Methamphetamine (METH) is a sympathomimetic amine that belongs to phenethylamine and amphetamine class of psychoactive drugs, which are widely abused for their stimulant, euphoric, empathogenic, and hallucinogenic properties. Many of these effects result from acute increases in dopamine and serotonin neurotransmission. Subsequent to these acute effects, METH produces persistent damage to dopamine and serotonin release in nerve terminals, gliosis, and apoptosis. This review summarized the numerous interdependent mechanisms including excessive dopamine, ubiquitin-proteasome system dysfunction, protein nitration, endoplasmic reticulum stress, p53 expression, inflammatory molecular, D 3 receptor, microtubule deacetylation, and HIV-1 Tat protein that have been demonstrated to contribute to this damage. In addition, the feasible therapeutic strategies according to recent studies were also summarized ranging from drug and protein to gene level.
Amyloid imaging represents a major advance in neuroscience, enabling the detection and quantification of pathologic protein aggregations in the brain. In this review we survey current amyloid imaging techniques, focusing on positron emission tomography (PET) with (11)carbon-labelled Pittsburgh Compound-B (C-11-PIB), the most extensively studied and best validated tracer. PIB binds specifically to fibrillar beta-amyloid (A beta) deposits, and is a sensitive marker for A beta pathology in cognitively normal older individuals and patients with mild cognitive impairment (MCI) and Alzheimer's disease (AD). PIB-PET provides us with a powerful tool to examine in vivo the relationship between amyloid deposition, clinical symptoms, and structural and functional brain changes in the continuum between normal aging and AD. Amyloid imaging studies support a model in which amyloid deposition is an early event on the path to dementia, beginning insidiously in cognitively normal individuals, and accompanied by subtle cognitive decline and functional and structural brain changes suggestive of incipient AD. As patients progress to dementia, clinical decline and neurodegeneration accelerate and proceed independently of amyloid accumulation. In the future, amyloid imaging is likely to supplement clinical evaluation in selecting patients for anti-amyloid therapies, while MRI and FDG-PET may be more appropriate markers of clinical progression.
Structural magnetic resonance imaging (MRI) studies of Alzheimer's disease and mild cognitive impairment (MCI) have focused on the hippocampus and entorhinal cortex, gray matter structures in the medial temporal lobe. Few studies have investigated the integrity of white matter in patients with AD or MCI. Diffusion tensor imaging (DTI) is a MRI technique that allows for the interrogation of the microstructural integrity of white matter. Based on increases in translational diffusion (mean diffusivity: MD) and decreases directional diffusion (fractional anisotropy: FA) damage to white matter can be assessed. Studies have identified regions of increased MD and decreased FA in patients with AD and MCI in all lobes of the brain, as well as medial temporal lobe structures including the hippocampus, entorhinal cortex and parahippocampal white matter. The pattern of white matter integrity disruption tends to follow an anterior to posterior gradient with greater damage noted in posterior regions in AD and MCI. Recent studies have exploited inter-voxel directional similarities to develop models of white matter pathways, and have used these models to assess the integrity of inter-cerebral connections. Particular focus has been applied to the parahippocampal white matter (including the perforant path) and the posterior cingulum. Although many studies have found DTI indicators of impaired white matter in AD and MCI, other studies have failed to detect any differences in MD or FA between the groups.. demonstrating the need for large replicative studies. DTI is an evolving technique and advances in its application ought to provide new insights into AD and MCI.
In the last years, there has been a significant growth in the literature exploiting transcranial magnetic stimulation (TMS) with the aim at gaining further insights into the electrophysiological and neurochemical basis underlying vascular cognitive impairment (VCI). Overall, TMS points at enhanced brain cortical excitability and synaptic plasticity in VCI, especially in patients with overt dementia, and neurophysiological changes seem to correlate with disease process and progress. These findings have been interpreted as part of a glutamate-mediated compensatory effect in response to vascular lesions. Although a single TMS parameter owns low specificity, a panel of measures can support the VCI diagnosis, predict progression, and possibly identify early markers of "brain at risk" for future dementia, thus making VCI a potentially preventable cause of both vascular and degenerative dementia in late life. Moreover, TMS can be also exploited to select and evaluate the responders to specific drugs, as well as to become an innovative rehabilitative tool in the attempt to restore impaired neural plasticity. The present review provides a perspective of the different TMS techniques by further understanding the cortical electrophysiology and the role of distinctive neurotransmission pathways and networks involved in the pathogenesis and pathophysiology of VCI and its subtypes.
The recovery of hand function is one of the most challenging topics in stroke rehabilitation. Although the robot-assisted therapy has got some good results in the latest decades, the development of hand rehabilitation robotics is left behind. Existing reviews of hand rehabilitation robotics focus either on the mechanical design on designers' view or on the training paradigms on the clinicians' view, while these two parts are interconnected and both important for designers and clinicians. In this review, we explore the current literature surrounding hand rehabilitation robots, to help designers make better choices among varied components and thus promoting the application of hand rehabilitation robots. An overview of hand rehabilitation robotics is provided in this paper firstly, to give a general view of the relationship between subjects, rehabilitation theories, hand rehabilitation robots, and its evaluation. Secondly, the state of the art hand rehabilitation robotics is introduced in detail according to the classification of the hardware system and the training paradigm. As a result, the discussion gives available arguments behind the classification and comprehensive overview of hand rehabilitation robotics.
Functional MRI (fMRI) studies of mild cognitive impairment (MCI) and Alzheimer's disease (AD) have begun to reveal abnormalities in large-scale memory and cognitive brain networks. Since the medial temporal lobe (MTL) memory system is a site of very early pathology in AD, a number of studies have focused on this region of the brain. Yet it is clear that other regions of the large-scale episodic memory network are affected early in the disease as well, and fMRI has begun to illuminate functional abnormalities in frontal, temporal, and parietal cortices as well in MCI and AD. Besides predictable hypoactivation of brain regions as they accrue pathology and undergo atrophy, there are also areas of hyperactivation in brain memory and cognitive circuits, possibly representing attempted compensatory activity. Recent fMRI data in MCI and AD are beginning to reveal relationships between abnormalities of functional activity in the MTL memory system and in functionally connected brain regions, such as the precuneus. Additional work with "resting state" fMRI data is illuminating functional-anatomic brain circuits and their disruption by disease. As this work continues to mature, it will likely contribute to our understanding of fundamental memory processes in the human brain and how these are perturbed in memory disorders. We hope these insights will translate into the incorporation of measures of task-related brain function into diagnostic assessment or therapeutic monitoring, which will hopefully one day be useful for demonstrating beneficial effects of treatments being tested in clinical trials.
Apathy has been defined as lack of motivation. It has been traditionally considered as a symptom of psychiatric disorders, such as major depression and schizophrenia, but more recently it has been recognized as a specific neuropsychiatric syndrome associated with neurodegenerative such as Parkinson's disease (PD). As a consequence the reported prevalence of apathy in PD ranges from 13.9% to 70%; the mean prevalence is 35%. Prevalence of "pure apathy" (i.e., of apathy without comorbid depression and dementia) seems to be substantially lower, from 3 to 47.9%. High levels of apathy in PD are associated with decreased daily function, specific cognitive deficits and increased stress for families. Although neuroimaging studies do not provide a unique anatomic pattern, several data suggest that the ventromedial prefrontal cortex and the basal ganglia connected through frontal-subcortical circuits, are particularly involved in the genesis of apathy. At present, there are no approved medications for the treatment of apathy in and no proof of efficacy exists for any drug in current use. Further studies and innovative pharmacologic approaches are thus needed to ameliorate our understanding and treatment of apathy in PD.
Purpose. To develop a predictive model of speech loss in persons with amyotrophic lateral sclerosis (ALS) based on measures of respiratory, phonatory, articulatory, and resonatory functions that were selected using a data-mining approach. Method. Physiologic speech subsystem (respiratory, phonatory, articulatory, and resonatory) functions were evaluated longitudinally in 66 individuals with ALS using multiple instrumentation approaches including acoustic, aerodynamic, nasometeric, and kinematic. The instrumental measures of the subsystem functions were subjected to a principal component analysis and linear mixed effects models to derive a set of comprehensive predictors of bulbar dysfunction. These subsystem predictors were subjected to a Kaplan-Meier analysis to estimate the time until speech loss. Results. For amajority of participants, speech subsystem decline was detectible prior to declines in speech intelligibility and speaking rate. Among all subsystems, the articulatory and phonatory predictors were most responsive to early bulbar deterioration; and the resonatory and respiratory predictors were as responsive to bulbar decline as was speaking rate. Conclusions. The articulatory and phonatory predictors are sensitive indicators of early bulbar decline due to ALS, which has implications for predicting disease onset and progression and clinical management of ALS.
Two clinically distinct diseases, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), have recently been classified as two extremes of the FTD/ALS spectrum. The neuropathological correlate of FTD is frontotemporal lobar degeneration (FTLD), characterized by tau-, TDP-43-, and FUS-immunoreactive neuronal inclusions. An earlier discovery that a hexanucleotide repeat expansion mutation in chromosome 9 open reading frame 72 (C9orf72) gene causes ALS and FTD established a special subtype of ALS and FTLD with TDP-43 pathology (C9FTD/ALS). Normal individuals carry 2-10 hexanucleotide GGGGCC repeats in the C9orf72 gene, while more than a few hundred repeats represent a risk for ALS and FTD. The proposed molecular mechanisms by which C9orf72 repeat expansions induce neurodegenerative changes are C9orf72 loss-of-function through haploinsufficiency, RNA toxic gain-of-function, and gain-of-function through the accumulation of toxic dipeptide repeat proteins. However, many more cellular processes are affected by pathological processes in C9FTD/ALS, including nucleocytoplasmic transport, RNA processing, normal function of nucleolus, formation of membraneless organelles, translation, ubiquitin proteasome system, Notch signalling pathway, granule transport, and normal function of TAR DNA-binding protein 43 (TDP-43). Although the exact molecular mechanisms through which C9orf72 repeat expansions account for neurodegeneration have not been elucidated, some potential therapeutics, such as antisense oligonucleotides targeting hexanucleotide GGGGCC repeats in mRNA, were successful in preclinical trials and are awaiting phase 1 clinical trials. In this review, we critically discuss each proposed mechanism and provide insight into the most recent studies aiming to elucidate the molecular underpinnings of C9FTD/ALS.
Background. Little is known about physical activity and its association with volumes of whole brain gray matter and white matter and deep gray matter structures in persons with multiple sclerosis (MS). Purpose. This study examined the association between levels of physical activity and brain volumetric measures from magnetic resonance imaging (MRI) in MS. Method. 39 persons with MS wore an accelerometer for a 7-day period and underwent a brain MRI. Normalized GM volume (NGMV), normalized WM volume (NWMV), and deep GM structures were calculated from 3D T1-weighted structural brain images. We conducted partial correlations (pr) controlling for demographic and clinical variables. Results. Moderate-to-vigorous physical activity (MVPA) was significantly associated with NGMV (pr = 0.370, p < 0.05), NWMV (pr = 0.433, p < 0.01), hippocampus (pr = 0.499, p < 0.01), thalamus (pr = 0.380, p < 0.05), caudate (pr = 0.539, p < 0.01), putamen (pr = 0.369, p < 0.05), and pallidum (pr = 0.498, p < 0.01) volumes, when controlling for sex, age, clinical course of MS, and Expanded Disability Status Scale score. There were no associations between sedentary and light physical activity with MRI outcomes. Conclusion. Our results provide the first evidence that MVPA is associated with volumes of whole brain GM and WM and deep GM structures that are involved in motor and cognitive functions in MS.
Objectives. This study is aimed at elucidating the prevalence of depression in patients with myasthenia gravis (MG) and examining the risk factors associated with depression. Methods. We evaluated adult patients with MG who were recruited from two tertiary hospitals in the central region (Riyadh) of Saudi Arabia. Data were collected with a two-part standardized questionnaire: the first part included data on sociodemographic and clinical features of MG including disease type and duration, therapies, prednisolone dose, time of the last relapse, previous critical care unit admissions, MG status (controlled, partially controlled, or uncontrolled), and comorbid diseases; the second part included items from the previously validated Arabic version of the Patient Health Questionnaire-9 (PHQ-9). Results. In total, 104/150 (69.3%) patients participated (72 females) with a mean age of 38.0±16.0 years. The mean PHQ-9 score was 7.02±6.1. Among all the participants, 27 (26.0%) patients had depression (PHQ‐9≥10). Multiple logistic regression analysis revealed that uncontrolled MG status (OR=12.31, 95%CI=1.13‐133.8, P=0.04) was the only factor independently associated with depression. Collectively, the prevalence of depression among patients of the primary care clinics (PCC) as reported by 5 previous studies across multiple regions of the country was 15.8%. The odds of depression among MG patients were twofold higher than those among PCC patients (OR=2.05, 95%CI=1.30‐3.22, P=0.002). Conclusions. Approximately a quarter of MG patients have depression. Achieving a minimal manifestation or better MG status may decrease the depression rate in these patients.
Introduction. Among the nonmotor features of Parkinson's disease (PD), cognitive impairment is one of the most troublesome problems. New diagnostic criteria for mild and major neurocognitive disorder (NCD) in PD were established by Diagnostic and Statistical Manual of Mental Disorders 5th edition (DSM-5). The aim of our study was to establish the diagnostic accuracy of widely used screening tests for NCD in PD. Methods. Within the scope of our study we evaluated the sensitivity and specificity of different neuropsychological tests (Addenbrooke's Cognitive Examination (ACE), Mattis Dementia Rating Scale (MDRS), Mini Mental State Examination (MMSE), and Montreal Cognitive Assessment (MoCA)) in 370 PD patients without depression. Results. MoCA and ACE feature the finest diagnostic accuracy for detecting mild cognitive disorder in PD (DSM-5) at the cut-off scores of 23.5 and 83.5 points, respectively. The diagnostic accuracy of these tests was 0.859 (95% CI: 0.818-0.894, MoCA) and 0.820 (95% CI: 0.774-0.859, ACE). In the detection of major NCD (DSM-5), MoCA and MDRS tests exhibited the best diagnostic accuracy at the cut- off scores of 20.5 and 132.5 points, respectively. The diagnostic accuracy of these tests was 0.863 (95% CI: 0.823-0.897, MoCA) and 0.830 (95% CI: 0.785-0.869, MDRS). Conclusion. Our study demonstrated that the MoCA may be the most suitable test for detecting mild and major NCD in PD.
At the moment, dementia is affecting around 47 million people worldwide, with a forecast amount of 135 million affected people in 2050. Dementia is a growing health concern worldwide with no treatment currently available, but only symptomatic medication. Effective interventions in the prevention and management of dementia are urgently needed to contain direct and indirect costs of this disease. Indeed, the economic impact of dementia is a vast and continually growing figure, but it is still difficult to quantify. Due to an increase in both the disease spreading and its direct and indirect costs, national and international action plans have to be implemented. As a virtuous example, the Italian national plan for dementia has been summarized. Faced with an increasingly less sustainable disease impact at national and international levels, the plan suggests that it is certainly the entire welfare model that should be rethought, strengthening the network of services and providing interventions to support affected people and their caregivers. Alongside this synergistic approach, scientific research could play a crucial role for pharmacological and nonpharmacological treatments capable of delaying the state of loss of self-sufficiency of the patient, with a significant impact on social and health costs.
Background. Obstructive sleep apnea syndrome (OSAS) affects up to 4% of a pediatric population, with many comorbidities in the medium-long term. Functional alterations in the prefrontal cortex (PFC) may explain why OSAS impacts aspects such as executive functions, memory, motor control, attention, visual-spatial skills, learning, and mood regulation. Emotional intelligence (EI) is a complex neuropsychological function that could be impaired in many clinical conditions. Purpose. The aim of the study is to evaluate the difference in emotional intelligence skills among children with OSAS and healthy subjects (nOSAS). Methods. 129 children (72 males; mean age 7.64 +/- 1.98 years) affected by OSAS were compared to 264 non-OSAS (nOSAS) children (138 males; mean age 7.98 +/- 2.13) similar for gender, age, and socioeconomic status. In order to assess the emotional quotient, the Bar-On Emotional Quotient Inventory: Youth Version (EQ-i:YV) was used. Results. The comparison for means and standard deviation between OSAS children and nOSAS children for EQ-i:YV scores showed significant differences for Interpersonal, Adaptability, and Stress Management scales and EQ Total score. Conclusions. Our findings highlighted the role of intermittent hypoxia in the genesis of the effects of sleep-related respiratory disorders, which involves also aspects different from physical impairments.
Background. Epilepsy is one of the common neurological illnesses which affects millions of individuals globally. Although the majority of epileptic patients have a good response for the currently available antiepileptic drugs (AEDs), about 30-40% of epileptic patients are developing resistance. In addition to low safety profiles of most of existing AEDs, there is no AED available for curative or disease-modifying actions for epilepsy so far. Objectives. This systematic review is intended to evaluate the effect of metformin in acute and chronic animal models of an epileptic seizure. Methods. We searched PubMed, SCOPUS, Sciences Direct, and grey literature in order to explore articles published in English from January 2010 to November 2018, using key terms epilepsy, seizure, metformin, oral hypoglycemic agents, and oral antidiabetic drugs. The qualities of all the included articles were assessed according to the Collaborative Approach to Meta-Analysis and Review of Animal Data from Experimental Studies (CAMARADES). Results. Out of six hundred fifty original articles retrieved, eleven of them fulfilled the inclusion criteria and were included for final qualitative analysis. In these studies, metformin showed to control seizure attacks by attenuating seizure generation, delaying the onset of epilepsy, reducing hippocampal neuronal loss, and averting cognitive impairments in both acute and chronic models of an epileptic seizure. The possible mechanisms for its antiseizure or antiepileptic action might be due to activation of AMPK, antiapoptotic, antineuroinflammatory, and antioxidant properties, which possibly modify disease progression through affecting epileptogenesis. Conclusion. This review revealed the benefits of metformin in alleviating symptoms of epileptic seizure and modifying different cellular and molecular changes that affect the natural history of the disease in addition to its good safety profile.
Introduction. Antiepileptic drugs are effective in the treatment of epilepsy to the extent that about 70% of people with epilepsy can be seizure-free, but poor adherence to medication is major problem to sustained remission and functional restoration. The aim of this study was to assess the prevalence and associated factors of antiepileptic drug nonadherence. Methods. Cross-sectional study was conducted on 450 individuals who were selected by systematic random sampling method. Antiepileptic drug nonadherence was measured by Morisky Medication Adherence Scale (MMAS) and logistic regression was used to look for significant associations. Result. The prevalence of AEDs nonadherence was 37.8%. Being on treatment for 6 years and above [AOR = 3.47, 95% CI: 1.88, 6.40], payment for AEDs [AOR = 2.76, 95% CI: 1.73, 4.42], lack of health information [AOR = 2.20, 95% CI: 1.41,3.43], poor social support [AOR = 1.88, 95%, CI: 1.01, 3.50], perceived stigma [AOR = 2.27, 95% CI: 1.45, 3.56], and experience side effect [AOR = 1.70, 95% CI: 1.06, 2.72] were significantly associated with antiepileptic drug nonadherence. Conclusion. More than one-third of people with epilepsy were not compliant with their AEDs. Giving health information about epilepsy and its management and consequent reduction in stigma will help for medication adherence.
Previous studies have shown that the neural mechanisms underlying visual spatial attention rely on top-down control information from the frontal and parietal cortexes, which ultimately amplifies sensory processing of stimulus occurred at the attended location relative to those at unattended location. However, the modulations of effective brain networks in response to stimulus at attended and unattended location are not yet clear. In present study, we collected event-related potentials (ERPs) from 15 subjects during a visual spatial attention task, and a partial directed coherence (PDC) method was used to construct alpha-band effective brain networks of two conditions (targets at attended and nontargets at unattended location). Flow gain mapping, effective connectivity pattern, and graph measures including clustering coefficient (C), characteristic path length (L), global efficiency (Eglobal), and local efficiency (Elocal) were compared between two conditions. Flow gain mapping showed that the frontal region seemed to serve as the main source of information transmission in response to targets at attended location while the parietal region served as the main source in nontarget condition. Effective connectivity pattern indicated that in response to targets, there existed obvious top-down connections from the frontal, temporal, and parietal cortexes to the visual cortex compared with in response to nontargets. Graph theory analysis was used to quantify the topographical properties of the brain networks, and results revealed that in response to targets, the brain networks were characterized by significantly smaller characteristic path length and larger global efficiency than in response to nontargets. Our findings suggested that smaller characteristic path length and larger global efficiency could facilitate global integration of information and provide a substrate for more efficient perceptual processing of targets at attended location compared with processing of nontargets at ignored location, which revealed the neural mechanisms underlying visual spatial attention from the perspective of effective brain networks and graph theory for the first time and opened new vistas to interpret a cognitive process.
Objectives. Unknown onset stroke (UOS) is usually excluded from intravenous thrombolysis concerning the unclear symptom onset time. Attempts have been done to use thrombolytic therapy in these patients. The current meta-analysis was done to examine the efficacy and safety of intravenous thrombolysis in UOS. Methods. PubMed, Web of Science, and Cochrane Library were searched for studies comparing thrombolysis with conservative therapy among UOSs. Data of good outcome (mRS, 0-2), mortality, and intracerebral hemorrhage (ICH) and symptomatic ICH (sICH) were extracted and analyzed using the Revman 5.2 software. Results. In total, 8 studies with 1271 subjects (542 with thrombolysis and 729 with conservative therapy) were included in this meta-analysis. The data showed that patients receiving thrombolysis had a higher incidence of 90-day good outcome (P=0.0005) than conservative therapy. The comparison of discharge (P=0.89) and 90-day mortality (P=0.10) in both groups did not find any significances. The incidences of ICH (P=0.42) and sICH (P=0.06) were relatively comparable between the two therapies. Conclusions. Intravenous thrombolysis is a better choice for UOS patients for its efficacy and safety. In addition, pretreatment imaging assessment is beneficial for improving the efficacy of thrombolytic therapy. However, it needs more supporting evidences for clinical use in the future.
Aim. To assess the clinical course of disability, cognitive, and emotional impairments in patients with severe TBI (s-TBI) from 3 months to up to 7 years post trauma. Methods. A prospective cohort study of s-TBI in northern Sweden was conducted. Patients aged 18-65 years with acute Glasgow Coma Scale 3-8 were assessed with the Glasgow Outcome Scale Extended (GOSE), the Hospital Anxiety and Depression Scale (HADS), and the Barrow Neurological Institute Screen for Higher Cerebral Functions (BNIS) at 3 months, 1 year, and 7 years after the injury. Results. The scores on both GOSE and BNIS improved significantly from 3 months (GOSE mean: 4.4 +/- 2.3, BNIS mean: 31.5 +/- 7.0) to 1 year (GOSE mean: 5.5 +/- 2.7, p=0.003, BNIS mean: 33.2 +/- 6.3, p=0.04), but no significant improvement was found from 1 year to 7 years (GOSE mean: 4.7 +/- 2.8, p=0.13, BNIS mean: 33.5 +/- 3.9, p=0.424) after the injury. The BNIS subscale "speech/language" at 1 year was significantly associated with favourable outcomes on the GOSE at 7 years (OR=2.115, CI: 1.004-4.456, p=0.049). Conclusions. These findings indicate that disability and cognition seem to improve over time after s-TBI and appear to be relatively stable from 1 year to 7 years. Since cognitive function on some of the BNIS subscales was associated with outcome on the GOSE, these results indicate that both screening and follow-up of cognitive function could be of importance for the rehabilitation of persons with s-TBI.