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1.
J Neurosci ; 42(29): 5681-5694, 2022 07 20.
Article in English | MEDLINE | ID: mdl-35705486

ABSTRACT

Adolescence is characterized by the maturation of cortical microstructure and connectivity supporting complex cognition and behavior. Axonal myelination influences brain connectivity during development by enhancing neural signaling speed and inhibiting plasticity. However, the maturational timing of cortical myelination during human adolescence remains poorly understood. Here, we take advantage of recent advances in high-resolution cortical T1w/T2w mapping methods, including principled correction of B1+ transmit field effects, using data from the Human Connectome Project in Development (HCP-D; N = 628, ages 8-21). We characterize microstructural changes relevant to myelination by estimating age-related differences in T1w/T2w throughout the cerebral neocortex from childhood to early adulthood. We apply Bayesian spline models and clustering analysis to demonstrate graded variation in age-dependent cortical T1w/T2w differences that are correlated with the sensorimotor-association (S-A) axis of cortical organization reported by others. In sensorimotor areas, T1w/T2w ratio measures start at high levels at early ages, increase at a fast pace, and decelerate at later ages (18-21). In intermediate multimodal areas along the S-A axis, T1w/T2w starts at intermediate levels and increases linearly at an intermediate pace. In transmodal/paralimbic association areas, T1w/T2w starts at low levels and increases linearly at the slowest pace. These data provide evidence for graded variation of the T1w/T2w ratio along the S-A axis that may reflect cortical myelination changes during adolescence underlying the development of complex information processing and psychological functioning. We discuss the implications of these results as well as caveats in interpreting magnetic resonance imaging (MRI)-based estimates of myelination.SIGNIFICANCE STATEMENT Myelin is a lipid membrane that is essential to healthy brain function. Myelin wraps axons to increase neural signaling speed, enabling complex neuronal functioning underlying learning and cognition. Here, we characterize the developmental timing of myelination across the cerebral cortex during adolescence using a noninvasive proxy measure, T1w/T2w mapping. Our results provide new evidence demonstrating graded variation across the cortex in the timing of T1w/T2w changes during adolescence, with rapid T1w/T2w increases in lower-order sensory areas and gradual T1w/T2w increases in higher-order association areas. This spatial pattern of microstructural brain development closely parallels the sensorimotor-to-association axis of cortical organization and plasticity during ontogeny.


Subject(s)
Connectome , Neocortex , Adolescent , Adult , Bayes Theorem , Child , Humans , Magnetic Resonance Imaging/methods , Myelin Sheath , Young Adult
2.
Psychol Sci ; 34(1): 60-74, 2023 01.
Article in English | MEDLINE | ID: mdl-36283029

ABSTRACT

Peer relationships and social belonging are particularly important during adolescence. Using a willingness-to-work paradigm to quantify incentive motivation, we examined whether evaluative information holds unique value for adolescents. Participants (N = 102; 12-23 years old) rated peers, predicted how peers rated them, and exerted physical effort to view each peer's rating. We measured grip force, speed, and opt-out behavior to examine the motivational value of peer feedback, relative to money in a control condition, and to assess how peer desirability and participants' expectations modulated motivated effort across age. Overall, when compared with adolescents, adults were relatively less motivated for feedback than money. Whereas adults exerted less force and speed for feedback when expecting rejection, adolescents exerted greater force and speed when expecting to be more strongly liked or disliked. These findings suggest that the transition into adulthood is accompanied by a self-protective focus, whereas adolescents are motivated to consume highly informative feedback, even if negative.


Subject(s)
Motivation , Physical Exertion , Adult , Humans , Adolescent , Young Adult , Child , Feedback , Peer Group , Emotions
3.
Multivariate Behav Res ; 58(3): 526-542, 2023.
Article in English | MEDLINE | ID: mdl-35133946

ABSTRACT

In this article we focus on interpreting multidimensional scaling (MDS) configurations using facet theory. The facet theory approach is attempting to partition a representational space, facet by facet, into regions with certain simplifying constraints on the regions' boundaries (e.g., concentric circular sub-spaces). A long-standing problem has been the lack of computational methods for optimal facet-based partitioning. We propose using support vector machines (SVM) to perform this task. SVM is highly attractive for this purpose as they allow for linear as well as nonlinear classification boundaries in any dimensionality. Using various classical examples from the facet theory literature we elaborate on the combined use of MDS and SVM for facet-based partitioning. Different types of MDS are discussed, and options for SVM kernel specification, tuning, and performance evaluation are illustrated.


Subject(s)
Multidimensional Scaling Analysis , Support Vector Machine
4.
Br J Psychiatry ; 220(1): 41-43, 2022 01.
Article in English | MEDLINE | ID: mdl-35045901

ABSTRACT

Researchers, clinicians and patients are increasingly using real-time monitoring methods to understand and predict suicidal thoughts and behaviours. These methods involve frequently assessing suicidal thoughts, but it is not known whether asking about suicide repeatedly is iatrogenic. We tested two questions about this approach: (a) does repeatedly assessing suicidal thinking over short periods of time increase suicidal thinking, and (b) is more frequent assessment of suicidal thinking associated with more severe suicidal thinking? In a real-time monitoring study (n = 101 participants, n = 12 793 surveys), we found no evidence to support the notion that repeated assessment of suicidal thoughts is iatrogenic.


Subject(s)
Suicidal Ideation , Suicide , Humans , Iatrogenic Disease , Incidence , Surveys and Questionnaires
5.
Soc Psychiatry Psychiatr Epidemiol ; 57(8): 1591-1601, 2022 Aug.
Article in English | MEDLINE | ID: mdl-34424350

ABSTRACT

PURPOSE: To investigate the associations of childhood adversities (CAs) with lifetime onset and transitions across suicidal thoughts and behaviors (STB) among incoming college students. METHODS: Web-based self-report surveys administered to 20,842 incoming college students from nine countries (response rate 45.6%) assessed lifetime suicidal ideation, plans and attempts along with seven CAs: parental psychopathology, three types of abuse (emotional, physical, sexual), neglect, bully victimization, and dating violence. Logistic regression estimated individual- and population-level associations using CA operationalizations for type, number, severity, and frequency. RESULTS: Associations of CAs with lifetime ideation and the transition from ideation to plan were best explained by the exact number of CA types (OR range 1.32-52.30 for exactly two to seven CAs). Associations of CAs with a transition to attempts were best explained by the frequency of specific CA types (scaled 0-4). Attempts among ideators with a plan were significantly associated with all seven CAs (OR range 1.16-1.59) and associations remained significant in adjusted analyses with the frequency of sexual abuse (OR = 1.42), dating violence (OR = 1.29), physical abuse (OR = 1.17) and bully victimization (OR = 1.17). Attempts among ideators without plan were significantly associated with frequency of emotional abuse (OR = 1.29) and bully victimization (OR = 1.36), in both unadjusted and adjusted analyses. Population attributable risk simulations found 63% of ideation and 30-47% of STB transitions associated with CAs. CONCLUSION: Early-life adversities represent a potentially important driver in explaining lifetime STB among incoming college students. Comprehensive intervention strategies that prevent or reduce the negative effects of CAs may reduce subsequent onset of STB.


Subject(s)
Bullying , Suicidal Ideation , Child , Humans , Risk Factors , Students/psychology , Suicide, Attempted/psychology
6.
Neuroimage ; 243: 118487, 2021 11.
Article in English | MEDLINE | ID: mdl-34419594

ABSTRACT

Over the past decade extensive research has examined the segregation of the human brain into large-scale functional networks. The resulting network maps, i.e. parcellations, are now commonly used for the a priori identification of functional networks. However, the use of these parcellations, particularly in developmental and clinical samples, hinges on four fundamental assumptions: (1) the various parcellations are equally able to recover the networks of interest; (2) adult-derived parcellations well represent the networks in children's brains; (3) network properties, such as within-network connectivity, are reliably measured across parcellations; and (4) parcellation selection does not impact the results with regard to individual differences in given network properties. In the present study we examined these assumptions using eight common parcellation schemes in two independent developmental samples. We found that the parcellations are equally able to capture networks of interest in both children and adults. However, networks bearing the same name across parcellations (e.g., default network) do not produce reliable within-network measures of functional connectivity. Critically, parcellation selection significantly impacted the magnitude of associations of functional connectivity with age, poverty, and cognitive ability, producing meaningful differences in interpretation of individual differences in functional connectivity based on parcellation choice. Our findings suggest that work employing parcellations may benefit from the use of multiple schemes to confirm the robustness and generalizability of results. Furthermore, researchers looking to gain insight into functional networks may benefit from employing more nuanced network identification approaches such as using densely-sampled data to produce individual-derived network parcellations. A transition towards precision neuroscience will provide new avenues in the characterization of functional brain organization across development and within clinical populations.


Subject(s)
Brain/diagnostic imaging , Magnetic Resonance Imaging/methods , Adolescent , Child , Cognition , Connectome , Female , Humans , Image Interpretation, Computer-Assisted , Individuality , Male , Neural Pathways/diagnostic imaging , Neuroimaging
7.
J Child Psychol Psychiatry ; 61(10): 1116-1125, 2020 10.
Article in English | MEDLINE | ID: mdl-32185808

ABSTRACT

BACKGROUND: Adolescence is characterized by substantial changes in sleep behavior, heightened exposure to stressful life events (SLEs), and elevated risk for internalizing problems like anxiety and depression. Although SLEs are consistently associated with the onset of internalizing psychopathology, the mechanisms underlying this relationship remain poorly understood, especially at the within-person level. Here, we leverage a high-frequency longitudinal design to examine sleep as a potential mechanism linking SLEs to increases in anxiety and depression symptoms over a one-year period. METHODS: Thirty female adolescents aged 15-17 years completed 12 monthly in-laboratory assessments of exposure to SLEs and symptoms of anxiety and depression (n = 355 monthly assessments), and wore an actigraphy wristband for continuous monitoring of sleep for the duration of the study (n = 6,824 sleep days). Multilevel models examined concurrent and lagged within-person associations between SLEs, sleep duration and timing regularity, and anxiety and depression symptoms. RESULTS: Within-person fluctuations in SLEs were associated with variability in sleep duration both concurrently and prospectively, such that when adolescents experienced greater SLEs than was typical for them, they exhibited more variable sleep duration that same month as well as the following month. In turn, within-person increases in sleep duration variability predicted greater anxiety symptoms in the same month and mediated the association between SLEs and anxiety. CONCLUSIONS: These findings highlight sleep disruptions as a mechanism underlying the longitudinal associations between SLEs and anxiety symptoms, and suggest that interventions promoting sleep schedule consistency may help mitigate risk for stress-related psychopathology in adolescence.


Subject(s)
Anxiety/psychology , Depression/psychology , Life Change Events , Sleep , Stress, Psychological/psychology , Adolescent , Female , Humans , Longitudinal Studies , Prospective Studies
8.
J Clin Child Adolesc Psychol ; 49(6): 737-751, 2020.
Article in English | MEDLINE | ID: mdl-30657721

ABSTRACT

An emerging trend in youth psychotherapy is measurement-based care (MBC): treatment guided by frequent measurement of client response, with ongoing feedback to the treating clinician. MBC is especially needed for treatment that addresses internalizing and externalizing problems, which are common among treatment-seeking youths. A very brief measure is needed, for frequent administration, generating both youth- and caregiver-reports, meeting psychometric standards, and available at no cost. We developed such a measure to monitor youth response during psychotherapy for internalizing and externalizing problems. Across 4 studies, we used ethnically diverse, clinically relevant samples of caregivers and youths ages 7-15 to develop and test the Behavior and Feelings Survey (BFS). In Study 1, candidate items identified by outpatient youths and their caregivers were examined via an MTurk survey, with item response theory methods used to eliminate misfitting items. Studies 2-4 used separate clinical samples of youths and their caregivers to finalize the 12-item BFS (6 internalizing and 6 externalizing items), examine its psychometric properties, and assess its performance in monitoring progress during psychotherapy. The BFS showed robust factor structure, internal consistency, test-retest reliability, convergent and discriminant validity in relation to three well-established symptom measures, and slopes of change indicating efficacy in monitoring treatment progress during therapy. The BFS is a brief, free youth- and caregiver-report measure of internalizing and externalizing problems, with psychometric evidence supporting its use for MBC in clinical and research contexts.


Subject(s)
Child Behavior/psychology , Emotions/physiology , Psychometrics/methods , Psychotherapy/methods , Adolescent , Child , Female , Humans , Longitudinal Studies , Male , Reproducibility of Results , Surveys and Questionnaires , Treatment Outcome
9.
Behav Res Methods ; 52(1): 279-294, 2020 02.
Article in English | MEDLINE | ID: mdl-30887369

ABSTRACT

Most common analysis tools for the detection of differential item functioning (DIF) in item response theory are restricted to the use of single covariates. If several variables have to be considered, the respective method is repeated independently for each variable. We propose a regularization approach based on the lasso principle for the detection of uniform DIF. It is applicable to a broad range of polytomous item response models with the generalized partial credit model as the most general case. A joint model is specified where the possible DIF effects for all items and all covariates are explicitly parameterized. The model is estimated using a penalized likelihood approach that automatically detects DIF effects and provides trait estimates that correct for the detected DIF effects from different covariates simultaneously. The approach is evaluated by means of several simulation studies. An application is presented using data from the children's depression inventory.


Subject(s)
Likelihood Functions , Depression , Female , Humans , Male , Psychometrics/methods
10.
Behav Res Methods ; 52(2): 464-488, 2020 04.
Article in English | MEDLINE | ID: mdl-31152384

ABSTRACT

This paper introduces the R package WRS2 that implements various robust statistical methods. It elaborates on the basics of robust statistics by introducing robust location, dispersion, and correlation measures. The location and dispersion measures are then used in robust variants of independent and dependent samples t tests and ANOVA, including between-within subject designs and quantile ANOVA. Further, robust ANCOVA as well as robust mediation models are introduced. The paper targets applied researchers; it is therefore kept rather non-technical and written in a tutorial style. Special emphasis is placed on applications in the social and behavioral sciences and illustrations of how to perform corresponding robust analyses in R. The R code for reproducing the results in the paper is given in the Supplementary Materials.


Subject(s)
Behavioral Sciences , Models, Statistical
11.
Proc Natl Acad Sci U S A ; 112(48): 14788-92, 2015 Dec 01.
Article in English | MEDLINE | ID: mdl-26554005

ABSTRACT

One of the cornerstones of the R system for statistical computing is the multitude of packages contributed by numerous package authors. This amount of packages makes an extremely broad range of statistical techniques and other quantitative methods freely available. Thus far, no empirical study has investigated psychological factors that drive authors to participate in the R project. This article presents a study of R package authors, collecting data on different types of participation (number of packages, participation in mailing lists, participation in conferences), three psychological scales (types of motivation, psychological values, and work design characteristics), and various socio-demographic factors. The data are analyzed using item response models and subsequent generalized linear models, showing that the most important determinants for participation are a hybrid form of motivation and the social characteristics of the work design. Other factors are found to have less impact or influence only specific aspects of participation.


Subject(s)
Cooperative Behavior , Mathematical Computing , Motivation , Humans , Linear Models , Psychometrics , Regression Analysis , Surveys and Questionnaires , Work
12.
Eur Spine J ; 26(2): 510-517, 2017 02.
Article in English | MEDLINE | ID: mdl-27600250

ABSTRACT

PURPOSE: Dynamic trunk flexion-extension testing has been proven to objectively diagnose low back pain in persons under the age of 60 years but older persons have difficulty complying with standardized movement velocity. METHODS: 190 patients and 71 matched healthy volunteers (18-90 years of age) performed modified testing by holding static positions at standing, half, and full trunk flexion. RESULTS: Lumbar extensor muscle activity in isometric positions was significantly higher in patients with higher activity in the oldest (60-90 years) and the middle-aged (40-59 years) but not in the youngest (18-39 years) subgroups compared to normal. There were no differences in gross trunk range of motion, half flexion relaxation ratio, proprioception, muscle activity differences between positions, and fear-avoidance behavior. The diagnostic accuracy as expressed by the area under the curve was fair (0.74). CONCLUSIONS: Lumbar extensor muscle activity demonstrated moderate to good diagnostic value in old patients.


Subject(s)
Back Muscles/physiology , Chronic Pain/physiopathology , Low Back Pain/physiopathology , Movement/physiology , Adolescent , Adult , Aged , Aged, 80 and over , Case-Control Studies , Electromyography , Female , Humans , Male , Middle Aged , Muscle Strength/physiology , Young Adult
13.
J Neuroeng Rehabil ; 13: 16, 2016 Feb 19.
Article in English | MEDLINE | ID: mdl-26896325

ABSTRACT

BACKGROUND: The root mean square surface electromyographic activity of lumbar extensor muscles during dynamic trunk flexion and extension from standing has repeatedly been recommended to objectively assess muscle function in chronic low back pain patients. However, literature addressing older patients is sparse. This cross sectional study sought to examine differences in neuromuscular activation between age groups (>60 versus 40-60 versus <40 years) and sexes during a standardized trunk flexion-extension task. METHODS: A total of 216 patients (62 older, 84 middle-aged, 70 younger) performed maximum trunk extensions followed by trunk flexion extension testing thereby holding static positions at standing, half, and full trunk flexion. The lumbar extensor muscle activity and 3d-accelerometric signals intended to monitor hip and trunk position angles were recorded from the L5 (multifidus) and T4 (semispinalis thoracis) levels. Permutation ANOVA with bootstrapped confidence intervals were performed to examine for age and gender related differences. Ridge-regressions investigated the impact of physical-functional and psychological variables to the half flexion relaxation ratio (i.e. muscle activity at the half divided by that in maximum flexion position). RESULTS: Maximum back extension torque was slightly but significantly higher in youngest compared to oldest patients if male and females were pooled. Normalized RMS-SEMG revealed highest lumbar extensor muscle activity at standing in the oldest and the female groups. Patients over 60 years showed lowest activity changes from standing to half (increments) and from half to the maximum flexion position (decrements) leading to a significantly lower half flexion relaxation ratio compared to the youngest patients. These oldest patients demonstrated the highest hip and lowest lumbothoracic changes of position angles. Females had higher regional hip and gross trunk ranges of movement compared to males. Lumbothoracic flexion and the muscle activity at standing had a significant impact on the half flexion relaxation ratio. CONCLUSIONS: The neuromuscular activation pattern and the kinematics in this trunk flexion-extension task involving static half flexion position changed according to age and sex. The test has a good potential to discriminate between impaired and unimpaired neuromuscular regulation of back extensors in cLBP patients, thereby allowing the design of more individualized exercise programs.


Subject(s)
Low Back Pain/physiopathology , Movement , Muscle, Skeletal/physiopathology , Torso/physiopathology , Accelerometry , Adolescent , Adult , Aged , Aged, 80 and over , Aging , Cross-Sectional Studies , Electromyography , Female , Hip/physiopathology , Humans , Lumbosacral Region/physiopathology , Male , Middle Aged , Muscle Contraction , Muscle Relaxation , Muscle Strength Dynamometer , Muscle, Skeletal/innervation , Sex Characteristics , Young Adult
14.
Multivariate Behav Res ; 51(6): 772-789, 2016.
Article in English | MEDLINE | ID: mdl-27802073

ABSTRACT

Judging goodness of fit in multidimensional scaling requires a comprehensive set of diagnostic tools instead of relying on stress rules of thumb. This article elaborates on corresponding strategies and gives practical guidelines for researchers to obtain a clear picture of the goodness of fit of a solution. Special emphasis will be placed on the use of permutation tests. The second part of the article focuses on goodness-of-fit assessment of an important variant of multidimensional scaling called unfolding, which can be applied to a broad range of psychological data settings. Two real-life data sets are presented in order to walk the reader through the entire set of diagnostic measures, tests, and plots. R code is provided as supplementary information that makes the whole goodness-of-fit assessment workflow, as presented in this article, fully reproducible.


Subject(s)
Multivariate Analysis , Algorithms , Attitude , China , Data Interpretation, Statistical , Earthquakes , Goals , Humans , Models, Psychological , Personality , Psychiatric Status Rating Scales , Software , Stress Disorders, Post-Traumatic/diagnosis , Stress Disorders, Post-Traumatic/etiology , Stress Disorders, Post-Traumatic/psychology
15.
J Neuroeng Rehabil ; 12: 3, 2015 Jan 07.
Article in English | MEDLINE | ID: mdl-25566847

ABSTRACT

BACKGROUND: The root mean square surface electromyographic activity of lumbar extensor muscles during dynamic trunk flexion and extension from a standing position and task specific spine ranges of motion objectively assess muscle function in healthy young and middle age individuals. However, literature on neuromuscular activation and associated spine and hip kinematics in older individuals is sparse. This cross sectional study sought to examine the sex and age (<40 versus >60 years) related differences in the neuromuscular activation profiles of the lumbar extensors and the related spine and hip kinematics from healthy individuals during a standardized trunk flexion-extension task. METHODS: Twenty five older (13 females, 60-90 years) and 24 younger (12 females, 18-40 years) healthy individuals performed trunk flexion-extension testing by holding static positions at half-flexion way and full range of motion between standing and maximum trunk flexion. The associated lumbar extensor muscle activity was derived from measurements at standing, half, and maximum flexion positions. The range of motion at the hip and lumbar spine was recorded using 3d accelerometers attached to the skin overlying the multifidus and semispinalis thoracis muscles lateral to the L5 and T4 spinous processes, respectively. Statistical calculations were performed using a permutation ANOVA with bootstrap confidence intervals. RESULTS: The muscle activity in the half related to the maximum flexion position (half flexion relaxation ratio) was significantly smaller in older males when compared with younger males. Moreover, measurements revealed smaller activity changes from standing to the half and from half to the maximum flexion position in older compared to younger individuals. Older males displayed smaller gross trunk range of motion from standing to maximum flexion than any other group. CONCLUSIONS: Gender and normal aging significantly affect both the activation patterns of the lumbar extensor muscles and the kinematics of the trunk during a standardized trunk flexion-extension task. Measurement results from healthy young and middle age individuals should not be used for the assessment of individuals older than 60 years of age.


Subject(s)
Biomechanical Phenomena/physiology , Movement/physiology , Muscle, Skeletal/innervation , Muscle, Skeletal/physiology , Accelerometry , Adolescent , Adult , Aged , Aged, 80 and over , Aging/physiology , Cross-Sectional Studies , Electromyography , Female , Hip/anatomy & histology , Hip/diagnostic imaging , Hip/physiology , Humans , Lumbosacral Region/innervation , Lumbosacral Region/physiology , Male , Middle Aged , Muscle Strength Dynamometer , Muscle, Skeletal/growth & development , Radionuclide Imaging , Sex Characteristics , Spine/anatomy & histology , Spine/innervation , Spine/physiology , Thorax/innervation , Thorax/physiology , Young Adult
16.
J Neuroeng Rehabil ; 11: 106, 2014 Jul 02.
Article in English | MEDLINE | ID: mdl-24985941

ABSTRACT

BACKGROUND: To examine whether or not median frequency surface electromyographic (MF-EMG) back muscle fatigue monitoring would be able to identify alterations in back muscle function in elderly muscles, if a protocol was used that allowed optimum standardization of the processes underlying electromyographic fatigue, and whether these tests were reliable from day to day. METHODS: A total of 42 older (21 females; 67 (±10.5) years old) and 44 younger persons (19 females; 33 (±10) years) performed maximum isometric back extensions which were followed by one 30 s lasting 80% submaximum extension. Participants were seated on a dynamometer with their trunks 30° anteflexed, and they repeated all tests after 1-2 days and 6 weeks. SEMG was recorded bilaterally from the L1 (iliocostalis lumborum), L2 (longissimus), and L5 (multifidus) recording sites. Outcome variables included maximum back extension torque, initial MF-EMG (IMF-EMG), MF-EMG slope declines, and individual MF-EMG muscular imbalance scores. Two-factorial ANOVAs served to examine the age and gender-specific effects, and models from Generalizability Theory (G-Theory) were used for assessing retest-reliability. RESULTS: Maximum back extension moment was non-significantly smaller in elders. IMF-EMG was overall higher in elders, with significant differences at the L5 recordings sites. In the elderly, MF-EMG fatigue declines were significantly smaller in L5, in the recording with the most negative slope, or if the slope of all electrodes was considered. Retest reliability was unanimous in young and older persons. ICC-type measurements from G-Theory of both the IMF and the fatigue slopes ranged from 0.7 to 0.85. Absolute SEM values were found clinically acceptable for the IMF-EMG, but relatively high for the fatigue slope declines. CONCLUSIONS: The MF-EMG fatigue method is able to elucidate alterations of aging back muscles. This method, thus, might be suggested as a potential biomarker to objectively identify persons at risk for sarcopenia. Considering the clinical relevance of the IMF-EMG relative to the MF-EMG slope declines, spectral EMG may also be used as an outcome monitoring tool in elderly populations.


Subject(s)
Aging/pathology , Back Muscles/physiopathology , Electromyography/methods , Muscle Fatigue/physiology , Sarcopenia/diagnosis , Adult , Aged , Aged, 80 and over , Aging/physiology , Female , Humans , Male , Mass Screening/methods , Middle Aged , Muscle Contraction/physiology , Signal Processing, Computer-Assisted , Young Adult
17.
JMIR Form Res ; 8: e53441, 2024 Apr 30.
Article in English | MEDLINE | ID: mdl-38687600

ABSTRACT

BACKGROUND: Heightened stress and insufficient sleep are common in the transition to college, often co-occur, and have both been linked to negative health outcomes. A challenge concerns disentangling whether perceived stress precedes or succeeds changes in sleep. These day-to-day associations may vary across individuals, but short study periods and group-level analyses in prior research may have obscured person-specific phenotypes. OBJECTIVE: This study aims to obtain stable estimates of lead-lag associations between perceived stress and objective sleep duration in the individual, unbiased by the group, by developing an individual-level linear model that can leverage intensive longitudinal data while remaining parsimonious. METHODS: In total, 55 college students (n=6, 11% second-year students and n=49, 89% first-year students) volunteered to provide daily self-reports of perceived stress via a smartphone app and wore an actigraphy wristband for the estimation of daily sleep duration continuously throughout the academic year (median usable daily observations per participant: 178, IQR 65.5). The individual-level linear model, developed in a Bayesian framework, included the predictor and outcome of interest and a covariate for the day of the week to account for weekly patterns. We validated the model on the cohort of second-year students (n=6, used as a pilot sample) by applying it to variables expected to correlate positively within individuals: objective sleep duration and self-reported sleep quality. The model was then applied to the fully independent target sample of first-year students (n=49) for the examination of bidirectional associations between daily stress levels and sleep duration. RESULTS: Proof-of-concept analyses captured expected associations between objective sleep duration and subjective sleep quality in every pilot participant. Target analyses revealed negative associations between sleep duration and perceived stress in most of the participants (45/49, 92%), but their temporal association varied. Of the 49 participants, 19 (39%) showed a significant association (probability of direction>0.975): 8 (16%) showed elevated stress in the day associated with shorter sleep later that night, 5 (10%) showed shorter sleep associated with elevated stress the next day, and 6 (12%) showed both directions of association. Of note, when analyzed using a group-based multilevel model, individual estimates were systematically attenuated, and some even reversed sign. CONCLUSIONS: The dynamic interplay of stress and sleep in daily life is likely person specific. Paired with intensive longitudinal data, our individual-level linear model provides a precision framework for the estimation of stable real-world behavioral and psychological dynamics and may support the personalized prioritization of intervention targets for health and well-being.

18.
Behav Res Ther ; 180: 104574, 2024 May 23.
Article in English | MEDLINE | ID: mdl-38838615

ABSTRACT

Most theories of suicide propose within-person changes in psychological states cause suicidal thoughts/behaviors; however, most studies use between-person analyses. Thus, there are little empirical data exploring current theories in the way they are hypothesized to occur. We used a form of statistical modeling called group iterative multiple model estimation (GIMME) to explore one theory of suicide: The Interpersonal Theory of Suicide (IPTS). GIMME estimates personalized statistical models for each individual and associations shared across individuals. Data were from a real-time monitoring study of individuals with a history of suicidal thoughts/behavior (adult sample: participants = 111, observations = 25,242; adolescent sample: participants = 145, observations = 26,182). Across both samples, none of theorized IPTS effects (i.e., contemporaneous effect from hopeless to suicidal thinking) were shared at the group level. There was significant heterogeneity in the personalized models, suggesting there are different pathways through which different people come to experience suicidal thoughts/behaviors. These findings highlight the complexity of suicide risk and the need for more personalized approaches to assessment and prediction.

19.
Emotion ; 23(1): 278-288, 2023 Feb.
Article in English | MEDLINE | ID: mdl-35201792

ABSTRACT

Research shows negative affect increases in healthy adolescents, and this normative change is paralleled by increasing risk for the onset of psychopathology. However, research is limited in characterizing qualitative differences in the type of negative affect experienced beyond the positive-negative valence dimension. In the current study, we establish the relationship between different forms of negative affect and functioning outcomes (i.e., different facets of social functioning and life satisfaction), and examine whether these forms of negative affect are differentially prevalent across late childhood and adolescence. Seven-hundred and 70 participants aged 8-17 years completed self-report measures that assessed a wide range of negative affective experiences. A factor analysis on the negative affect items revealed a four-factor solution that characterized the dimensions of affective experience, with factors reflecting general anxiety, anger, evaluative anxiety, and sadness. Generalized additive model approaches revealed general anxiety increased nonlinearly with age and was associated with decreased reports of emotional support, a facet of social functioning. Anger was associated with increased perceived hostility, perceived rejection, and decreased life satisfaction, and remained stable across the age range. Evaluative anxiety was associated with greater loneliness and increased linearly with increasing age. Sadness was associated with all outcome measures and showed nonlinear changes with age, with notable increases in midadolescence. These results show that subsuming these subtypes of negative affect under a singular concept may obscure meaningful relationships between affect, age, and functioning. Exploring diverse forms of negative affect may help refine theories of emotional development and ultimately inform windows of risk for psychopathology. (PsycInfo Database Record (c) 2023 APA, all rights reserved).


Subject(s)
Anger , Emotions , Humans , Adolescent , Child , Anxiety/psychology , Sadness/psychology , Anxiety Disorders
20.
Emotion ; 23(6): 1796-1801, 2023 Sep.
Article in English | MEDLINE | ID: mdl-36595384

ABSTRACT

Research into correlates and predictors of emotion regulation has focused almost exclusively on individual differences and the immediate situation. Here, we consider whether features of macro-social contexts may also shape emotion regulation. To test this hypothesis, we conducted a longitudinal study of 502 gay and bisexual men living in 269 U.S. counties that varied in the level of stigma surrounding sexual minorities. We find that gay and bisexual men living in higher- (vs. lower-) stigma counties consistently reported more suppression, which consequently explained longitudinal increases (vs. decreases) in their lack of emotional clarity over 24 months. Results were robust to demographic characteristics, stigma at the interpersonal level (i.e., sexual orientation-related discrimination), and another form of social inequality (i.e., county-level income inequality). These findings suggest that broadening the lens of emotion regulation research to include characteristics of the macro-social environment may yield new insights into determinants of emotion regulation. (PsycInfo Database Record (c) 2023 APA, all rights reserved).


Subject(s)
Homosexuality, Male , Sexual and Gender Minorities , Humans , Male , Female , Homosexuality, Male/psychology , Longitudinal Studies , Sexual Behavior/psychology , Emotions , Social Environment
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