory differences were associated with activity differences in the left hippocampus (Delta), right frontal-parietal network (Alpha), and default-mode network (Beta). We demonstrate the utility of simple cognitive and EEG measures in evaluating drug responses after acute and chronic donepezil administration. The presentation of previously established markers of age-related cognitive decline indicates that AChEIs can impair cognitive function in healthy older individuals. To our knowledge this is the first study to identify the precise neuroanatomical origins of EEG drug markers using simultaneous EEG/fMRI. The results of this study may be useful for evaluating novel drugs for cognitive enhancement.
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Cognição/efeitos dos fármacos , Indanos/farmacologia , Memória/efeitos dos fármacos , Piperidinas/farmacologia , Idoso , Análise de Variância , Inibidores da Colinesterase/efeitos adversos , Inibidores da Colinesterase/farmacologia , Cognição/fisiologia , Estudos Cross-Over , Diarreia/induzido quimicamente , Donepezila , Método Duplo-Cego , Eletroencefalografia/métodos , Feminino , Hipocampo/efeitos dos fármacos , Hipocampo/fisiologia , Humanos , Indanos/efeitos adversos , Imageamento por Ressonância Magnética/métodos , Masculino , Memória/fisiologia , Pessoa de Meia-Idade , Náusea/induzido quimicamente , Piperidinas/efeitos adversos , Vômito/induzido quimicamenteRESUMO
The current study examines the EEG coherence of young, old, and old declined adults performing a visual paired-associates task. In order to examine the effects of encoding context and stimulus repetition, target pairs were presented on either detailed or white backgrounds and were repeatedly presented during both early and late phases of encoding. Younger adults were found to have lower levels of frontal-temporal and temporal-parietal coherence, but higher levels of frontal-parietal coherence, particularly for the gamma frequency band. A number of differential coherence responses to background context and early- versus late-encoding phases were also observed across the groups, particularly for lower alpha and upper alpha frequencies. Coherence-performance maps were generated to further explore topographical differences in the relationship between coherence and performance across groups. Results revealed a more diffuse pattern of negative coherence-performance relations in older declined adults. Results are discussed in light of the literature on age-related cognitive decline.
Assuntos
Envelhecimento/fisiologia , Eletroencefalografia/métodos , Memória/fisiologia , Estimulação Luminosa/métodos , Desempenho Psicomotor/fisiologia , Idoso , Ritmo alfa/fisiologia , Humanos , Tempo de Reação/fisiologia , Reconhecimento Psicológico/fisiologia , Adulto JovemRESUMO
Current treatments of neuropathic pain arising from conditions such as nerve injury/compression are only partially effective, and limited in their use by side-effects. p38 mitogen-activated protein kinase (MAPK) is involved in the regulation and synthesis of inflammatory mediators, and is the target for a novel class of cytokine-suppressive anti-inflammatory drugs. p38 inhibitors may reduce neuronal sensitisation in preclinical models of neuropathic pain, particularly where there is a substantial inflammatory component. An exploratory, multicentre, double-blind, placebo-controlled, two-period, cross-over trial was undertaken to evaluate the effect of dilmapimod (SB-681323), a selective p38 MAPK inhibitor, on neuropathic pain symptoms and signs. Fifty patients with nerve trauma, radiculopathy or carpal tunnel syndrome were randomised; 43 patients completed the study. Eligible patients received oral dilmapimod and placebo twice daily for 2 weeks, with an intervening washout period of 2-4 weeks. Subjects attended weekly for efficacy and safety assessments, which included evaluation of daily and current pain intensity using an 11-point numerical rating scale (NRS), quantitative sensory testing, allodynia and global impression of change. There was a statistically significant reduction in the primary endpoint of average daily pain score during the second week of treatment among patients treated with dilmapimod (15 mg/day) compared to placebo using NRS [0.80; 95% CI (0.28, 1.33); p=0.0034]. A similar trend for effect was seen in some secondary endpoints. Dilmapimod was well tolerated, with no clinically relevant safety findings. p38 MAPK inhibitors merit further evaluation for neuropathic pain in larger clinical trials, particularly for clinically meaningful analgesic effect size.