Biomedical subjects

I W Schmidt

Publications and source records attributed to I W Schmidt.

8 recordsLinked to original sources

PubMed2001

Relations between subjective evaluations of memory and objective memory performance.

Several explanations for the weak relations between subjective memory judgements and objective memory performance were investigated in two groups of normal older adults. Group 1 sampled a general population (mean age 61.6 yr., range 46-89), while Group 2 sampled subjects who were on a waiting list for memory training (mean age 63.0 yr., range 45-85 years). In both groups, subjective memory judgments were assessed with global ratings of memory capacity and with ratings of frequency of forgetting in specific memory situations. Memory performance was assessed with several well-known tests and with recently developed tests for domain-specific aspects of memory. Most tests concerned episodic memory. Study 1 also included measures of semantic, incidental and working memory. Study 2 further examined the influence of the domain-specificity of objective and subjective measures for remembering names, intentions, and texts. Relations between memory self-reports and performance were weak in both groups and for all kinds of tests. Against expectations, the low correlations could not be explained by differences between ecological and laboratory tests or incidentally and intentionally remembered information, or by differences between specific failures compared to global, stereotyped judgments. Surprisingly, correlations did not increase when subjective and objective measures assessed the same ability, like remembering names. Also noncognitive variables (mood and lifestyle) did not influence the relations. The (weak) relations between subjective and objective memory measures were comparable for subjects over and under 65 years of age. Furthermore, relations were comparable for the general population sample and the memory compliant group.

Aged↗

PubMed2001

[Memory strategies of elderly: training efficacy].

Does memory strategy training improve the quantity and quality of reported strategy use of normal older adults (N = 111, mean age 63 years, range 46-85 years) in daily life? Three strategy training conditions, remembering names (N = 26), intentions (N = 20) and verbal information (N = 20) and an educational training (N = 23) were compared to a test-retest control group (N = 22). Strategy use was assessed with a Strategy Frequency Questionnaire (investigating the reported frequency of strategy use on five scales: encoding, retrieval, general, external and no strategies) and a Memory Situations Questionnaire (investigating the preference of strategies in specific situations). Three months after training, the frequency of strategy use as assessed by the scale scores had not increased more in the strategy training conditions than in the control condition. No demographic or psychological characteristics were identified that could predict which individuals were most likely to change their strategy use. When strategies were analyzed separately, only after names training a specific effect was demonstrated, indicating that subjects more frequently used the strategy for remembering names (association) at follow-up. With regard to changes in the strategies used in specific situations, subjects in the names and intention training conditions reported an increase in the use of the trained strategies on names and prospective situations respectively. Moreover, there was some evidence of a generalization of training to strategies that were not directly dealt with during training. The control group showed that repeated practice with memory tests may result in changes in strategy use in specific situations, which are not always for the better, how-ever.

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PubMed2000

[Suboptimal health and memory performance of elderly].

The influence of health-related incidents on memory test performance and subjective memory ratings was assessed in a) a group of healthy older adults recruited via the register of population (group 1: N = 117, mean age 62 years, range 46-89) and b) a group of healthy older subjects having memory complaints and applying for memory training (group 2: N = 111, mean age 63 years, range 45-85). The study tries to cross-validate a previous study, where the presence and frequency of health-related incidents were related to cognitive performance. The presence of 9 categories of health-related incidents (consultation of a neurologist, systemic diseases, repeated mild concussions, repeated anaesthesia, use of psychotropic medication, alcohol use, other neurotoxic factors, such as exposure to organic solvents, psychiatric disorders, birth complications or developmental problems) was assessed in a semi-structured interview. Memory performance was assessed with a battery covering different aspects of memory. Memory self-ratings were assessed with questionnaires asking for frequencies of memory failures and a general judgement of memory capacity. Health-related incidents occurred in about half of both subject groups and were not related to age or other demographic characteristics. In both subject groups, the presence, nor the number of health-related incidents was related to memory performance or memory complaints and there was no interaction with age. The results are not in agreement with the notion that health-related indices explain age differences in cognitive performance.

Age Factors↗

PubMed2000

[Memory tests in healthy elderly: age factors and norms].

The study aimed to assess the strength of age effects on both standard laboratory and ecological memory tests and the psychometric qualities of these tests. Furthermore, norm data are constructed. Memory performance was assessed in a random group of older adults (mean age 62 years, range 46-89) and a group of older adults having memory complaints who applied for memory training (mean age 63 years, range 45-85). Age effects were found on almost all memory tests, whether artificial laboratory or more ecological tests were used. Age effects remained generally present after correction for educational level. Retest reliabilities of the ecological memory tests did not differ systematically from those of standard laboratory tests. However, not all tests showed satisfactory retest reliabilities, this was even true for tests often used in clinical settings. For tests with retest reliabilities above r = .65 norms corrected for age and educational level were provided. The group of older adults having memory complaints performed on average better than the random group of older adults from the population. In the first group, higher performance thresholds should be employed in assessing whether memory performance is deviant.

Age Factors↗

PubMed1999

[Memory strategies in the elderly].

The frequency and preference of memory strategies were investigated in a group of independently living older adults (N = 111, 45-85 year) who were interested in memory training because of subjective and objective memory problems. Mokken scale analysis identified, besides the use of 'no strategy', four strategy scales, viz. encoding, retrieval, general, and external strategies. These five scales allowed for a differentiated analysis of strategy use. Frequency judgments showed that external strategies were used most frequently, followed by retrieval strategies. Encoding strategies were used least often. Reports on the preference of strategies in specific situations showed that subjects reported to use specific strategies in the majority of situations, although here too external strategies were used most generally. Strategy reports were more related to psychological variables (mental speed, primary memory ability, need for cognition and memory complaints) than to demographic characteristics (age, educational level and sex). The explained variances, however, were low which suggests substantial individual differences in use and preference of memory strategies.

Adaptation, Psychological↗

PubMed1998

[Memory and learning abilities in everyday life of the elderly].

Self-evaluations by adults (varying in age from 45-92 years) of their memory and learning abilities were investigated and related to performance on laboratory and ecological memory tasks. Hardly any association was found between subjective and objective measures. Self-evaluations were strongly influenced by (systematically varied) frames of reference: optimistic in comparisons with other people, pessimistic in comparisons with their own previous level of functioning. The most frequent problems were 'learning something new' and 'remembering names'. In contrast to external memory aids, cognitive strategies were rarely used spontaneously. Strategy training led to significant improvement of performance, that remained stable at follow-up. A further opportunity for improving performance was realized by ergonomic adaptations of computerized systems (teleshopping). Problems in learning to use such systems were strongly reduced by decreasing the load on working memory and by adapting the system to existing knowledge and skills of the users. A general observation in the different projects was that age-differences could explain only a small percentage of the variance in subjective and objective memory measures.

Adaptation, Psychological↗

PubMed1997

[Memory training for remembering names: initial results in the healthy elderly].

In this study, a memory training program for remembering names was developed. It was assumed that names are remembered better if they have meaning. The effect of training is compared with two control conditions a) a placebo training, aimed at reducing worries about forgetfulness by giving information about memory and aging and b) a retest control group. Participants were healthy persons over 43 years old (M = 70 years) having subjective memory complaints and objective memory problems. The effect of training is evaluated with tasks for remembering names. Because the learned memory strategy can be applied to these tasks, these are called target memory tests. Other evaluation measures concerned remembering verbal information and intentions. These are called control memory tests, because the memory strategy learned cannot be applied directly. In accordance with the expectations, performance in the placebo training group (n = 10) did not improve more than in the retest control group (n = 11). The names training group (n = 13) improved more than both control groups on tests for remembering names. This improvement was maintained for at least three months after training. As expected, the improvement in performance on the target memory tests did not generalize to the control tasks, because of the specificity of the learned strategies.

Aged↗

PubMedDate not supplied

Flexible adaptation to changing task demands in severe closed head injury patients: a driving simulator study.

The assessment of fitness to drive in patients with closed head injury (CHI) does not usually include executive functioning. Executive functions may be particularly important for the tactical (e.g. anticipatory adaptation of speed) and strategical (e.g. choice of route and time) aspects of driving. The literature lacks evidence on the tactical aspects, which are critical in the assessment of actual driving. Executive functioning was therefore assessed in a task context relevant to tactical decision making in driving. Twenty very severe chronic CHI patients and 20 healthy control subjects were tested with a driving simulator test and an extended neuropsychological test battery. In the driving simulator test, executive function was operationally defined as the flexible adaptation to changing task demands. A specific feature of the test was the experimental control for slow information processing, a persistent sequel of severe CHI. Given this control for slow information processing, it was found that patients were unimpaired in their flexible adaptations. Similar findings were obtained with a neuropsychological test battery. Patients were consistently slower, but planning and flexibility were found to be unimpaired.

Journal Article↗