Significant Individual Changes Research Articles

Bempedoic acid: A nonstatin drug for the management of hypercholesterolemia.

Bempedoic acid: A nonstatin drug for the management of hypercholesterolemia.

Assessing the Significance of Individual Change in 2 Samples of Patients in Treatment for Low Back Pain Using 5 Different Statistical Indicators

ObjectiveThe purpose of this study was to estimate the significance of individual change using 5 statistical indicators in 2 samples of patients treated for low back pain. MethodsThis secondary analysis used observational and clinical trial data from 2 samples of patients with low back pain to compare 5 ways of estimating significant individual change on the Impact Stratification Score (ISS) administered at the following 2 time points: 3 months apart in an observational study of 1680 patients undergoing chiropractic care, and 6 weeks apart in a randomized trial of 750 active-duty military personnel with low back pain. The following 5 methods were compared: (1) standard deviation index; (2) standard error of measurement (SEM); (3) standard error of estimate (SEE); (4) standard error of prediction (SEP); and (5) the reliable change index (RCI). The ISS is the sum of the Patient-Reported Outcomes Measurement Information System (PROMIS)-29 v2.1 physical function, pain interference, and pain intensity scores and is scored to have a possible range of 8 (least impact) to 50 (greatest impact). ResultsThe amount of change on the ISS needed for significant individual change in both samples was 5 for the SEM and for the SEE and 7 for the SEP and RCI. ConclusionsThe results of the current study provide some preliminary support for use of the SEP or the RCI to identify significant individual change and provide estimated thresholds of individual change that can be used for the ISS. The SEP and RCI estimates of significant change were consistent with retrospective ratings of change of at least moderately better in prior research. These 2 were less likely than other methods to classify people with low back pain as responders who have not actually gotten better (false positive). In contrast, the SEM and SEE were less likely to miss real change (false negative).

Serum prokineticin-2 in prepubertal and adult Klinefelter individuals.

The prokineticin-2 (PROK2) is a small peptide belonging to the prokineticin family. In humans and rodents this chemokine is primarily involved in the control of central and peripheral reproductive processes. Klinefelter's syndrome (KS) is the first cause of male genetic infertility, due to an extra X chromosome, which may occur with a classical karyotype (47, XXY) or mosaic forms (46, XY/47, XXY). In affected subjects, pubertal maturation usually begins at an adequate chronological age, but when development is almost complete, they display a primary gonadal failure, with early spermatogenesis damage, and later onset of testosterone insufficiency. Thus, the main aim of the present study was to investigate the serum levels of PROK2 in prepubertal and adult KS patients, comparing them with healthy subjects. We showed for the first time the presence of PROK2 in the children serum but with significant changes in KS individuals. Indeed, compared with healthy subjects characterized by PROK2 serum elevation during the growth, KS individuals showed constant serum levels during the sexual maturation phase (higher during the prepubertal phase but lower during the adult age). In conclusion, these data indicate that in KS individuals PROK2 may be considered a biomarker for investigating the SK infertility process.

Estimation of potassium intake: single versus repeated measurements and the associated cardiorenal risk.

High potassium intake has been associated with lower blood pressure and a lower incidence of chronic kidney disease and cardiovascular events. In cohort studies, potassium intake is often estimated with a single 24-h urine collection. However, this may not represent actual long-term individual intake. We assessed whether a single baseline versus multiple follow-up measurements of 24-h urine potassium excretion results in different estimates of individual potassium intake and different associations between potassium intake and long-term outcome. We performed a retrospective cohort study in outpatient subjects with an estimated glomerular filtration rate >60 mL/min/1.73 m2 who had sampled a 24-h urine collection at baseline and had ≥1 collection during a 17-year follow-up. Potassium intake was estimated with a single baseline 24-h urine collection but also during 1-year, 5-year, and 15-year follow-up. We used cox regression analysis to assess the association between cardiorenal outcome and estimated potassium intake. Average population (n = 541) 24-h potassium excretion was similar at baseline and follow-up but significant individual changes in potassium intake between baseline and follow-up were observed. Forty-four percent of the subjects switched between tertiles of estimated potassium intake when follow-up measurements were used instead of baseline measurements. Hazard ratios for renal and cardiovascular outcomes were 6.9 and 1.7 times higher when follow-up estimates of potassium intake were replaced by baseline estimates. Estimated potassium intake and its association with long-term outcome change significantly when multiple follow-ups 24-h urine collections are used for estimation of potassium intake instead of a single baseline measurement.

Using Item Response Theory to Identify Responders to Treatment: Examples with the Patient-Reported Outcomes Measurement Information System (PROMIS\xae) Physical Function Scale and Emotional Distress Composite

The reliable change index has been used to evaluate the significance of individual change in health-related quality of life. We estimate reliable change for two measures (physical function and emotional distress) in the Patient-Reported Outcomes Measurement Information System (PROMIS®) 29-item health-related quality of life measure (PROMIS-29 v2.1). Using two waves of data collected 3 months apart in a longitudinal observational study of chronic low back pain and chronic neck pain patients receiving chiropractic care, and simulations, we compare estimates of reliable change from classical test theory fixed standard errors with item response theory standard errors from the graded response model. We find that unless true change in the PROMIS physical function and emotional distress scales is substantial, classical test theory estimates of significant individual change are much more optimistic than estimates of change based on item response theory.

Лиминальная идентичность поколения COVID

The author’s reflection is aimed at identifying the specifics of the representatives of generation Z (“Homelanders”/“Centenials”/ “Artists”/ “Homebodies”) personal state who relate themselves to specific social communities in the context of the COVID-19 virus pandemic. The remote format of organizing communication and activities affected the mechanisms of socialization, both primary and secondary. The sequential passage of three phases: adaptation, individualization and integration in the context of the pandemic acquired additional characteristics which, in turn, affected the formation of an individual’s identity. The representatives of the middle and older generations (Y, X, Baby boomers) appeared to be in a dissonant state, while Homelanders showed a greater willingness to live in the digital space. The author focuses on the cause-and-effect relationships of this circumstance, insisting on the need to use the “Liminality” category to characterize the identity state of representatives of generation Z, and describes the liminal state itself as “a threshold” and transitional one characterizing the individuals in the conditions of significant individual and social changes. The vector of the research interest involves the operationalization of the concepts and the subsequent comparison of the specifics of the liminal identity with the trends of social movement in the direction of social singularity.

Quadriceps activation during maximal isometric and isokinetic contractions: The minimal real difference and its implications

BACKGROUND: A method of measurement of voluntary activation (VA, percent of full muscle recruitment) during isometric and isokinetic concentric contractions of the quadriceps femoris (QF) at 60∘/s and 120∘/s was previously validated. OBJECTIVE: This study aimed to quantify the test-retest minimal real difference (MRD) of VA during isometric (ISOM) and isokinetic concentric contractions of QF (100∘/s, ISOK) in a sample of healthy individuals. METHODS: VA was measured through the interpolated twitch technique. Pairs of electrical stimuli were delivered to the QF at 40∘ of knee flexion during maximal voluntary contractions. Twenty-five healthy participants (20–38 years, 12 women, 13 men) completed two testing sessions with a 14-day interval. VA values were linearized through logit transformation (VAl). The MRD was estimated from intraclass correlation coefficients (model 2.1). RESULTS: The VA (median, range) was 84.20% (38.2–99.9%) in ISOM and 94.22% (33.8–100%) in ISOK. MRD was 0.78 and 1.12 logit for ISOM and ISOK, respectively. As an example, in terms of percent VA these values correspond to a change from 76% to 95% and from 79% to 98% in ISOM and in ISOK, respectively. CONCLUSIONS: The provided MRD values allow to detect significant individual changes in VA, as expected after training and rehabilitation programs.

The Gut Microbiome in Polycystic Ovary Syndrome and Its Association with Metabolic Traits.

Despite the gut microbiome being widely studied in metabolic diseases, its role in polycystic ovary syndrome (PCOS) has been scarcely investigated. Compare the gut microbiome in late fertile age women with and without PCOS and investigate whether changes in the gut microbiome correlate with PCOS-related metabolic parameters. Prospective, case-control study using the Northern Finland Birth Cohort 1966. General community. A total of 102 PCOS women and 201 age- and body mass index (BMI)-matched non-PCOS control women. Clinical and biochemical characteristics of the participants were assessed at ages 31 and 46 and analyzed in the context of gut microbiome data at the age of 46. (s): None. Bacterial diversity, relative abundance, and correlations with PCOS-related metabolic measures. Bacterial diversity indices did not differ significantly between PCOS and controls (Shannon diversity P = .979, unweighted UniFrac P = .175). Four genera whose balance helps to differentiate between PCOS and non-PCOS were identified. In the whole cohort, the abundance of 2 genera from Clostridiales, Ruminococcaceae UCG-002, and Clostridiales Family XIII AD3011 group, were correlated with several PCOS-related markers. Prediabetic PCOS women had significantly lower alpha diversity (Shannon diversity P = .018) and markedly increased abundance of genus Dorea (false discovery rate = 0.03) compared with women with normal glucose tolerance. PCOS and non-PCOS women at late fertile age with similar BMI do not significantly differ in their gut microbial profiles. However, there are significant microbial changes in PCOS individuals depending on their metabolic health.

Markov chain Monte Carlo for active module identification problem

BackgroundIntegrative network methods are commonly used for interpretation of high-throughput experimental biological data: transcriptomics, proteomics, metabolomics and others. One of the common approaches is finding a connected subnetwork of a global interaction network that best encompasses significant individual changes in the data and represents a so-called active module. Usually methods implementing this approach find a single subnetwork and thus solve a hard classification problem for vertices. This subnetwork inherently contains erroneous vertices, while no instrument is provided to estimate the confidence level of any particular vertex inclusion. To address this issue, in the current study we consider the active module problem as a soft classification problem.ResultsWe propose a method to estimate probabilities of each vertex to belong to the active module based on Markov chain Monte Carlo (MCMC) subnetwork sampling. As an example of the performance of our method on real data, we run it on two gene expression datasets. For the first many-replicate expression dataset we show that the proposed approach is consistent with an existing resampling-based method. On the second dataset the jackknife resampling method is inapplicable due to the small number of biological replicates, but the MCMC method can be run and shows high classification performance.ConclusionsThe proposed method allows to estimate the probability that an individual vertex belongs to the active module as well as the false discovery rate (FDR) for a given set of vertices. Given the estimated probabilities, it becomes possible to provide a connected subgraph in a consistent manner for any given FDR level: no vertex can disappear when the FDR level is relaxed. We show, on both simulated and real datasets, that the proposed method has good computational performance and high classification accuracy.

Manifestações orofaciais da lipodistrofia generalizada congênita: uma revisão sistemática

O presente estudo objetiva-se a verificar os achados orofaciais da lipodistrofia generalizada congênita (LGC) em pacientes diagnosticados com essa condição. Trata-se de uma revisão sistemática da literatura, realizada em conformidade com as bases de dados PubMed, Web of Science e Scopus. Foram incluídos 14 estudos publicados nos últimos 15 anos que abordassem os achados clínicos orofaciais da LGC. A LGC é uma condição autossômica recessiva rara, apresentando uma ampla variedade de manifestações que acometem as regiões oral e facial. Os principais achados orofaciais identificados foram prognatismo, ausência de gordura subcutânea facial, saliências frontais e supraorbitais proeminentes, linha frontal do cabelo baixa, face triangular, hirsutismo facial, macroglossia, hipertrofia labial, morfologia dentária anormal, cárie dentária, ausências dentárias, diastemas e apinhamentos dentários. Os resultados indicam que a LGC pode causar alterações orofaciais significativas nos indivíduos, sendo importante que esses pacientes sejam acompanhados por uma equipe de saúde multiprofissional, e que esses profissionais tenham conhecimento baseado em evidências científicas a respeito desses achados clínicos, para oferecer um melhor prognóstico para esses pacientes.

The Space Between: Transformative Learning and Type 2 Diabetes Self-Management.

Immigrant populations experience higher type 2 diabetes mellitus (T2DM) prevalence rates and worse health outcomes secondary to T2DM than native-born populations. But as the largest immigrant population in the United States, the experience of T2DM diagnosis and self-management among Spanish-speaking, limited English-language proficient Latinx immigrants remains largely unexamined. This study used semistructured interviews to explore these phenomena among a cohort of 30 recent Latinx immigrants. All aspects of data collection were conducted in Spanish. Quantitative and qualitative data were collected. Data analysis included descriptive statistical procedures. Qualitative data analysis was conducted using a grounded theory approach. Patterns in the data analysis of 30 interviews identified accepting T2DM as a common transitional process that required significant changes in individuals' self-perspective and ways of being. Accepting T2DM was identified by the participants as a precursor to treatment initiation. And while for most participants this transition period was brief, for some it took months to years. Distinct transitional stages were identified, categorized, and considered within the context of several theoretical orientations and were observed to align with those in transformative learning. Understanding differing responses and processing of a T2DM diagnosis could be leveraged to better support patients' acceptance and transition into treatment.

Is a Good Quality of Life and Health Status Possible in Older Patients Dying from Critical Limb-Threatening Ischemia: A Prospective Clinical Study

Revascularization is the cornerstone in the treatment of patients with critical limb-threatening ischemia (CLTI). However, the 2-year mortality rate is up to 50% in these patients. Therefore, the clinical benefit of revascularization needs to be considered carefully. The question emerges if there are changes in quality of life (QoL) and health status (HS) in the end-of-life phase of CLTI in older patients. Patients with CLTI and of an age of 70years or older were included in a prospective observational cohort study. Treatment consisted of endovascular revascularization, surgical revascularization, or conservative therapy. The follow-up period was 2years. Within this follow-up period, patients completed the following questionnaires at six specified time intervals: the WHOQOL-BREF and the SF-12. Patients who died within 2 years after inclusion were analyzed. Final scores were defined as the last measurement at end of follow-up or death. Eighty two patients (42.1%) died during the 24-month follow-up. QoL and HS before death did not decrease with treatment (option: endovascular intervention, surgical revascularization, or conservative therapy). Older patients with CLTI and a life expectancy less than 2years had no differences in QoL and HS before death compared to their previous measurement. Except for the mental HS domain, no differences in the percentage of patients showing significant individual change in QoL and HS were found between the treatments. For clinicians, it is important to use patient-reported outcome measure when discussing treatment for older frail patients with CLTI in a shared decision-making process.

Surgical Excision Versus Ablation for Superficial Endometriosis-Associated Pain: A Randomized Controlled Trial

Study ObjectiveTo compare surgical excision and ablation of endometriosis for treatment of chronic pelvic pain. DesignRandomized clinical trial with 12-month follow-up (Canadian Task Force classification I). SettingSingle academic tertiary care hospital. PatientsWomen with minimal to mild endometriosis undergoing laparoscopy. InterventionsExcision or ablation of superficial endometriosis at the time of robot-assisted laparoscopy. Measurements and Main ResultsPrimary outcome was visual analog scale (VAS) scoring at baseline and 6 and 12 months for menstrual pain, nonmenstrual pain, dyspareunia, and dyschezia. Secondary outcomes included survey results at baseline and 6 and 12 months from the Short Form Health Survey, Pelvic Organ Prolapse/Urinary Incontinence Sexual Function Questionnaire, and the International Pelvic Pain Assessment. From December 2013 to October 2014, 73 patients were randomized intraoperatively to excision (n = 37) or ablation (n = 36) of endometriosis. Patients were followed at 6 and 12 months to evaluate the above outcomes. After ablation of endometriosis, dyspareunia (VAS scores) improved at 6 months (mean change [MC], −14.07; 95% confidence interval [CI], −25.93 to −2.21; p = .02), but improvement was not maintained at 12 months. Dysmenorrhea improved at 6 months (MC, −26.99; 95% CI, −41.48 to −12.50; p < .001) and 12 months (MC, −24.15; 95% CI, 39.62 to −8.68; p = .003) with ablation. No significant changes were seen in VAS scores after excision at 6 or 12 months. When comparing ablation and excision, the only significant difference was a change in dyspareunia at 6 months (MC, −22.96; 95% CI, −39.06 to −6.86; p = .01). ConclusionTreatment with ablation improved dysmenorrhea at 6 and 12 months and improved dyspareunia at 6 months as compared with preoperative data. However, only dyspareunia demonstrated a significant difference between ablation and excision. Excision and ablation showed similar effectiveness for the treatment of pain associated with superficial endometriosis, with ablation showing more significant individual changes. Careful patient counseling regarding expectations of surgical intervention is vital in the management of endometriosis.

ВИВЧЕННЯ ГОСТРОЇ ТОКСИЧНОСТІ ПРЕПАРАТУ АРГОЦИД ПРИ ВНУТРІШНЬООЧЕРЕВИННОМУ ВВЕДЕННІ

Мета роботи. Вивчення гострої токсичності ветеринарного препарату Аргоцид, розчин для інтрацистернального введення, при внутрішньоочеревинному введенні статевозрілим білим щурам.Матеріали і методи. Об'єктом дослідження були серії препарату Аргоцид, який містить цитрат срібла, D- пантенол та L- аргінін, призначений для лікування субклінічного маститу великої рогатої худоби. Дослідження гострої токсичності тест-зразків препарату Аргоцид проводили у дослідах на білих нелінійних статевозрілих щурах обох статей, віповідно до вимог, що висувають до потенційних ліків. Випробування проведені при внутрішньочеревному введенні препарату в різних дозах – від 2,0 до 6,3 мл / кг. Статистична обробка даних була виконана з використанням t-критерію Стьюдента. Для статистичної обробки даних використано програму MS Excel.Результати й обговорення. У результаті дослідження гострої токсичності препарату Аргоцид встановлено, що інтегральні показники життєдіяльності тварин – маса та температура тіла не зазнавали суттєвих індивідуальних змін вподовж 14 діб спостереження після одноразового внутрішньоочеревинного введення. При досліджені дози препарату у діапазоні від 1,58 мл/кг маси тіла тварини до 5,0 мл/кг визначено, що жодного випадку загибелі тварин не зареєстровано за внутрішньоочеревинного введення препарату у будь-якій дозі. При застосуванні препарату у дозах 2,5 мл/кг та вище у тварин проявилися клінічні ознаки інтоксикації відразу після введення препарату, що може бути пов’язано з подразненням очеревини. Через 3 доби після внутрішньоочеревинного застосування Аргоциду жодних клінічних ознак інтоксикації не спостерігали.Висновки. Аналіз отриманих даних дозволяє віднести препарат Аргоцид, розчин для інтрацистернального введення за ступенем небезпеки до відносно нешкідливих препаратів (VI клас) оскільки середня летальна доза перевищує 3,0 мл/кг маси тіла тварини за внутрішньоочеревинного введення.

Moral Judgments of In-Group and Out-Group Harm in Post-conflict Urban and Rural Croatian Communities.

Our research brings to light features of the social world that impact moral judgments and how they do so. The moral vignette data presented were collected in rural and urban Croatian communities that were involved to varying degrees in the Croatian Homeland War. We argue that rapid shifts in moral accommodations during periods of violent social strife can be explained by considering the role that coordination and social agents' ability to reconfigure their social network (i.e., relational mobility) play in moral reasoning. Social agents coordinate on (moral) norms, a general attitude which broadly facilitates cooperation, and makes possible the collective enforcement of compliance. During social strife interested parties recalibrate their determination of others' moral standing and recast their established moral circle, in accordance with their new or prevailing social investments. To that extent, social coordination—and its particular promoters, inhibitors, and determinants—effects significant changes in individuals' ranking of moral priorities. Results indicate that rural participants evaluate the harmful actions of third parties more harshly than urban participants. Coordination mediates that relationship between social environment and moral judgment. Coordination also matters more for the moral evaluation of the harmful actions of moral scenarios involving characters belonging to different social units than for scenarios involving characters belonging to the same group. Participants high in relational mobility—that ability to recompose one's social network—moralize similarly wrongdoings perpetrated by both in- and out-group members. Those low in relational mobility differentiate when an out-group member causes the harm. Additionally, perceptions of third-party guilt are also affected by specifics of the social environment. Overall, we find that social coordination and relational mobility affect moral reasoning more so than ethnic commitment.

Multivariate Hypothesis Testing Methods for Evaluating Significant Individual Change.

The measurement of individual change has been an important topic in both education and psychology. For instance, teachers are interested in whether students have significantly improved (e.g., learned) from instruction, and counselors are interested in whether particular behaviors have been significantly changed after certain interventions. Although classical test methods have been unable to adequately resolve the problems in measuring change, recent approaches for measuring change have begun to use item response theory (IRT). However, all prior methods mainly focus on testing whether growth is significant at the group level. The present research targets a key research question: Is the "change" in latent trait estimates for each individual significant across occasions? Many researchers have addressed this research question assuming that the latent trait is unidimensional. This research generalizes their earlier work and proposes four hypothesis testing methods to evaluate individual change on multiple latent traits: a multivariate Z-test, a multivariate likelihood ratio test, a multivariate score test, and a Kullback-Leibler test. Simulation results show that these tests hold promise of detecting individual change with low Type I error and high power. A real-data example from an educational assessment illustrates the application of the proposed methods.

Attention-training with children from socioeconomically disadvantaged backgrounds in Cape Town

Objective: Attention is a core process underlying competence in higher-order cognitive abilities. Previous research suggests that healthy children from low socioeconomic status (SES) backgrounds perform poorly, relative to those from higher SES backgrounds, on tasks assessing attentional abilities. In this pilot study, we investigated the effects of an attention-training intervention on task performance in low-SES children.Method: We conducted a quasi-controlled trial with stratified randomisation, using a pre-test/ post-test design. Participants were low-SES children aged 7–13 years. Each was assigned to either an intervention group, a play control group, or a test-only control group (n = 5 per group). We implemented a ten-week manualised cognitive rehabilitation program, Pay Attention!, administering standardised tests of attention, working memory, and inhibition before and after the intervention. Between- and within-group analyses and Reliable Change Index statistics evaluated differences in scores from pre- to post-intervention.Results: Analyses detected no notable between-group differences at either pre- or post-intervention testing. However, on tests of selective attention, attentional control, and inhibition, there were significant within-group and positive individual reliable changes exclusive to the intervention-group participants.Conclusions: Given the variability in our findings, more research needs be conducted with a larger sample to determine, with greater rigour, the efficacy of the intervention within samples of healthy children from low-SES backgrounds.

Anatomical brain difference of subthreshold depression in young and middle-aged individuals.

BackgroundSubthreshold depression (StD) is associated with substantial functional impairments due to depressive symptoms that do not fully meet the diagnosis of major depressive disorder (MDD). Its high incidence in the general population and debilitating symptoms has recently put it at the forefront of mood disorder research.AimIn this study we investigated common volumetric brain changes in both young and middle-aged StD patients.MethodsTwo cohorts of StD patients, young and middle-aged, (n = 57) and matched controls (n = 76) underwent voxel-based morphometry (VBM).ResultsVBM analysis found that: 1) compared with healthy controls, StD patients showed decreased gray matter volume (GMV) in the bilateral globus pallidus and precentral gyrus, as well as increased GMV in the left thalamus and right rostral anterior cingulate cortex/medial prefrontal cortex; 2) there is a significant association between Center for Epidemiological Studies Depression Scale scores and the bilateral globus pallidus (negative) and left thalamus (positive); 3) there is no interaction between age (young vs. middle-age) and group (StD vs. controls).ConclusionsOur findings indicate significant VBM brain changes in both young and middle-aged individuals with StD. Individuals with StD, regardless of age, may share common neural characteristics.

Clarifying Discrepancies in Responsiveness Between Reliable Change Indices.

Several reliable change indices (RCIs) exist to evaluate statistically significant individual change with repeated neuropsychological assessment. Yet there is little guidance on model selection and subsequent implications. Using existing test-retest norms, key parameters were systematically evaluated for influence on different RCI models. Normative test-retest data for selected Wechsler Memory Scale-IV subtests were chosen based on the direction and magnitude of differential practice (inequality of test and retest variance). The influence of individual relative position compared to the normative mean was systematically manipulated to evaluate for predictable differences in responsiveness for three RCI models. With respect to negative change, RCI McSweeny was most responsive when individual baseline scores were below the normative mean, irrespective of differential practice. When an individual score was greater than the normative mean, RCI Chelune was most responsive with lower retest variance, and RCI Maassen most responsive with greater retest variance. This pattern of results can change when test-retest reliability is excellent and there is greater retest variability. Order of responsiveness is reversed if positive change is of interest. RCI models tend to agree when the individual approximates the normative mean at baseline and test-retest variability is equal. However, no RCI model will be universally more or less responsive across all conditions, and model selection may influence subsequent interpretation of change. Given the systematic and predictable differences between models, a more rationale choice can now be made. While a consensus on RCI model preference does not exist, we prefer the regression-based model for several reasons outlined.

Infant sleep-wake behaviors at two weeks, three and six months

Although infant sleep-wake behavior presents several developmental changes during the first six months, literature lacks on reference values and few studies have explored the role of individual change and stability on infant sleep-wake behavior during the first six months. This study aimed (1) to describe infant sleep-wake behaviors during the 24-h period, day and night, at two weeks, three, and six months, (2) and to explore developmental changes and the role of individual change and stability on infant sleep-wake behaviors from two weeks to six months. Ninety-four primiparous mothers completed measures on infant sleep-wake behaviors at two weeks, three and six months. Significant developmental changes were found on infant sleep-wake behaviors from two weeks to six months. Two-week-old infants sleep 13.3h, spend 8.7h awake, awake 6.1 times, have 0.4h of latency to sleep, and 3.2h of longest sleep period. Three-month-old infants sleep 13.0h, spend 9.2h awake, awake 5.5 times, have 0.4h of latency to sleep, and 5.2h of longest sleep period. Six-month-old infants sleep 12.2h, spend 10.0h awake, awake 5.2 times, have 0.4h of latency to sleep, and 5.6h of longest sleep period. Significant individual change and stability were also found on infant sleep-wake behaviors from two weeks to six months. Despite significant developmental and individual changes, individual stability explains a significant amount of the variance on infant sleep-wake behaviors over the first six months of life.