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PubMed2005

Predicting improvement in gait after stroke: a longitudinal prospective study.

BACKGROUND AND PURPOSE: To study the longitudinal relationship of functional change in walking ability and change in time-dependent covariates and to develop a multivariate regression model to predict longitudinal change of walking ability. METHODS: A total of 101 acute stroke patients with first-ever ischemic middle cerebral artery strokes was used as the population. Prospective cohort study based on 18 repeated measurements over time during the first poststroke year. Baseline characteristics as well as longitudinal information from functional ambulation categories (FAC), Fugl-Meyer leg score (FM-leg), Motricity index leg score (MI-leg), letter cancellation task (LCT), Fugl-Meyer balance (FM-balance), and timed balance test (TBT) were obtained. Intervention consisted of a basic rehabilitation program with additional arm, leg, or air splint therapy. Main outcome measure constituted change scores on FAC over time. RESULTS: In total, 1532 of the 1717 change scores were available for regression analysis. The regression model showed that TBT change scores were the most important factor in predicting improvement on FAC (beta=0.094; P<0.001) followed by changes scores on FM-leg (beta=0.014; P<0.001) and reduction in LCT omissions (beta=-0.010; P<0.001) and MI leg test (beta=0.001; P<0.001). In addition, time itself was significantly negatively associated with improvement (beta=-0.002; P<0.001). CONCLUSIONS: Improvement in standing balance control is more important than improvement in leg strength or synergism to achieve improvement in walking ability, whereas reduction in visuospatial inattention is independently related to improvement of gait. Finally, time itself is an independent covariate that is negatively associated with change on FAC, suggesting that most pronounced improvements occur earlier after stroke.

Adult↗

PubMed2026

Plasma von Willebrand Factor and ADAMTS13 Interact With APOE-ε4 in Predicting Longitudinal Brain Atrophy and Cognitive Decline Over a 9-Year Follow-Up.

BACKGROUND: Von Willebrand factor (VWF) and ADAMTS13 (a disintegrin and metalloproteinase with thrombospondin type 1 motif, 13) are linked to dementia risk, and limited evidence suggests apolipoprotein E (APOE)-ε4 alters VWF release. This study assessed whether baseline VWF and ADAMTS13 levels predict neurodegeneration and cognitive decline and evaluated effect modification by APOE-ε4 carriership. METHODS: Vanderbilt Memory and Aging Project cohort participants (n=332, 73±7 years, 59% male) completed serial blood draw, neuropsychological assessment, and brain magnetic resonance imaging over 6.4 years (range 1.4-9.7 years). Baseline plasma VWF and ADAMTS13 levels were quantified using mass spectrometry and Olink. Fully adjusted linear mixed-effects models related protein×time and protein×APOE-ε4×time interaction terms to longitudinal brain magnetic resonance imaging and neuropsychological outcomes. RESULTS: Lower baseline ADAMTS13 predicted faster declines in language (β=0.11, P=0.01), information processing speed (β=0.27, P=0.001), executive function (β=0.01, P=0.03), episodic memory (β=0.01, P=0.03), and visuospatial ability (β=0.11, P=0.001) and faster increases in global (β=-0.29, P=0.01) and frontal (β=-0.17, P=0.01) white matter hyperintensity volumes. Associations between ADAMTS13 and faster rates of cognitive decline and white matter injury were driven by APOE-ε4 carriers. Models relating VWF to longitudinal outcomes were null. APOE-ε4 interacted with VWF on longitudinal gray matter volumetric outcomes, such that faster rates of global gray matter atrophy were observed with higher baseline VWF levels among APOE-ε4 noncarriers only (β=-1530.5, P<0.001). CONCLUSIONS: ADAMTS13 shows promise as a potential plasma biomarker for brain aging outcomes, but additional research is warranted to understand the performance of VWF in the presence versus absence of an APOE-ε4 allele.

Humans↗

PubMed1999

Predictors of longitudinal change in diffusing capacity over 8 years.

Low single-breath diffusing capacity (DL(CO)) values are associated with anatomic emphysema, but the predictors of longitudinal change in DL(CO) over many years are unknown. Study subjects were adult participants in the longitudinal Tucson Epidemiology Study of Obstructive Lung Disease who had at least one DL(CO) measurement during either of two surveys 8 yr apart (n = 543). Smoking status was determined at each examination (current, former, or never smoker). Quitters were defined as those currently smoking at the baseline DL(CO) examination (1982-1983) and self-reported as no longer smoking at the follow-up exam (1990-1991). The longitudinal DL(CO) data were analyzed using repeated measures analysis; because of missing observations this was done using a saturated random effects model. The results showed that males had higher levels of DL(CO) than females, current smokers had significantly lower levels of DL(CO) than never smokers, but there was no difference in their mean slopes over time. Smoking history, assessed using pack-years of smoking, was associated with reduced DL(CO) levels, independent of whether current or ex-smokers. Males and females demonstrated equivalent rates of decline in DL(CO) that accelerated with increasing age, and mean DL(CO) declines were associated with declines in FEV(1) between surveys.

Adult↗

PubMed1991

Blood eosinophilia and FEV1. Cross-sectional and longitudinal analyses.

A previous cross-sectional analysis of 1980 data from a population of working men in the Paris area has shown a significant relationship of blood eosinophilia to a reduced FEV1 among nonsmokers, remaining after excluding men with a history of asthma. In the present report, we reexamine this relationship, after taking into account asthma, bronchial hyperresponsiveness, and positive skin prick tests, using data collected in 1985 in a subsample of 363 men from the initial population. Blood eosinophilia, defined by 5% or more eosinophils or by 250 or more eosinophils per cubic millimeter appeared to be associated with a lower FEV1, primarily in nonsmokers. A difference of approximately 0.40 L was observed in never-smokers with eosinophilia (greater than or equal to 5% of eosinophils) compared with those without. This association persisted after exclusion of subjects with atopy, asthma, and bronchial hyperresponsiveness. Longitudinally, no significant association was observed between 1980 eosinophilia and the annual FEV1 decline between 1980 and 1985, even in nonsmokers. The results of our cross-sectional analyses suggest that asthma or asthma-like disorder does not explain the association between eosinophilia and FEV1. The role of eosinophil in respiratory disorders may go beyond its intervention in allergy. Further longitudinal studies are needed to better understand discrepancies between cross-sectional and longitudinal data and whether eosinophilia is a risk factor for chronic air-flow limitation.

Adult↗

PubMed1980

The influence of smoking habits and body weight on vital capacity and FEV1 in male Air Force personnel: a longitudinal and cross-sectional analysis.

Vital capacity (VC) and forced expiratory volume in one second (FEV1) measured in 7,123 men during annual or biennial medical examination were analyzed as a function of age (A), weight (W), and standing height (H). The subjects were grouped according to their smoking habits. A cross-sectional and longitudinal study was performed. Vital capacity and FEV1 were found to increase with age during the first 22 to 23 yr; thereafter, a steady decline was observed, more pronounced in smokers than in nonsmokers. In both longitudinal and cross-sectional surveys, body weight influenced the values of VC and FEV1. An increase of weight tended to be accompanied by an increase in VC and FEV1 in the younger, taller, and lighter subjects. This effect lessened and even reversed with increasing age and weight, decreasing height, and heavier smoking (in the longitudinal study). The influence of height on VC and FEV1 appeared to depend markedly on the weight of the subjects.

Adolescent↗

PubMed2005

Corneal asphericity and apical curvature in children: a cross-sectional and longitudinal evaluation.

PURPOSE: The contour of the human cornea is closely modeled by a conic section, which is fully described by asphericity (Q) and apical radius of curvature (r(o)). The relationship between corneal shape and other ocular dimensions in children, including anterior and vitreous chamber depths, axial length, and spherical equivalent refractive error, was investigated. METHODS: Corneal asphericity and r(o) were calculated by using corneal topography data on 643 children (72 myopes, 370 emmetropes, and 201 hyperopes), ages 6 to 15 years, who participated in the Orinda Longitudinal Study of Myopia (OLSM) during 1991. Measurements from a younger subset of these children, including 8 myopes, 92 emmetropes, and 75 hyperopes, ages 6 to 9 years in 1991, were compared to 1996 data for longitudinal analysis. RESULTS: Mean +/- SD Q of the 1991 study sample was -0.346 +/- 0.101, representing a prolate corneal shape. Almost all (99.7%) of the corneas examined were prolate. Corneal asphericity was less prolate among myopes than in emmetropes and hyperopes (P = 0.010). Less prolate corneas were related to deeper anterior chamber depths among emmetropes (r = 0.324, P < 0.0001) and hyperopes (r = 0.275, P < 0.0001), but not among myopes (r = 0.230, P = 0.0515). Flatter values of r(o) were related to longer vitreous chamber depth (r = 0.607, P < 0.0001) and axial length (r = 0.606, P < 0.0001) in all refractive error groups. Initial corneal shape was unrelated to change in refractive error over a 5-year period. CONCLUSIONS: Most corneas examined in this study were prolate in contour. Deeper anterior chamber depths were related to less prolate corneas among emmetropes and hyperopes, which is probably the result of mechanical influences on the peripheral cornea as the anterior chamber elongates during ocular growth. Longitudinal results suggest initial corneal shape is of little or no value in predicting refractive error progression.

Adolescent↗

PubMed2001

A longitudinal and retrospective study of PTSD among older prisoners of war.

OBJECTIVE: The authors examined the longitudinal changes in posttraumatic stress disorder (PTSD) symptom levels and prevalence rates over a 4-year time period among American former prisoners of war (POWs) from World War II and the Korean War. Retrospective symptom reports by World War II POWs dating back to shortly after repatriation were examined for 1) additional evidence of changing PTSD symptom levels and 2) evidence of PTSD cases with a long-delayed onset. METHOD: PTSD prevalence rates and symptom levels were measured by the Mississippi Scale for Combat-Related Posttraumatic Stress Disorder. For the longitudinal portion of the study, participants were 177 community-dwelling World War II and Korean POWs. For the retrospective portion, participants were 244 community-dwelling World War II POWs. RESULTS: PTSD prevalence rates and symptom levels increased significantly over the 4-year measurement interval. Retrospective symptom reports indicated that symptoms were highest shortly after the war, declined for several decades, and increased within the past two decades. Long-delayed onset of PTSD symptoms was rare. Demographic and psychosocial variables were used to characterize participants whose symptoms increased over 4 years and differentiate participants who reported a long-delayed symptom onset. CONCLUSIONS: Both longitudinal and retrospective data support a PTSD symptom pattern of immediate onset and gradual decline, followed by increasing PTSD symptom levels among older survivors of remote trauma.

Age Factors↗

PubMed2006

Identifying, recruiting, and retaining seriously-ill patients and their caregivers in longitudinal research.

BACKGROUND: In order to improve the state of science in palliative care, we must increase our ability to document the real-time experience of patients and families as they traverse the end of life. Yet, frequently, prospective measurement is impeded by difficulty with patient identification, recruitment, enrollment, and retention. The palliative care literature is replete with descriptions of studies unable to meet enrollment goals, and that as a result, do not have adequate power to test hypotheses or draw conclusions. OBJECTIVES: To review the literature describing difficulties associated with ascertainment, enrollment, and attrition. To outline the successful recruitment methods of a new longitudinal study of patients and their caregivers. DESIGN: A two-year longitudinal study of 240 patients with Stage IV cancer (breast, prostate, colorectal, lung), advanced congestive heart failure (CHF) LVEFB < 40 or advanced chronic obstructive pulmonary disease (COPD) pCO(2) > 46, and their caregivers, interviewed monthly for up to two years. Patients were identified using clinical and administrative databases from one geographic region. RESULTS: Representative and successful ascertainment was associated with use of clinical criteria and medical record review versus physician or other provider prognostication, use of recruitment letters from personal physician, recruitment letter content, brochure content, small monetary incentives, refined phone scripts, use of matched ethnicity interviewers, in-home and phone interview strategies, measure selection, patient and caregiver rapport, and on-going staff support (including grief and bereavement). CONCLUSIONS: Recruitment to prospective longitudinal studies at the end of life is difficult, but possible. The lessons learned from this study are applicable to future investigators conducting prospective research.

Caregivers↗

PubMed2006

Mood, cognition and serotonin transporter availability in current and former ecstasy (MDMA) users: the longitudinal perspective.

Although 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) is a known serotonergic neurotoxin in different animal species, there is to date no conclusive evidence of its neurotoxicity in humans. MDMA use was associated with impairments of psychological well-being, verbal memory and altered serotonergic functioning in a number of cross-sectional studies. Due to inherent methodological limitations, such as the notorious polydrug use of ecstasy users and lack of control of possible pre-existing differences between ecstasy users and control participants, researchers have called for well-controlled, prospective longitudinal studies to shed more light on the issue of MDMA neurotoxicity to the human brain. This longitudinal study investigated whether mood, cognition and central serotonin transporters (SERT) would deteriorate with continued MDMA use and whether or not they would recover over increasing periods of MDMA abstinence. In a repeated-measures design, 11 current and ten ex-ecstasy users, and 11 polydrug (but not MDMA) and 15 drug-naive controls participated three times within approximately two years. Both ecstasy user groups reported a polydrug use pattern besides heavy ecstasy use. Subjective reports of ecstasy use or abstinence were verified by toxicological analyses. On each trial, the participants underwent a cognitive test battery and filled in the Symptom Check List. The availability of central SERT was assessed with positron emission tomography using the McN5652 ligand for all groups at t1, and only for the ecstasy user groups on follow-ups. The factor Group yielded significant results in the SCL-90 scales Global Severity Index, Anxiety, Obsessive/compulsive and Interpersonal sensitivity, with the ex-ecstasy users reporting the highest symptom scores. There were significant Group effects in all measures of verbal memory, with the lowest performance in the group of ex-ecstasy users. The repeated-measures analyses yielded no significant Group x Time interactions in any SCL-90 scales or measures of memory performance, with the exception of AVLT 1 immediate recall. Thus the ex-ecstasy users' psychopathological symptoms and memory performance failed to improve, and the current ecstasy users' failed to deteriorate, over time relative to the other groups. While there was a significant effect of Group in all brain regions examined (except the control region white matter), the current users' SERT availability seems to have recovered in the mesencephalon, as indicated by a significant Group x Time interaction. Reduced SERT availability might be a transient effect of heavy ecstasy use, since it partially recovered as the current users reduced their MDMA use. However, this measure may not necessarily be a valid indicator of the number or integrity of serotonergic neurons. Ex-ecstasy users' verbal memory showed no sign of improvement even after over 2.5 years of abstinence and thus may represent persistent functional consequences of MDMA neurotoxicity. However, alternative causes such as pre-existing group differences cannot be completely ruled out in spite of the longitudinal design.

Affect↗

PubMed2006

Longitudinal assessment of neuropsychologic and language function in children with benign rolandic epilepsy.

Previous studies of benign rolandic epilepsy have reported improvement in cognitive functioning over time. Their focus was the impact of paroxysmal electroencephalographic (EEG) activity on neuropsychologic function. Comprehensive longitudinal language assessment has not previously been undertaken. In a cross-sectional study, we demonstrated that some children with benign rolandic epilepsy have difficulties in verbal and visual memory and phonologic awareness. The current study evaluated a subgroup longitudinally to determine if difficulties improved. Twenty-eight patients underwent comprehensive longitudinal neuropsychologic and language assessments. The clinical features evaluated included seizure frequency, absolute age, medications, and a follow-up EEG. Differences in performance were analyzed using t-tests. Improvement in cognitive functioning, particularly in the areas of verbal memory, receptive language ability, and phonemic manipulation, was demonstrated. Visual memory and aspects of phonologic awareness showed no change. The improvements were not related to the clinical variables. It is important to recognize cognitive difficulties in children with benign rolandic epilepsy. Some difficulties can resolve; however, continued monitoring, particularly in areas of visual memory and phonologic awareness, is required.

Adolescent↗

PubMed2005

Longitudinal models of growth and survival applied to the early detection of Alzheimer's disease.

This article explores new statistical methodologies for using longitudinal data in the early prediction of Alzheimer's disease (AD). Specifically, the authors examine some new techniques that allow the joint or "shared" estimation of longitudinal components based on both duration (survival) and quantitative changes (growth curves). These new shared growth-survival parameter models may be used to characterize the declining functions that anticipate the onset of AD. The authors apply these models to data from the Kungsholmen Project, a longitudinal study of aging in Stockholm, Sweden. They examine age-based survival-frailty models for the onset of AD, latent growth-decline curve models for changes in cognition over age, and 3 alternative forms of models for the shared relationships of survival and early cognitive decline. The accuracy and reliability of this approach is considered for a better understanding of the developmental course of AD in these data, including the potential removal of biases due to subject selection.

Adult↗

PubMed1998

Empirical testing of a longitudinal model derived from the Roy adaptation model.

This article presents the steps and results of the empirical testing of a theoretical longitudinal model, derived from Roy's nursing conceptual model, of the psychosocial determinants of adaptation in different target groups. The model was elaborated and empirically verified based on the integrated results of four longitudinal studies involving groups vulnerable to mental health problems. By means of structural equation analyses, the cross-sectional model was verified at two points in time. The results showed that the model was relatively stable over time. The model was also tested using longitudinal data. Results showed little consistency in the patterns of relationships across studies. The significant links that emerged from the analyses shed some light on the complexity of the process of adaptation to different types of stressors. They underscore the importance for nursing practice to develop interventions aimed at certain variables: perceived stress, conflicts in the exchange of support, and passive and avoidance coping strategies. The results also highlight the importance of the relationship between perceived stress, passive/avoidance coping strategies and psychological distress.

Adaptation, Psychological↗

PubMed2005

Predicting self-care behaviors among older adults coping with arthritis: a cross-sectional and 1-year longitudinal comparative analysis.

OBJECTIVE: The purpose of this investigation is to examine correlates and predictors of self-care activities for persons diagnosed with arthritis both cross-sectionally and longitudinally. METHOD: Data from telephone surveys conducted with 313 older (M = 68.8, SD = 8.93) individuals, chosen from a larger sample, who reported professionally diagnosed arthritis, were used. RESULTS: A total of 10 of the 11 self-care activities changed significantly during the 1-year interval, with 9 showing increased participation. Results from hierarchical regressions showed that all three blocks of predictors explained significant portions of variance, with gender and perceived importance of general health significantly predicting self-care activities at Time 1, at Time 2, and longitudinally. DISCUSSION: These results highlight the influence of demographic, health status, and health belief variables on self-care both cross-sectionally and longitudinally. Future work should focus on the mediating effects of these and other variables to better understand the processes by which individuals engage in self-care behavior.

Adaptation, Psychological↗

PubMed2000

An overview of group sequential methods in longitudinal clinical trials.

During the last decade, several papers have been published on group sequential methods in general and on sequential longitudinal clinical trials in particular. This paper gives an overview of the proposed methods, emphasizing longitudinal clinical trials. Furthermore, it tries to answer some practical questions that may arise during the conduct of interim analyses in longitudinal trials. Simulations have been carried out to obtain insight in these practical considerations.

Clinical Trials as Topic↗

PubMed1994

Analysis of longitudinal data in craniofacial research: some strategies.

Although it is generally acknowledged that longitudinal data provide the most information on growth and development and other time-dependent phenomena, such data are often analyzed by conventional (cross-sectional) statistical methods. This widespread practice ignores the distinctive characteristics (e.g., covariance structure) of longitudinal data and may yield misleading results. The purpose of this article is to present some strategies and make available computer programs for the appropriate analysis of longitudinal data. User-friendly PC programs for the estimation of average growth curves, computation of tracking indices, prediction of future values, diagnosis, classification, clustering, estimation of missing values, and testing hypotheses concerning individual and group differences are presented. Benefits of these methods over the usual techniques are illustrated with the example of maxillary growth in the rhesus monkey.

Animals↗

PubMed1993

A study of hospital admissions over time, using longitudinal latent structure analysis.

The aim was to study patterns of utilization of non-psychiatric admissions over time and factors affecting the utilization. The study cohort includes all individuals born 1934-66, living in one of two Danish municipalities and admitted to a non-psychiatric department at least once in 1977 (n = 2,686). The hospitalizations of the cohort were followed during a 5-year period by means of the Danish National Patient Register. The data were analysed using a longitudinal latent class (LC) model and a longitudinal latent Markov (LM) model. The LC model suggests that among the cases in the cohort there were 4 variants of utilization patterns. The LM model adequately described the sample in only 3 variants or classes. These classes may be interpreted as a small group of "chronically ill" individuals (1.9% of the cohort), a major group of "healthy" individuals, with no, or only a single, random re-admission during the follow-up period (74.4% of the sample), and finally an intermediate group of "high utilizers" (23.7% of the sample). This "chronicity" variable was markedly associated with mental illness, multiple discharge diagnoses from non-psychiatric departments and total utilization of hospitalizations during the follow-up period. Conversely, gender, age and days in hospital per admission were without importance. The study implies that the analysis of patterns of hospital admissions over time can yield important insight into health service utilization and that longitudinal latent structure analyses are powerful statistical tools in this aspect.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1999

Clustering of biological risk factors for cardiovascular disease and the longitudinal relationship with lifestyle of an adolescent population: the Northern Ireland Young Hearts Project.

OBJECTIVE: To determine whether clustering of biological cardiovascular disease (CVD) risk factors exists and to investigate the longitudinal relationship between lifestyle parameters (dietary intake, physical activity and smoking behaviour) and clustering of biological CVD risk factors, which was defined as belonging to one or more sex-specific 'high-risk' quartiles for the ratio between levels of total serum cholesterol and high-density lipoprotein cholesterol, diastolic blood pressure, body fatness (sum of four skinfolds) and cardiopulmonary fitness (number of laps accomplished on a 20 m shuttle-run test). METHODS: The study was part of the Northern Ireland Young Hearts Project, a 3-year observational longitudinal study concerning adolescent boys (n=229) and girls (n=230) who were initially aged 12 years. The longitudinal relationships were analysed with generalized estimating equations. RESULTS: Significant clustering of biological CVD risk factors was observed both for boys and for girls, but the stability over time was rather low. Smoking was the only lifestyle parameter related to this clustering and was observed only among girls (rate ratio 1.5, P < 0.01); furthermore, none of the lifestyle parameters was significantly related to this clustering. CONCLUSIONS: Because biological CVD risk factors tend to cluster, it is important to investigate these risk factors together. However, for subjects in this age group, according to our analysis, lifestyle parameters were hardly related to this clustering.

Adolescent↗

PubMed2003

Comparison of longitudinal variance components and regression-based approaches for linkage detection on chromosome 17 for systolic blood pressure.

We compare two methods to detect genetic linkage by using serial observations of systolic blood pressure in pedigree data from the Framingham Heart Study focusing on chromosome 17. The first method is a variance components (VC) approach that incorporates longitudinal pedigree data, and the second method is a regression-based approach that summarizes all longitudinal measures in one single measure. No evidence of linkage was found either using the VC longitudinal approach or the regression-based approach, except when all time points were used from Cohorts 1 and 2 and only subjects aged 25 and 75 years were included.

Adult↗