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PubMed1991

Preliminary results from a meta-analysis of drinking behavior in multiple longitudinal studies.

This paper introduces the scope and rationale of The Collaborative Alcohol-Related Longitudinal Project and describes the individual longitudinal studies which contribute to this large collaborative project, representing studies from 15 countries. It also serves as an introduction to four reports of the preliminary findings from the project. The project is distinguished by (1) its interdisciplinary research approach which has assembled a multidisciplinary group of scholars to direct and interpret analyses, (2) its use of primary data from multiple longitudinal studies, (3) the parallel analyses of primary data from multiple studies, using comparable measures across studies recorded to a standard format and common analytic model, and (4) its use of meta-analysis to combine results across studies. Its research objectives include determining the cross-study consistency of findings of (1) the incidence and chronicity of drinking patterns and problems, (2) exogeneous factors which initiate and alter drinking careers, (3) socio-behavioral factors measured in childhood and adolescence which predict adult drinking problems, (4) inter-generational biological and social factors which predict adult drinking problems, and (5) aggregate-level factors which account for study differences. The method of sampling of studies from the world's alcohol-related general population longitudinal research is described.

Alcohol Drinking↗
PubMed1993

Longitudinal assessment of amniotic fluid index.

OBJECTIVE: To derive a longitudinal gestational reference range for amniotic fluid index and to compare it with the established cross-sectional reference range. DESIGN: Longitudinal prospective study. SETTING: Liverpool Maternity Hospital and Mill Road Maternity Hospital, both teaching hospitals in central Liverpool. SUBJECTS: One hundred and fifteen pregnant women, in whom the expected date by the last menstrual period and ultrasound scan at 18 to 19 weeks were in agreement by seven days, were recruited. They were divided into two groups and scanned at four weekly intervals as follows: Group A: scanned at 20, 24, 28, 32, 36, 40; and Group B: scanned at 22, 26, 30, 34, 38, 42. RESULTS: Amniotic fluid index varies with gestation, rising from early gestation to peak at 30 weeks and then falling from 36 to 42 weeks. Comparison of our reference range with that of Moore and Cayle (1990) shows obvious differences at the lower limit. CONCLUSION: We have established a normal longitudinal reference range for the amniotic fluid index. Our ranges, derived from longitudinal data, would seem a more appropriate reference than the established reference ranges derived from cross-sectional data. In particular, the differences at the lower limits may have considerable clinical implication in the use of amniotic fluid index in the prediction of fetal compromise.

Amniotic Fluid↗
PubMed1990

Alcohol intake in the healthy elderly. Changes with age in a cross-sectional and longitudinal study.

Several cross-sectional studies have shown a decline in alcohol intake with increasing age. Longitudinal studies have failed to confirm this trend, which suggests that cohort effects may account for the reported decline. To address this, both cross-sectional and longitudinal analyses of alcohol use in 270 healthy elderly persons over a seven-year period (1980-1987) were performed. Alcohol consumption was assessed by three-day diet records. One hundred sixty-five subjects (61.1%) remained in the study until 1987; 143 (53%) completed diet records for every year. Longitudinal analysis showed a statistically significant decline in the percent of subjects consuming any alcohol over time (slope = -2% per year; 95% confidence interval -2.8, -1.1%). A cross-sectional analysis of the 1980 data revealed a similar decline in percent drinkers with increasing age (slope = -2.7% per year; 95% confidence interval -4.4, -1.1%). Mean alcohol intake for those who continued to drink did not change over time except among heavy drinkers (consumption of greater than 30 g per day in 1980), who did show a significant decline in mean alcohol intake (P = .02). Thus, in our population the decline in percent of drinkers with age found by a cross-sectional analysis was confirmed in longitudinal analyses, suggesting that this represents a true age-related decline rather than a cohort effect.

Age Factors↗
PubMed2005

Individual and population penalized regression splines for accelerated longitudinal designs.

In an accelerated longitudinal design (ALD), individuals enter the study at different points of their growth trajectory and are observed over a short time span relative to the entire time span of interest. ALD data are combined across independent units to provide an estimate of an overall population curve and predictions of individual patterns of change. As a modest extension of the work of Ruppert et al. (2003, Semiparametric Regression, Cambridge University Press), we develop a computationally efficient procedure for the application of longitudinal semiparametric methods under ALD sampling schemes. We compare balanced and complete longitudinal designs to ALDs using the Berkeley Growth Study data and apply our method to longitudinal magnetic resonance imaging (MRI) brain structure size (volume) measurements from an ongoing developmental study. Potential applications extend beyond growth studies to many other fields in which cost and feasibility constraints impose restrictions on sample size and on the numbers and timings of repeated measurements across subjects.

Adolescent↗
PubMed2007

Mouthguards: difference in longitudinal dimensional stability between single- and double-laminated fabrication techniques.

Though the use of mouthguards (MGs) has increased with the increase in sporting activities, little is known about the influence of their fabrication methods on longitudinal dimensional stability. The objective of this study was to compare the difference in the longitudinal dimensional stability between single and laminated MGs. Single-layer MGs were made from a 4.0 mm thick ethylene vinyl acetate (EVA) sheet and laminated MGs were made from two 2.0 mm thick sheets of EVA. MGs were kept in a 37 degrees C water bath for 60 h, equivalent to the time period of 3-months inter-oral use. MG deformation was analyzed by measuring designated points on the MG border using a profile projector (J-12, Nikon Inc., Tokyo, Japan) before and after the water immersion. A finite-element model was also created to examine the time course of stress accumulation during the sheet forming process using Finite Element software. Longitudinal deformation was smaller in the laminated MGs than in the single-layer MGs in the anterior area (P < 0.05). Finite element method (FEM) analysis also showed the largest stress accumulation in the anterior incisal area where deformations were mainly observed. Laminated double layer MGs have advantages over single-layer MGs in terms of longitudinal stability due to lower stress accumulation during the fabrication process.

Equipment Design↗
PubMed1989

Individual growth curves and longitudinal growth charts between 0 and 3 years.

From a statistical viewpoint, the construction of longitudinal growth norms involves two classes of problems: (a) the choice of a mathematical function having a few constants as possible, but suitable for describing individual growth process in the growth period of concern; (b) the estimation of the mean growth constants for a homogeneous group of subjects, and of the covariance matrix of data collected longitudinally, to compute tolerance intervals which enable us to draw growth charts. Although growth constants should have some biological interpretation, the choice of functions rests mainly on the criterion of following observed growth as closely as possible. As to the second problem, the simplest situation implies that growth function is linear in the constants and all subjects have measures on the same prefixed occasions: in this case, multivariate Potthoff-Roy model (1964) directly applies. In longitudinal growth studies, however, it happens that subjects do not come for measurements at exactly the age specified: two-stage models seem to be more appropriate to this latter case. They consist of (a) fitting individual growth curve on each subject to obtain estimates of 1st-stage constants; (b) obtaining estimates of 2nd-stage constants, characteristic of the whole group of subjects, in terms of weighted averages of the estimates of the 1st-stage constants. This paper deals with the application of a two-stage model to the growth in length of 203 girls and 217 boys born in Naples between 1977 and 1981. Children, whose growth records are used to trace longitudinal standards, have been measured at birth, and at least 5 times in the course of a follow-up made up of 8 visits, between 3 months and 3 years of life.

Child, Preschool↗
PubMed2005

Arthritis instantaneously causes collagen type I and type II degradation in patients with early rheumatoid arthritis: a longitudinal analysis.

BACKGROUND: Markers of collagen type I (CTX-1) and type II (CTX-II) degradation, reflecting bone and cartilage breakdown, appear to predict long term radiographic progression in chronic persistent arthritis. OBJECTIVE: To analyse longitudinally whether changes in arthritis severity are linked to immediate changes in the level of CTX-I and CTX-II degradation. METHODS: CTX-I and CTX-II were measured in urine samples from 105 patients with early rheumatoid arthritis who had participated in the COBRA trial at baseline and at 3, 6, 9, and 12 months after the start of treatment. The course of the biomarkers over time was compared with the course of ESR, swollen and tender joint counts, and 28 joint disease activity score (DAS28), measured at the same time points, with adjustment for rheumatoid factor, treatment, and baseline radiographic damage, by generalised estimating equations (GEE) with first order autoregression. RESULTS: GEE showed that CTX-I was longitudinally associated with DAS28, but not with ESR, swollen joint count, or tender joint count. CTX-II, however, was longitudinally associated with ESR, swollen joint count and DAS28, but not with tender joint count. The longitudinal association implies that an increase in the extent of arthritis is immediately followed by an increase in collagen type II degradation, and to a lesser extent collagen type I degradation. CONCLUSIONS: Cartilage degradation as measured by CTX-II and to a lesser extent bone degradation as measured by CTX-I closely follows indices of arthritis. Clinically perceptible arthritis is responsible for immediate damage, which will become visible on plain x rays only much later.

Adult↗
PubMed2006

Longitudinal course of depression symptoms in multiple sclerosis.

BACKGROUND: Despite the high lifetime prevalence of depression in multiple sclerosis (MS), its longitudinal course is poorly understood. OBJECTIVE: To examine the longitudinal course of and reliable change in different depression symptom clusters in MS, and the longitudinal association of interferon beta treatment and coping with depression symptoms. METHODS: 53 MS patients were examined at two time points three years apart on the Beck Depression Inventory (BDI) and the Chicago Multiscale Depression Inventory (CMDI). RESULTS: Correlations from time 1 to time 2 for BDI, CMDI-total, CMDI-evaluative scale, and CMDI-vegetative scale were all highly significant, and reliable change indices reflected little change over time. In contrast, the correlation over time for the CMDI-mood scale was significantly lower (p<0.05) than the CMDI-evaluative and CMDI-vegetative scale correlations, and over 40% of patients showed reliable change. Patients who improved in their mood showed increased use of active coping, while patients who worsened showed decreased active coping strategies; the latter were also significantly more likely to have been taking interferon beta drugs at both time points than patients who did not change in their mood functioning. CONCLUSIONS: Mood symptoms of depression are significantly more variable over time than neurovegetative or negative evaluative symptoms in MS patients. Decreased use of active coping strategies may put patients at risk of increased depressed mood, whereas increased use of active coping may result in decreased depressed mood longitudinally. Interferon beta use may put patients at risk of increases in depressed mood.

Adaptation, Psychological↗
PubMed1988

Rate of increase in pulmonary distensibility in a longitudinal study of smokers.

To examine the hypothesis that an abnormally rapid increase in pulmonary distensibility occurs in cigarette smokers, 39 adult smokers (24 men), mean age 47 (SD 8) years, who were not disabled were studied on two occasions over a mean interval of 3.5 (SD 0.5) years. Exponential analysis of static pressure-volume data obtained during deflation of the lungs gave the exponent K, an index of distensibility. Total lung capacity (TLC) was measured in a body plethysmograph. At entry into the longitudinal study means values for K and static recoil pressure in the 39 smokers available for follow up were similar to those obtained in the original group of 101 smokers (73 men), mean age 42 (SD 11) years, in the cross sectional study. Over the interval of the study, ln K and TLC increased and FEV1 decreased at rates greater than those found in a previous longitudinal study of 34 non-smokers (24 men), mean age 42 (SD 15) years. In the longitudinal study of smokers the observed changes in K and in recoil pressure over the interval of study were greater than the values obtained from the regression slopes found in the cross sectional study of smokers. On the basis of the regression model used previously in the longitudinal study of non-smokers, the age coefficient for ln K was greater than that found in the non-smokers (p less than 0.01). The regression model also showed that the slope of ln K on age increased in older subjects. Because K is related to peripheral airspace size, a rapid rate of increase in K identifies smokers in whom airspace size is increasing abnormally rapidly. In this study the rate of increase in K and the variation between subjects was sufficient to explain the magnitude of the increased pulmonary distensibility found in cigarette smokers who present with emphysema.

Adult↗
PubMed1996

Longitudinal effects of change in body mass on measurements of ventilatory capacity.

BACKGROUND: In several longitudinal studies changes in body mass and in forced expiratory volume in one second (FEV1) have been found to be negatively correlated. This paper tests the hypothesis that failure to allow for the association can lead to error in the interpretation of longitudinal measurements of ventilatory capacity. METHODS: Male shipyard workers (n = 1005) were assessed on two occasions with an average interval between measurements of 6.9 years. A respiratory symptoms questionnaire, detailed anthropometric measurements, and dynamic spirometric tests were undertaken. Multiple regression analysis was used to identify variables which contributed to the changes in lung function. RESULTS: After allowing for age and growth in stature, a change in body mass of 1 kg was, on average, associated with a mean (SE) converse change in FEV1 of 17.6 (2.0) ml, and in forced vital capacity (FVC) of 21.1 (2.5) ml. Neglect of changes in body mass (which in this context reflected changes in body fat) led to underestimation of the longitudinal decline in FEV1 with age and failure to detect significant improvements in FEV1, both in smokers following discontinuation of smoking and in shipyard welders and caulker/burners as a consequence of leaving their employment. The estimated peak ages and associated peak levels of the indices were found to differ, depending on whether or not they were expressed at constant body mass. CONCLUSIONS: Neglect of changes in body mass can lead to erroneous conclusions being drawn from longitudinal measurements of FEV1.

Adolescent↗
PubMedDate not supplied

Predictors of longitudinal changes in pulmonary function among swine confinement workers.

OBJECTIVE: To determine predictors of longitudinal changes in pulmonary function in swine confinement workers. DESIGN: Longitudinal study conducted from November 1989 to June 1991 and January 1994 to May 1995. SETTING: Swine confinement workers in Saskatchewan. PARTICIPANTS: Forty-two swine confinement workers who were studied in 1989/90 and studied again in 1994/95. RESULTS: Of 98 male swine confinement workers (mean age SD 36.3 11.1 years) studied at baseline, 42 were studied again five years following. Complete information on baseline across-shift pulmonary function (preshift forced expiratory volume in 1 s [FEV1], forced vital capacity [FVC], and every 2 h FEV1 and FVC during the shift), and five-year follow-up pulmonary function (with FEV1 and FVC) were available on all 42 subjects. Mean across-shift changes (preshift measurement to last measurement of the day) at baseline were -159. 8 61.7 mL in FEV1 and -35.3 65.6 mL in FVC. Mean annual rate change between baseline and follow-up for FEV1 was -53.9 61.7 mL/year and for FVC -48.9 71.6 mL/year. After adjusting for age, height, smoking and hours spent in the barn, the baseline across-shift change in FEV1 and FVC was a significant predictor of annual rate change in FEV1 (P=0.01) and FVC (P=0.02), respectively. To determine the effects of indoor air quality on longitudinal lung function decline, indoor air environmental measurements were analysed. Complete information on respiratory health and indoor air quality was available on 34 of the 42 subjects. Assessment of indoor environment of swine barns included a summer and winter measurement for airborne dust, gases and endotoxin levels. After adjusting for age, height, smoking, ammonia and hours spent in the barn, the endotoxin level (Eu/mg)was a significant predictor of annual rate change for FEV1 but not FVC. CONCLUSIONS: These results suggest that shift change is an important predictor of longitudinal changes in lung function in swine confinement workers and that endotoxin exposures may mediate annual decline in FEV1 in these workers.

Adolescent↗
PubMedDate not supplied

Changes in bicycle ergometer test performance and survival in men and women from 50 to 60 and from 70 to 80 years of age: two longitudinal studies in the Glostrup (Denmark) population.

BACKGROUND: During the aging process longitudinal changes for sustained work in humans are poorly understood. Only a few longitudinal follow-up studies have been published thus far, and most of them have been based on highly selected groups, such as physical education teachers or senior athletes. OBJECTIVE AND METHODS: On the basis of random samples of a general population, the purpose of this study was to analyze changes in bicycle test performance in two longitudinal designs: a 10-year follow-up period from 50 to 60 years of age, using a submaximal test protocol, and another 10-year follow-up period from 70 to 80 years of age, using indirect voluntary maximal tests. In addition, the preventive value of the bicycle test results for survival at different age levels was analyzed. The subjects in the first part of the study were members of a random sample of originally 514 men and 461 women living in the Glostrup area, close to Copenhagen, Denmark, in 1964. Of these, 367 men (71.4%) and 206 women (44.7%) were tested at the age of 50 years, and 309 men and 245 women were tested 10 years later. The subjects in the second part of the study came from the same original sample. At 70 years of age 171 men and 154 women and at 80 years of age 70 men and 68 women took part in the maximal test. RESULTS: The submaximal test results between the ages of 50 and 60 years showed a mean annual decline in body mass adjusted maximal power in sustained work (W/kg) of 0.54% in men and of 0.90% in women. Between the ages of 70 and 80 years, when the indirect maximal tests were applied, the annual decline in men was on average 1.79% and in women 3.03%. When the associations of submaximal test results at ages 50-60 years and the voluntary maximal test results at the higher ages were analyzed, a moderate positive correlation was observed with the results obtained at the age of 70 years. The survival analyses showed that the submaximal bicycle test results (W/kg body mass) at the age of 60 years had a predictive value for survival in women during the subsequent 10-year period. The same was true for the maximal test results obtained at the age of 70 years in men; a significantly larger proportion of men in the lowest quintile died during the subsequent 10 years than of those belonging to the higher quintiles. CONCLUSIONS: The changes in body mass related maximal power in sustained work observed in this population on the basis of longitudinal studies among the age groups 50-60 and 70-80 years indicated a steeper decline at the higher ages. The decline was relatively more pronounced in women than in men. However, differences in the test protocols employed at different times limit the possibilities for overall comparisons across the data. The results of the submaximal bicycle ergometer tests in middle-aged female subjects (60 years old) had a predictive value for survival over the 10 years immediately following the test; likewise, the voluntary maximal test results at higher ages predicted survival in men.

Age Distribution↗
PubMed2005

Nonlinear relations of blood pressure to cognitive function: the Baltimore Longitudinal Study of Aging.

This investigation examined cross-sectional and longitudinal relations, both linear and nonlinear, of blood pressure (BP) and its interaction with demographic and lifestyle variables to a broad spectrum of cognitive functions. Eight hundred forty-seven participants (503 men and 344 women) from the Baltimore Longitudinal Study of Aging completed tests of verbal and nonverbal memory, attention, perceptuo-motor speed, executive functions, and confrontation naming, and clinical assessment of BP on 1 to 7 occasions over 11 years. Mixed-effects regression models, adjusted for age, education, gender, alcohol consumption, smoking status, depression scores, and use of antihypertensive medications, revealed nonlinear relations of systolic BP with longitudinal change on tests of nonverbal memory and confrontation naming; cognitive decline was apparent among older (80 years) individuals with higher systolic BP. Cross-sectional findings, across testing sessions, indicated moderated U- and J-shaped relations between BP and cognitive function. Both high and low diastolic BP were associated with poorer performance on tests of executive function and confrontation naming among less-educated persons; with tests of perceptuo-motor speed and confrontation naming among nonmedicated (antihypertensives) individuals; and with executive function among older individuals. Cross-sectional linear relations included higher systolic BP and poorer nonverbal memory in nondrinkers, and higher diastolic BP and poorer working memory among less-educated individuals. Results indicate that cross-sectional and longitudinal relations of BP to cognitive function are predominantly nonlinear and moderated by age, education, and antihypertensive medications. Careful monitoring and treatment of both high and low BP levels may be critical to the preservation of cognitive function.

Aged↗
PubMed1996

Longitudinal and cross-sectional analyses of lung function in steelworkers.

We evaluated associations between dust exposure, demographic factors, and lung function by longitudinal and cross-sectional analyses in 475 steelworkers who participated in at least three spirometry tests over 5 yr between 1982 and 1991. Baseline and follow-up spirometry and changes between baseline and final follow-up assessment attributable to age, height, weight, weight gain, smoking status, pack-years, and years worked in dusty areas were examined using stepwise multiple linear regression techniques. Smoking, aging, being overweight, excessive weight gain, and dust exposure were related to a lower level and a steeper slope of decline of pulmonary function. Cigarette smoking was also an important risk factor. Dust exposure was related to the level of lung function, with a stronger effect at baseline than at follow-up. Estimated loss at baseline of FEV1, FVC, and FEV1/FVC% was 9.3, 6.4 ml, and 0.1 % per year of employment in a dusty area, respectively, whereas the association between dust exposure and longitudinal decline of lung function was weak. However, a strong relationship between weight gain and longitudinal decline of FEV1 and FVC was found. Estimated decreases in FEV1 and FVC attributable to weight gain were 4.7 and 6.3 ml per lb/yr, respectively. This work suggests that weight gain is an important determinant for longitudinal lung function decline. This large impact of weight gain in the decline of lung function in a middle-age and relatively overweight working population has not been previously reported. Additional work needs to be undertaken to show the strength of this relationship in other populations.

Adult↗
PubMed1986

Longitudinal changes in forced expiratory volume in one second in adults. Methodologic considerations and findings in healthy nonsmokers.

Longitudinal changes in FEV1 (delta FEV1) have been examined in a sample of the general population of Tucson, Arizona. Adults with satisfactory spirometric tests in all 7 surveys performed over a period of 11 yr showed some between-survey differences in mean FEV1. Although small in absolute magnitude, such survey biases (which would be impossible to detect unless multiple spirometric tests were carried out on a relatively large group of subjects) could have a marked effect on calculated changes in FEV1 and may explain the widely divergent delta FEV1 values reported in the literature. After adjusting for survey biases, the relationships of delta FEV1 to age, sex, and body size were examined in "healthy" nonsmokers in the population who were followed for an average of 9.6 yr. The FEV1 showed an accelerating decline with age, and delta FEV1 was best explained by a model of proportional change in which it is a function of Age X Height3. Longitudinally determined delta FEV1 showed much less decline in function and a later apparent age of onset of decline than suggested by cross-sectional analyses. While small "learning effects" in longitudinal calculations cannot be excluded, most of the cross-sectional versus longitudinal differences are probably ascribable to past events that have adversely affected the FEV1 in older adults, thereby increasing cross-sectional age effects. Present findings also suggest that generally applicable "prediction equations" for delta FEV1 probably cannot be developed and that delta FEV1 values should only be compared between groups studied in an identical manner within a given study.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1998

Hypothalamic-pituitary-adrenal axis dysfunction in Alzheimer's disease: lack of association between longitudinal and cross-sectional findings.

OBJECTIVE: The authors examined longitudinal hypothalamic-pituitary-adrenal (HPA) axis function in Alzheimer's disease. METHOD: Cortisol levels of 30 patients with Alzheimer's disease and 17 healthy elderly subjects were measured before and after administration of dexamethasone. These measures were repeated at 9-month intervals in the patients with Alzheimer's disease. RESULTS: At baseline, cortisol levels were higher in the Alzheimer's disease group before and after dexamethasone administration. Although only two of the four patients whose cortisol levels were not suppressed by dexamethasone also had high cortisol levels before dexamethasone administration, basal and postdexamethasone cortisol levels were correlated. HPA axis dysfunction correlated with severity of dementia at baseline but was not stable longitudinally and did not increase with follow-up. CONCLUSIONS: There was no association between longitudinal and cross-sectional findings. The longitudinal data were not consistent with a role for the glucocorticoid cascade hypothesis (that hippocampal cell loss in Alzheimer's disease results in hypercortisolism, which in turn acts as a co-factor in further degeneration) in the pathophysiology of mild and moderate Alzheimer's disease.

Aged↗
PubMed1999

Variations in dental anxiety among middle-aged and elderly women in Sweden: a longitudinal study between 1968 and 1996.

Cross-sectional studies have shown that older individuals are significantly less dentally anxious than younger ones. However, research has not been able to show if this is a cohort effect or an effect of fear declining with age. If it is a cohort effect, dental anxiety among the elderly may pose a greater-than-expected problem for the providers of dental services. With the exception of longitudinal studies in children and a three-year follow-up on adults, no truly longitudinal epidemiological studies concerning dental anxiety have been performed. The aim of this project was to investigate how dental anxiety changes with aging. In a longitudinal population study of women in Göteborg, Sweden, starting in 1968, 1462 women aged 38 to 54 participated. A representative subsample of 778 women took part in a psychiatric examination where an investigation of dental anxiety was included. The same questions were also included when these women were re-examined in 1974, 1992, and 1996. Three hundred seventy-five women were still eligible for investigation in 1996. In 1968-69, 48 (12.8%) of the participating women assessed themselves as "very afraid" or "terrified" when visiting the dentist, and in 1996 the frequency was 21 (5.6%) among the same women. In 1968-69, 180 women (48%) reported no dental anxiety when visiting the dentist, and 28 years later the frequency was 230 (61%). In the three youngest age groups, dental anxiety decreased significantly (p < 0.001) over the 28-year period. Older compared with younger women reported significantly less dental anxiety, and this was an age effect rather than a cohort effect. Thus, this longitudinal study supported the hypothesis that dental fear, like many other general and specific phobias, declines with age.

Age Distribution↗
PubMedDate not supplied

Longitudinal research in learning disabilities: report on an international symposium.

In June of 1995 an international symposium on longitudinal research in learning disabilities (LD) was held in Missillac, France. The purpose of the symposium was to bring together an international panel of experts in this area to promote international dialogue on longitudinal research in LD, define and develop guidelines for conducting such research, identify problems inherent in this type of research and methods to alleviate them, and establish research priorities. This article synthesizes and highlights the information that emerged from individual presentations and ensuing discussions. Generic considerations regarding longitudinal research are presented; however, particular emphasis is given to the confluence of longitudinal research and learning disabilities.

California↗