O. Almkvist - Academia.edu (original) (raw)

Papers by O. Almkvist

Research paper thumbnail of Cerebrospinal fluid levels of alpha-secretase-cleaved soluble amyloid precursor protein mirror cognition in a Swedish family with Alzheimer disease and a gene mutation

Archives of neurology, 1997

To explore the relationship between possible biological markers of Alzheimer disease that are rel... more To explore the relationship between possible biological markers of Alzheimer disease that are related to amyloid metabolism and mental functions. Twelve individuals from a Swedish family with Alzheimer disease and a double mutation at codons 670/671 of the amyloid precursor protein gene participated in the study. Cerebrospinal fluid levels of alpha-secretase cleaved soluble amyloid precursor protein (alpha-sAPP), total sAPP, and amyloid beta-peptide were correlated with data on multiple cognitive functions that covered the whole range of human performance. The Alzheimer's Disease Research Centre, Department of Clinical Neuroscience, Section of Geriatric Medicine, Karolinska Institute, Huddinge University Hospital, Huddinge, Sweden. There were highly significant linear correlations between low levels of alpha-sAPP and poor performance on neuropsychological tests that assessed intelligence, verbal and visuospatial functions, memory, and attention. Within the group of nonmutation c...

Research paper thumbnail of White matter changes in familial Alzheimer's disease

Journal of Internal Medicine, 2015

Research paper thumbnail of Visual Rating of Age-Related White Matter Changes on Magnetic Resonance Imaging: Scale Comparison, Interrater Agreement, and Correlations With Quantitative Measurements

Stroke, 2003

To provide further insight into the MRI assessment of age-related white matter changes (ARWMCs) w... more To provide further insight into the MRI assessment of age-related white matter changes (ARWMCs) with visual rating scales, 3 raters with different levels of experience tested the interrater agreement and comparability of 3 widely used rating scales in a cross-sectional and follow-up setting. Furthermore, the correlation between visual ratings and quantitative volumetric measurement was assessed. Three raters from different sites using 3 established rating scales (Manolio, Fazekas and Schmidt, Scheltens) evaluated 74 baseline and follow-up scans from 5 European centers. One investigator also rated baseline scans in a set of 255 participants of the Austrian Stroke Prevention Study (ASPS) and measured the volume of ARWMCs. The interrater agreement for the baseline investigation was fair to good for all scales (kappa values, 0.59 to 0.78). On the follow-up scans, all 3 raters depicted significant ARWMC progression; however, the direct interrater agreement for this task was poor (kappa, 0.19 to 0.39). Comparison of the interrater reliability between the 3 scales revealed a statistical significant difference between the scale of Manolio and that of Fazekas and Schmidt for the baseline investigation (z value, -2.9676; P=0.003), demonstrating better interrater agreement for the Fazekas and Schmidt scale. The rating results obtained with all 3 scales were highly correlated with each other (Spearman rank correlation, 0.712 to 0.806; P< or =0.01), and there was significant agreement between all 3 visual rating scales and the quantitative volumetric measurement of ARWMC (Kendall W, 0.37, 0.48, and 0.57; P<0.001). Our data demonstrate that the 3 rating scales studied reflect the actual volume of ARWMCs well. The 2 scales that provide more detailed information on ARWMCs seemed preferential compared with the 1 that yields more global information. The visual assessment of ARWMC progression remains problematic and may require modifications or extensions of existing rating scales.

Research paper thumbnail of Impaired cerebral glucose metabolism and cognitive functioning predict deterioration in mild cognitive impairment

Neuroreport, 2001

The objective of this study was to assess whether reduced glucose metabolism (rCMRGlu) and cognit... more The objective of this study was to assess whether reduced glucose metabolism (rCMRGlu) and cognitive functioning could predict development of Alzheimer's disease (AD) in subjects with mild cognitive impairment (MCI). Twenty MCI patients underwent baseline and follow-up investigations of rCMRGlu, as measured by PET, and cognitive function measured by neuropsychological test assessments. Subjects were clinically followed up with an average interval of 36.5 months. Two groups were obtained after the second clinical assessment. Nine patients were diagnosed as AD and classified as progressive MCI (P-MCI), whereas 11 patients remained clinically stable and were classified as stable MCI (S-MCI). There were no differences in demographic variables or baseline MMSE between the two subgroups. Logistic regression indicated the two variables that most effectively predicted future development of AD were rCMRGlu from the left temporoparietal area and performance on the block design. These combined measures gave an optimal 90% correct classification rate, whereas only rCMRGlu or neuropsychology alone gave 75% and 65% correct classification, respectively. Measures of temporoparietal cerebral metabolism and visuospatial function may aid in predicting the evolution to AD for patients with MCI.

Research paper thumbnail of Quantitative electroencephalography in mild cognitive impairment: longitudinal changes and possible prediction of Alzheimer’s disease

Neurobiology of Aging, 2000

The present study evaluated the clinical course of patients with mild cognitive impairment (MCI),... more The present study evaluated the clinical course of patients with mild cognitive impairment (MCI), the pattern of electroencephalography (EEG) changes following cognitive deterioration, as well as the potential of neurophysiological measures in predicting dementia. Twenty-seven subjects with MCI were followed for a mean follow up period of 21 months. Fourteen subjects (52%) progressed (P MCI) to clinically manifest Alzheimer's disease (AD), and 13 (48%) remained stable (S MCI). The two MCI subgroups did not differ in baseline EEG measures between each other and the healthy controls (n = 16), but had significantly lower theta relative power at left temporal, temporo-occipital, centro-parietal, and right temporo-occipital derivation when compared to the reference AD group (n = 15). The P MCI baseline alpha band temporo-parietal coherence, alpha relative power values at left temporal and temporo-occipital derivations, theta relative power values at frontal derivations, and the mean frequency at centro-parietal and temporo-occipital derivations overlapped with those for AD and control groups. After the follow-up, the P MCI patients had significantly higher theta relative power and lower beta relative power and mean frequency at the temporal and temporo-occipital derivations. A logistic regression model of baseline EEG values adjusted for baseline Mini-Mental Test Examination showed that the important predictors were alpha and theta relative power and mean frequency from left temporo-occipital derivation (T5-O1), which classified 85% of MCI subjects correctly.

Research paper thumbnail of 454 Combined measurement of regional brain volume and perfusion in Alzheimer's disease using coregistred MRI/SPECT

Neurobiology of Aging, 1996

Research paper thumbnail of Amino acid concentrations in cerebrospinal fluid and plasma in Alzheimer's disease and healthy control subjects

Journal of Neural Transmission - Parkinson's Disease and Dementia Section, 1990

Cerebrospinal fluid (CSF) and plasma levels of 18 amino acids were studied in 22 subjects with de... more Cerebrospinal fluid (CSF) and plasma levels of 18 amino acids were studied in 22 subjects with dementia of the Alzheimer type (DAT) and in 11 healthy volunteers with no clinical or family history of dementia. Significant decreases of plasma taurine and glutamate were seen in the DAT cases compared with the controls. The CSF concentrations of glycine, leucine and valine were also significantly reduced in the DAT cases. Furthermore, in the DAT cases significant decreases were observed in the ratio between CSF and plasma (CSF/P) levels for alanine, glutamine, glycine, phenylalanine and valine, when compared with controls. In the DAT group there were significant correlations between behaviour and CSF glutamine; memory and cognitive functions and CSF valine; copying ability and CSF glutamate. CSF/P ratios of glutamine and glutamate correlated with behaviour and copying performances, respectively. The results of this study provide further evidence for a disruption of amino acid metabolism in DAT.

Research paper thumbnail of First Symptoms – Frontotemporal Dementia versus Alzheimer’s Disease

Dementia and Geriatric Cognitive Disorders, 2000

Frontotemporal dementia (FTD) is often misdiagnosed as Alzheimer’s disease (AD). We hypothesized ... more Frontotemporal dementia (FTD) is often misdiagnosed as Alzheimer’s disease (AD). We hypothesized that the first symptoms associated with FTD would be different from those seen in AD and that the first symptoms in FTD would reflect loss of function in the frontal region with the greatest degree of degeneration. The objective of the study was to compare the earliest symptoms

Research paper thumbnail of Bilateral Temporal Lobe Volume Reduction Parallels Cognitive Impairment in Progressive Aphasia

Archives of Neurology, 1997

Patients with isolated aphasia in the absence of other cognitive abnormalities have been the focu... more Patients with isolated aphasia in the absence of other cognitive abnormalities have been the focus of several studies during the past decade. It has been called primary progressive aphasia (PPA), and the typical features of this syndrome are marked atrophy of the left temporal lobe according to the radiological examination and a language disorder as the initial symptom. In previous studies of PPA, the selection of the patients was based mainly on linguistic symptoms. Now, when computed tomography or magnetic resonance imaging scans are part of the routine investigation of cognitive impairment and suspected dementia, the patients with lobar atrophy will be found at an earlier stage. In the present study, we used a new approach and defined the study group by selecting patients with obvious left temporal lobe atrophy, assessed by MRI, and we referred to them as patients with temporal lobe atrophy (TLA). To identify the features that distinguish TLA from other primary neurodegenerative disorders. Six patients with TLA were compared with patients with Alzheimer disease (AD), patients with frontal lobe dementia (FLD), and healthy control subjects. The investigations included magnetic resonance imaging volumetry, single photon emission computed tomography, and neuropsychologic and linguistic evaluations. In the TLA group, the mean volume of the left temporal lobe was 35% smaller than the right, while in the AD and FLD groups, the atrophy was symmetrical and bilateral. In the TLA group, the absolute volumes of the temporal lobes were significantly smaller on the left side compared with the AD and FLD groups, whereas there was no difference on the right side. The cerebral blood flow pattern in TLA was asymmetric and differed from that in the other study groups. All patients with TLA had a history of progressive Wernicke-type aphasia, ranging from 2 to 6 years. They showed primary verbal memory impairment but had preserved visuospatial functions. The clinical condition of all patients with TLA deteriorated during the study period; severe aphasia developed, and the patients exhibited signs of frontal lobe dysfunction. Serial volumetric measurements in 4 of 6 patients showed an annual 8% to 9% decrease of both left and right temporal lobes. The initial marked asymmetry in cognitive function found in patients with TLA contrasts with the general decline found in patients with AD. The bilateral degenerative process evident in patients with TLA paralleled the clinical deterioration, indicating TLA to be a non-AD lobar atrophy that develops into generalized cognitive dysfunction and dementia.

Research paper thumbnail of Olfactory Dysfunction for Pyridine and Dementia Progression in Alzheimer Disease

Archives of Neurology, 1997

To investigate whether odor detection sensitivity for pyridine, suggested by previous research no... more To investigate whether odor detection sensitivity for pyridine, suggested by previous research not to be affected, is impaired in Alzheimer disease (AD) and whether an association exists between odor threshold and both degree of dementia and rate of dementia progression in AD. The method of constant stimuli was used to determine odor thresholds for pyridine in 18 patients with AD (Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised and National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria) and 16 healthy elderly control subjects. All participants were carefully examined with medical and neuropsychological tests. Six patients with AD but none of the controls were anosmic (total olfactory loss) to pyridine, and the 12 nonanosmic patients had significantly higher detection thresholds (50% probability for detection, 323 parts per billion [ppb]) than did the controls (50% probability for detection, 105 ppb). In addition, an association was found between odor threshold and both degree of dementia and rate of dementia progression in AD. In contrast to previous findings, our results provide evidence that odor sensitivity in AD is impaired for pyridine. Odor sensitivity, in addition to other suggested predictors of progression rate, may be of interest for defining subgroups of AD or for clinical prognostic judgments of single patients.

Research paper thumbnail of A European multicentre PET study of fibrillar amyloid in Alzheimer’s disease

European Journal of Nuclear Medicine and Molecular Imaging, 2013

Purpose Amyloid PET tracers have been developed for in vivo detection of brain fibrillar amyloid ... more Purpose Amyloid PET tracers have been developed for in vivo detection of brain fibrillar amyloid deposition in Alzheimer's disease (AD). To serve as an early biomarker in AD the amyloid PET tracers need to be analysed in multicentre clinical studies. Methods In this study 238 [ 11 C]Pittsburgh compound-B (PIB) datasets from five different European centres were Electronic supplementary material The online version of this article (pooled. Of these 238 datasets, 18 were excluded, leaving [ 11 C]PIB datasets from 97 patients with clinically diagnosed AD (mean age 69±8 years), 72 patients with mild cognitive impairment (MCI; mean age 67.5±8 years) and 51 healthy controls (mean age 67.4±6 years) available for analysis. Of the MCI patients, 64 were longitudinally followed for 28 ± 15 months. Most participants (175 out of 220) were also tested for apolipoprotein E (ApoE) genotype.

Research paper thumbnail of Cerebrospinal fluid levels of alpha-secretase-cleaved soluble amyloid precursor protein mirror cognition in a Swedish family with Alzheimer disease and a gene mutation

Archives of neurology, 1997

To explore the relationship between possible biological markers of Alzheimer disease that are rel... more To explore the relationship between possible biological markers of Alzheimer disease that are related to amyloid metabolism and mental functions. Twelve individuals from a Swedish family with Alzheimer disease and a double mutation at codons 670/671 of the amyloid precursor protein gene participated in the study. Cerebrospinal fluid levels of alpha-secretase cleaved soluble amyloid precursor protein (alpha-sAPP), total sAPP, and amyloid beta-peptide were correlated with data on multiple cognitive functions that covered the whole range of human performance. The Alzheimer's Disease Research Centre, Department of Clinical Neuroscience, Section of Geriatric Medicine, Karolinska Institute, Huddinge University Hospital, Huddinge, Sweden. There were highly significant linear correlations between low levels of alpha-sAPP and poor performance on neuropsychological tests that assessed intelligence, verbal and visuospatial functions, memory, and attention. Within the group of nonmutation c...

Research paper thumbnail of White matter changes in familial Alzheimer's disease

Journal of Internal Medicine, 2015

Research paper thumbnail of Visual Rating of Age-Related White Matter Changes on Magnetic Resonance Imaging: Scale Comparison, Interrater Agreement, and Correlations With Quantitative Measurements

Stroke, 2003

To provide further insight into the MRI assessment of age-related white matter changes (ARWMCs) w... more To provide further insight into the MRI assessment of age-related white matter changes (ARWMCs) with visual rating scales, 3 raters with different levels of experience tested the interrater agreement and comparability of 3 widely used rating scales in a cross-sectional and follow-up setting. Furthermore, the correlation between visual ratings and quantitative volumetric measurement was assessed. Three raters from different sites using 3 established rating scales (Manolio, Fazekas and Schmidt, Scheltens) evaluated 74 baseline and follow-up scans from 5 European centers. One investigator also rated baseline scans in a set of 255 participants of the Austrian Stroke Prevention Study (ASPS) and measured the volume of ARWMCs. The interrater agreement for the baseline investigation was fair to good for all scales (kappa values, 0.59 to 0.78). On the follow-up scans, all 3 raters depicted significant ARWMC progression; however, the direct interrater agreement for this task was poor (kappa, 0.19 to 0.39). Comparison of the interrater reliability between the 3 scales revealed a statistical significant difference between the scale of Manolio and that of Fazekas and Schmidt for the baseline investigation (z value, -2.9676; P=0.003), demonstrating better interrater agreement for the Fazekas and Schmidt scale. The rating results obtained with all 3 scales were highly correlated with each other (Spearman rank correlation, 0.712 to 0.806; P< or =0.01), and there was significant agreement between all 3 visual rating scales and the quantitative volumetric measurement of ARWMC (Kendall W, 0.37, 0.48, and 0.57; P<0.001). Our data demonstrate that the 3 rating scales studied reflect the actual volume of ARWMCs well. The 2 scales that provide more detailed information on ARWMCs seemed preferential compared with the 1 that yields more global information. The visual assessment of ARWMC progression remains problematic and may require modifications or extensions of existing rating scales.

Research paper thumbnail of Impaired cerebral glucose metabolism and cognitive functioning predict deterioration in mild cognitive impairment

Neuroreport, 2001

The objective of this study was to assess whether reduced glucose metabolism (rCMRGlu) and cognit... more The objective of this study was to assess whether reduced glucose metabolism (rCMRGlu) and cognitive functioning could predict development of Alzheimer's disease (AD) in subjects with mild cognitive impairment (MCI). Twenty MCI patients underwent baseline and follow-up investigations of rCMRGlu, as measured by PET, and cognitive function measured by neuropsychological test assessments. Subjects were clinically followed up with an average interval of 36.5 months. Two groups were obtained after the second clinical assessment. Nine patients were diagnosed as AD and classified as progressive MCI (P-MCI), whereas 11 patients remained clinically stable and were classified as stable MCI (S-MCI). There were no differences in demographic variables or baseline MMSE between the two subgroups. Logistic regression indicated the two variables that most effectively predicted future development of AD were rCMRGlu from the left temporoparietal area and performance on the block design. These combined measures gave an optimal 90% correct classification rate, whereas only rCMRGlu or neuropsychology alone gave 75% and 65% correct classification, respectively. Measures of temporoparietal cerebral metabolism and visuospatial function may aid in predicting the evolution to AD for patients with MCI.

Research paper thumbnail of Quantitative electroencephalography in mild cognitive impairment: longitudinal changes and possible prediction of Alzheimer’s disease

Neurobiology of Aging, 2000

The present study evaluated the clinical course of patients with mild cognitive impairment (MCI),... more The present study evaluated the clinical course of patients with mild cognitive impairment (MCI), the pattern of electroencephalography (EEG) changes following cognitive deterioration, as well as the potential of neurophysiological measures in predicting dementia. Twenty-seven subjects with MCI were followed for a mean follow up period of 21 months. Fourteen subjects (52%) progressed (P MCI) to clinically manifest Alzheimer's disease (AD), and 13 (48%) remained stable (S MCI). The two MCI subgroups did not differ in baseline EEG measures between each other and the healthy controls (n = 16), but had significantly lower theta relative power at left temporal, temporo-occipital, centro-parietal, and right temporo-occipital derivation when compared to the reference AD group (n = 15). The P MCI baseline alpha band temporo-parietal coherence, alpha relative power values at left temporal and temporo-occipital derivations, theta relative power values at frontal derivations, and the mean frequency at centro-parietal and temporo-occipital derivations overlapped with those for AD and control groups. After the follow-up, the P MCI patients had significantly higher theta relative power and lower beta relative power and mean frequency at the temporal and temporo-occipital derivations. A logistic regression model of baseline EEG values adjusted for baseline Mini-Mental Test Examination showed that the important predictors were alpha and theta relative power and mean frequency from left temporo-occipital derivation (T5-O1), which classified 85% of MCI subjects correctly.

Research paper thumbnail of 454 Combined measurement of regional brain volume and perfusion in Alzheimer's disease using coregistred MRI/SPECT

Neurobiology of Aging, 1996

Research paper thumbnail of Amino acid concentrations in cerebrospinal fluid and plasma in Alzheimer's disease and healthy control subjects

Journal of Neural Transmission - Parkinson's Disease and Dementia Section, 1990

Cerebrospinal fluid (CSF) and plasma levels of 18 amino acids were studied in 22 subjects with de... more Cerebrospinal fluid (CSF) and plasma levels of 18 amino acids were studied in 22 subjects with dementia of the Alzheimer type (DAT) and in 11 healthy volunteers with no clinical or family history of dementia. Significant decreases of plasma taurine and glutamate were seen in the DAT cases compared with the controls. The CSF concentrations of glycine, leucine and valine were also significantly reduced in the DAT cases. Furthermore, in the DAT cases significant decreases were observed in the ratio between CSF and plasma (CSF/P) levels for alanine, glutamine, glycine, phenylalanine and valine, when compared with controls. In the DAT group there were significant correlations between behaviour and CSF glutamine; memory and cognitive functions and CSF valine; copying ability and CSF glutamate. CSF/P ratios of glutamine and glutamate correlated with behaviour and copying performances, respectively. The results of this study provide further evidence for a disruption of amino acid metabolism in DAT.

Research paper thumbnail of First Symptoms – Frontotemporal Dementia versus Alzheimer’s Disease

Dementia and Geriatric Cognitive Disorders, 2000

Frontotemporal dementia (FTD) is often misdiagnosed as Alzheimer’s disease (AD). We hypothesized ... more Frontotemporal dementia (FTD) is often misdiagnosed as Alzheimer’s disease (AD). We hypothesized that the first symptoms associated with FTD would be different from those seen in AD and that the first symptoms in FTD would reflect loss of function in the frontal region with the greatest degree of degeneration. The objective of the study was to compare the earliest symptoms

Research paper thumbnail of Bilateral Temporal Lobe Volume Reduction Parallels Cognitive Impairment in Progressive Aphasia

Archives of Neurology, 1997

Patients with isolated aphasia in the absence of other cognitive abnormalities have been the focu... more Patients with isolated aphasia in the absence of other cognitive abnormalities have been the focus of several studies during the past decade. It has been called primary progressive aphasia (PPA), and the typical features of this syndrome are marked atrophy of the left temporal lobe according to the radiological examination and a language disorder as the initial symptom. In previous studies of PPA, the selection of the patients was based mainly on linguistic symptoms. Now, when computed tomography or magnetic resonance imaging scans are part of the routine investigation of cognitive impairment and suspected dementia, the patients with lobar atrophy will be found at an earlier stage. In the present study, we used a new approach and defined the study group by selecting patients with obvious left temporal lobe atrophy, assessed by MRI, and we referred to them as patients with temporal lobe atrophy (TLA). To identify the features that distinguish TLA from other primary neurodegenerative disorders. Six patients with TLA were compared with patients with Alzheimer disease (AD), patients with frontal lobe dementia (FLD), and healthy control subjects. The investigations included magnetic resonance imaging volumetry, single photon emission computed tomography, and neuropsychologic and linguistic evaluations. In the TLA group, the mean volume of the left temporal lobe was 35% smaller than the right, while in the AD and FLD groups, the atrophy was symmetrical and bilateral. In the TLA group, the absolute volumes of the temporal lobes were significantly smaller on the left side compared with the AD and FLD groups, whereas there was no difference on the right side. The cerebral blood flow pattern in TLA was asymmetric and differed from that in the other study groups. All patients with TLA had a history of progressive Wernicke-type aphasia, ranging from 2 to 6 years. They showed primary verbal memory impairment but had preserved visuospatial functions. The clinical condition of all patients with TLA deteriorated during the study period; severe aphasia developed, and the patients exhibited signs of frontal lobe dysfunction. Serial volumetric measurements in 4 of 6 patients showed an annual 8% to 9% decrease of both left and right temporal lobes. The initial marked asymmetry in cognitive function found in patients with TLA contrasts with the general decline found in patients with AD. The bilateral degenerative process evident in patients with TLA paralleled the clinical deterioration, indicating TLA to be a non-AD lobar atrophy that develops into generalized cognitive dysfunction and dementia.

Research paper thumbnail of Olfactory Dysfunction for Pyridine and Dementia Progression in Alzheimer Disease

Archives of Neurology, 1997

To investigate whether odor detection sensitivity for pyridine, suggested by previous research no... more To investigate whether odor detection sensitivity for pyridine, suggested by previous research not to be affected, is impaired in Alzheimer disease (AD) and whether an association exists between odor threshold and both degree of dementia and rate of dementia progression in AD. The method of constant stimuli was used to determine odor thresholds for pyridine in 18 patients with AD (Diagnostic and Statistical Manual of Mental Disorders, Third Edition, Revised and National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria) and 16 healthy elderly control subjects. All participants were carefully examined with medical and neuropsychological tests. Six patients with AD but none of the controls were anosmic (total olfactory loss) to pyridine, and the 12 nonanosmic patients had significantly higher detection thresholds (50% probability for detection, 323 parts per billion [ppb]) than did the controls (50% probability for detection, 105 ppb). In addition, an association was found between odor threshold and both degree of dementia and rate of dementia progression in AD. In contrast to previous findings, our results provide evidence that odor sensitivity in AD is impaired for pyridine. Odor sensitivity, in addition to other suggested predictors of progression rate, may be of interest for defining subgroups of AD or for clinical prognostic judgments of single patients.

Research paper thumbnail of A European multicentre PET study of fibrillar amyloid in Alzheimer’s disease

European Journal of Nuclear Medicine and Molecular Imaging, 2013

Purpose Amyloid PET tracers have been developed for in vivo detection of brain fibrillar amyloid ... more Purpose Amyloid PET tracers have been developed for in vivo detection of brain fibrillar amyloid deposition in Alzheimer's disease (AD). To serve as an early biomarker in AD the amyloid PET tracers need to be analysed in multicentre clinical studies. Methods In this study 238 [ 11 C]Pittsburgh compound-B (PIB) datasets from five different European centres were Electronic supplementary material The online version of this article (pooled. Of these 238 datasets, 18 were excluded, leaving [ 11 C]PIB datasets from 97 patients with clinically diagnosed AD (mean age 69±8 years), 72 patients with mild cognitive impairment (MCI; mean age 67.5±8 years) and 51 healthy controls (mean age 67.4±6 years) available for analysis. Of the MCI patients, 64 were longitudinally followed for 28 ± 15 months. Most participants (175 out of 220) were also tested for apolipoprotein E (ApoE) genotype.