scholarly journals Individual level reliability of PAS-induced neural plasticity

2017 ◽  
Author(s):  
Yeun Kim ◽  
Jacqueline P. Ngo ◽  
Choi Deblieck ◽  
Dylan J. Edwards ◽  
Bruce Dobkin ◽  
...  
Keyword(s):  
Individual Differences ◽  
Neural Plasticity ◽  
Motor Evoked Potentials ◽  
Recovery Of Function ◽  
Group Analysis ◽  
Base Line ◽  
List Type ◽  
Paired Associative Stimulation ◽  
Individual Level ◽  
Minimum Number

AbstractObjectiveWe assessed the individual level reliability of neural plasticity changes induced by paired associative stimulation (PAS), which combines peripheral nerve stimulation with transcranial magnetic stimulation to induce short-term plastic changes in the brain.MethodsFor 5 consecutive weeks, motor evoked potentials (MEPs) of 8 healthy subjects were acquired every 10 minutes post-PAS intervention for a period of 60 minutes. The post-PAS MEPs were evaluated against base-line MEPs using permutation and Kolmogorov-Smirnov tests to determine whether the MEP magnitudes changed after PAS. Moreover, various sample sizes of the MEP data were used to deduce the minimum number of MEPs needed to reliably detect individual propensity to neural plasticity.ResultsGroup analysis exhibited significant increase in post-PAS MEPs, confirming previous results. While high between-sessions variability was observed at individual level, data show that between 40 to 50 MEPs can reliably assess each subject’s responsiveness to PAS. Subjects exhibited three different plasticity patterns: in the modulated hemisphere only, both hemispheres, or neither hemisphere.ConclusionsPAS can reliably assess individual differences in neural plasticity.SignificanceA marker of individual plasticity may be useful to predict the effects of a motor rehabilitation, drug or other intervention to increase recovery of function after brain injury.HighlightsPaired associative stimulation (PAS) assesses neural plasticity non invasively.The study shows how PAS can reliably determine individual differences in plasticity.PAS may be used to predict intervention outcome or individualize treatment dose.

scholarly journals Multi-level modeling and multiple group analysis of disparities in continuity of care and viral suppression among Nigerian adolescents and youths living with HIV

2020 ◽  
Author(s):  
Okikiolu Abimbola Badejo ◽  
Christiana Noestlinger ◽  
Toyin Jolayemi ◽  
Juliet Adeola ◽  
Prosper Okonkwo ◽  
...  
Keyword(s):  
Young Adults ◽  
Viral Suppression ◽  
Group Analysis ◽  
Age Groups ◽  
Retention In Care ◽  
List Type ◽  
Healthcare Facilities ◽  
Individual Level ◽  
New Findings ◽  
Living With Hiv

AbstractIntroductionSubstantial disparities in care outcomes exist between different sub-groups of adolescents and youths living with HIV(ALHIV). Understanding variation in individual and health-facility characteristics could be key to identifying targets for interventions to reduce these disparities. We modeled variation in ALHIV retention in care and viral suppression, and quantified the extent to which individual and facility characteristics account for observed variations.MethodsWe included 1,177 young adolescents (10-14 years), 3,206 older adolescents (15-19 years) and 9,151 young adults (20-24 years) who were initiated on antiretroviral therapy (ART) between January 2015 and December 2017 across 124 healthcare facilities in Nigeria. For each age-group, we used multilevel modeling to partition observed variation of main outcomes(retention in care and viral suppression at 12 months post ART initiation) by individual (level one) and health facility (level two) characteristics. We used multiple group analysis to compare the effects of individual and facility characteristics across age-groups.ResultsFacility characteristics explained most of the observed variance in retention in care in all the age-groups, with smaller contributions from individual-level characteristics (14-22.22% vs 0 - 3.84%). For viral suppression, facility characteristics accounted for a higher proportion of variance in young adolescents (15.79%), but not in older adolescents (0%) and young adults(3.45%). Males were more likely to not be retained in care(aOR=1.28; p<0.001 young adults) and less likely to achieve viral suppression (aOR=0.69; p<0.05 older adolescent). Increasing facility-level viral load testing reduced the likelihood of non-retention in care, while baseline regimen TDF/3TC/EFV or NVP increased the likelihood of viral suppression.ConclusionsDifferences in characteristics of healthcare facilities accounted for observed disparities in retention in care and, to a lesser extent, disparities in viral suppression. An optimal combination of individual and health-services approaches is, therefore, necessary to reduce disparities in the health and wellbeing of ALHIV.Key MessagesWhat is already known?Adolescents and youths living with HIV have worse care and treatment outcomes compared to other groupsSignificant disparity in care and treatment outcomes exist between different adolescent and youth subgroupsWhat are the new findings?Differences in characteristics of healthcare facilities delivering services are associated with disparities in outcomes within and across adolescent and youth age-groups.What do the new findings imply?An optimal combination of individual and health-services approaches is necessary to reduce disparities in the health and wellbeing of adolescent and youths living with HIV.

scholarly journals Individual differences in functional connectivity during naturalistic viewing conditions

2016 ◽  
Author(s):  
Tamara Vanderwal ◽  
Jeffrey Eilbott ◽  
Emily S. Finn ◽  
R. Cameron Craddock ◽  
Adam Turnbull ◽  
...  
Keyword(s):  
Individual Differences ◽  
Functional Connectivity ◽  
Identification Algorithm ◽  
List Type ◽  
Dynamic Stimuli ◽  
Individual Level ◽  
Eyes Open ◽  
The Individual ◽  
The Impact ◽  
Work First

AbstractNaturalistic viewing paradigms such as movies have been shown to reduce participant head motion and improve arousal during fMRI scanning relative to task-free rest, and have been used to study both functional connectivity and task-evoked BOLD-signal changes. These task-evoked changes result in cortical activity that is synchronized across subjects and involves large areas of the cortex, and it is unclear whether individual differences in functional connectivity are enhanced or diminished under such naturalistic conditions. This work first aims to characterize variability in functional connectivity (FC) across two distinct movie conditions and eyes-open rest (n=34 healthy adults, 2 scan sessions each). At the whole-brain level, we found that movies have higher intra- and inter-subject correlations in cluster-wise FC relative to rest. The anatomical distribution of inter-subject variability was similar across conditions, with higher variability occurring at the lateral prefrontal lobes and temporoparietal junctions. Second, we used an unsupervised test-retest matching (or “finger-printin”) algorithm that identifies individual subjects from within a group based on functional connectivity patterns, quantifying the accuracy of the algorithm across the three conditions. We also evaluated the impact of parcellation resolution, scan duration, and number of edges on observed inter-individual differences. The movies and resting state all enabled identification of individual subjects based on FC matrices, with accuracies between 62 and 100%. Overall, pairings involving movies outperformed rest, and the more social and faster-paced movie attained 100% accuracy. When the parcellation resolution, scan duration and number of edges used were increased, accuracies improved across conditions, and the pattern of movies>rest was preserved. These results suggest that using dynamic stimuli such as movies enhances the detection of FC patterns that are distinct at the individual level.HighlightsIntra- and inter-subject FC correlations are compared across rest and movies.Movies outperformed rest in an unsupervised identification algorithm based on FC.Movies outperform rest regardless of parcellation, scan length, or number of edges.Watching movies enhances the detection of individual differences in FC.

scholarly journals Multilevel modelling and multiple group analysis of disparities in continuity of care and viral suppression among adolescents and youths living with HIV in Nigeria

2020 ◽  
Vol 5 (11) ◽  
pp. e003269
Author(s):  
Okikiolu Badejo ◽  
Christiana Noestlinger ◽  
Toyin Jolayemi ◽  
Juliette Adeola ◽  
Prosper Okonkwo ◽  
...  
Keyword(s):  
Young Adults ◽  
Viral Suppression ◽  
Group Analysis ◽  
Age Groups ◽  
Multilevel Modelling ◽  
Retention In Care ◽  
Healthcare Facilities ◽  
Individual Level ◽  
Multiple Group ◽  
Facility Level

IntroductionSubstantial disparities in care outcomes exist between different subgroups of adolescents and youths living with HIV (AYLHIV). Understanding variation in individual and health facility characteristics could be key to identifying targets for interventions to reduce these disparities. We modelled variation in AYLHIV retention in care and viral suppression, and quantified the extent to which individual and facility characteristics account for observed variations.MethodsWe included 1170 young adolescents (10–14 years), 3206 older adolescents (15–19 years) and 9151 young adults (20–24 years) who were initiated on antiretroviral therapy (ART) between January 2015 and December 2017 across 124 healthcare facilities in Nigeria. For each age group, we used multilevel modelling to partition observed variation of main outcomes (retention in care and viral suppression at 12 months after ART initiation) by individual (level one) and health facility (level two) characteristics. We used multiple group analysis to compare the effects of individual and facility characteristics across age groups.ResultsFacility characteristics explained most of the observed variance in retention in care in all the age groups, with smaller contributions from individual-level characteristics (14%–22.22% vs 0%–3.84%). For viral suppression, facility characteristics accounted for a higher proportion of variance in young adolescents (15.79%), but not in older adolescents (0%) and young adults (3.45%). Males were more likely to not be retained in care (adjusted OR (aOR)=1.28; p<0.001 young adults) and less likely to achieve viral suppression (aOR=0.69; p<0.05 older adolescent). Increasing facility-level viral load testing reduced the likelihood of non-retention in care, while baseline regimen TDF/3TC/EFV or NVP increased the likelihood of viral suppression.ConclusionsDifferences in characteristics of healthcare facilities accounted for observed disparities in retention in care and, to a lesser extent, disparities in viral suppression. An optimal combination of individual and health services approaches is, therefore, necessary to reduce disparities in the health and well-being of AYLHIV.

scholarly journals Induction of Neural Plasticity Using a Low-Cost Open Source Brain-Computer Interface and a 3D-Printed Wrist Exoskeleton

Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 572
Author(s):  
Mads Jochumsen ◽  
Taha Al Muhammadee Janjua ◽  
Juan Carlos Arceo ◽  
Jimmy Lauber ◽  
Emilie Simoneau Buessinger ◽  
...  
Keyword(s):  
Open Source ◽  
Neural Plasticity ◽  
Motor Evoked Potentials ◽  
Low Cost ◽  
True Positive Rate ◽  
Positive Rate ◽  
3D Printed ◽  
Major Factors ◽  
And Control ◽  
Bci System

Brain-computer interfaces (BCIs) have been proven to be useful for stroke rehabilitation, but there are a number of factors that impede the use of this technology in rehabilitation clinics and in home-use, the major factors including the usability and costs of the BCI system. The aims of this study were to develop a cheap 3D-printed wrist exoskeleton that can be controlled by a cheap open source BCI (OpenViBE), and to determine if training with such a setup could induce neural plasticity. Eleven healthy volunteers imagined wrist extensions, which were detected from single-trial electroencephalography (EEG), and in response to this, the wrist exoskeleton replicated the intended movement. Motor-evoked potentials (MEPs) elicited using transcranial magnetic stimulation were measured before, immediately after, and 30 min after BCI training with the exoskeleton. The BCI system had a true positive rate of 86 ± 12% with 1.20 ± 0.57 false detections per minute. Compared to the measurement before the BCI training, the MEPs increased by 35 ± 60% immediately after and 67 ± 60% 30 min after the BCI training. There was no association between the BCI performance and the induction of plasticity. In conclusion, it is possible to detect imaginary movements using an open-source BCI setup and control a cheap 3D-printed exoskeleton that when combined with the BCI can induce neural plasticity. These findings may promote the availability of BCI technology for rehabilitation clinics and home-use. However, the usability must be improved, and further tests are needed with stroke patients.

Individual Differences in Intrinsic Brain Networks Predict Symptom Severity in Autism Spectrum Disorders

2020 ◽  
Vol 31 (1) ◽  
pp. 681-693 ◽  
Author(s):  
Emmanuel Peng Kiat Pua ◽  
Phoebe Thomson ◽  
Joseph Yuan-Mou Yang ◽  
Jeffrey M Craig ◽  
Gareth Ball ◽  
...  
Keyword(s):  
Autism Spectrum Disorders ◽  
Individual Differences ◽  
Face Perception ◽  
Symptom Severity ◽  
Brain Networks ◽  
Monozygotic Twins ◽  
Autism Spectrum ◽  
Social Impairment ◽  
Individual Level ◽  
Spectrum Disorders

Abstract The neurobiology of heterogeneous neurodevelopmental disorders such as Autism Spectrum Disorders (ASD) is still unknown. We hypothesized that differences in subject-level properties of intrinsic brain networks were important features that could predict individual variation in ASD symptom severity. We matched cases and controls from a large multicohort ASD dataset (ABIDE-II) on age, sex, IQ, and image acquisition site. Subjects were matched at the individual level (rather than at group level) to improve homogeneity within matched case–control pairs (ASD: n = 100, mean age = 11.43 years, IQ = 110.58; controls: n = 100, mean age = 11.43 years, IQ = 110.70). Using task-free functional magnetic resonance imaging, we extracted intrinsic functional brain networks using projective non-negative matrix factorization. Intrapair differences in strength in subnetworks related to the salience network (SN) and the occipital-temporal face perception network were robustly associated with individual differences in social impairment severity (T = 2.206, P = 0.0301). Findings were further replicated and validated in an independent validation cohort of monozygotic twins (n = 12; 3 pairs concordant and 3 pairs discordant for ASD). Individual differences in the SN and face-perception network are centrally implicated in the neural mechanisms of social deficits related to ASD.

scholarly journals On the Number of Tetrahedra with Minimum, Unit, and Distinct Volumes in Three-Space

2008 ◽  
Vol 17 (2) ◽  
pp. 203-224 ◽  
Author(s):  
ADRIAN DUMITRESCU ◽  
CSABA D. TÓTH
Keyword(s):  
Unit Volume ◽  
Time Algorithm ◽  
Combinatorial Problems ◽  
List Type ◽  
Type Number ◽  
Point Sets ◽  
Minimum Number ◽  
Three Space

We formulate and give partial answers to several combinatorial problems on volumes of simplices determined bynpoints in 3-space, and in general inddimensions.(i)The number of tetrahedra of minimum (non-zero) volume spanned bynpoints in$\mathbb{R}$3is at most$\frac{2}{3}n^3-O(n^2)$, and there are point sets for which this number is$\frac{3}{16}n^3-O(n^2)$. We also present anO(n3) time algorithm for reporting all tetrahedra of minimum non-zero volume, and thereby extend an algorithm of Edelsbrunner, O'Rourke and Seidel. In general, for every$k,d\in \mathbb{N}, 1\leq k \leq d$, the maximum number ofk-dimensional simplices of minimum (non-zero) volume spanned bynpoints in$\mathbb{R}$dis Θ(nk).(ii)The number of unit volume tetrahedra determined bynpoints in$\mathbb{R}$3isO(n7/2), and there are point sets for which this number is Ω(n3log logn).(iii)For every$d\in \mathbb{N}$, the minimum number of distinct volumes of all full-dimensional simplices determined bynpoints in$\mathbb{R}$d, not all on a hyperplane, is Θ(n).

scholarly journals Investigating the Intervention Parameters of Endogenous Paired Associative Stimulation (ePAS)

2021 ◽  
Vol 11 (2) ◽  
pp. 224
Author(s):  
Gemma Alder ◽  
Nada Signal ◽  
Alain C. Vandal ◽  
Sharon Olsen ◽  
Mads Jochumsen ◽  
...  
Keyword(s):  
Neural Plasticity ◽  
Repeated Measures ◽  
Single Pulse ◽  
Stroke Recovery ◽  
Motor Threshold ◽  
Additive Interaction ◽  
Post Intervention ◽  
Paired Associative Stimulation ◽  
Intervention Efficacy ◽  
Movement Type

Advances in our understanding of neural plasticity have prompted the emergence of neuromodulatory interventions, which modulate corticomotor excitability (CME) and hold potential for accelerating stroke recovery. Endogenous paired associative stimulation (ePAS) involves the repeated pairing of a single pulse of peripheral electrical stimulation (PES) with endogenous movement-related cortical potentials (MRCPs), which are derived from electroencephalography. However, little is known about the optimal parameters for its delivery. A factorial design with repeated measures delivered four different versions of ePAS, in which PES intensities and movement type were manipulated. Linear mixed models were employed to assess interaction effects between PES intensity (suprathreshold (Hi) and motor threshold (Lo)) and movement type (Voluntary and Imagined) on CME. ePAS interventions significantly increased CME compared to control interventions, except in the case of Lo-Voluntary ePAS. There was an overall main effect for the Hi-Voluntary ePAS intervention immediately post-intervention (p = 0.002), with a sub-additive interaction effect at 30 min’ post-intervention (p = 0.042). Hi-Imagined and Lo-Imagined ePAS significantly increased CME for 30 min post-intervention (p = 0.038 and p = 0.043 respectively). The effects of the two PES intensities were not significantly different. CME was significantly greater after performing imagined movements, compared to voluntary movements, with motor threshold PES (Lo) 15 min post-intervention (p = 0.012). This study supports previous research investigating Lo-Imagined ePAS and extends those findings by illustrating that ePAS interventions that deliver suprathreshold intensities during voluntary or imagined movements (Hi-Voluntary and Hi-Imagined) also increase CME. Importantly, our findings indicate that stimulation intensity and movement type interact in ePAS interventions. Factorial designs are an efficient way to explore the effects of manipulating the parameters of neuromodulatory interventions. Further research is required to ensure that these parameters are appropriately refined to maximise intervention efficacy for people with stroke and to support translation into clinical practice.

DIAGNOSTIC VALUE OF THE LH-RELEASING HORMONE STIMULATION TEST IN FUNCTIONAL AMENORRHEA

1975 ◽  
Vol 78 (4) ◽  
pp. 625-633 ◽  
Author(s):  
D. Vandekerckhove ◽  
M. Dhont ◽  
J. Van Eyck
Keyword(s):  
Anorexia Nervosa ◽  
Diagnostic Value ◽  
Base Line ◽  
List Type ◽  
Releasing Hormone ◽  
The Absolute ◽  
Lh Rh ◽  
Lh Releasing Hormone ◽  
Circulating Levels ◽  
Secretory Capacity

ABSTRACT LH-releasing hormone (25 μg, iv.) was administered to 37 women with functional amenorrhea. In addition to the clinical classification, these patients were divided into three groups according to the basal level of serum LH. A significant correlation was found between the base-line levels of LH and the serum concentration of oestradiol plus oestrone. The absolute increment of LH after the injection of LH-RH was found to be dependent only on the base-line level of LH. Except for the patients with anorexia nervosa, the base-line levels and the response pattern of FSH were almost the same for all three groups. From the results of this study, it was concluded that: The circulating levels of oestradiol and oestrone, where derived from ovarian secretion, actually depend on the gonadotrophic stimulus. In patients with functional amenorrhea, the oestrogens do not make an independent contribution to the pituitary response to LH-RH. Dysregulation of releasing hormones, whether located at the hypothalamic or suprahypothalamic level, necessarily influences the secretory capacity of the pituitary gland; long-standing deficiency of LH-RH may finally lead to a state of pituitary "functional" unresponsiveness to releasing hormones. In view of the excellent correlation between the base-line levels of LH and the absolute increment of LH following stimulation with LH-RH, this test only accentuates the existing pituitary secretory capacity, which can be roughly estimated from the circulating levels of LH and FSH. This test may be useful in distinguishing the milder cases of psychogenic amenorrhea from extreme gonadotrophic dysfunction in patients with anorexia nervosa.

Systematic Review of Preventing Suicide in Old Age: 2005–2010

2011 ◽  
Vol 26 (S2) ◽  
pp. 2020-2020
Author(s):  
C.A. de Mendonça Lima ◽  
R.M. Rodrigues
Keyword(s):  
Health Care ◽  
Old Age ◽  
Health Care Providers ◽  
The Elderly ◽  
Educational Interventions ◽  
List Type ◽  
Care Providers ◽  
Individual Level ◽  
Survivors Of Suicide ◽  
Somatic Disorders

Suicide is a typical phenomenon of the elderly and mainly among men. Besides the importance of suicide in terms of public health there is fewer interest to prevent suicide in old age. This can be explained by stigma, poor evaluation of the dimension of the problem and lack of politic will.Suicide prevention and the care of survivors of suicide depend on the mental health network of care. Interventions to reduce suicide can be made at individual level and at level of the development of policies and strategies. The detection of the persons at risk of suicide and the management of the suicide attempt are two main strategies to prevent suicide. Both received recently an important support from WHO with its publication mhGAP Intervention Guide which was conceived to be used in non-specialized health-care settings by health-care providers working at first- and second-level facilities. It includes guidance on evidence-based interventions to make the diagnosis and manage a number of priority conditions, including suicide.Our review of the literature pointed to the necessity to develop additional research to determine:•the role of somatic disorders as precipitant factor;•the role on suicide of the pre-morbid personality, cognitive functioning, social support and recent and chronic stressing events;•the participation of normal and pathological ageing on the expression of the suicide behavior;•the biological markers of suicide in old age;•the potential impact on suicide rates of educational interventions for the general public and for caregivers.

scholarly journals Right Ventrolateral Prefrontal Cortex Mediates Individual Differences in Conflict-driven Cognitive Control

2011 ◽  
Vol 23 (12) ◽  
pp. 3903-3913 ◽  
Author(s):  
Tobias Egner
Keyword(s):  
Conflict Resolution ◽  
Individual Differences ◽  
Cognitive Control ◽  
Inferior Frontal Gyrus ◽  
Group Analysis ◽  
Individual Variability ◽  
Primary Role ◽  
Conflict Adaptation ◽  
Traditional Group ◽  
Behavioral Expression

Conflict adaptation—a conflict-triggered improvement in the resolution of conflicting stimulus or response representations—has become a widely used probe of cognitive control processes in both healthy and clinical populations. Previous fMRI studies have localized activation foci associated with conflict resolution to dorsolateral PFC (dlPFC). The traditional group analysis approach employed in these studies highlights regions that are, on average, activated during conflict resolution, but does not necessarily reveal areas mediating individual differences in conflict resolution, because between-subject variance is treated as noise. Here, we employed a complementary approach to elucidate the neural bases of variability in the proficiency of conflict-driven cognitive control. We analyzed two independent fMRI data sets of face–word Stroop tasks by using individual variability in the behavioral expression of conflict adaptation as the metric against which brain activation was regressed while controlling for individual differences in mean RT and Stroop interference. Across the two experiments, a replicable neural substrate of individual variation in conflict adaptation was found in ventrolateral PFC (vlPFC), specifically, in the right inferior frontal gyrus, pars orbitalis (BA 47). Unbiased regression estimates showed that variability in activity in this region accounted for ∼40% of the variance in behavioral expression of conflict adaptation across subjects, thus documenting a heretofore unsuspected key role for vlPFC in mediating conflict-driven adjustments in cognitive control. We speculate that vlPFC plays a primary role in conflict control that is supplemented by dlPFC recruitment under conditions of suboptimal performance.

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