Age Effects on Decision-Making, Drift Diffusion Model

Training can improve human decision-making performance. After several training sessions, a person can quickly and accurately complete a task. However, decision-making is always a trade-off between accuracy and response time. Factors such as age and drug abuse can affect the decision-making process. This study examines how training can improve the performance of different age groups in completing a random dot motion (RDM) task. The participants are divided into two groups: old and young. They undergo a three-phase training and then repeat the same RDM task. The hierarchical drift-diffusion model analyzes the subjects' responses and determines how the model's parameters change after training for both age groups. The results show that after training, the participants were able to accumulate sensory information faster, and the model drift rate increased. However, their decision boundary decreased as they became more confident and had a lower decision-making threshold. Additionally, the old group had a higher boundary and lower drift rate in both pre and post-training, and there was less difference between the two group parameters after training

INCIDENCE AND ETIOLOGY OF PEDIATRIC STROKE IN SOUTHERN KHORASAN

&nbsp; Abstract INTRODUCTION: Ischemic stroke is rarely seen in childhood. The pediatric causes of stroke are very different from adult causes. methods: This population-based study was conducted to determine the incidence, clinical manifestations and etiology of pediatric ischemic stroke in Southern Khorasan, Iran, during 2002-2007. In this province, every child with possible diagnosis of stroke is referred to a stroke neurologist and routinely admitted to the Pediatric Division of Vali-e-Asr tertiary care hospital. The diagnosis of ischemic stroke was made based on the clinical presentation and brain imagery. All of the patients underwent a standard battery of diagnostic investigations. results: Seventeen children with ischemic stroke (7 girls, 10 boys) were evaluated. The incidence of pediatric ischemic stroke in Khorasan province is 1.8 cases per 100,000 children population per year. Meningoencephalitis-induced vasculopathy constituted 23.5% of the etiology followed by Fallot tetralogy, head trauma, dehydration, migraine, and hypercoagulable state. 23.5% of our patients had uncertain causes of stroke. In-hospital mortality of our pediatric ischemic stroke patients was 11.7%. CONCLUSIONS: The incidence and clinical characteristics of pediatric brain infarction in Iran are the same as in other studies. Meningoencephalitis-induced vasculopathy is the most common determined etiology of pediatric ischemic stroke in Southern Khorasan. &nbsp; &nbsp; Keywords: Child, stroke, incidence, etiology.</div

ATHEROSCLEROSIS RISK FACTORS AND ETIOLOGIC MECHANISMS OF LACUNAR STROKE

&nbsp; Abstract INTRODUCTION: It is thought that lacunae occur in patients with hypertension or diabetes mellitus as small-vessel involvement. The frequency of other stroke mechanisms in patients with lacunae was evaluated in this study. methods: Consecutive stroke patients admitted to Valie-Asr Hospital, Khorasan in 2006 were enrolled in a prospective study. Diagnosis of stroke and its risk factors was made by a stroke neurologist. All of the stroke patients underwent a standard battery of diagnostic investigations. Brain infarction was categorized as lacunae and large-vessel territory infarction (LVTI). Chi-square test and odds ratios were used for statistical analysis. results: Ninety-six patients with lacunae and 252 patients with LVTI were studied. The frequency of diabetes and hypercholesterolemia was significantly higher in patients with lacunar stroke than in those with LVTI (P=0.034 and P&lt;0.001, respectively). The frequency of hypertension, smoking, transient ischemic attacks (TIA) and ipsilateral carotid stenosis was not significantly different between the two groups (P=0.94, P=0.59, P=0.37 and P=0.13, respectively). Atrial fibrillation was significantly more frequent in patients with LVTI (P&lt;0.001). The frequency of various etiologic mechanisms was not significantly different in lacunar stroke and LVTI patients (df=4, P=0.164). CONCLUSIONS: Hypertension in patients with lacunar stroke is not more frequent than in other stroke patients. Cardioembolism and artery-to-artery embolism are important but less common mechanisms of lacunae. &nbsp; &nbsp; Keywords: Atherosclerosis, lacune, stroke.</div

CARDIAC SOURCES OF EMBOLISM IN IRANIAN STROKE PATIENTS

AbstractINTRODUCTION: Rheumatic valvular disease is a common complication of rheumaticfever in children in developing countries. Later in life, rheumatic valvular diseasebecomes an important modifiable risk factor of stroke. The incidence of rheumaticvalvular disease and its complications are unknown in Iran.METHODS: This is a prospective study of 302 consecutive patients admitted to atertiary care hospital in Iran, with a diagnosis of non-hemorrhagic stroke between June2005 and June 2006. All patients underwent diagnostic workup to determine strokeetiology according to clinical indications. Diagnosis and classification of stroke was madebased on the PIC criteria.RESULTS: In 302 patients with stroke (mean age: 66.78&plusmn;14.36 years), 60 patients(20%) (mean age: 65.61&plusmn;17.48 years) had cardiac sources of embolism (CSE). Rheumaticmitral stenosis was present in 28 (46.6%) of these patients. Atrial fibrillation wasdocumented in 19 patients (67.8%) with rheumatic valvular disease. The remaining 32patients (53.3%) had other CSE. In the latter group, 8 patients (25%) had non-valvularatrial fibrillation. In the entire group with CSE, a total of 30 patients were candidates foranticoagulation; among them, 14 (46.6%) were anticoagulated, but only 6 (20%) werewithin therapeutic range at the time of their stroke.CONCLUSIONS: Rheumatic valvular disease seems to be the most common CSE in Iran.Many patients with rheumatic or non-rheumatic CSE are not adequately managed forsecondary prevention of cardioembolic stroke.Key Words: Cardioembolic, stroke, rheumatic

Risk factors of short-term stroke recurrence in patients with minor ischemic cerebrovascular events

BACKGROUND: Assessing the risk of recurrent ischemic events in patients with transient ischemic attack (TIA) and minor ischemic stroke (MIS) is of a great importance in clinical practice. METHODS: Consecutive patients with TIA or MIS who were visited in Ghaem Hospital, (Mashhad, Iran) were enrolled in a prospective cohort study during 2010 to 2011. Diagnosis of TIA or MIS was accomplished by a stroke neurologist. Only those who presented within 24 hours from the onset of symptoms were recruited. MIS was considered as an ischemic stroke with National Institutes of Health Stroke Scale (NIHSS) &lt; 4. The endpoint of the study was a new ischemic cerebrovascular event or vascular death in 90 days and additionally in 3 days. The decision to admit and type of treatment in each case was left to the discretion of the stroke neurologist. The association between 20 potential factors with recurrent ischemic events in 3 and 90 days was investigated using univariate and multivariate analysis (MVA). RESULTS: 393 TIA patients (238 males and 155 females) and 118 MIS patients (77 males and 41 females) were enrolled in the study. Stroke occurred in 117 (23.2%) patients, TIA in 99 (19.6%), and there was 11 (2.2%) vascular deaths within 3 months in the total 511 patients with minor ischemic events. Crescendo TIAs and multiple TIAs were associated with greater risk of stroke in 3 days in a univariate analysis (OR = 5.12, P &lt; 0.001) and (OR = 3.98, P = 0.003), respectively. Patients with index stroke had 11.5% lower risk of recurrent stroke in 3 days than patients with index TIA in multivariate analysis (OR = 0.115, P = 0.039). Diabetes was independently associated with 3 months stroke recurrence in the patients with minor ischemic events (OR = 2.65, P = 0.039). CONCLUSION: Multiple and crescendo TIAs are the main predictors of stroke recurrence, derived from the univariate analysis of the patients with minor ischemic events. &nbsp; Keywords: Transient Ischemic Attacks, Infarction, Brain, Recurrence, Risk</div

Intravenous Thrombolysis, Time Window, Dosage, and Off-Label

Despite the development of Intravenous thrombolysis with tissue Plasminogen Activator (IVtPA) guidelines in each affiliated stroke center, protocol violations may be observed in each hospital with IVtPA facilities. An extensive search of scientific electronic databases including PubMed, OVID, Index Medicus, Index Copernicus, Google, ISI, and Scopus was performed with keywords of Thrombolysis, Off-label, Out of Protocol, Violation, Time Window, Dose, tPA, and Stroke terminated on 01 May 2018. Safety and functional outcomes are less favorable beyond three hours; however, the wider time window until 4.5 hours is recommended. Lower dose of alteplase (0.6 mg/kg) is approved in Japan. The proposed dose of tPA in Iranian population is similar to that of the Japanese. Overall, the outcomes in patients treated with off-label IVtPA or protocol violation were better than those of the controls based on registry data. There is little disagreement about time window of IVtPA. The dose of 0.6 mg/kg is used in some Asian countries with similar therapeutic results

The Response of Soil Physicochemical Properties in the Hyrcanian Forests of Iran to Forest Fire Events

When forest fires occur, highly complex effects on soil properties and hydrological processes are activated. However, in countries such as Iran, these consequences are not widely studied and there is a lack of studies. Therefore, the main aim of this study was to investigate the effects of wildfire on soil quality characteristics in a representative forest area located in the Hyrcanian forests, specifically, in the Zarrinabad watershed of Sari. For this purpose, four different sites, including unburnt natural (UNF), burned natural (BNF), unburnt plantation (UPF), and burned plantation forests (BPF) were selected. Soil sampling was performed at each site using the random, systematic method at a depth from 0 to 30 cm. To investigate the effects of fire on physical and chemical properties indicators, 10 plots with dimensions of 0.5 &times; 0.5 m were placed at a distance of 1.5 m from each other at each site. Soil samples were transported to the laboratory and their physical and chemical properties were determined. The results showed that the percentage of sand, silt, aggregate stability, soil hydrophobicity, organic carbon, organic matter, soil total nitrogen, absorbable potassium and phosphorus, electrical conductivity, and pH, increased significantly when the soil surface is burned (p &le; 0.01, p &le; 0.05). However, clay percentage, initial, final, and average infiltration in the burned areas showed a decreasing trend in comparison with other forest statuses. Furthermore, no significant effects were observed on the true and bulk density, porosity, and soil moisture (p &ge; 0.05). These findings demonstrate that forest fire effects in Iran must be considered as a key topic for land managers because soil properties and hydrological processes are drastically modified, and land degradation could be irreparably activated