The clock drawing test is an important contribution to the Mini Mental State Examination in screening for cognitive impairment

BACKGROUND

The clock drawing test (CDT) and the Mini Mental State Examination (MMSE) are frequently used screening instruments for cognitive impairment, however, the precise contribution of the CDT to the MMSE is largely unknown.

METHODS

We studied patients with subjective cognitive impairment (SCI, n = 481), mild cognitive impairment (MCI, n = 628) and Alzheimer's disease (AD, n = 1099). Discrimination between patients was examined with multiple logistic regression, adjusted for age, sex, and education. Four groups were constructed based on a normal/abnormal MMSE (cut-off <24/30) versus normal/abnormal CDT (cut-off ≤2/3). Visually rated medial temporal lobe atrophy (MTA) on CT was used as parameter of neurodegeneration.

RESULTS

The CDT significantly contributed to the MMSE in discriminating SCI from both MCI and AD patients. Our four group analyses showed that of those patients with a normal MMSE and incorrectly classified as SCI, an abnormal CDT could significantly identify 10.0% as MCI and 13.2% as AD. Among those with an abnormal MMSE, the percentage AD patients shifted from 53.1% to 82.1% due to an abnormal CDT. Presence of an abnormal CDT was significantly related to MTA increase, regardless of the MMSE score.

CONCLUSION

The CDT is an important additional screening tool to the MMSE. An abnormal CDT with a normal MMSE is an indicator for cognitive impairment. An abnormal CDT in combination with an abnormal MMSE can be considered as an indicator of disease progression.

What patients want to know, and what we actually tell them: The ABIDE project

BACKGROUND

We studied to what degree and at whose initiative 25 informational topics, formerly identified as important, are discussed in diagnostic consultations.

METHODS

Audio recordings of clinician-patient consultations of 71 patients and 32 clinicians, collected in eight Dutch memory clinics, were independently content-coded by two coders. The coding scheme encompassed 25 informational topics.

RESULTS

Approximately half (Mdn = 12) of the 25 topics were discussed per patient during the diagnostic process, with a higher frequency among individuals receiving a dementia diagnosis (Mdn = 14) compared to others (Mdn = 11). Individual topics ranged from being discussed with 2/71 (3%) to 70/71 (99%) of patients. Patients and/or care partners rarely initiated topic discussion (10%). When they did, they often enquired about one of the least frequently addressed topics.

CONCLUSION

Most patients received information on approximately half of the important informational topics. Providing the topic list to patients and care partners beforehand could allow consultation preparation and stimulate participation.

Communicating uncertainties when disclosing diagnostic test results for (Alzheimer's) dementia in the memory clinic: The ABIDE project

Background

The development of novel diagnostics enables increasingly earlier diagnosis of Alzheimer's disease (AD). Timely diagnosis may benefit patients by reducing their uncertainty regarding the cause of symptoms, yet does not always provide patients with the desired certainty.

Objective

To examine, using both quantitative and qualitative methods, uncertainty communicated by memory clinic clinicians in post‐diagnostic testing consultations with patients and their caregivers.

Methods

First, we identified all uncertainty expressions of 22 clinicians in audiotaped post‐diagnostic testing consultations with 78 patients. Second, we statistically explored relationships between patient/clinician characteristics and uncertainty expressions. Third, the transcribed uncertainty expressions were qualitatively analysed, determining the topic to which they pertained, their source and initiator/elicitor (clinicians/patients/caregivers).

Results

Within 57/78 (73%) consultations, clinicians expressed in total 115 uncertainties, of which 37% elicited by the patient or caregiver. No apparent relationships were found between patient/clinician characteristics and whether or not, and how often clinicians expressed uncertainty. Uncertainty expressions pertained to ten different topics, most frequently patient's diagnosis and symptom progression. Expressed uncertainty was mostly related to the unpredictability of the future and limits to available knowledge.

Discussion and conclusions

The majority of clinicians openly discussed the limits of scientific knowledge and diagnostic testing with patients and caregivers in the dementia context. Noticeably, clinicians did not discuss uncertainty in about one quarter of consultations. More evidence is needed on the beneficial and/or harmful effects on patients of discussing uncertainty with them. This knowledge can be used to support clinicians to optimally convey uncertainty and facilitate patients' uncertainty management.

Diagnostic performance of Elecsys immunoassays for cerebrospinal fluid Alzheimer's disease biomarkers in a nonacademic, multicenter memory clinic cohort: The ABIDE project

Introduction

We compared the automated Elecsys and manual Innotest immunoassays for cerebrospinal fluid (CSF) Alzheimer's disease biomarkers in a multicenter diagnostic setting.

Methods

We collected CSF samples from 137 participants in eight local memory clinics. Amyloid β(1–42) (Aβ42), total tau (t-tau), and phosphorylated tau (p-tau) were centrally analyzed with Innotest and Elecsys assays. Concordances between methods were assessed.

Results

Biomarker results strongly correlated between assays with Spearman's ρ 0.94 for Aβ42, 0.98 for t-tau, and 0.98 for p-tau. Using Gaussian mixture modeling, cohort-specific cut-points were estimated at 1092 pg/mL for Aβ42, 235 pg/mL for t-tau, and 24 pg/mL for p-tau. We found an excellent concordance of biomarker abnormality between assays of 97% for Aβ42 and 96% for both t-tau and p-tau.

Discussion

The high concordances between Elecsys and Innotest in this nonacademic, multicenter cohort support the use of Elecsys for CSF Alzheimer's disease diagnostics and allow conversion of results between methods.

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Method comparison of 137 CSF samples collected in eight nonacademic memory clinics.

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Innotest and Elecsys strongly correlated: ρ = 0.94 Aβ42; 0.98 t-tau; 0.98 p-tau.

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Concordances of biomarker abnormalities: 97% Aβ42; 96% t-tau and p-tau.

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Concordance of NIA-AA–based Alzheimer's disease profile (Aβ42 decreased and p-tau increased): 89%.

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Preanalytical protocol deviations did not show effects on biomarker correlations.

Patients' and caregivers' views on conversations and shared decision making in diagnostic testing for Alzheimer's disease: The ABIDE project

Introduction

This study aims to assess patients' and caregivers' views on and experiences with (1) decisions about diagnostic testing for Alzheimer's disease (AD) and (2) receiving test results.

Methods

We conducted separate focus groups with patients from three hospitals who underwent diagnostic testing for AD (N = 11) and their caregivers (N = 11). Audio recordings were transcribed verbatim and analyzed using MaxQDA.

Results

Patients and caregivers preferred and perceived active involvement in decision making, but the decision to initiate diagnostic testing seems to be made before the clinician-patient encounter. Patients and caregivers indicate that decisions are driven by a strong need to explain the patient's symptoms. They missed information on why different diagnostic tests were used, what the results of these tests were, and to what extent these results were (ab)normal.

Discussion

The decision-making process around diagnostic testing for AD and the information provision before and after diagnostic testing could be improved.

Practical use of visual medial temporal lobe atrophy cut-off scores in Alzheimer's disease: Validation in a large memory clinic population

Objective

To provide age-specific medial temporal lobe atrophy (MTA) cut-off scores for routine clinical practice as marker for Alzheimer’s disease (AD).

Methods

Patients with AD (n = 832, mean age 81.8 years) were compared with patients with subjective cognitive impairment (n = 333, mean age 71.8 years) in a large single-centre memory clinic. Mean of right and left MTA scores was determined with visual rating (Scheltens scale) using CT (0, no atrophy to 4, severe atrophy). Relationships between age and MTA scores were analysed with regression analysis. For various MTA cut-off scores, decade-specific sensitivity and specificity and area under the curve (AUC) values, computed with receiver operator characteristic curves, were determined.

Results

MTA strongly increased with age in both groups to a similar degree. Optimal MTA cut-off values for the age ranges <65, 65–74, 75–84 and ≥85 were: ≥1.0, ≥1.5, ≥ 2.0 and ≥2.0. Corresponding values of sensitivity and specificity were 83.3% and 86.4%; 73.7% and 84.6%; 73.7% and 76.2%; and 84.0% and 62.5%.

Conclusion

From this large unique memory clinic cohort we suggest decade-specific MTA cut-off scores for clinical use. After age 85 years, however, the practical usefulness of the MTA cut-off is limited.

Key Points

• We suggest decade-specific MTA cut-off scores for AD.

• MTA cut-off after the age of 85 years has limited use.

• CT is feasible and accurate for visual MTA rating.

Determinants of quantitative spectral electroencephalography in early Alzheimer's disease: cognitive function, regional cerebral blood flow, and computed tomography

Electroencephalography (EEG) bands may have different clinical or physiological correlates at initial diagnosis of Alzheimer's disease (AD). We studied 163 consecutive patients with probable (n = 105) and possible (n = 58) AD with measurements of cognitive function (CAMCOG), regional cerebral blood flow (rCBF) with single photon emission computed tomography using technetium-99m-labeled hexamethylpropylene amine oxime, and computed tomography (CT). Lower CAMCOG scores were significantly and most strongly associated with lower parieto-occipital and fronto-central alpha power. In a separate analysis of cognitive domains, disturbances in language, praxis, attention, and abstraction were also significantly and most consistently related to decrease in alpha power. Presence of cortical atrophy as measured on CT showed some statistically significant relations with EEG bands, but these associations were not consistent. Lower temporal and parietal rCBF were significantly related to lower parieto-occipital alpha activity. Presence of leukoaraiosis was significantly associated with lower beta values, but also with higher absolute theta and delta activity. The results suggest that alpha on EEG is most closely linked to cognitive function and rCBF, while beta and theta activity more likely reflect lower cortical or subcortical changes. Our study thus provides evidence that the EEG bands reflect differential pathophysiologic changes in AD.

The diagnostic value of electroencephalography in mild senile Alzheimer's disease

OBJECTIVE

We investigated the diagnostic value of the visually assessed electroencephalogram (EEG) in patients with mild Alzheimer's disease (AD), using the grand total of EEG (GTE) score.

METHODS

Forty-nine non-demented control subjects with and without minimal cognitive impairment from the general population and 86 probable AD patients (NINCDS-ADRDA criteria), consecutively referred to a memory clinic, participated in this study.

RESULTS

Frequency of rhythmic background activity (P<0.05), diffuse slow activity (P<0.001), and reactivity of the rhythmic background activity (P<0.001) were statistically significant related to the diagnosis control subject or AD patient, using logistic regression analysis with adjustment for age and sex. When these subscores were used to confirm the diagnosis of AD, thus at high specificity of 89.1% (GTE cut-off point of 3), the sensitivity was 44.6% and positive predictive value was 88.1%. Incremental ruling-in and ruling-out curves showed a maximum diagnostic gain of 38% for a positive test result at a prior probability ranging from 30 to 40%. At high pretest probability levels of 80-90%, the diagnostic gain for a positive test result was low, varying from 7 to 14%.

CONCLUSION

In conclusion, the visually assessed EEG may give a clinically meaningful contribution to the diagnostic evaluation of AD when there is diagnostic doubt.

Measurement of temporal regional cerebral perfusion with single-photon emission tomography predicts rate of decline in language function and survival in early Alzheimer's disease

We determined the relationship between regional cerebral blood flow (rCBF) measured with single-photon emission tomography (SPET) and decline in cognitive function and survival in Alzheimer's disease. In a prospective follow-up study, 69 consecutively referred patients with early probable Alzheimer's disease (NINCDS/ADRDA criteria) underwent SPET performed at the time of initial diagnosis using technetium-99m-labelled hexamethylpropylene amine oxime. Neuropsychological function was assessed at baseline and after 6 months and survival data were available on all patients, extending to 5.5 years of follow-up. Lower left temporal (P<0.01) and lower left parietal (P<0.01) rCBF were statistically significantly related to decline in language function after 6 months. The association between left temporal rCBF and survival was also statistically significant (P<0.05) using Cox proportional hazards regression analysis. Performing analysis with quartiles of the distribution, we found a threshold effect for low left temporal rCBF (rCBF<73.7%, P<0. 01) and high risk of mortality. In this lowest quartile, median survival time was 2.7 years (follow-up to 5.2 years), compared with 4.4 years in the other quartiles (follow-up to 5.5 years). Kaplan-Meier survival curves showed statistically significant (P<0. 05, log rank test) survival curves for the lowest versus other quartiles of left temporal rCBF. All results were unaffected by adjustment for age, sex, dementia severity, duration of symptoms, education and ratings of local cortical atrophy. We conclude that left temporal rCBF predicts decline in language function and survival in patients with early probable Alzheimer's disease, with a threshold effect of low rCBF and high risk of mortality.

A simple test of copying ability and sex define survival in patients with early Alzheimer's disease

BACKGROUND

We studied whether heterogeneous profiles of cognitive function are relevant to survival in patients with early Alzheimer's disease.

METHODS

CAMCOG subscales of cognitive function were used as predictors of survival, together with gender in 157 consecutively referred patients with early Alzheimer's disease. Statistical analysis was performed with Cox proportional hazards analysis and Kaplan-Meier survival curves. Survival rates were compared with those in the general population.

RESULTS

Eighty patients (51%) died during the follow-up that extended to 5.7 years, with a median survival of 4.4 years after entry. Only the praxis subscore was statistically significant related to survival (P < 0.0001). Its predictive power was based on only two items, including copying ability for a spiral and a three-dimensional house, independent of age, sex, education, overall CAMCOG score, dementia severity and symptom duration. Kaplan-Meier curves for the combined score of these items (0, 1, or 2) showed three groups with significantly different survival rates for both men and women. Comparison of gender specific survival rates with data from the general population showed that excess mortality was statistically significant (P < 0.01) higher in men (51%) than in women (21%) after follow-up extending to 5 years.

CONCLUSIONS

A simple test of copying ability defines subgroups of AD patients with large differences in survival rates. This suggests that parietal lobe impairment is an important predictor of mortality in AD. Also, the course of AD may be more benign in women than in men.

Slowing on quantitative spectral EEG is a marker for rate of subsequent cognitive and functional decline in early Alzheimer disease

The relation between quantitative spectral electroencephalogram (qEEG) parameters and subsequent rate of cognitive, functional, and behavioral decline in 82 consecutive patients with early probable Alzheimer disease (NINCDS-ADRDA criteria) was examined in a prospective study. The qEEG was performed at initial examination and global cognitive function, activities of daily living, and behavior were assessed at initial evaluation and after a period of 6 months. Using multiple linear regression analysis, higher frontocentral and parieto-occipital theta values, lower parieto-occipital beta values, and lower peak frequency were significantly associated with more decline in global cognitive function over the follow-up period. In addition, lower parieto-occipital beta values were significantly related to more decline in activities of daily living. These associations were independent of demographic (age, sex, and education) and disease characteristics [initial Cambridge Examination for Mental Disorders of the Elderly Cognitive test (CAMCOG) or Mini-Mental State Examination scores, estimated duration of symptoms, estimated prior rate of decline, and dementia severity]. In a separate multiple logistic regression analysis, prediction of rapidly progressive decline, defined as 8 or more points decline in CAMCOG scores (n = 21), could be made with parieto-occipital and frontocentral beta values. The results suggest that slowing on qEEG is a marker for subsequent rate of cognitive and functional decline in mildly demented AD patients, independent of demographic or disease characteristics.

Predicting survival in patients with early Alzheimer's disease

We investigated whether an index based on clinical features, electroencephalogram and computed tomography is useful to predict survival in early Alzheimer's disease. One hundred and sixty-three consecutively referred patients to an outpatient memory clinic and first diagnosed with Alzheimer's disease (105 'probable' and 58 'possible', NINCDS-ADRDA criteria) were studied and outcome measure was death. Cox proportional hazards regression analysis and Kaplan-Meier survival curves were used to investigate relations between baseline parameters and survival. Eighty-four patients (51. 5%) died during the follow-up period that extended to 5.8 years, with a median duration of survival after entry of 4.3 years. Baseline factors that were statistically significant and independently related to increased risk of mortality were high age, male sex, poor cognitive function as measured with the CAMCOG, low alpha and beta power on electroencephalogram, and temporoparietal atrophy on computed tomography scan. These results were independent of the diagnosis probable or possible Alzheimer's disease. Based on the coefficients from the regression equation, we computed a survival index for each patient and we constructed three groups according to tertiles of this index. After 5.2 years of follow-up, survival curves showed a low mortality group with 81.7% patients alive (median survival at least 5.7 years), an intermediate mortality group with 35.9% patients alive (median survival 3.8 years), and a high mortality group with no patients alive (median survival 2.3 years). Log rank tests were statistically significant for comparisons between all three groups. We conclude that an overall index combining demographic, cognitive, electroencephalogram and computed tomography features is a strong predictor of survival in early Alzheimer's disease.

Quantitative spectral electroencephalography in predicting survival in patients with early Alzheimer disease

OBJECTIVE

To determine whether measures of quantitative spectral electroencephalography (EEG) can predict survival in patients with early Alzheimer disease.

DESIGN

Prospective cohort study; median duration of follow-up was 4.4 years in survivors and 2.6 years in nonsurvivors. Cox proportional hazards models, with adjustment for age and sex were used to estimate relationships between EEG measures and survival. Log relative percentage values of EEG bands were used as predictors.

SETTING

Outpatient university memory clinic.

PARTICIPANTS

One hundred one consecutively referred patients with early probable Alzheimer disease according to National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria were studied with EEG at the time of diagnosis. The mean age of the patients was 79.2 years, which was higher than in previous EEG studies.

MAIN OUTCOME MEASURE

Mortality.

RESULTS

Fifty-one patients (50.5%) died during follow-up, with a median survival time in all patients of 4.1 years. The following EEG variables were significantly associated with increased risk of mortality: from parieto-occipital leads, higher theta (hazard ratio, 2.05; 95% confidence interval, 1.15-3.66; P<.05), lower alpha (hazard ratio, 0.43; 95% confidence interval, 0.25-0.76; P<.01), and lower beta (hazard ratio, 0.38; 95% confidence interval, 0.22-0.68; P<.001) activity; and from frontocentral leads, higher theta activity (hazard ratio, 2.07; 95% confidence interval, 1.17-3.66; P<.05). Stepwise Cox regression analysis showed that loss of parieto-occipital beta (P<.01) and alpha (P<.05) power were independent and significant predictors of mortality. Both beta (12.6-35.4 Hz) and alpha (7.5-12.5 Hz) activity remained significantly associated with mortality after adjustment for education, dementia severity, symptom duration, level of cognitive function, presence of extrapyramidal symptoms or hallucinations, presence of vascular risk factors, and presence of leukoaraiosis or local cortical atrophy.

CONCLUSIONS

Decreases of beta and alpha activity on quantitative spectral EEG are independent predictors of mortality in patients with early Alzheimer disease. In the clinical context, the use of EEG technology for prediction of survival in individual patients remains to be determined.

Determinants of global clinical change assessment in patients with early Alzheimer's disease

Global clinical impression (GCI) of change is assumed to integrate aspects of both cognitive and noncognitive functioning. We evaluated 140 consecutive patients with probable (n = 90) and possible (n = 50) early Alzheimer's disease at baseline and after 6 months with measurements of global cognitive function (CAMCOG), behavior, activities of daily living, and burden of the caregiver. After 6 months, both the clinician (GCI-clin) and the caregiver (GCI-care) rated clinical change on a 3-point scale (worse, no change, improved). Data were analyzed with multiple polychotomous logistic regression, adjusted for age and sex. Change in global cognitive function and GCI-care were significantly and independently related to GCI-clin, while changes in activities of daily living and in behavior were significantly and independently associated with GCI-care. The findings suggest a double dissociation. Change in cognition appears to be the major determinant of the clinician's global impression but not change in behavioral and functional parameters, while global impression of the caregiver is primarily based on change in behavioral and functional measures but not on change in cognition.

Registration of MR and SPECT without using external fiducial markers

The aim of our work is to present, test and validate an automated registration method used for matching brain SPECT scans with corresponding MR scans. The method was applied on a data set consisting of ten brain IDEX SPECT scans and ten T1- and T2-weighted MR scans of the same subjects. Of two subjects a CT scan was also made. (Semi-) automated algorithms were used to extract the brain from the MR, CT and SPECT images. Next, a surface registration technique called chamfer matching was used to match the segmented brains. A perturbation study was performed to determine the sensitivity of the matching results to the choice of the starting values. Furthermore, the SPECT segmentation threshold was varied to study its effect on the resulting parameters and a comparison between the use of MR T1- and T2-weighted images was made. Finally, the two sets of CT scans were used to estimate the accuracy by matching MR to CT and comparing the MR-SPECT match to the SPECT-CT match. The perturbation study showed that for initial perturbations up to 6 cm the algorithm fails in less than 4% of the cases. A variation of the SPECT segmentation threshold over a realistic range (25%) caused an average variation in the optimal match of 0.28 cm vector length. When T2 is used instead of T1 the stability of the algorithm is comparable but the results are less realistic due the large deformations. Finally, a comparison of the direct SPECT-MR match and the indirect match with CT as intermediate yields a discrepancy of 0.4 cm vector length. We conclude that the accuracy of our automatic matching algorithm for SPECT and MR, in which no external markers were used, is comparable to the accuracies reported in the literature for non-automatic methods or methods based on external markers. The proposed method is efficient and insensitive to small variations in SPECT segmentation.

Lisuride treatment of Alzheimer's disease. A preliminary placebo-controlled clinical trial of safety and therapeutic efficacy

In this article, the authors examine the effect of lisuride on 22 patients with probable Alzheimer's disease (NINCDS/ADRDA criteria) in a randomized double-blind, placebo-controlled, parallel group design. Ten patients received lisuride and 12 patients received placebo. Lisuride was administered in a dose-finding phase of four weeks and an efficacy phase of eight weeks, with a maximum dose of 0.3 mg daily. Outcome measures included global clinical impression, general cognitive function, mood, verbal and visual memory, attention, and psychomotor function. Average decline in Mini-Mental State Examination score after 12 weeks treatment was less often statistically significant in lisuride treated patients than in patients receiving a placebo (p < 0.05). Patients treated with lisuride improved their average total score and short-delay cued recall score on the California Verbal Learning Test, a test of verbal memory, whereas placebo-treated patients showed worse performance compared with baseline. These differences approached statistical significance, with p = 0.06 and p = 0.05, respectively. No other differences between the treatment groups were evident. The authors failed to find a consistent effect of lisuride on symptoms of Alzheimer's disease. However, this study's sample size was relatively small, and larger studies are needed to ascertain the treatment effects of serotonergic antagonists on Alzheimer's disease.

Reversible blindness in AIDS-related cryptococcal meningitis

A 30-year-old AIDS-patient with cryptococcal meningitis developed subacute bilateral visual loss associated with high cerebrospinal fluid (CSF) pressure. With immediate CSF drainage the blindness was reversible. The importance of prompt CSF drainage in AIDS-related cryptococcal meningitis with visual failure is stressed.

Regional cerebral blood flow and cerebrovascular risk factors in the elderly population

Regional cerebral blood flow (rCBF) was studied in 60 elderly persons (aged 65 to 84 years) recruited from a population-based study, with single photon emission computed tomography using technetium 99m-labeled hexamethylpropylene amine oxime. We investigated whether it is only age that affects rCBF or whether other factors can be indentified that explain this relationship. Using multiple linear regression analysis, increasing age was significantly associated with rCBF decrease in parietal, temporo-parietal, and temporal cortex, but not in frontal cortex. Adjustment with several risk factors for cerebrovascular disease, including hypertension, history of myocardial infarction, factor VIIc, factor VIIIc, cholesterol and HDL cholesterol, smoking, and diabetes mellitus had no influence on these relations. Conversely, the association between age and rCBF was no longer statistically significant after adjustment with fibrinogen and indicators of carotid atherosclerosis, including intima-media wall thickness of the carotid artery and plaques in the carotid artery. Correction with local ratings of cortical atrophy did not affect the relations between age and rCBF. The results suggest that in the elderly population rCBF declines with age in posterior cortical areas and that these changes may well be explained by the presence of atherosclerosis. Reduced contractility of the vascular muscle wall with increasing age resulting from atherosclerosis may be the underlying mechanism.

Demonstration of a reduction in muscarinic receptor binding in early Alzheimer's disease using iodine-123 dexetimide single-photon emission tomography

Decreased muscarinic receptor binding has been suggested in single-photon emission tomography (SPET) studies of Alzheimer's disease. However, it remains unclear whether these changes are present in mildly demented patients, and the role of cortical atrophy in receptor binding assessment has not been investigated. We studied muscarinic receptor binding normalized to neostriatum with SPET using [123I]4-iododexetimide in five mildly affected patients with probable Alzheimer's disease and in five age-matched control subjects. Region of interest (ROI) analysis was performed in a consensus procedure blind to clinical diagnosis using matched magnetic resonance (MRI) images. Cortical atrophy was assessed by calculating percentages of cerebrospinal fluid in each ROI. An observer study with three observers was conducted to validate this method. Alzheimer patients showed statistically significantly less [123I]4-iododexetimide binding in left temporal and right temporo-parietal cortex compared with controls, independent of age, sex and cortical atrophy. Mean intra-observer variability was 3.6% and inter-observer results showed consistent differences in [123I]4-iododexetimide binding between observers. However, differences between patients and controls were comparable among observers and statistically significant in the same regions as in the consensus procedure. Using an MRI-SPET matching technique, we conclude that [123I]4-iododexetimide binding is reduced in patients with mild probable Alzheimer's disease in areas of temporal and temporo-parietal cortex.

Basal ganglia disease and visuospatial cognition: Are there disease-specific impairments?

Visuospatial deficits in basal ganglia disease may be a non-specific function of the severity of dementia or they could reflect disease-specific impairments. To examine this question, Huntington (HD) patients, demented and non-demented Parkinson (PD) patients and healthy controls were examined with neuropsychological tests emphasising visuospatial abilities. Global intellectual function and general visuospatial cognition were less efficient in the two demented patient groups relative to both controls and non-demented PD patients and they did not differ significantly between non-demented Parkinsonians and controls nor between demented PD and HD patients. However, HD patients but not demented PD patients were impaired on a test of person-centred spatial judgement compared to non-demented subjects while demented PD patients scored significantly lower than HD patients on a test of field independence. Factor analysis yielded a factor reflecting general visuospatial processing capacity which discriminated between demented and non-demented PD patients but not between demented PD and HD patients. A unique factor associated with the manipulation of person-centred space discriminated between demented PD and HD patients. These results suggest general visuospatial processing is impaired as a non-specific function of dementia presence in HD and PD. Abnormalities in circumscribed aspects of visuospatial function, on the other hand, may differentiate between HD and PD, suggesting differential involvement of the basal ganglia in the respective illnesses.

Vascular risk factors, atherosclerosis, cerebral white matter lesions and cerebral perfusion in a population-based study

We studied risk factors for cerebral vascular disease (blood pressure and hypertension, factor VIIc, factor VIIIc, fibrinogen), indicators of atherosclerosis (intima-media thickness and plaques in the carotid artery) and cerebral white matter lesions in relation to regional cerebral blood flow (rCBF) in 60 persons (aged 65-85 years) recruited from a population-based study. rCBF was assessed with single-photon emission tomography using technetium-99m d, l-hexamethylpropylene amine oxime (99mTc-HMPAO). Statistical analysis was performed with multiple linear regression with adjustment for age, sex and ventricle-to-brain ratio. A significant positive association was found between systolic and diastolic blood pressure and temporo-parietal rCBF. In analysis with quartiles of the distribution, we found a threshold effect for the relation of low diastolic blood pressure (</=60 mmHg) and low temporo-parietal rCBF. Levels of plasma fibrinogen were inversely related to parietal rCBF, with a threshold effect of high fibrinogen levels (>3.2 g/l) and low rCBF. Increased atherosclerosis was related to low rCBF in all cortical regions, but these associations were not significant. No consistent relation was observed between severity of cerebral white matter lesions and rCBF. Our results may have implications for blood pressure control in the elderly population.

Attentional deficits in Alzheimer's, Parkinson's, and Huntington's diseases

INTRODUCTION

Attentional deficits have been shown in Alzheimer's disease but it is unknown whether this reflects disease specific impairment or is present in other neurodegenerative disorders.

MATERIALS & METHODS

We administered a verbal dichotic listening task (free recall and selective allocation to the left or right ear) to 17 patients with Alzheimer's disease, 19 patients with Huntington's disease, 10 patients with idiopathic Parkinson's disease with clinical evidence of dementia (DemPD), 22 non-demented patients with Parkinson's disease (PD), and 22 healthy controls. Patients with dementia were matched for dementia severity and performance in the 3 recall conditions was used as a measure of attentional capacity.

RESULTS

Patients with dementia (Alzheimer and Huntington patients, DemPD) were less accurate than those without dementia (PD and normal subjects). Demented subjects performed at comparable levels regardless of specific diagnosis; likewise those without dementia also achieved similar levels. All groups had a right ear preference under the free recall condition. Alzheimer and Huntington patients showed consistent right ear preference under all recall conditions, while PD patients, like controls, could selectively allocate attention to the left under left ear recall, regardless of the presence of dementia.

CONCLUSION

The findings suggest a double dissociation. Non-selective attentional processing is affected by dementia presence versus absence but not by specific disease, while selective attentional processing shows disease specific impairments, regardless of the presence of dementia.

A novel approach to the determination and characterization of HIV dementia

BACKGROUND

Neuropsychological studies of the pattern and extent of cognitive impairment in HIV-infected patients have mostly used deviations from control values and/or cut-off scores as criteria for classification of dementia. There is, however, no agreement as to how to define impairment, and classification is imprecise.

METHOD

The current study used a dementia classification matrix, developed with a step-wise linear discriminant analysis of neuropsychological data from patients with primary neurodegenerative dementias, to classify symptomatic HIV patients as demented or non-demented, and further to differentiate cortical and subcortical dementia patterns. Thirty-two male and 2 female patients (mean age 39 +/- 2) with symptomatic HIV disease (mean absolute CD4 count 195 +/- 41) participated in the study.

RESULTS

Thirty-five per cent of patients were classified as demented. Of these, 83% showed a subcortical pattern and 17% a cortical profile of deficits. Significant differences between patients classified as subcortically demented and those categorized as normal on neuropsychological measures associated with subcortical integrity further validated the classification. Measures of psychiatric status between subgroups were similar.

CONCLUSION

Since certain treatments may delay or reverse cognitive deficits, the use of an objective classification method based on discriminant analysis may help to identify patients who may benefit from therapy.

Prevalence of Alzheimer's disease and vascular dementia: association with education. The Rotterdam study

OBJECTIVE

To estimate the prevalence of dementia and its subtypes in the general population and examine the relation of the disease to education.

DESIGN

Population based cross sectional study.

SETTING

Ommoord, a suburb of Rotterdam.

SUBJECTS

7528 participants of the Rotterdam study aged 55-106 years.

RESULTS

474 cases of dementia were detected, giving an overall prevalence of 6.3%. Prevalence ranged from 0.4% (5/1181 subjects) at age 55-59 years to 43.2% (19/44) at 95 years and over. Alzheimer's disease was the main subdiagnosis (339 cases; 72%); it was also the main cause of the pronounced increase in dementia with age. The relative proportion of vascular dementia (76 cases; 16%), Parkinson's disease dementia (30; 6%), and other dementias (24; 5%) decreased with age. A substantially higher prevalence of dementia was found in subjects with a low level of education. The association with education was not due to confounding by cardiovascular disease.

CONCLUSIONS

The prevalence of dementia increases exponentially with age. About one third of the population aged 85 and over has dementia. Three quarters of all dementia is due to Alzheimer's disease. In this study an inverse dose-response relation was found between education and dementia--in particular, Alzheimer's disease.

Differential classification of dementia

In the absence of biological markers, dementia classification remains complex both in terms of characterization as well as early detection of the presence or absence of dementing symptoms, particularly in diseases with possible secondary dementia. An empirical, statistical approach using neuropsychological measures was therefore developed to distinguish demented from non-demented patients and to identify differential patterns of cognitive dysfunction in neurodegenerative disease. Age-scaled neurobehavioral test results (Wechsler Adult Intelligence Scale-Revised and Wechsler Memory Scale) from Alzheimer's (AD) and Huntington's (HD) patients, matched for intellectual disability, as well as normal controls were used to derive a classification formula. Stepwise discriminant analysis accurately (99% correct) distinguished controls from demented patients, and separated the two patient groups (79% correct). Variables discriminating between HD and AD patient groups consisted of complex psychomotor tasks, visuospatial function, attention and memory. The reliability of the classification formula was demonstrated with a new, independent sample of AD and HD patients which yielded virtually identical results (classification accuracy for dementia: 96%; AD versus HD: 78%). To validate the formula, the discriminant function was applied to Parkinson's (PD) patients, 38% of whom were classified as demented. The validity of the classification was demonstrated by significant PD subgroup differences on measures of dementia not included in the discriminant function. Moreover, a majority of demented PD patients (65%) were classified as having an HD-like pattern of cognitive deficits, in line with previous reports of the subcortical nature of PD dementia. This approach may thus be useful in classifying presence or absence of dementia and in discriminating between dementia subtypes in cases of secondary or coincidental dementia.

Assessment of cerebral perfusion with single-photon emission tomography in normal subjects and in patients with Alzheimer's disease: effects of region of interest selection

The shape, size and location of regions of interest (ROIs) show considerable variability between single-photon emission tomography (SPET) studies in aging and Alzheimer's disease, but the possible influence on study results remains unknown. We compared three different ROIs in a SPET study with 60 controls and in 48 patients with probable Alzheimer's disease diagnosed according to the NINCDS-ADRDA criteria. Regional cerebral blood flow (rCBF) was assessed with SPET using technetium-99m d,l-hexamethylpropylene amine oxime (99mTc-HMPAO), normalized to the mean activity in a cerebellar reference slice. The three different ROIs were: a multi-slice and a single-slice ROI with reference to the normal brain anatomy (using an anatomical atlas), and a rectangular (2 x 4 pixels) ROI in the frontal, temporal, temporoparietal and occipital cortices. No differences were observed for the means of rCBF values between the single-slice and multi-slice ROI's with reference to the normal anatomy, but some variability was present for individual comparisons. In contrast, significantly higher mean rCBF values were obtained with the single-slice rectangular ROIs in all four regions for both patients and controls and considerable variability was shown for individual subjects. After analysis with multivariate logistic regression and receiver operator characteristic curves, the ability of SPET to discriminate between controls and Alzheimer patients was similar in the three methods for mild and moderate Alzheimer patients (Global Deterioration Scale = GDS of 3 and 4). However, with increasing dementia severity (GDS > 4) the rectangular ROIs showed lower ability to discriminate between groups compared to the single-slice and multi-slice anatomically defined ROIs.(ABSTRACT TRUNCATED AT 250 WORDS)

Cerebral white matter lesions, vascular risk factors, and cognitive function in a population-based study: the Rotterdam Study

Cerebral white matter lesions are a common finding on MRI in elderly persons. We studied the prevalence of white matter lesions and their relation with classic cardiovascular risk factors, thrombogenic factors, and cognitive function in an age- and gender-stratified random sample from the general population that consisted of 111 subjects 65 to 84 years of age. Overall, 27% of subjects had white matter lesions. The prevalence and severity of lesions increased with age. A history of stroke or myocardial infarction, factor VIIc activity, and fibrinogen level were each significantly and independently associated with the presence of white matter lesions. Significant relations with blood pressure level, hypertension, and plasma cholesterol were present only for subjects aged 65 to 74 years. White matter lesions tended to be associated with lower scores on tests of cognitive function and were significantly associated with subjective mental decline. This study suggests that classic cardiovascular risk factors, as well as thrombogenic factors, are associated with white matter lesions in subjects over 65 years of age in the general population, and that these lesions may be related to cognitive function.

Cardiovascular disease and distribution of cognitive function in elderly people: the Rotterdam Study

OBJECTIVE

To investigate the distribution of cognitive function in elderly people and to assess the impact of clinical manifestations of atherosclerotic disease on this distribution.

DESIGN

Single centre population based cross sectional door to door study.

SETTING

Ommoord, a suburb of Rotterdam, the Netherlands.

SUBJECTS

4971 subjects aged 55 to 94 years.

MAIN OUTCOME MEASURE

Cognitive function as measured by the mini mental state examination.

RESULTS

The overall participation rate in the study was 80%. Cognitive test data were available for 90% of the participants. Increasing age and lower educational level were associated with poorer cognitive function. Previous vascular events, presence of plaques in the carotid arteries, and presence of peripheral arterial atherosclerotic disease were associated with worse cognitive performance independent of the effects of age and education. On average the differences were moderate; however, they reflected the net result of a shift of the total population distribution of cognitive function towards lower values. Thereby, they resulted in a considerable increase in the proportion of subjects with scores indicative of dementia.

CONCLUSIONS

These findings are compatible with the view that atherosclerotic disease accounts for considerable cognitive impairment in the general population.

Cognitive correlates of ventricular enlargement and cerebral white matter lesions on magnetic resonance imaging. The Rotterdam Study

BACKGROUND AND PURPOSE

Ventricular enlargement and white matter lesions are frequent findings on cerebral magnetic resonance imaging scans of elderly subjects. In demented subjects they seem related to the severity of the dementia, but in nondemented subjects their clinical significance is less clear. We investigated the relation of size of the lateral ventricles and white matter lesions with cognitive function in a population-based random sample of nondemented elderly persons.

METHODS

The study population consisted of 90 subjects, aged 65 to 84 years, who were randomly selected from the cohort of the Rotterdam Study, and who were not demented. The presence of white matter lesions and the ventricle-to-brain ratio were assessed on magnetic resonance scans. Participants were tested with a neuropsychological battery that covered a broad range of cognitive functions.

RESULTS

Ventricular enlargement and white matter lesions were both and independently associated with poorer performance on all tests. After adjustment for age and sex, ventricular enlargement was significantly associated with worse scores on tests assessing global cognitive function (Mini-Mental State Examination, P = .02; Groninger Intelligence Test, P = .01), memory (Word List Learning delayed recall, P = .03), and executive control functions (Stroop part II, P = .02; Trial Making Test B, P < .01); for white matter lesions the differences were significant for tests measuring executive control functions and mental speed (Trail Making Test A and B, P = .01 and P < .01, respectively; verbal fluency, P = .01), and memory (Word List Learning delayed recall, P = .04).

CONCLUSIONS

This study suggests that white matter lesions are primarily related to impairment of subcorticofrontal functions, whereas enlargement of the lateral ventricles is associated with disturbances of cortical functions as well.

The diagnostic value of SPECT with Tc 99m HMPAO in Alzheimer's disease: a population-based study

We studied the diagnostic accuracy of single-photon emission computed tomography (SPECT) with technetium 99m-labeled hexamethylpropylene amine oxime (Tc 99m HMPAO) in 48 patients with probable Alzheimer's disease (AD) according to NINCDS-ADRDA criteria and in 60 controls recruited from a population-based study. With logistic regression, we identified decreased temporal regional cerebral blood flow as the best discriminating variable between patients and controls. Receiver-operator characteristic curves showed that the discriminative ability of SPECT improved with increasing dementia severity. With specificity set at 90%, sensitivity figures were 42% in mild, 56% in moderate, and 79% in severe AD. The diagnostic gain as a function of the prior probability of the disease being present was computed for those with mild AD. When the prior probability varied at around 50%, the diagnostic gain for mild AD patients was substantial (a maximum of 34%) for a positive test result but poor for a negative test result. The results suggest that the practical usefulness of SPECT as a diagnostic adjunct in patients suspected of having mild AD is confined to situations in which, on clinical grounds, there is considerable diagnostic doubt.

Nootropic drugs in Alzheimer's disease: symptomatic treatment with pramiracetam

The cognitive-enhancing effects of pramiracetam in animal models of learning and memory are characterized by an inverted U-shaped dose-response curve. We evaluated antidementia efficacy of this drug in 10 patients with probable Alzheimer's disease employing a 2-phase, placebo-controlled, enrichment-type trial design. Eight patients evidenced a best dose in the dose-finding phase, but in the subsequent replication phase only two again improved to a similar degree. PETs with fluorodeoxyglucose obtained in two individuals showed no definite change. Doses up to 4,000 mg pramiracetam are unlikely to confer symptomatic benefit to Alzheimer's disease patients.

Clinical trials in dementia: learning effects with repeated testing

The possible confounding role of learning effects during multiple test administration in clinical trials in demented subjects remains uncertain. Seventeen mildly to severely affected patients with Alzheimer's disease (AD) and 16 controls were evaluated with an extensive neuropsychological battery of manually administered and computerized tests. Subjects received 3 weekly sessions using alternate test forms, to mimic a baseline, placebo, and drug condition. Mean scores of AD patients as a group showed no stable improvement, but more subtle learning effects were suggested by an association of dementia severity and change scores in verbal and visual learning. Controls evidenced consistent learning in 3 of 9 tests. These results suggest that clinical trials data from AD patients, especially those with moderately severe impairment, are not contaminated by learning. Degree of cognitive impairment may be related to learning capacity, suggesting caution for learning effects in controls and possibly in patients with mild AD.

Visuospatial cognition in Huntington's disease

The notion of specificity of visuospatial dysfunction in Huntington's disease (HD) was evaluated in a sample of afflicted patients as a function of symptom duration, age at onset, and overall dementia severity. Factor analytic procedures indicated that overall visuospatial processing capacity (factor 1) as well as the ability for spatial manipulation (factor 3) was markedly affected in HD patients. In contrast, consistency of spatial judgment (factor 2) appeared to remain relatively intact in these patients. Age at onset seemed to have no relationship with any of these variables, whereas dementia severity demonstrated a significant relationship with overall visuospatial processing capacity. Most importantly, duration of symptoms was significantly associated with the declining ability to mentally perform spatial manipulations. The observation of circumscribed visuospatial impairment in HD patients may have important consequences for the further understanding of the neurobehavioral consequences of this disorder.

Clonidine treatment of Alzheimer's disease

A loss of cortical noradrenergic innervation may contribute to the intellectual deterioration in Alzheimer's disease. To test the hypothesis that noradrenergic replacement may confer symptomatic benefit, a double-blind, placebo-controlled therapeutic trial with clonidine hydrochloride (Catapres), a centrally active noradrenergic receptor agonist, was undertaken in eight patients with the clinical diagnosis of Alzheimer's disease. No statistically significant changes in cognitive function were found over a range of doses, including those that produced clinically observable side effects. These preliminary results indicate a need for alternative noradrenergic replacement strategies in Alzheimer's disease.