Carl Eckerström

Intra-individual stability of CSF biomarkers for Alzheimer's disease over two years.

This study examines the intra-individual stability of cerebrospinal fluid (CSF) biomarkers for Alzheimers disease (AD) over 2 years in 83 patients with mild cognitive impairment (MCI) and 17 cognitively healthy control individuals. All participants underwent clinical and neuropsychological evaluation and lumbar puncture at baseline and after 2 years at a university hospital memory clinic. CSF was analyzed for total tau (T-tau), phospho-tau(181) (P-tau(181)) and amyloid-beta(1-42) (Abeta(1-42)). During the 2-year observational time, 12 MCI patients progressed to AD and 3 progressed to vascular dementia, while 68 remained stable. Baseline T-tau and P-tau(181) levels were elevated in the MCI-AD group as compared to the stable MCI patients and the control group (p<0.01), while baseline Abeta(1-42) levels were lower (p<0.001). Stable MCI patients were biochemically indistinguishable from controls. The biomarker levels at baseline and after 2 years showed Pearson R values between 0.81 and 0.91 (p<0.001) and coefficients of variation of 7.2 to 8.7%. In conclusion, intra-individual biomarker levels are remarkably stable over 2 years. Thus, even minor biochemical changes induced by treatment against AD should be detectable using these biomarkers, which bodes well for their usefulness as surrogate markers for drug efficacy in clinical trials.

Small baseline volume of left hippocampus is associated with subsequent conversion of MCI into dementia: The Göteborg MCI study

BACKGROUND Earlier studies have reported that hippocampal atrophy can to some extent predict which patients with mild cognitive impairment (MCI) will subsequently convert to dementia, and that converters have an enhanced rate of hippocampal volume loss. OBJECTIVE To further validate the hypothesis that hippocampal atrophy predicts conversion from MCI to dementia, to relate baseline hippocampal volume to different forms of dementia, and to investigate the role of hippocampal side differences and rate of volume loss over time. PATIENTS The subjects (N=68) include patients with MCI at baseline and progression to dementia at the two-year follow-up (N=21), stable MCI patients (N=21), and controls (N=26). Among the progressing patients, 13 were diagnosed as having AD. METHODS The Göteborg MCI study is a clinically based longitudinal study with biannual clinical assessments. Hippocampal volumetry was performed manually on the MRI investigations at baseline and at the two-year follow-up. RESULTS Hippocampal volumetry could predict conversion to dementia in both the AD and the non-AD subgroup of converters. Left hippocampal volume in particular discriminated between converting and stable MCI. Cut off points for individual discrimination were shown to be potentially useful. The converting MCI group had a significantly higher rate of hippocampal volume loss as compared to the stable MCI group. CONCLUSIONS In MCI patients, hippocampal volumetry at baseline gives prognostic information about possible development of AD and non-AD dementia. Contrary to earlier studies, we found that left hippocampal volume has the best predictive power. Reliable predictions appear to be possible in many individual cases.

Neuronal and Glia-Related Biomarkers in Cerebrospinal Fluid of Patients with Acute Ischemic Stroke

Background Cerebral ischemia promotes morphological reactions of the neurons, astrocytes, oligodendrocytes, and microglia in experimental studies. Our aim was to examine the profile of CSF (cerebrospinal fluid) biomarkers and their relation to stroke severity and degree of white matter lesions (WML). Methods A total of 20 patients (mean age 76 years) were included within 5–10 days after acute ischemic stroke (AIS) onset. Stroke severity was assessed using NIHSS (National Institute of Health stroke scale). The age-related white matter changes (ARWMC) scale was used to evaluate the extent of WML on CT-scans. The concentrations of specific CSF biomarkers were analyzed. Results Patients with AIS had significantly higher levels of NFL (neurofilament, light), T-tau, myelin basic protein (MBP), YKL-40, and glial fibrillary acidic protein (GFAP) compared with controls; T-Tau, MBP, GFAP, and YKL-40 correlated with clinical stroke severity, whereas NFL correlated with severity of WML (tested by Mann–Whitney test). Conclusions Several CSF biomarkers increase in AIS, and they correlate to clinical stroke severity. However, only NFL was found to be a marker of degree of WML.

A Combination of Neuropsychological, Neuroimaging, and Cerebrospinal Fluid Markers Predicts Conversion from Mild Cognitive Impairment to Dementia

BACKGROUND Mild cognitive impairment (MCI) is a condition with increased risk for further cognitive decline. A considerable challenge lies in predicting which patients will eventually convert to dementia. OBJECTIVE To study prediction of dementia in MCI using neuropsychological tests, commonly used cerebrospinal fluid (CSF) biomarkers, and hippocampal volume. METHODS Twenty-one MCI patients converting to dementia, 21 stable MCI patients, and 26 controls were included in the study with a follow-up time of two years. The study participants underwent comprehensive examinations at inclusion: a neuropsychological assessment comprising 20 tests, MRI scanning with subsequent hippocampal volumetry, and CSF analyses of T-tau, P-tau, and Aβ42. RESULTS Neuropsychological tests, hippocampal volume, and the CSF markers Aβ42, P-tau, and T-tau all predicted conversion from MCI to dementia. A combination of all classes of markers was the most successful at predicting dementia (AUC 0.96) with a memory test (RAVLT) as the best individual predictor (AUC 0.93). Similar findings are reported for the prediction of Alzheimers disease. CONCLUSION Neuropsychological tests were the best individual predictors of dementia. A combination of markers improved the predictive ability with the combination of neuropsychological tests, CSF, and hippocampal volume as the best predictors of dementia.

Biomarkers in relation to cognitive reserve in patients with mild cognitive impairment--proof of concept.

Background: The concept of the cognitive reserve (CR) posits that factors such as education enable compensation for the effect of brain pathology. Consequently, pathology should be more pronounced in individuals with higher CR before becoming clinically apparent. Biomarkers such as total tau (t-tau) and β-amyloid 42 (Aβ42) may be surrogates for pathology in relation to CR in patients with neurodegenerative disease. Objective: To examine the applicability of biomarkers as surrogates for pathology in relation to the CR in patients with mild cognitive impairment (MCI) either converting to dementia or remaining stable at follow-up. Method: Comparisons of baseline t-tau, Aβ42, educational years and global cognition for MCI patients either converting to dementia (n = 57) or remaining stable (n = 91) were made. Patients converting to dementia were grouped on the basis of educational level and compared considering biomarkers and neuropsychological tests. Results: Stable MCI patients were better educated, performed better cognitively, had higher Aβ42 levels and lower levels of t-tau. Converting MCI patients with higher education had lower levels of Aβ42 and performed equally in neuropsychological tests compared to those with lower education. Conclusion: Our results suggest that highly educated MCI patients subsequently converting to dementia display more amyloid pathology.

Combination of Hippocampal Volume and Cerebrospinal Fluid Biomarkers Improves Predictive Value in Mild Cognitive Impairment

Background: Mild cognitive impairment (MCI) is a heterogeneous condition, and the prognosis differs within the group. Recent findings suggest that hippocampal volumetry and CSF biomarkers can be used to predict which MCI patients have an underlying neurodegenerative disorder. Objective: To examine the combined predictive value of hippocampal volume and CSF levels of total tau (T-tau) and β-amyloid42 (Aβ42) in stable and converting MCI patients. The participants (n = 68) included patients with MCI at baseline and who converted to dementia by the time of the 2-year follow-up (n = 21), stable MCI patients (n = 21) and healthy controls (n = 26). Methods: The Göteborg MCI study is a clinically based longitudinal study with biannual clinical assessments. Hippocampal volumetry was performed manually, based on data from the 0.5-tesla MRI investigations at baseline. Baseline CSF levels of T-tau and Aβ42 were measured using commercially available, enzyme-linked immunosorbent assays. Results: The converting MCI group had significantly smaller left hippocampi, lower CSF Aβ42 and higher T-tau compared to both the stable MCI group and the healthy controls. Multivariate analysis revealed that a combination of the variables outperformed the prognostic ability of the separate variables. Conclusions: Hippocampal volumes supplement the prognostic accuracy of CSF Aβ42 and T-tau in MCI.

Multimodal prediction of dementia with up to 10 years follow up: the Gothenburg MCI study.

BACKGROUND Neuropsychological tests, CSF Aβ42, T-tau, P-tau181, hippocampal volume, and white matter lesions have been shown to predict conversion to dementia in patients with mild cognitive impairment (MCI). OBJECTIVE To examine the predictive value of combinations of these markers and to examine if the absence of pathological markers provides a lasting reduction of conversion rates. METHODS The Gothenburg MCI study is a clinically based study. Seventy-three MCI patients were included in the present sub-study and followed for a maximum of ten years. Thirty-four patients converted to dementia (18 to AD) and 39 remained stable. At inclusion, patients were classified into positive or negative risk groups according to results from neuropsychological testing (Rey auditory verbal learning test, Boston naming test, Trail making test B), CSF biomarkers (amyloid β42, T-tau, and P-tau181), and MRI scans (hippocampal volume, white matter lesions). RESULTS Trail making test B (TMT-B) was the best single predictor for the prediction of dementia (AUC 0.89, HR 25), and T-tau was the best predictor of AD (AUC 0.97, HR 41). The combination of hippocampal volume and TMT-B was the best combination for the prediction of dementia (HR 25), and the combination of hippocampal volume and T-tau was the best combination for the prediction of AD (HR 37). CONCLUSION Neuropsychological tests, CSF markers, and hippocampal volume predicted conversion from MCI to AD and general dementia. The absence of pathological markers provided a long-time protection from dementia.

High White Matter Lesion Load Is Associated with Hippocampal Atrophy in Mild Cognitive Impairment

Background: Mild cognitive impairment (MCI) is a heterogeneous condition suggested as a prodromal state of Alzheimer’s disease (AD) and subcortical vascular dementia (SVD). Recent findings suggest that white matter lesions (WML) may be associated with hippocampal atrophy. The objective of the study was to examine hippocampal and WML volumes in MCI patients and to examine if WML were linked to hippocampal atrophy. Methods: The Gothenburg MCI study is a clinically based longitudinal study with biennial clinical assessments. The participants (n = 166) consist of 92 patients with stable MCI, 30 patients with converting MCI, and 44 healthy controls. WML volumes was measured manually using MRIcron. Automated segmentation of hippocampal and total white matter volumes was performed using FreeSurfer. Results: The patients converting from MCI to dementia had reduced hippocampal volume. Stable MCI patients had fewer WML and converting MCI patients had more WML compared to controls. Hippocampal volume was only correlated to WML volume (ρ = 0.57; p < 0.01) in the quartile (n = 42) with the most WML. Conclusions: Hippocampal atrophy is present in both AD and SVD. Hippocampal volume was associated with WML volume only in the high WML quartile, suggesting that the WML volume must reach a threshold before hippocampal atrophy is seen.

The Gothenburg MCI study: Design and distribution of Alzheimer’s disease and subcortical vascular disease diagnoses from baseline to 6-year follow-up

There is a need for increased nosological knowledge to enable rational trials in Alzheimer’s disease (AD) and related disorders. The ongoing Gothenburg mild cognitive impairment (MCI) study is an attempt to conduct longitudinal in-depth phenotyping of patients with different forms and degrees of cognitive impairment using neuropsychological, neuroimaging, and neurochemical tools. Particular attention is paid to the interplay between AD and subcortical vascular disease, the latter representing a disease entity that may cause or contribute to cognitive impairment with an effect size that may be comparable to AD. Of 664 patients enrolled between 1999 and 2013, 195 were diagnosed with subjective cognitive impairment (SCI), 274 with mild cognitive impairment (MCI), and 195 with dementia, at baseline. Of the 195 (29%) patients with dementia at baseline, 81 (42%) had AD, 27 (14%) SVD, 41 (21%) mixed type dementia (=AD + SVD = MixD), and 46 (23%) other etiologies. After 6 years, 292 SCI/MCI patients were eligible for follow-up. Of these 292, 69 (24%) had converted to dementia (29 (42%) AD, 16 (23%) SVD, 15 (22%) MixD, 9 (13%) other etiologies). The study has shown that it is possible to identify not only AD but also incipient and manifest MixD/SVD in a memory clinic setting. These conditions should be taken into account in clinical trials.

White Matter Lesion Assessment in Patients with Cognitive Impairment and Healthy Controls: Reliability Comparisons between Visual Rating, a Manual, and an Automatic Volumetrical MRI Method—The Gothenburg MCI Study

Age-related white matter lesions (WML) are a risk factor for stroke, cognitive decline, and dementia. Different requirements are imposed on methods for the assessment of WML in clinical settings and for research purposes, but reliability analysis is of major importance. In this study, WML assessment with three different methods was evaluated. In the Gothenburg mild cognitive impairment study, MRI scans from 152 participants were used to assess WML with the Fazekas visual rating scale on T2 images, a manual volumetric method on FLAIR images, and FreeSurfer volumetry on T1 images. Reliability was acceptable for all three methods. For low WML volumes (2/3 of the patients), reliability was overall lower and nonsignificant for the manual volumetric method. Unreliability in the assessment of patients with low WML with manual volumetry may mainly be due to intensity variation in the FLAIR sequence used; hence, intensity standardization and normalization methods must be used for more accurate assessments. The FreeSurfer segmentations resulted in smaller WML volumes than the volumes acquired with the manual method and showed deviations from visible hypointensities in the T1 images, which quite likely reduces validity.