Cellulose microfibril deposition: coordinated activity at the plant plasma membrane

Plant cell wall production is a membrane-bound process. Cell walls are composed of cellulose microfibrils, embedded inside a matrix of other polysaccharides and glycoproteins. The cell wall matrix is extruded into the existing cell wall by exocytosis. This same process also inserts the cellulose synthase complexes into the plasma membrane. These complexes, the nanomachines that produce the cellulose microfibrils, move inside the plasma membrane leaving the cellulose microfibrils in their wake. Cellulose microfibril angle is an important determinant of cell development and of tissue properties and as such relevant for the industrial use of plant material. Here, we provide an integrated view of the events taking place in the not more than 100 nm deep area in and around the plasma membrane, correlating recent results provided by the distinct field of plant cell biology. We discuss the coordinated activities of exocytosis, endocytosis, and movement of cellulose synthase complexes while producing cellulose microfibrils and the link of these processes to the cortical microtubules.

Increased cortical atrophy in patients with Alzheimer's disease and type 2 diabetes mellitus

BACKGROUND

The risk of Alzheimer's disease (AD) is increased in type 2 diabetes (DM2). This increased risk has been attributed to vascular comorbidity, but other mechanisms, such as accelerated ageing of the brain, have also been implicated.

OBJECTIVE

To determine whether AD in patients with DM2 is associated with an increased occurrence of vascular lesions in the brain, by increased cerebral atrophy, or a combination of both.

METHODS

In total, 29 patients with AD and DM2 and 58 patients with AD and without DM2 were included in the study. Clinical characteristics were recorded, and a neuropsychological examination and magnetic resonance imaging (MRI) scan were performed. MRI scans were rated for cortical and subcortical atrophy, medial temporal lobe atrophy, white matter lesions, and infarcts.

RESULTS

The neuropsychological profiles of the two groups were identical. Patients with AD and DM2 had increased cortical atrophy on MRI (p<0.05) compared with the non-DM2 group. In addition, infarcts were more common (odds ratio 2.4; 95% CI 0.8 to 7.8), but this effect did not account for the increased atrophy. The other MR measures did not differ between the groups.

CONCLUSION

The results suggest that non-vascular mechanisms, leading to increased cortical atrophy, are also involved in the increased risk of AD in DM2.

Brain atrophy and lesion load as explaining parameters for cognitive impairment in multiple sclerosis

Multiple sclerosis (MS) is a multifocal demyelinating disease of the central nervous system, with lesions widespread through the brain and spinal cord. An important manifestation is cognitive impairment, which, though difficult to measure, may have a major social impact. To better understand the relationship between structural tissue damage and cognitive impairment, we examined the extent and spatial distribution of brain lesions, as measured by magnetic resonance imaging (MRI), in relation to abnormal cognitive performance as measured by the Brief Repeatable Battery (BRB) in 82 MS patients. Possible confounders, like fatigue, pain and depression were also assessed. Brain MR image analysis included hyperintense T2 and hypointense T1 lesion load in the whole brain and the four lobes separately, as well as whole brain volume measurements. Cognitive impairment (defined as more than two abnormal tests) was found in 67% of the patients. Moderately strong correlations were found between the subtests of the BRB and the lesion loads in the brain regions hypothesized to be associated with that cognitive test, although these correlations were in general not much stronger than those between the subtests and the overall lesion load (due to strong interrelationships). The Spatial Recall Test correlated best with parietal lesion load; the Symbol Digit Modalities Test, the Paced Auditory Serial Addition Task (PASAT) and the Word List Generation best with frontal, parietal and temporal lesion load; while the Verbal List Generation Test Index correlated only with atrophy. Atrophy and lesion load were the main factors determining the test scores, explaining 10-25% of the variance in the test results, and were more important than fatigue, pain and depression; only depression had a minor, but significant, additional effect on the PASAT. In conclusion, cognitive impairment in MS is moderately dependent on amount (and distribution) of structural brain damage, especially in the more physically impaired patients group.

Biomarker profiles and their relation to clinical variables in mild cognitive impairment

The aim of the study was to compare clinical variables between MCI patients at different risk for Alzheimer's disease (AD) according to their biomarker profile. Fifty-four percent out of 39 MCI patients had a low Abeta42 and high tau in cerebrospinal fluid (CSF) (high-risk), 26% either a low CSF Abeta32 or high CSF tau (intermediate-risk) and 20% a normal CSF Abeta42 and tau (low-risk). Both high-and intermediate-risk subjects differed from the low-risk group in episodic memory, executive functions and the preclinical AD scale (PAS),which combines a set of clinical parameters. Subjects at high risk did not differ from subjects with an intermediate risk. Abeta42 levels correlated with the MTA and PAS scores, tau levels with episodic memory. These correlations suggest that the biomarkers are not independent when compared to the other AD markers. Longitudinal studies are necessary to interpret the correlations between biomarkers, imaging, and neuropsychological markers.

Visual association test to detect early dementia of the Alzheimer type

BACKGROUND

The visual association test (VAT) is a brief learning task based on imagery mnemonics. The test materials consist of six line drawings of pairs of interacting objects or animals-for example, an ape holding an umbrella. The person is asked to name each object and, later, is presented with one object from the pair and asked to name the other.

OBJECTIVE

To verify that the task induces robust incidental or effortless learning (study 1), and to study the efficiency of the test as a discriminator between early dementia of the Alzheimer type (DAT) and non-demented people (study 2) and non-DAT types of dementia (study 3).

METHODS

Study 1: two groups of elderly volunteers were administered the VAT. The stimuli were presented in the interactive fashion to group A-for example, a monkey carrying an umbrella (n=83)-and side by side to group B-for example, separate pictures of a monkey alone and an umbrella alone (n=79). Group B received learning instructions, but group A did not. Study 2: three groups of subjects were selected from a population based follow up study: incident DAT cases (n=24), cognitively declining subjects not diagnosed with dementia (n=21), and stable non-demented subjects (n=204). Test performance of the non-demented group at baseline was compared with that of patients with DAT at the time of their diagnosis, of patients with DAT a year before their diagnosis, and of non-demented declining subjects at baseline. Study 3: subjects were patients referred for neuropsychological assessment because of suspected dementia. They were diagnosed by consensus criteria of various dementia syndromes.

RESULTS

Study 1: recall was more than twice as high in group A as in group B. Thus interactive presentation, even in the absence of learning instructions, enhances learning. Study 2: at a level of 97.5% specificity, the VAT had a sensitivity of 87.5% for DAT cases at the time of diagnosis and 66.7% one year before diagnosis. The cognitively declining group scored significantly lower on the VAT at baseline than the non-demented group. The VAT discriminated more effectively than both the MMSE and the six item picture learning task from the CAMCOG. Study 3: VAT scores were significantly lower in patients with DAT (n=48) than in patients with vascular dementia (n=37), frontotemporal dementia (n=9), or subcortical dementia (n=15), but not lower than in patients with Lewy body dementia (n=7). Mean mini mental state examination scores of these groups were not significantly different. The VAT discriminated patients with DAT from patients with other types of dementia more effectively than a prose recall test. Sensitivity was 79% and specificity 69%.

CONCLUSIONS

The VAT detects with high specificity a sizeable proportion of patients with DAT a year before the diagnosis, and a low VAT score is relatively uncommon in patients with non-DAT dementia.

The brief repeatable battery of neuropsychological tests: normative values allow application in multiple sclerosis clinical practice

The Brief Repeatable Battery of Neuropsychological Tests (BRB-N) is a sensitive measure of cognitive impairment in multiple sclerosis (MS) patients. It consists of the Selective Reminding Test, the 10/36 Spatial Recall Test, the Symbol Digit Modalities Test, the Paced Auditory Serial Addition Test and the Word List Generation Test. We administered one of two parallel versions of the test battery to 140 healthy subjects to produce normative values for both versions. As expected, test scores were influenced by certain variables like age, gender and education. Although constructed as two equivalent versions, for some tests the two versions showed significant differences in test scores, which could not be explained by differences in these variables.

Early detection of Alzheimer's disease using the Cambridge Cognitive Examination (CAMCOG)

BACKGROUND

Dementia screening instruments, such as the Cambridge Cognitive Examination (CAMCOG), measure a variety of cognitive functions. However, memory impairment generally is the first sign of Alzheimer's disease (AD). It seems logical, therefore, to use only memory-related items for the early detection of AD. We divided the CAMCOG into a memory section and a non-memory section, and tested the hypothesis that the memory section predicts AD better than the non-memory section. We also provide normative data for both sections.

METHODS

Normal subjects (N = 169) and patients with incident AD (i.e. satisfying AD criteria between 1 and 3 years from baseline: N = 25) were participants in the Amsterdam Study of the Elderly (AMSTEL), a population-based longitudinal study on cognitive decline and dementia. Patients with prevalent AD (i.e. satisfying AD criteria at baseline: N = 155) were either recruited in a memory clinic or came from AMSTEL. Normal subjects were cognitively intact at baseline and remained so for at least 3 years. The CAMCOG was administered to all subjects. AD was diagnosed by DSM-III-R criteria.

RESULTS

Logistic regression analysis showed that the memory section was related to prevalent AD, whereas in multivariate analysis the non-memory section was not (after correction for the memory score and demographic characteristics). A similar analysis showed that the memory section predicted incident AD, as did a higher score on the non-memory section. The MMSE did not predict incident AD better than age alone.

CONCLUSION

For the early detection of AD it is best to use the memory and non-memory sections separately instead of the total CAMCOG score.

[Is 'attention' important for the results of dementia screening? Relation among Digit Span Test, CST amd ADS in elderly patients]

This study focused on the relationship between attention and dementia screening test performance, using the adapted Wechsler's Digit Span test for elderly patients, the Cognitive Screening Test (CST) and the Amsterdam Dementia Screening Test (ADS6). Participants were dementia patients and psychiatric patients (n = 147). In both groups no floor-effect was found on the Digit Span test. Principal components analysis showed that CST and ADS6-scores had relatively high loadings on one factor, in contrast to digit span scores that loaded on a second factor. On average, psychiatric patients did hardly worse than normal controls. Attention deficits were more apparent in dementia patients. Considering a maximum of r = .41, these more or less subtle deficits were only moderately related to dementia screening test performance. It is concluded that the adapted Digit Span test is suitable for measuring attention deficits in elderly patients. However, Digit Span predicts performance on dementia screening test only to a modest degree.

[Normal values for a short form of the Raven Colored Progressive Matrices]

Psychometric data are presented for the Raven Coloured Progressive Matrices (RCPM), shortened to series A and B. The data were derived from a sample of 2791 persons aged 55 to 85 years. Six 5-year age strata were equally represented, as well as both sexes. The distribution of educational attainment was representative for the elderly population. Norms were stratified for age and education; gender differences were too small to necessitate separate norms. Analysis of reliability according to Mokken's IRT-model indicated modest scalability, but high internal consistency. A loss of 2 to 4 points at retest (depending on personal characteristics) is interpretable as a loss of capacity. Ample attention is paid to qualitative aspects of test performance, but it is concluded that error analysis is mainly useful to def1p4 positional preferences.

Comparative double blind clinical trial of phenytoin and sodium valproate as anticonvulsant prophylaxis after craniotomy: efficacy, tolerability, and cognitive effects

OBJECTIVE

To determine the efficacy, tolerability, and impact on quality of life and cognitive functioning of anticonvulsant prophylaxis with phenytoin or sodium valproate in patients after craniotomy.

METHODS

A prospective, stratified, randomised, double blind single centre clinical trial was performed, comparing two groups of 50 patients each, who underwent craniotomy for different pathological conditions and who were treated for 1 year after surgery with either 300 mg phenytoin/day or 1500 mg sodium valproate/day. During the study period patients were seen in the outpatient clinic at 1.5, 3, 6, and 12 months, when medical history, adverse events, and drug plasma concentrations were evaluated. Neuropsychological functioning and quality of life were assessed on the last three visits. In cases of a seizure an EEG was performed, drug plasma concentration assessed, and medication subsequently increased.

RESULTS

Of the 100 included patients 14 (seven in each group) experienced one or more postoperative seizures. Severity of the seizures was comparable in the two groups. In all patients, drug plasma concentrations were in the low or subtherapeutic ranges at the time of the first postoperative seizure. Five patients in the phenytoin group and two in the valproate group had to stop their treatment due to drug related adverse events. Sixty patients completed the 12 month period. Analysis of neuropsychological and quality of life data showed no significant differences.

CONCLUSION

For efficacy, tolerability, impact on cognitive functioning, and quality of life, no major differences were found between phenytoin and valproate prophylaxis. Valproate is an alternative for anticonvulsant prophylaxis in patients after craniotomy.

Education and incident Alzheimer's disease: a biased association due to selective attrition and use of a two-step diagnostic procedure?

BACKGROUND

It is still not clear whether a low level of education increases the risk of developing Alzheimer's disease (AD). Two common problems in cohort studies involving an elderly population and a two-step diagnostic procedure are the loss to follow-up without data on the presence of AD, and the fact that, in general, people with higher levels of education perform better on traditional cognitive tests, such as the Mini-Mental State Examination (MMSE). Both phenomena may lead to misclassification, resulting in a biased association between level of education and AD. This study investigated to what extent these selection mechanisms may influence this association.

METHODS

In the community-based Amsterdam Study of the Elderly (AMSTEL) a cohort at risk for AD was selected of 3778 people aged 65-84 years. Level of education was expressed in two categories: low (primary education or less) versus high (partial secondary education to completed university education). At follow-up, a subsample of elderly people was selected for further diagnostic evaluation, using a memory test in addition to the MMSE. Clinical diagnoses of AD were made according to DSM-IV (Diagnostic and Statistical Manual of Mental Disorders) criteria. To examine the extent to which loss to follow-up may have affected the results, a sensitivity analysis was performed comparing two extreme possibilities. Furthermore, to examine to what extent use of the MMSE only may have affected the results, the observed odds ratio (OR) was compared with the OR based on only those AD patients who were selected for diagnostics with the MMSE alone.

RESULTS

After an average of 3.2 years, 77 people had developed AD. Multivariate logistic regression analyses indicated that a low level of education was associated with incident AD (OR adjusted for age and sex 2.09; 95% CI: 1.29-3.38). The results of the sensitivity analysis still indicated that a low level of education was associated with incident AD. Screening with only the MMSE led to a higher OR than the one observed.

CONCLUSION

Selective attrition and use of cognitive screening tests that are associated with educational level may influence the strength of the association between a low level of education and incident AD; however, it appears that these influences cannot completely explain this association.

Cognitive deficits after postoperative adjuvant chemotherapy for breast carcinoma

BACKGROUND

A number of patients who have undergone adjuvant (CMF) chemotherapy for operative primary breast carcinoma have reported impaired cognitive function, sometimes even years after completion of therapy. The possible role of cytostatic treatment as a causative factor has scarcely been investigated. The objective of the current study was to examine the late effects on neuropsychologic functioning of CMF adjuvant chemotherapy given to patients with breast carcinoma.

METHODS

Thirty-nine breast carcinoma patients who had been treated with adjuvant CMF (6 courses) followed (n = 20) by 3 years of tamoxifen 20 mg daily or not (n = 19) were examined with neuropsychologic tests and interviews. The control group consisted of 34 age-matched axillary lymph node negative breast carcinoma patients who received the same surgical and radiation therapy but no systemic adjuvant treatment. The CMF patients were examined a median of 1.9 years after the sixth CMF course, and the controls a median of 2.4 years after surgery of the primary tumor.

RESULTS

Patients treated with CMF reported significantly more problems with concentration (31% vs. 6%, P = 0.007) and with memory (21% vs. 3%, P = 0.022) than the control patients. No relation was found between reported complaints and results on the neuropsychologic tests. Impairment in cognitive function was found in 28% of the patients treated with chemotherapy compared with 12% of the patients in the control group (odds ratio 6.4 [95% confidence interval 1.5-27.6] P = 0.013). Hormonal therapy had no influence on patients' self-reports of symptoms or cognitive function. Cognitive impairment following chemotherapy was noticed in a broad domain of functioning, including attention, mental flexibility, speed of information processing, visual memory, and motor function.

CONCLUSIONS

Breast carcinoma patients treated with adjuvant CMF chemotherapy have a significantly higher risk of late cognitive impairment than breast carcinoma patients not treated with chemotherapy (OR 6.4). This cognitive impairment is unaffected by anxiety, depression, fatigue, and time since treatment, and not related to the self-reported complaints of cognitive dysfunction.

Neuropsychological correlates of a right unilateral lacunar thalamic infarction

OBJECTIVES

To report on a patient with a lacunar infarction in the right intralaminar nuclei of the thalamus. The role of the thalamic intralaminar nuclei in cognitive function is as yet insufficiently known. The patient described has shown signs of apathy and loss of initiative, in combination with cognitive deficits, which have persisted essentially unaltered up to the present day since an abrupt onset 17 years ago.

METHODS

High resolution MRI was performed to show the extent of the lesion; a combination of published and experimental neuropsychological techniques was administered to show the nature of the cognitive defects; Single photon emission computed tomography (SPECT) was employed to obtain a measure of cortical perfusion.

RESULTS

Brain MRI disclosed an isolated lacunar infarction in the dorsal caudal intralaminar nuclei of the thalamus. Neuropsychological evaluation indicated problems with attention and concentration, executive disturbances, and memory deficits both in the visual and verbal domains. The memory deficits could not be attributed to problems in the early stages of information processing, and are hence regarded as resulting from a failure of retrieval rather than encoding or storage. Brain SPECT disclosed a hypoperfusion of the right frontal cortex.

CONCLUSION

The data indicate that the cognitive profile is the result of a dysfunction of executive functions. This is corroborated by the finding of decreased blood flow in the right frontal cortex, and by evidence from the neuroanatomical literature. Thus the dysexecutive symptoms are thought to be caused by disconnection of the prefrontal cortex from the brainstem activating nuclei through the strategic localisation of the right thalamic infarction.

Association between apolipoprotein E epsilon4 and the rate of cognitive decline in community-dwelling elderly individuals with and without dementia

OBJECTIVE

To determine whether the apolipoprotein E epsilon4 allele (apoE epsilon4) is associated with cognitive decline in individuals with and without dementia, we conducted a 4-year longitudinal study of subjects with a range of cognitive function.

SETTING

At baseline, respondents (n=511) were randomly selected according to age and Mini-Mental State Examination score from a community-based study of dementia among noninstitutionalized persons aged 65 to 84 years. Respondents were examined at baseline and followed up in 3 annual visits. At baseline, subjects were classified as having normal cognitive function, minimal dementia, or dementia, according to criteria from the Cambridge Examination for Mental Disorders of the Elderly (CAMDEX) and the Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition. Of the 511 respondents at baseline, 405 who were examined at least 2 times are included in this analysis.

MAIN OUTCOME MEASURES

Cognitive decline was determined by a slope estimating yearly change in score on the neuropsychological test, the CAMCOG (the cognitive section of the CAMDEX), and its sub-scales of memory and nonmemory functions.

RESULTS

Among the subjects who had normal cognitive function at baseline, apoE epsilon4 carriers showed a significantly greater decline (P<.001) in score on the CAMCOG compared with noncarriers. Differences in decline on the memory and nonmemory subtests were also significant (P<.001). Rates of cognitive decline were not related to apoE epsilon4 status in the groups with minimal dementia and dementia.

CONCLUSIONS

In our community-based sample, apoE epsilon4 was associated with the rate of cognitive decline prior to the clinically symptomatic phase of dementia. Knowing the apoE epsilon4 status of those already symptomatic for dementia may not improve knowledge about a patient's prognosis.

Functional correlates of callosal atrophy in relapsing-remitting multiple sclerosis patients. A preliminary MRI study

In multiple sclerosis (MS), periventricular lesions produce atrophy of the corpus callosum (CC), as evidenced by magnetic resonance imaging (MRI). We investigated whether CC atrophy in relapsing-remitting MS patients is related to functional deficits. We compared 14 mildly disabled (mean Expanded Disability Status Scale score 2.7) relapsing-remitting MS patients with 14 age- und sex-matched controls. CC size was determined using sagittal T1-weighted MRI. The function of the CC was studied using a neuropsychological battery and neurophysiological evaluation based on visual stimulation using a divided visual field paradigm. The total area of the CC in patients (mean 5.3 cm2) was significantly (P = 0.002) smaller than in controls (mean 6.6 cm2). Patients showed left ear extinction using the dichotic listening test and impaired name learning, which was correlated with atrophy of the splenium. There were no differences in interhemispheric transfer time between patients and controls. Marked atrophy of the CC can be encountered in relapsing-remitting MS patients. The associated cerebral disconnection correlated with atrophy of expected regions of the CC, thus supporting topographical organization.

Cognitive complaints in patients after whiplash injury: the impact of malingering

OBJECTIVES

The validity of memory and concentration complaints that are often reported after a whiplash trauma is controversial. The prevalence of malingering or underperformance in post-whiplash patients, and its impact on their cognitive test results were studied.

METHODS

The Amsterdam short term memory (ASTM) test, a recently developed malingering test, was used as well as a series of conventional memory and concentration tests. The study sample was a highly selected group of patients, who were examined either as part of a litigation procedure (n=36) or in the normal routine of an outpatient clinic (n=72).

RESULTS

The prevalence of underperformance, as defined by a positive score on the malingering test, was 61% (95% CI: 45-77) in the context of litigation, and 29% (95% CI: 18-40) in the outpatient clinic (p=0.003). Furthermore, the scores on the memory and concentration test of malingering post-whiplash patients (n=43) and non-malingering post-whiplash patients (n=65) were compared with the scores of patients with closed head injury (n=20) and normal controls (n=46). The malingering post-whiplash patients scored as low as the patients with closed head injury on most tests.

CONCLUSIONS

The prevalence of malingering or cognitive underperformance in late post-whiplash patients is substantial, particularly in litigation contexts. It is not warranted to explain the mild cognitive disorders of whiplash patients in terms of brain damage, as some authors have done. The cognitive complaints of non-malingering post-whiplash patients are more likely a result of chronic pain, chronic fatigue, or depression.

Reading ability as an estimator of premorbid intelligence: does it remain stable in emergent dementia?

The 6-year stability of reading performance was investigated in subjects who were normal at baseline but suspect for dementia at follow-up (MMSE score < or = 23; n = 197), and in a cognitively intact control group (n = 117). The Dutch version of the National Adult Reading Test (DART) was used. The DART-based estimate of IQ appeared to be very stable in healthy elderly. In the "suspect" group, the decline after 6 years was about 3 IQ-points in subjects who were still not demented, minimally demented, or mildly demented. Reliability remained satisfactory in these subgroups. In cases with moderate and severe dementia, the decline was considerable (> or = 15 IQ points). The decline of DART IQ was related to deterioration of semantic memory as reflected in verbal abstraction and category fluency. It is concluded that the DART remains a valid estimator of premorbid verbal intelligence in mild and questionable dementia. A formula is presented which can correct the underestimation on the basis of the MMSE score.

Visual association encoding activates the medial temporal lobe: a functional magnetic resonance imaging study

The involvement of structures in the medial temporal lobe during the encoding of visual associations was studied with functional magnetic resonance imaging. In 11 out of 12 normal healthy volunteers this task resulted in activation in posterior portions of the parahippocampal region, close to the collateral sulcus. In seven subjects activation was encountered in the hippocampal formation. The visual association task as adapted for this study may provide a sensitive measure to study anterograde amnesia prevalent in Alzheimer's disease. Therefore, the present paradigm enables the study of individual changes in learning and memory capacities over time.

Apolipoprotein E phenotype is not related to late-life depression in a population-based sample

Apolipoprotein E (ApoE) allele frequencies were examined in a population-based sample (n = 475: age range 65-84 years: Amsterdam Study of the Elderly). The relation of ApoE epsilon 4 with dementia and with various types of late-life depression was studied. Depression was measured with the Geriatric Mental State schedule. Dementia was diagnosed by DSM-III-R criteria. It was expected that ApoE epsilon 4 allele frequencies would be elevated not only in Alzheimer's disease and dementia in general, but also in first episode, late-life depression accompanied by subtle cognitive impairment (possibly organic depression). However, the results indicated that epsilon 4 allele frequency is related to (family history of) dementia and cognitive impairment, but not to possibly organic depression. The main predictor of late-life depression is an episode of psychiatric problems before the age of 65 years.

The effects of intelligence and education on the development of dementia. A test of the brain reserve hypothesis

BACKGROUND

A number of recent epidemiological studies have shown that the prevalence and incidence of dementia are increased in population strata with low compared to high levels of education. This has been explained as a consequence of a greater 'brain reserve capacity' in people with a high level of education. Theoretically, however, brain reserve capacity is better reflected by intelligence than by level of education. Thus, the emergence of dementia will be better predicted by low pre-morbid intelligence than by low education.

METHODS

This prediction was tested in a population based sample of elderly subjects (N = 2063; age range 65-84; Amsterdam Study of the Elderly) who were followed over 4 years. Dementia was diagnosed using the Geriatric Mental State examination (GMS). Pre-morbid intelligence was measured using the Dutch Adult Reading Test (DART), a short reading test which gives a good estimate of verbal intelligence, and is relatively insensitive to brain dysfunction. The effects of age, gender, occupational level, number of diseases affecting the central nervous system and family history of dementia or extreme forgetfulness were also examined.

RESULTS

Logistic regression analysis showed that low DART-IQ predicted incident dementia better than low level of education. A high occupational level (having been in charge of subordinates) had a protective effect.

CONCLUSIONS

This result supports the brain reserve theory. It also indicates that low pre-morbid intelligence is an important risk factor for cognitive decline and dementia. Use of reading ability tests is to be preferred over years of education as estimator of pre-morbid cognitive level in (epidemiological) dementia research.

Subjective memory complaints in the elderly: depressive symptoms and future dementia

BACKGROUND

Population studies indicate that subjective memory complaints by elderly people are correlated with cognitive performance. These complaints have some predictive power regarding the development of dementia. The present study attempted to replicate this finding, and investigated which variables determine subjective memory complaints.

METHOD

Participants in the Amsterdam Study of the Elderly (n = 2114; 65-84 years of age), who were not demented and had a normal MMSE score (> 23) at baseline, were re-examined after four years. Subjective complaints were measured using a previously developed scale. Dementia and depression were measured using the Geriatric Mental State Schedule (GMS). Premorbid intelligence was measured by the Dutch Adult Reading Test (DART).

RESULTS

Memory complaints at baseline contributed a small but significant amount of diagnostic information with respect to the prediction of future dementia. Depressive symptoms at baseline had no predictive value when these memory complaints were accounted for. Subjective memory complaints were associated with depression, baseline MMSE score, and premorbid intelligence.

CONCLUSIONS

Subjective memory complaints are not just secondary to depression, but in part reflect realistic self-observations of cognitive decline.

Low education is a genuine risk factor for accelerated memory decline and dementia

A relatively high prevalence and incidence of dementia have been found in population strata with low levels of education in comparison to population strata with high levels of education. However, doubt remains whether this may be an artifact of education bias in the screening tests used. To investigate this matter, we analyzed results of two Dutch population surveys in which unbiased measures of memory decline were used. In the Longitudinal Aging Study Amsterdam (n = 1774) the percentage of words retained in a verbal learning test was found to be disproportionately low in the oldest age cohort (80-85 years) with less than 11 years of education. The Amsterdam Study of the Elderly (n = 4051) found a "dose-response" relationship between education and dementia prevalence. Cross-sectional and longitudinal results showed that, in less educated people, memory decline is faster and sets in at an earlier age. These findings indicate that the relationship between dementia and education is not just an artifact of case detection methods.

Increased risk of mortality in Alzheimer's disease patients with higher education? A replication study

The objective of this study was to replicate findings from an earlier study by Stern et al. of an increased risk of mortality in Alzheimer's disease (AD) patients with higher levels of education and to compare this risk with the risk of death in the elderly population. As part of a community-based follow-up study on dementia (Amsterdam Study of the Elderly [AMSTEL]) a cohort of 4,051 noninstitutionalized elderly age 65 to 84 years stratified in four 5-year strata of equal size was screened for dementia using the MMSE (Mini-Mental State Examination). Those suspected of dementia received diagnostic evaluation using the CAMDEX (Cambridge examination for mental disorders in the elderly). Clinical diagnoses of probable AD were made according to NINCDS-ADRDA criteria. Thirty-six prevalent patients were diagnosed as having AD. The suspected subcohort was followed up yearly over a period of 4 years. During the three yearly follow-ups, 30 incident patients received a diagnosis as well. After 6 years mortality data were obtained from municipality records. Cox proportional hazards models adjusted for age and sex were used to estimate the relative risk of death associated with the level of education. Relative risk of death decreased (although not statistically significant) in AD patients as level of education increased (RR = 0.86; 95% CI, 0.63 to 1.19). In the full baseline sample, relative risk of death decreased as level of education increased (RR = 0.93; 95% CI, 0.89 to 0.97). In this study we could not replicate the findings of Stern et al. of an increased risk of death in more highly educated AD patients. Several major differences between the two studies, among which difference in populations used is considered to be most important, are discussed that might explain the conflicting results. We conclude that higher education is not associated with increased risk of mortality in AD patients.

Amsterdam Short-Term Memory test: a new procedure for the detection of feigned memory deficits

The validity of two malingering tests, the newly developed Amsterdam Short-Term Memory (ASTM) test and the Distraction test (Baker, Hanley, Jackson, Kimmance, & Slade, 1993) was examined in a group of patients with closed-head injury (CHI), a normal control group, and a control group with instruction to feign memory deficits. Both control groups consisted of first-degree relatives of the patients. The ASTM test is a forced-choice verbal memory test, based on the technique of symptom validity testing. Stimulus material was chosen from category norms and chance level is not transparent. The CHI and normal control groups scored near ceiling on the ASTM test, whereas the feigned deficit group scored significantly worse. The ASTM test classified all subjects correctly. Contrary to expectation, the Distraction test appeared to be invalid. The score profiles of the CHI and feigning groups on conventional memory and concentration tests were indistinguishable from each other. Thus, the ASTM test may be very useful for the detection of malingering and other kinds of less than optimal performance. The test may readily be constructed in any language for which category norms are available.

Effects of adjustment on the case-finding potential of cognitive tests

Adjustment of a cognitive test for an expected level of performance improves the discrimination between brain-diseased and healthy subjects. However, this improvement is subject to severe limitations and may be worthwhile only in clinical settings, where test results tend to be low regardless of disease status. The objective of this study was to provide an empirical demonstration of these principles, applied to the detection of dementia with the Mini-Mental State Examination (MMSE). The subjects, derived from a population-based sample, consisted of 36 cases of dementia (23 diagnosed shortly after testing and 13 at follow-up 1 year later) and 301 nondemented subjects defined by a negative follow-up diagnosis. A simulated group of 179 clinically suspect normals was obtained by selecting all cases with an MMSE score below 27. Adjustment was based on the Dutch version (DART) of the National Adult Reading Test (NART), which was highly correlated (0.53) with the MMSE score of nondemented subjects. The results were in accordance with the predictions. We conclude that adjustment is unlikely to improve case finding in representative samples, but can be profitable in clinical practice, where it will be especially helpful in ruling out cerebral disease.

[Item series of the cognitive screening test compared to those of the mini-mental status examination]

The items of the ¿mini-mental state examination' (MMSE) and a Dutch dementia screening instrument, the ¿cognitive screening test' (CST), as well as the ¿geriatric mental status schedule' (GMS) and the ¿Dutch adult reading test' (DART), were administered to 4051 elderly people aged 65 to 84 years. This study was part of the Amsterdam Study of the Elderly (AMSTEL-project), which is a population survey of cognitive decline and dementia. Based on the item-pool, CST and MMSE scores were calculated. Both tests were comparable as far as their validity as dementia screeners is concerned (dementia criterion was GMS Organic syndrome, cut-point 2/3). The abbreviated version of the CST (CST-14) has a somewhat lower validity. The reliabilities of the unabbreviated CST (CST-20) and the MMSE are also comparable. The influence of age, education, depression, and premorbid intelligence (DART-IQ) was most notable in the MMSE. Thus, the CST-20 item set has slightly better psychometric properties than the MMSE. A figure is presented by which CST scores can be transformed into MMSE scores.

Memory complaints and memory impairment in older individuals

OBJECTIVE

To examine whether subjective memory complaints, measured with a series of four questions, are associated with performance on cognitive tests.

DESIGN

Cross-sectional study of individuals, 65 to 85 years of age, who lived in the community of Amsterdam.

PARTICIPANTS

Individuals were selected randomly within 5-year age strata from the patient lists of 30 general practitioners. Of the 4051 participants, 2537 nondepressed and nondemented respondents were included in the analysis.

MEASURES

Four categories of subjective memory complaints were developed on the basis of answers to questions about the presence or absence of memory complaints and memory-related problems in daily functioning. Tests of cognitive function were derived from the subscales of the CAMCOG.

MAIN RESULTS

Individuals with complaints and memory-related problems performed more poorly on tests of memory and memory-related functions. This relationship was strengthened after adjusting for age, sex, and premorbid verbal intelligence, all of which were related to complaint status and to performance on cognitive tests.

CONCLUSION

Simple questions about memory function are related to memory performance in nondepressed, nondemented community-dwelling older people. Subjective memory complaints may be a promising indicator of memory impairment that signals the need for follow-up.

Subjective memory complaints may announce dementia

Whether subjective memory complaints in the absence of objective memory decline can predict future dementia has been investigated only in highly selected clinical and volunteer cohorts. Our study examines this question in a subsample of AMSTEL (Amsterdam Study of the Elderly), a longitudinal population study on cognitive decline and dementia. Subjects (aged 65 to 84 years; n = 357) without dementia or other psychiatric disorders at baseline were followed for 3 years. After this interval, 16 of 203 re-examined patients developed a dementia. Logistic regression analyses indicated that memory complaints at baseline contributed a small but significant amount of diagnostic information. However, the most powerful predictor of future dementia was deficient memory performance. We conclude that subjective memory complaints may predict dementia within 3 years, particularly when there are objective signs of memory deterioration.

Relation between education and dementia: the role of test bias revisited

Several authors have suggested that dementia screening tests may be biased against low levels of education, whereas others find that a low level of education is a genuine risk factor for dementia. The present paper attempts to reconcile these conflicting views by examining item bias and test bias indices of the mini mental state examination (MMSE). Psychometric calculations and receiver operating characteristics (ROC) analyses of sensitivity and specificity as performed by earlier studies were replicated and extended from the database of the Amsterdam Study of the Elderly. This is a population survey on cognitive decline and dementia (age range 65-84). Subjects with a low level of education (primary school) were compared with better educated subjects (at least some secondary education). Cases were matched by age and sex. The results indicate that the MMSE is not educationally biased as far as item characteristics, reliability, and construct validity are concerned. Yet its predictive validity as a screening test for dementia is educationally biased. This bias will effectively be eliminated with a two point higher cut off score for the subjects whose education extends beyond primary school. Even after such score correction, a low level of education probably remains a genuine risk factor for dementia.

Medial temporal lobe atrophy in an open population of very old persons: cognitive, brain atrophy, and sociomedical correlates

Medial temporal lobe structures may be important for memory. We examined the cognitive, brain atrophy, and sociomedical correlates of medial temporal lobe atrophy (MTA) in 59 individuals (79.2 +/- 4.6 years old) randomly selected from a population-based study within strata of age and severity of clinically assessed DSM-III-R dementia (45 clinically normal and 14 mild/severely demented). MTA was qualitatively assessed on coronal T-1-weighted MRI. Thirty-three percent of the sample showed MTA, which was associated with dementia severity (p < 0.01), and cortical and white matter atrophy. MTA was not associated with age, education, sex, depressive symptoms, or presence of infarction. Controlling for age, education, and associated brain atrophy, those with MTA performed more poorly on a general test of cognitive function (the neuropsychological test component of the Cambridge Examination for Mental Disorders of the Elderly; p < 0.04) and its subtests of memory function (p < 0.02) and memory-related functions, including perception, fluency, and orientation (p < 0.05). In the clinically normal subsample, those with MTA performed more poorly on the memory function (p < 0.05) subtests. We conclude that MTA is common among very old persons, is associated with other brain abnormalities implicated in cognitive function, but may specifically contribute to memory dysfunction in the general population of very old persons.

Late-life depressive disorder in the community, early onset and the decrease of vulnerability with increasing age

This study examined reports of a history of psychiatric illness related to age and depression in 4051 community residents aged 65-84. Depression was twice as common among subjects with a history of psychiatric illness before age 65. 78% of depressed subjects reported no history. The rate of reported history was inversely proportionate to the subjects actual age. This did not appear to be due to recollection bias but it did match the proportions previously reported to result from excess mortality of individuals with a psychiatric history. A psychiatric history may be an important risk factor for late-life depression but in the aging process after age 65 it may become increasingly uncommon.

Late-life depressive disorder in the community. II. The relationship between psychiatric history, MMSE and family history

BACKGROUND

In previous studies, dementia was linked to a family history of dementia and Down's syndrome. This study tested the hypothesis that late-life depression accompanied by cognitive impairment in elderly individuals with no history of psychiatric illness is also associated with these family histories.

METHOD

We investigated an age-stratified sample of 4051 elderly people in the community aged 65-84 (AMSTEL). The relationship between family history (CAMDEX questionnaire) and depression (GMS-AGECAT diagnosis) was studied.

RESULTS

A family history of mental health problems was associated with all subtypes of depression. Family history of dementia was associated with depression in subjects with a psychiatric history, but a family history of Down's syndrome was only associated with the combination of depression and cognitive impairment in subjects with no history of psychiatric illness.

CONCLUSIONS

The heritability pattern confirms the concept of a dementia-related subtype of late-life depression.

Late-life depressive disorder in the community. I. The relationship between MMSE score and depression in subjects with and without psychiatric history

BACKGROUND

In previous studies cognitive impairment in depressed elderly in-patients tends to be associated with a late onset of depression. This study tests the hypothesis that cognitive impairment is associated with depression only in elderly individuals with no history of psychiatric illness.

METHOD

We investigated an age-stratified sample of 4051 elderly people living in the community, aged between 65 and 84 (AMSTEL). The relationship between depression (GMS-AGECAT diagnosis) and scores on the Mini Mental State Examination was studied in subjects with and without a reported psychiatric history (CAMDEX questionnaire).

RESULTS

Low MMSE scores (MMSE < or = 25) were only associated with depression in subjects with no psychiatric history (young/old: OR = 2.75, 95% CI = 1.83, 4.19; old/old: OR = 2.21, 95% CI = 1.61, 3.03).

CONCLUSIONS

We concluded that the combination of cognitive impairment and first-episode depression in elderly individuals may indicate cerebral deterioration. Depression as such may not be associated with cognitive impairment.

[Differentiation between dementia and functional psychiatric disorders in a geriatric ward of a general psychiatric hospital using the 'Amsterdam Dementia-Screening Test']

OBJECTIVE

Investigating the discriminative power of the Amsterdam Dementia Screening Test (ADS) in a heterogeneous elderly psychiatric population.

SETTING

Observation clinic for the elderly MFC Duinoord, Psychiatric Centre Vogelenzang, Bennebroek, Holland.

DESIGN

Retrospective comparison of test results and clinical diagnosis.

METHOD

Patients referred for neuropsychological evaluation in 1991-1992 were selected on the basis of DSM-III-R discharge diagnosis 'dementia' or 'psychiatric syndrome'. The ADS, MMSE and SPMSQ scores of 30 male and 74 female patients were compared with diagnostic classification.

RESULTS

The ADS appeared to be highly sensitive and specific. Only 10% of the psychiatric patients were incorrectly classified by the ADS, as against 55% using the MMSE, some MMSE items not differentiating at all. A significant correlation was found in the demented group between ADS and MMSE total scores on the one hand and demographic variables such as age and level of education on the other. The latter appears to be related to better performance on visuo-constructive tasks by more highly educated subjects.

CONCLUSION

Normative data for the ADS come from an inpatient population. This study shows that the ADS discriminates well in a mixed in/outpatient group with dementia syndromes or psychiatric disorders. The visuo-constructive tasks appear to be related to the level of education.

Cognitive functions and quality of life in patients with low-grade gliomas: the impact of radiotherapy

The role of early radiotherapy in the treatment of low-grade gliomas is controversial. For this reason the impact of radiotherapy on quality of life was studied in long-term survivors of biopsy-proved low-grade gliomas without signs of tumor recurrence. Twenty patients (age range, 18-66 years) had been treated with early radiotherapy; the other 21 patients (age range, 19-65 years) had undergone surgery or biopsy only. The interval from diagnosis to testing ranged from 1 to 12 years (mean, 3.5 years). Nineteen patients with low-grade hematological malignancies, surviving 1 to 15 years without central nervous system involvement, served as control subjects. Apart from the neurological and functional status, the patients' cognitive, affective, and psychological status was determined. None of the survivors had significant neurological impairment and the Karnofsky index for them was at least 70. However, more specific examinations of cognitive functions and the affective status (Profile of Mood States) indicated that, compared to the control subjects, the patients with low-grade gliomas had significantly more cognitive disturbances and suffered more frequently from fatigue and depressed moods. The two groups with low-grade gliomas, on the other hand, did not differ significantly on any of these measures. It is concluded that radiotherapy did not cause these disturbances and had no negative impact on quality of life in these patients.

[Digit series and Knox cubes as concentration tests for elderly subjects]

We studied psychometric properties of the Digit Span test and its nonverbal counterpart, the Knox Cube test, with reference to their utility in the clinical assessment of the elderly. Subjects were 100 residents of residential homes and semi-independent housing projects, aged 68 to 94. An administration of Digit Span with three trials per sequence length provides high reliability and minimizes floor effects, allowing separate interpretation of the Forward and Backward conditions. Due to its low internal consistency, the Knox Cube test cannot reliably distinguish differences among normal subjects, but may still be useful to detect impairment. Using regression equations, the Forward Digit Span score can be corrected for education level and both Digit Backward and Knox Cubes can be compared with Digit Span Forward.

Are age and education independent correlates of the Mini-Mental State Exam performance of community-dwelling elderly?

We examined the effects of selected health conditions and sensory functions, socioeconomic status, age, and education on cognitive functioning in 3,974 community-dwelling individuals aged 65-84 years. Logistic regression analysis was used to examine the independent and joint effects of these variables on borderline (Mini-Mental State Exam [MMSE] of 22-25) and poor (MMSE of < or = 21) functioning relative to adequate functioning (MMSE of 26-30). The effect of age and of education on MMSE performance was relatively stable, even after adjusting for age- and education-related health conditions and sensory impairments that also influenced level of cognitive functioning. These conditions included poor vision, Parkinson's disease, diabetes, depression, stroke (in 65-74-year-olds), and low socioeconomic status (in 75-84-year-olds). Education did not modify the effect of these variables on MMSE performance. Additional studies elucidating further the mechanisms that relate these sociodemographic factors to cognitive performance are warranted, as are studies of the relationship between these factors and the incidence of cognitive impairment.

[The diagnostic value of tests for mental control]

Designated as Mental Control, the recitation of word lists and arithmetic progressions is often used for a cursory examination of attention and concentration in elderly patients. We studied the psychometric properties of the EMCT (Expanded Mental Control Test), which consists of 12 mental control tasks. The test was given to 174 residents of rest homes and semi-independent housing projects (aged 68 to 94) and 74 neurologic patients (aged 65 to 87) who had been referred for neuropsychological assessment. The reliability of the EMCT was satisfactory. Performance was related to education level but not to sex or age. In healthy subjects the EMCT score was associated with the backward digit span score. The correlations between the EMCT and subtests of the Amsterdam Dementia Screening (Ads6) in patients appeared to depend on the complexity of the target behavior. Performance on the EMCT may reflect the functioning of the Supervisory Attentional System postulated by Shallice.

Some psychometric properties of the CAMCOG

The CAMCOG, the cognitive section of the Cambridge Examination for Mental Disorders of the Elderly (CAMDEX), was administered twice to 53 patients with a clinical diagnosis ranging from no dementia to severe dementia. The stability of the total CAMCOG score was high (0.97). Patients with less than moderate dementia were differentiated well by the total score and by subscales with a range of more than 8 points, except when education was low or age was higher than 78. Because performance on most (sub)scales is modified by age and education level, stratified norms are desirable. Only the Praxis subscale, and specifically performance on drawing tasks, appeared to be influenced by depression.

[Paced addition. A neuropsychological test for assessment of divided attention]

The Pasat (Paced auditory serial addition task) is a test requiring addition of simple digits presented auditorily in several series of a successively higher pace of presentation. The task reflects the capacity for divided attention, is a measure of information processing speed and has appeared to be sensitive to minor attention deficits. We made a Dutch version characterized by longer time intervals between digits, for use in a study among (altogether 130) middle-aged and elderly persons. This modified version was evaluated with respect to feasibility. It appeared to be fairly feasible, provided sufficient opportunity for practice is given. Two series with inter-stimulus intervals of 4 and 3 seconds respectively were then evaluated with respect to validity and reliability in subjects of 48 to 74 years. Both Pasat series correlated well with two tests of attention: Digit Symbol (WAIS) and d2-test (r = 0.53-0.67), the relation with reaction decision speed being generally weak (r = 0.29-0.33) and weak to absent with a number of memory tests (r = -0.04-0.29). The Pasat performance shows a positive relationship with educational level and intelligence (inter-stimulus interval 4 seconds: r = 0.28 and 0.33 resp.; inter-stimulus interval 3 seconds: r = 0.40, 0.57 resp.). The stability of test performance over a period of about two months is moderate (r = 0.54, 0.61 resp.). In view of the excellent inter-observer reliability (r = 0.99) and the good parallel-test reliability (r = 0.79, 0.68 resp.), this might be explained by fluctuations in the capacity measured, rather than measurement error.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of quality of life in patients treated for low-grade glioma: a preliminary report

In this pilot study quality of life was assessed in fourteen adult patients who were treated for a low-grade glioma with surgery and radiotherapy at least one year previously. Apart from widely used parameters, such as the neurological and functional status, the patients' cognitive functioning and actual affective status were determined. In addition the patients were interviewed to evaluate various aspects of quality of life. Generally no serious focal neurological deficits were found, although psychological examination showed serious cognitive and affective disturbances in most cases. Self report measures concerning cognitive functioning were not in all cases in accordance with objective test results. When the results of treatment in glioma patients are evaluated assessment of quality of life, including neuropsychological functioning, should be performed, especially as new therapeutic strategies are being developed.

A case of progressive aphasia without dementia: "temporal" Pick's disease?

We report a patient who suffered from progressive aphasia for nine years, before developing mild behavioural disturbances. Sequential computed tomography (CT) scanning and magnetic resonance (MRI) imaging showed progressive bilateral temporal atrophy. The case is thought to be a temporal form of Pick's disease, in which isolated progressive aphasia was the only symptom over many years.

Who needs cutting points?

Individual scores of discriminative tests can be connected to an estimate of the confidence of classification, which obviates the need for cutting points. Such estimates can be corrected for base rate conditions. It is suggested that, while base rates are largely imponderable, the prior probabilities of individual cases are not.

Interhemispheric disconnection effects in multiple sclerosis

Patients with multiple sclerosis reported less left ear numbers but more right ear numbers than controls in a dichotic listening test. The multiple sclerosis patients were also relatively impaired on three learning tasks; one of these, a test for paired-associate learning of names and faces, correlated with left ear findings; the results are interpreted as supporting a hypothesised disconnection mechanism.