Cognitive functioning in patients with suspected chronic toxic encephalopathy: evidence for neuropsychological disturbances after controlling for insufficient effort.

OBJECTIVES: Chronic toxic encephalopathy (CTE) caused by long term occupational exposure to organic solvents is still a controversial disorder. Neuropsychological testing is the cornerstone for diagnosing the syndrome, but can be negatively influenced by motivational problems. In this nationwide study, we investigated the neuropsychological functioning and psychological symptoms of a large group of patients with suspected CTE, and ruled out alternative explanations for their complaints, including suboptimal performance due to insufficient effort. METHODS: We studied participants with suspected CTE (n = 386) who were referred for further diagnosis to the Netherlands Centre of Occupational Diseases in the period 1998-2003 and who had completed the entire diagnostic protocol. Patients were excluded if there was the slightest suspicion that test performance had been negatively influenced by insufficient effort (n = 221), or if comprehensive assessment identified an alternative diagnosis (n = 80). Insufficient effort was defined by a combination of three indices. The neuropsychological test scores of the patient group (n = 85) were compared with those of a control group of building trade workers matched for sex, age, and educational level (n = 35). RESULTS: The patient group had significantly more psychological complaints and performed significantly worse than the control group on tests of speed of information processing and memory and learning. However, only a small percentage of the patients had clearly abnormal scores for cognitive speed (9%) or memory (8%). Attention, verbal abilities, and constructional functions were not disturbed. Exposure duration and cognitive complaints were significantly correlated, whereas the correlation between exposure duration and neuropsychological domain scores was not significant. CONCLUSIONS: Insufficient effort was present in a substantial part of the patient group. After minimising the likelihood that insufficient effort negatively influenced neuropsychological scores, we still found neuropsychological deficits in speed of cognitive processing and memory; however, these scores were clearly abnormal only in a minority of patients with suspected CTE. Screening instruments should focus on these domains.

Construct validity of concepts of attention in healthy controls and patients with CHI.

The present study aimed to examine the construct validity of three aspects of attention, namely focused, divided, and supervisory control of attention. Factor-analytic techniques were applied to scores of healthy subjects on a series of neuropsychological tests tapping these aspects of attention. The two components found did not match the hypothesized aspects and were labeled as Memory-driven Action and Stimulus-driven Reaction. The second question was whether the same components could be found in a group of patients with CHI. The pattern of attentional functions found in healthy subjects had changed qualitatively in patients with CHI. A possible explanation for this result in terms of a shift from automatic to controlled processing is discussed.

Slight cognitive impairment and magnetic resonance imaging abnormalities but normal school levels in children treated for acute lymphoblastic leukemia with chemotherapy only.

OBJECTIVES: To investigate persistent neuropsychologic late effects in children treated for acute lymphoblastic leukemia at a young age with chemotherapy only by means of serial neuropsychologic assessments (NPAs), magnetic resonance imaging (MRI) of the brain, and evaluation of school levels. STUDY DESIGN: Consecutive patients (n = 17) had 2 extensive NPAs (12 psychometric measures) after cessation of therapy. Test results were compared with those of both healthy control subjects and 28 previously treated children who received cranial irradiation. MRI findings were related to test scores. School levels were evaluated in the patients and their healthy siblings. RESULTS: Initial participation (n = 17) and availability of the study group after 8 years of follow-up were 100%. Significant group differences between patients who received chemotherapy and healthy control subjects were found for memory and fine-motor functioning. The 17 patients combined showed 16 deficits on various test measures. MRI abnormalities were seen in 6 children, but these did not correlate with cognitive performance. No differences in school levels were seen when the patients who received chemotherapy were compared with their siblings. The current nonirradiated patients demonstrated significantly better test results and significantly fewer learning disabilities and MRI abnormalities than did the previously irradiated group. CONCLUSION: Treatment with chemotherapy only may be associated with some cognitive impairment. However, these children attained normal school levels.

[Cognitive impairments among older drivers: medical examination and driving test]. / Autorijden bij ouderen met cognitieve functiestoornissen: medische keuring en rijtest.

The aim of this study was to gain insight in the prevalence of cognitive impairments among active older drivers and in driving performance of cognitively impaired ones. The study was implemented in the existing Dutch relicensing procedure for older drivers and consisted of three evaluation moments: a medical screening (for all subjects), a neuropsychological assessment and a test-drive (for candidates with cognitive impairments). In total, 2992 drivers were medically evaluated. In 4% of cases indications for impaired cognitive functioning were observed that could be evaluated and confirmed with neuropsychological tests. Eighty subjects performed an on-road test. Of these subjects, 57% were allowed to renew their driver's license, while in the remaining 43% no new licenses or restricted licenses were issued. During the test-drive, slow reactions and attention deficits were the most important causes for impaired fitness to drive.

[Memory strategies of elderly: training efficacy]. / Geheugenstrategieën van ouderen: te trainen?

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.

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.

Rehabilitation of stroke patients with apraxia: the role of additional cognitive and motor impairments.

PURPOSE: The present study investigated which additional cognitive and motor impairments were present in stroke patients with apraxia and which of these factors influenced the effects of treatment. METHOD: A group of 33 patients with apraxia were treated according to the guidelines of a therapy programme based on teaching patients strategies to compensate for the presence of apraxia. Patients were treated at occupational therapy departments in general hospitals, rehabilitation centres and nursing homes. The outcome of the strategy training was studied in a pre-post test design; measurements were conducted at baseline and after 12 weeks of therapy. The pretreatment scores of the patients with apraxia were compared to normscores and scores of a control group of patients without apraxia (n = 36) to investigate which impairments are present. The following variables were analysed in order to determine which factors influence outcome: additional neuropsychological deficits (comprehension of language, cognitive impairments due to dementia, neglect and short term memory), level of motor functioning, severity of apraxia and performance on activities of daily living (ADL), and some relevant patient characteristics (gender, age, type of stroke, time since stroke, and location of treatment). RESULTS: The results showed that the presence of apraxia is associated with the presence of additional cognitive and motor impairments. The successful outcome of strategy training was not negatively influenced by cognitive comorbidity. The outcome seemed to be more prominent in patients who were more severely impaired at the start of rehabilitation in terms of the degree of motor impairments, the severity of apraxia and the initial ADL dependence. The ADL observations, however, displayed a ceiling effect, which was taken into account in discussing the results. Demographic variables, especially age, did not predict the outcome of treatment. CONCLUSIONS: We suggest that the effect of this training is stronger in more severely disabled patients. However, neither the presence of additional cognitive impairments nor the severity of motor problems nor old age should be an indication for refraining from treating apraxia.

Executive functioning, attention and frontal lesions in patients with chronic CHI.

To study the presence and nature of dysexecutive problems after CHI, a series of unstructured tasks tapping executive functioning were selected. These were administered to a group of 51 participants with CHI in the chronic stage (i.e. several years post-injury) and to 45 healthy controls. In addition, well-known structured tests of attention and planning were administered. Of the executive tasks, only the Executive Route Finding task showed a significant difference between both groups. A multivariate analysis on the attention tests showed a significant difference between groups, indicating that patients in the chronic stage still process information slower than controls. Within the patient group, patients with and without frontal focal lesions were also compared on executive and attention tests. No differences were found with respect to the latter. However, patients with frontal lesions performed worse on a measure of the Executive Route Finding task. It is concluded that patients with CHI, especially when they have frontal damage, have to rely more heavily on externally provided cues, but this dysexecutive problem can only be demonstrated in tasks that resemble daily life tasks by providing very little structure.

[Memory tests in healthy elderly: age factors and norms]. / Geheugentests bij gezonde oudere mensen: leeftijdseffecten en normen.

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.

Prevalence of apraxia among patients with a first left hemisphere stroke in rehabilitation centres and nursing homes.

OBJECTIVE: To investigate the prevalence of apraxia in patients with a first left hemisphere stroke. SUBJECTS: Left hemisphere stroke patients staying at an inpatient care unit of a rehabilitation centre or nursing home and receiving occupational therapy (n = 600). MEASURES: A short questionnaire on general patient characteristics and stroke-related aspects was completed by occupational therapists for every left hemisphere stroke patient they treated. A diagnosis of apraxia or nonapraxia was made in every patient, on the basis of a set of clinical criteria. RESULTS: The prevalence of apraxia among 492 first left hemisphere stroke patients in rehabilitation centres was 28% (96/338) and in nursing homes 37% (57/154). No relationship was found between the prevalence of apraxia and age, gender or type of stroke (haemorrhage or infarct). CONCLUSIONS: This study shows that approximately one-third of left hemisphere stroke patients has apraxia.

[Suboptimal health and memory performance of elderly]. / Suboptimale gezondheid en geheugenprestaties van ouderen.

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.

[Cognitive screening test: short and long version]. / De Cognitieve Screening Test: kort en lang.

Three versions of the Cognitive Screening Test (CST), varying in length from seven to 20 items, are compared using the original data. The shortest version, the CST-7, is not inferior to the longer CST-14 and CST-20. Various psychometric properties are compared. According to the Mokken nonparametric IRT scaling technique, all three CST versions can be considered unidimensional. The Mokken scaling indices H and rho hardly differ in the three versions of the CST. The alpha indices from Classical Test Theory are also very comparable, as is the very good sensitivity and specificity (around 95%). Age and gender have no significant effect on the classification success of the CST-7. Cross-validation of the promising properties of this very short screening instrument is recommended.

Recovery versus retest effects in attention after closed head injury.

Recovery in 60 patients with a closed-head injury (CHI) in the first year posttrauma was assessed repeatedly with a series of attention tests. A matched group of healthy subjects was tested at the same intervals to allow us to control for practice effects. The results of a multilevel analysis for longitudinal data show retest effects in all but one of the tests. Patients performed more poorly on all tests, but their results on each test appeared to show recovery over time. The indicator of recovery was an improvement in test performance that was greater than the retest effect shown by the controls. On most tests, the performance of the more severely injured patients was initially worse, but showed more recovery over time. Test results differed with respect to changes over time, sensitivity to severity of injury, and subject specific characteristics like age and vocational level. Recovery rate was not related to age or vocational status. Despite their recovery, the patient group was still impaired 1 year posttrauma on all tests sensitive to mental slowness. Outcome after 1 year, scored on a modified Glasgow Outcome Scale, was predicted to a small extent by PTA duration and initial performance on the RT-Distraction task. Return to work 2 to 5 years posttrauma was predicted by initial performance and improvement over time on the Stroop Color Word Test.

[Memory strategies in the elderly]. / De geheugenstrategieën van ouderen.

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.

A diagnostic test for apraxia in stroke patients: internal consistency and diagnostic value.

The internal consistency and the diagnostic value of a test for apraxia in patients having had a stroke are presented. Results indicate that the items of the test form a strong and consistent scale: Cronbach's alpha as well as the results of a Mokken scale analysis present good reliability and good scalability. The diagnostic value of the test was determined by comparison of test results in three groups of patients: 44 stroke patients with apraxia (patients), 35 stroke patients without apraxia (patient controls), and 50 healthy nursing home residents with no history of stroke (normal controls). The diagnostic value is expressed by means of the sensitivity and specificity and the predictive value of the test. In addition, Receiver Operator Characteristics (ROC) curves are presented. The sensitivity and specificity of the apraxia test appear to be good: all values are higher than 80%. The test also has high predictive value. The ROC curves illustrate that the test is sufficiently discriminative to allow a differentiation between persons with apraxia and persons without apraxia.

Outcome of strategy training in stroke patients with apraxia: a phase II study.

OBJECTIVE: Evaluation of a therapy programme for stroke patients with apraxia. The programme is based on teaching patients strategies to compensate for the presence of apraxia. This programme was designed for assessment and treatment by occupational therapists. DESIGN: The outcome was studied in a pre-post test design. Measurements were conducted at baseline and 12 weeks later. SUBJECTS: Thirty-three stroke patients with apraxia were treated at occupational therapy departments n general hospitals, rehabilitation centres and nursing homes. MAIN OUTCOME MEASURES: The following measurements were conducted: an apraxia test, a motor functioning test, observation of activities of daily living (ADL), Barthel Index, and an ADL questionnaire for the therapist and the patient. RESULTS: The patients showed large improvements in ADL functioning on all measures and small improvements on the apraxia test and the motor functioning test. The effect sizes for the disabilities, ranging from 0.92 to 1.06, were large compared to the effect sizes for apraxia (0.34) and motor functioning (0.19). The significant effect of treatment is also seen when individual improvement and subjective improvement are considered. Measured with the Barthel Index for instance, 71% of the patients improved. CONCLUSIONS: These results suggest that the programme seems to be successful in teaching patients compensatory strategies that enable them to function more independently, despite the lasting presence of apraxia.

[Memory and learning abilities in everyday life of the elderly]. / Geheugen en leervermogen in het dagelijks leven van ouderen.

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.

[Memory training for remembering names: initial results in the healthy elderly]. / Geheugentraining voor het onthouden van namen: eerste resultaten bij gezonde ouderen.

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.

[Dementia and the Dutch Reading Tests for Adults]. / Dementie en de Nederlandse Leestest voor Volwassenen.

The Dutch Adult Reading Test (DART) is a method to assess premorbid intelligence in brain damaged patients. This article describes a study in which subjects without dementia (n = 25), with mild dementia (n = 11) and moderate to severe dementia (n = 11) were tested with the DART. DART-scores of the no dementia and mild dementia groups did not differ, but were significantly lower in moderate to severe dementia. So, the DART appears to be sensitive to more severe cerebral pathology as occurs in more advanced dementia, but is very useful with patients with mild cognitive deterioration. For the first time the test-retest-reliability of the DART was determined: r = 0.87 to 0.98. Except in the severe dementia group the DART strongly correlates with educational level.

Deficits of attention after closed-head injury: slowness only?

The performance of a group of 60 severely closed-head-injured patients in the subacute stage of recovery on a series of tests addressing focused, divided, and sustained attention, and supervisory attentional control was compared to the performance of a matched group of 60 healthy controls. Patients performed significantly worse on each test with time pressure (those addressing focused and divided attention), indicating basic slowness of information processing, and on the self-paced tasks for supervisory attentional control. No indication was found of a sustained attention deficit. In a subsequent analysis the influence of the demonstrated slowness of information processing and other possibly confounding cognitive factors was controlled for by means of covariance analyses. This resulted in a disappearance of group differences on tests for focused and divided attention. The only difference that remained concerned a test for supervisory attentional control.