scholarly journals Variation in reported human head tissue electrical conductivity values

2019 ◽  
Author(s):  
Hannah McCann ◽  
Giampaolo Pisano ◽  
Leandro Beltrachini
Keyword(s):  
Electrical Conductivity ◽  
Meta Analysis ◽  
Weighted Average ◽  
Human Head ◽  
Influential Factors ◽  
Volume Conductor ◽  
Tissue Temperature ◽  
Tissue Type ◽  
Current Frequency ◽  
Skull Conductivity

ABSTRACTElectromagnetic source characterisation requires accurate volume conductor models representing head geometry and the electrical conductivity field. Head tissue conductivity is often assumed from previous literature, however, despite extensive research, measurements are inconsistent. A meta-analysis of reported human head electrical conductivity values was therefore conducted to determine significant variation and subsequent influential factors. Of 3,121 identified publications spanning three databases, 56 papers were included in data extraction. Conductivity values were categorised according to tissue type, and recorded alongside methodology, measurement condition, current frequency, tissue temperature, participant pathology and age. We found variation in electrical conductivity of the whole-skull, the spongiform layer of the skull, isotropic, perpendicularly- and parallelly-oriented white matter (WM) and the brain-to-skull-conductivity ratio (BSCR) could be significantly attributed to a combination of differences in methodology and demographics. This large variation should be acknowledged, and care should be taken when creating volume conductor models, ideally constructing them on an individual basis, rather than assuming them from the literature. When personalised models are unavailable, it is suggested weighted average means from the current meta-analysis are used. Assigning conductivity as: 0.41 S/m for the scalp, 0.02 S/m for the whole skull, or when better modelled as a 3-layer skull 0.048 S/m for the spongiform layer, 0.007 S/m for the inner compact and 0.005 S/m for the outer compact, as well as 1.71 S/m for the CSF, 0.47 S/m for the grey matter, 0.22 S/m for WM and 50.4 for the BSCR.

scholarly journals Variation in Reported Human Head Tissue Electrical Conductivity Values

2019 ◽  
Vol 32 (5) ◽  
pp. 825-858 ◽  
Author(s):  
Hannah McCann ◽  
Giampaolo Pisano ◽  
Leandro Beltrachini
Keyword(s):  
Electrical Conductivity ◽  
Meta Analysis ◽  
Weighted Average ◽  
Human Head ◽  
Influential Factors ◽  
Volume Conductor ◽  
Tissue Temperature ◽  
Tissue Type ◽  
Current Frequency ◽  
Skull Conductivity

AbstractElectromagnetic source characterisation requires accurate volume conductor models representing head geometry and the electrical conductivity field. Head tissue conductivity is often assumed from previous literature, however, despite extensive research, measurements are inconsistent. A meta-analysis of reported human head electrical conductivity values was therefore conducted to determine significant variation and subsequent influential factors. Of 3121 identified publications spanning three databases, 56 papers were included in data extraction. Conductivity values were categorised according to tissue type, and recorded alongside methodology, measurement condition, current frequency, tissue temperature, participant pathology and age. We found variation in electrical conductivity of the whole-skull, the spongiform layer of the skull, isotropic, perpendicularly- and parallelly-oriented white matter (WM) and the brain-to-skull-conductivity ratio (BSCR) could be significantly attributed to a combination of differences in methodology and demographics. This large variation should be acknowledged, and care should be taken when creating volume conductor models, ideally constructing them on an individual basis, rather than assuming them from the literature. When personalised models are unavailable, it is suggested weighted average means from the current meta-analysis are used. Assigning conductivity as: 0.41 S/m for the scalp, 0.02 S/m for the whole skull, or when better modelled as a three-layer skull 0.048 S/m for the spongiform layer, 0.007 S/m for the inner compact and 0.005 S/m for the outer compact, as well as 1.71 S/m for the CSF, 0.47 S/m for the grey matter, 0.22 S/m for WM and 50.4 for the BSCR.

scholarly journals Proprotein Convertase Subtilisin/Kexin Type 9 Gene Variants in Familial Hypercholesterolemia: A Systematic Review and Meta-Analysis

Processes ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 283
Author(s):  
Nang Hoang Pham ◽  
Phuong Kim Truong ◽  
Thuan Duc Lao ◽  
Thuy Ai Huyen Le
Keyword(s):  
Familial Hypercholesterolemia ◽  
Hot Spot ◽  
Meta Analysis ◽  
Critical Role ◽  
Random Effect ◽  
Random Effect Model ◽  
Weighted Average ◽  
Atherosclerotic Cardiovascular Disease ◽  
Proprotein Convertase ◽  
Ldl Receptors

Proprotein Convertase Subtilisin Kexin type 9 (PCSK9), comprises 12 exons, encoded for an enzyme which plays a critical role in the regulation of circulating low density lipoprotein. The gain-of-function (GOF) mutations aggravate the degradation of LDL receptors, resulting in familial hypercholesterolemia (FH), while loss-of-function (LOF) mutations lead to higher levels of the LDL receptors, lower the levels of LDL cholesterol, and preventing from cardiovascular diseases. It is noted that, previous publications related to the mutations of PCSK9 were not always unification. Therefore, this study aims to present the spectrum and distribution of PCSK9 gene mutations by a meta-analysis. A systematic literature analysis was conducted based on previous studies published by using different keywords. The weighted average frequency of PCSK9 mutation was calculated and accessed by MedCalc®. A total of 32 cohort studies, that included 19,725 familial hypercholesterolemia blood samples, were enrolled in the current study. The analysis results indicated that, based on the random-effect model, the weighted prevalence of PCSK9 mutation was 5.67% (95%CI = 3.68–8.05, p < 0.0001). The prevalence of PCSK9 GOF mutations was 3.57% (95%CI = 1.76–5.97, p < 0.0001) and PCSK9 LOF mutations was 6.05% (95%CI = 3.35–9.47, p < 0.0001). Additionally, the first and the second exon were identified as the hot spot of mutation occurred in PCSK9. Both GOF and LOF mutations have a higher proportion in Asia and Africa compared with other regions. The GOF PCSK9 p.(Glu32Lys) and LOF PCSK9 p.(Leu21dup/tri) were dominant in the Asia region with the proportion as 6.58% (95%CI = 5.77–7.47, p = 0.62) and 16.20% (95%CI = 6.91–28.44, p = 0.0022), respectively. This systematic analysis provided scientific evidence to suggest the mutation of PCSK9 was related to the metabolism of lipoprotein and atherosclerotic cardiovascular disease.

Influential Factors for Older Users’ Acceptance of eHealth Services: an Integrated Acceptance Framework (IAF) (Preprint)

2021 ◽  
Author(s):  
Jiyeon Yu ◽  
Angelica de Antonio ◽  
Elena Villalba-Mora
Keyword(s):  
Systematic Review ◽  
Older Adults ◽  
New Technologies ◽  
Meta Analysis ◽  
Health Condition ◽  
Influential Factors ◽  
Current Status ◽  
Five Dimensions ◽  
The Impact ◽  
Acceptance Factors

BACKGROUND eHealth and Telehealth play a crucial role in assisting older adults who visit hospitals frequently or who live in nursing homes and can benefit from staying at home while being cared for. Adapting to new technologies can be difficult for older people. Thus, to better apply these technologies to older adults’ lives, many studies have analyzed acceptance factors for this particular population. However, there is not yet a consensual framework to be used in further development and the search for solutions. OBJECTIVE This paper presents an Integrated Acceptance Framework (IAF) for the older user’s acceptance of eHealth, based on 43 studies selected through a systematic review. METHODS We conducted a four-step study. First, through a systematic review from 2010 to 2020 in the field of eHealth, the acceptance factors and basic data for analysis were extracted. Second, we carried out a thematic analysis to group the factors into themes to propose and integrated framework for acceptance. Third, we defined a metric to evaluate the impact of the factors addressed in the studies. Last, the differences amongst the important IAF factors were analyzed, according to the participants’ health conditions, verification time, and year. RESULTS Through the systematic review, 731 studies were founded in 5 major databases, resulting in 43 selected studies using the PRISMA methodology. First, the research methods and the acceptance factors for eHealth were compared and analyzed, extracting a total of 105 acceptance factors, which were grouped later, resulting in the Integrated Acceptance Framework. Five dimensions (i.e., personal, user-technology relational, technological, service-related, environmental) emerged with a total of 23 factors. Also, we assessed the quality of the evidence. And then, we conducted a stratification analysis to reveal the more appropriate factors depending on the health condition and the assessment time. Finally, we assess which are the factors and dimensions that are recently becoming more important. CONCLUSIONS The result of this investigation is a framework for conducting research on eHealth acceptance. To elaborately analyze the impact of the factors of the proposed framework, the criteria for evaluating the evidence from the studies that have extracted factors are presented. Through this process, the impact of each factor in the IAF has been presented, in addition to the framework proposal. Moreover, a meta-analysis of the current status of research is presented, highlighting the areas where specific measures are needed to facilitate e-Health acceptance.

scholarly journals Lifetime prevalence of non-suicidal self-injury in patients with eating disorders: a systematic review and meta-analysis

2016 ◽  
Vol 46 (7) ◽  
pp. 1345-1358 ◽  
Author(s):  
A. Cucchi ◽  
D. Ryan ◽  
G. Konstantakopoulos ◽  
S. Stroumpa ◽  
A. Ş. Kaçar ◽  
...  
Keyword(s):  
Substance Abuse ◽  
Eating Disorders ◽  
Suicide Attempts ◽  
Meta Analysis ◽  
Weighted Average ◽  
Average Percentage ◽  
Lifetime History ◽  
Self Injury ◽  
History Of ◽  
Meta Analyses

BackgroundAgainst a backdrop of increasing research, clinical and taxonomic attention in non-suicidal self-injury (NSSI), evidence suggests a link between NSSI and eating disorders (ED). The frequency estimates of NSSI in ED vary widely. Little is known about the sources of this variation, and no meta-analysis has quantified the association between ED and NSSI.MethodUsing random-effects meta-analyses, meta-regression analyses, and 1816–6466 unique participants with various ED, we estimated the weighted average percentage of individuals with ED, those with anorexia nervosa (AN) and those with bulimia nervosa (BN) who are reported to have a lifetime history of NSSI across studies. We further examined predictors of NSSI in ED.ResultsThe weighted average percentage of patients with a lifetime history of NSSI was 27.3% [95% confidence interval (CI) 23.8–31.0%] for ED, 21.8% (95% CI 18.5–25.6%) for AN, and 32.7% (95% CI 26.9–39.1%) for BN. The difference between BN and AN was statistically significant [odds ratio (OR) 1.77, 95% CI 1.14–2.77, p = 0.013]. The odds of NSSI increased by 24% for every 10% increase in the percentage of participants with histories of suicide attempts (OR 1.24, 95% CI 1.04–1.48, p = 0.020) and decreased by 26% for every 10% increase in the percentage of participants with histories of substance abuse (OR 0.74, 95% CI 0.58–0.95, p = 0.023).ConclusionsIn the specific context of ED, NSSI is highly prevalent and correlates positively with attempted suicide, urging for NSSI-focused treatments. A novel finding is that NSSI is potentially antagonized by substance abuse.

Abstract WP65: Low-Versus Standard-Dose Alteplase for AcuteIschemic Strokes Within 4.5 Hours: An updated Meta Analysis

Stroke ◽  
2017 ◽  
Vol 48 (suppl_1) ◽  
Author(s):  
Huaguang Zheng ◽  
Xu Tong ◽  
Liping Liu ◽  
Zixiao Li ◽  
Xiaoling Liao ◽  
...  
Keyword(s):  
Cohort Studies ◽  
Random Effects ◽  
Standard Dose ◽  
Controlled Trial ◽  
Meta Analysis ◽  
Tissue Type ◽  
Random Effects Models ◽  
Dose Treatment ◽  
Randomized Controlled ◽  
Type Plasminogen Activator

Background and Purpose: We performed a meta-analysis to compare the outcomes between lower dose and standard dose intravenous tissue-type plasminogen activator (tPA) for acute ischemic stroke in randomized and non- randomized controlled trials. Methods: We searched PubMed for relevant studies and calculated pooled odds ratios (ORs) using random effects models.The primary endpoint was good functional outcome[modified Rankin Scale (mRS) of 0-1] at 3 month after stroke onset. Other major end points were all-cause mortality and symptomatic intracerebral haemorrhage (sICH). Results: From 2010 to 2016, 7 Cohort studies and 1 randomized controlled trial (ENCHANTED trial) were pooled in meta-analysis. The lower tPA strategy was likely to be less effective than the standard dose treatment (OR=0.87; 95% confidence interval [CI], 0.73-1.04, P=0.136; I 2 =47.9%, P=0.044 in random effects models and OR=0.88; 95% CI 0.88-0.98,P=0.016 ;I 2 =0.0%, P=0.693 in non- random effects models after 2 cohort studies were excluded due to heterogeneity). No difference was found for mortality at 90 days (OR=0.87; 95% CI 0.74-1.03, P=0.102 ;I 2 =0.0%, P=0.635 in non-random effects models)and sICH (OR=1.12; 95% CI 0.68-1.83,P=0.659; I 2 =57.6%, P=0.016 in random effects models and OR=1.23; 95% CI 0.92-1.65, P=0.168; I 2 =0.0%, P=0.547 in non-random effects models after 2 cohort studies were excluded due to heterogeneity ) between lower tPA group and standard dose . Conclusions: The low-dose alteplase strategy was less effective comparable to the standard-dose treatment .The safety was similar between the two strategies.

scholarly journals The value of the post-captopril aldosterone/renin ratio for the diagnosis of primary aldosteronism and the influential factors: A meta-analysis

2020 ◽  
Vol 21 (4) ◽  
pp. 147032032097203
Author(s):  
Qiao Xiang ◽  
Wen Wang ◽  
Tao Chen ◽  
Kai Yu ◽  
Qianrui Li ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Primary Aldosteronism ◽  
Meta Analysis ◽  
Challenge Test ◽  
Influential Factors ◽  
Time Interval ◽  
Study Region ◽  
Subgroup Analyses ◽  
Study Population ◽  
Meta Regression

Objective: The procedure for the captopril challenge test (CCT) in diagnosing primary aldosteronism (PA) is not standardized. We performed a meta-analysis to evaluate the controversial diagnostic value and influential factors of the post-captopril aldosterone/renin ratio (ARR). Methods: We searched literature in databases for eligible studies (until October 1, 2020). We extracted information regarding study and patient characteristics, CCT methods, outcome data. We pooled studies using the random-effect model. We performed meta-regression and six pre-specified subgroup analyses to explore heterogeneity. Results: Nineteen studies involving 4568 subjects were included. The pooled sensitivity and specificity were 0.825 (95% CI 0.804–0.844) and 0.919 (95% CI 0.908–0.928). The area under the summary receiver operating characteristic curve was 0.9487 (95% CI 0.9207–0.9767). Meta-regression revealed that heterogeneity might derive from time interval ( p = 0.0117) and study population ( p = 0.0033). Subgroup analyses showed significant differences between the subgroups stratified by the dose, posture, study region, time interval, cut-off value and study population for sensitivity and/or specificity ( p < 0.05). Conclusion: Post-captopril ARR is comparably valuable for diagnosing PA at cut-offs from 12.0 to 50.0. Conducting the CCT in the supine position with 25 mg of captopril may attain greater sensitivity. Conducting the CCT in the seated position with 50 mg of captopril may attain greater specificity. A 90-min time interval may perform best in both the sensitivity and specificity.

scholarly journals Thrombolysis Outcomes in Patients with Diabetes and Previous Stroke: A Meta-Analysis

2020 ◽  
Vol 47 (4) ◽  
pp. 486-493
Author(s):  
Azalea T. Pajo ◽  
Jose Danilo B. Diestro ◽  
Adrian I. Espiritu ◽  
Adam A. Dmytriw ◽  
Alejandro Enriquez-Marulanda ◽  
...  
Keyword(s):  
Ischemic Stroke ◽  
Acute Ischemic Stroke ◽  
Meta Analysis ◽  
Functional Independence ◽  
Tissue Type ◽  
Diabetic Patients ◽  
Eligibility Criteria ◽  
Symptomatic Intracerebral Hemorrhage ◽  
Patients With Diabetes ◽  
Newcastle Ottawa Scale

ABSTRACT:Background:Intravenous tissue-type plasminogen activator (IVtPA) is a proven treatment for acute ischemic stroke; however, diabetes mellitus (DM) and previous cerebral infarction (PCI) were considered relative contraindications for thrombolysis within the 3–4.5 h period.Objective:The study aimed to determine the safety and efficacy of IVtPA among diabetic patients with PCI presenting with acute ischemic stroke.Methods:Studies which evaluated the outcome of IVtPA in terms of symptomatic intracerebral hemorrhage (sICH), functional outcome in modified Rankin scale, and death among diabetic patients with PCI presenting with acute ischemic stroke within the 3–4.5 h period were systematically searched until July 2019. Screening and eligibility criteria were applied. Risk of bias was evaluated using the Newcastle–Ottawa Scale. Odds ratios (ORs) with 95% confidence interval (CI) were used to compare measures of treatment effect. Mantel–Haenszel method and random-effects model were also employed.Results:Four registry-based studies with a total of 44,572 patients were included for quantitative synthesis. Giving IVtPA among DM+/PCI+ patients did not result in significantly increased rate of sICH (OR, 1.09; 95% CI, 0.88, 1.36) compared to No DM+/PCI+ patients. However, there was significantly higher mortality (OR, 1.81; 95% CI, 1.60, 2.06) in the DM+/PCI+ group. Conversely, among those who survived, the DM+/PCI+ patients were more functionally independent at 3 months (OR, 0.76; 95% CI, 0.61, 0.94).Conclusion:Limited evidence suggests that thrombolysis in DM+/PCI+ patients does not result in significantly higher incidence of sICH and may improve functional independence. However, the significantly higher mortality in this group warrants an assessment of the individualized risk–benefit ratio in the use of IVtPA.

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