Diagnostic Accuracy of the Frontotemporal Dementia Consensus Criteria in the Late-Onset Frontal Lobe Syndrome

BACKGROUND/AIMS

We aimed to prospectively assess the diagnostic accuracy of the revised criteria for behavioural variant frontotemporal dementia (bvFTD) among subjects presenting with a frontal lobe syndrome in middle-late adulthood.

METHODS

Patients were included based on a predominant behavioural clinical presentation, a Frontal Behavioural Inventory (FBI) score of ≥11 and/or a Stereotypy Rating Inventory (SRI) score of ≥10. At baseline, the fulfilment of the international consensus criteria for behavioural variant FTD (FTDC) was systematically recorded. The 2-year follow-up consensus diagnosis was used as the gold standard to calculate sensitivity and specificity of the FTDC criteria for possible and probable bvFTD.

RESULTS

Two-year follow-up data were available for 116 patients (85%). Two-year follow-up consensus diagnoses consisted of probable/definite bvFTD (n = 27), other dementia (n = 30), psychiatric disorders (n = 46) and other neurological disorders (n = 13). Sensitivity for possible bvFTD was 85% (95% CI 70-95%) at a specificity of 27% (95% CI 19-37%). Sensitivity for probable bvFTD was 85% (95% CI 69-95%), whereas their specificity was 82% (95% CI 73-89%).

CONCLUSIONS

We found a good diagnostic accuracy for FTDC probable bvFTD. However, the specificity for FTDC possible bvFTD was low. Our results reflect the symptomatic overlap between bvFTD, other neurological conditions and psychiatric disorders, and the relevance of adding neuroimaging to the diagnostic process.

The effect of diagnostic criteria on outcome measures in preclinical and prodromal Alzheimer's disease: Implications for trial design

Introduction

We investigated the influence of different inclusion criteria for preclinical and prodromal Alzheimer's disease (AD) on changes in biomarkers and cognitive markers and on trial sample size estimates.

Methods

We selected 522 cognitively normal subjects and 872 subjects with mild cognitive impairment from the Alzheimer's Disease Neuroimaging Initiative study. Compared inclusion criteria were (1) preclinical or prodromal AD (amyloid marker abnormal); (2) preclinical or prodromal AD stage-1 (amyloid marker abnormal, injury marker normal); and (3) preclinical or prodromal AD stage-2 (amyloid and injury markers abnormal). Outcome measures were amyloid, neuronal injury, and cognitive markers.

Results

In both subjects with preclinical and prodromal AD stage-2, inclusion criteria resulted in the largest observed decline in brain volumetric measures on magnetic resonance imaging and cognitive markers.

Discussion

Inclusion criteria influence the observed rate of worsening in outcome measures. This has implications for trial design.

Design of the ExCersion-VCI study: The effect of aerobic exercise on cerebral perfusion in patients with vascular cognitive impairment

There is evidence for a beneficial effect of aerobic exercise on cognition, but underlying mechanisms are unclear. In this study, we test the hypothesis that aerobic exercise increases cerebral blood flow (CBF) in patients with vascular cognitive impairment (VCI). This study is a multicenter single-blind randomized controlled trial among 80 patients with VCI. Most important inclusion criteria are a diagnosis of VCI with Mini-Mental State Examination ≥22 and Clinical Dementia Rating ≤0.5. Participants are randomized into an aerobic exercise group or a control group. The aerobic exercise program aims to improve cardiorespiratory fitness and takes 14 weeks, with a frequency of three times a week. Participants are provided with a bicycle ergometer at home. The control group receives two information meetings. Primary outcome measure is change in CBF. We expect this study to provide insight into the potential mechanism by which aerobic exercise improves hemodynamic status.

The effect of hippocampal function, volume and connectivity on posterior cingulate cortex functioning during episodic memory fMRI in mild cognitive impairment

Objectives

Diminished function of the posterior cingulate cortex (PCC) is a typical finding in early Alzheimer’s disease (AD). It is hypothesized that in early stage AD, PCC functioning relates to or reflects hippocampal dysfunction or atrophy. The aim of this study was to examine the relationship between hippocampus function, volume and structural connectivity, and PCC activation during an episodic memory task-related fMRI study in mild cognitive impairment (MCI).

Method

MCI patients (n = 27) underwent episodic memory task-related fMRI, 3D-T1w MRI, 2D T2-FLAIR MRI and diffusion tensor imaging. Stepwise linear regression analysis was performed to examine the relationship between PCC activation and hippocampal activation, hippocampal volume and diffusion measures within the cingulum along the hippocampus.

Results

We found a significant relationship between PCC and hippocampus activation during successful episodic memory encoding and correct recognition in MCI patients. We found no relationship between the PCC and structural hippocampal predictors.

Conclusions

Our results indicate a relationship between PCC and hippocampus activation during episodic memory engagement in MCI. This may suggest that during episodic memory, functional network deterioration is the most important predictor of PCC functioning in MCI.

Key Points

• PCC functioning during episodic memory relates to hippocampal functioning in MCI.

• PCC functioning during episodic memory does not relate to hippocampal structure in MCI.

• Functional network changes are an important predictor of PCC functioning in MCI.

Electronic supplementary material

The online version of this article (doi:10.1007/s00330-017-4768-1) contains supplementary material, which is available to authorized users.

Cerebrospinal fluid biomarker examination as a tool to discriminate behavioral variant frontotemporal dementia from primary psychiatric disorders

INTRODUCTION

To prospectively determine the diagnostic value of cerebrospinal fluid (CSF) levels total-tau (tau) to amyloid-β_1-42 ratio (Aβ_1-42) ratio (tau/Aβ_1-42 ratio), phosphorylated-tau (p-tau) to tau ratio (p-tau/tau ratio), neurofilament light chain (NfL) and YKL40 in the late-onset frontal lobe syndrome, in particular for the differential diagnosis of behavioral variant frontotemporal dementia (bvFTD) versus primary psychiatric disorders (PSY).

METHOD

We included patients with a multidisciplinary 2-year-follow-up diagnosis of probable/definite bvFTD (n = 22) or PSY (n = 25), who underwent a detailed neuropsychiatric clinical examination, neuropsychological test battery, and magnetic resonance imaging at baseline. In all cases, CSF was collected through lumbar puncture at baseline. We compared CSF biomarker levels between the two groups and measured the diagnostic accuracy for probable/definite bvFTD, using the follow-up diagnosis as the reference standard.

RESULTS

The best discriminators between probable/definite bvFTD and PSY were the levels of CSF NfL (area under the curve [AUC] 0.93, P < .001, 95% confidence interval [CI] 0.85-1.00), p-tau/tau ratio (AUC 0.87, P < .001, 95% CI 0.77-0.97), and YKL40 (AUC 0.82, P = .001, 95% CI 0.68-0.97). The combination of these three biomarkers had a sensitivity of 91% (95% CI 66%-100%) at a specificity of 83% (95% CI 65%-95%) with an AUC of 0.94 (P < .001, 95% CI 0.87-1.00) for bvFTD. CSF tau/Aβ_1-42 ratio was less accurate in differentiating between bvFTD and PSY.

DISCUSSION

We found a good diagnostic accuracy for higher levels of CSF NfL and YKL40 and reduced p-tau/tau ratio in distinguishing bvFTD from PSY. We advocate the use of these CSF biomarkers as potential additional tools to neuroimaging in the diagnosis of bvFTD versus PSY.

Formal Psychiatric Disorders are not Overrepresented in Behavioral Variant Frontotemporal Dementia

While psychiatric misdiagnosis is well-known in behavioral variant frontotemporal dementia (bvFTD), a systematic evaluation of standardized criteria for psychiatric disorders in bvFTD is still missing. Our aim was to define frequency and character of DSM-IV psychiatric disorders among patients with probable and definite bvFTD compared to possible bvFTD, other neurodegenerative diseases, and psychiatric diagnoses, using MINI-International Neuropsychiatric Interview. We additionally compared psychiatric prodromes between these groups. Subjects were participants of the late-onset frontal lobe (LOF) study, a longitudinal multicenter study. In each patient, after baseline diagnostic procedure, a neurologist and geriatric psychiatrist made a joint clinical diagnosis. Independently, a structured diagnostic interview according to DSM-IV and ICD-10 criteria (MINI-Plus) was performed by a trained professional blinded to clinical diagnosis. Out of 91 patients, 23 with probable and definite bvFTD, 3 with possible bvFTD, 25 with a non bvFTD neurodegenerative disease, and 40 with a clinical psychiatric diagnosis were included. Overall frequency of formal current and past psychiatric disorders in probable and definite bvFTD (21.7% current, 8.7% past) did not differ from other neurodegenerative diseases (12.0% current, 16.0% past) or possible bvFTD (66.7% current, 66.7% past), but was less than in patients with a clinical psychiatric diagnosis (57.5% current, 62.5% past; p <  0.01). In probable and definite bvFTD unipolar mood disorders were most common. Formally diagnosed psychiatric disorders are not overrepresented in probable bvFTD, suggesting that psychiatric misdiagnosis in bvFTD can be reduced by strictly applying diagnostic criteria. In suspected bvFTD close collaboration between neurologists and psychiatrists will advance diagnostics and subsequent treatment.

Impact of Imaging and Cerebrospinal Fluid Biomarkers on Behavioral Variant Frontotemporal Dementia Diagnosis within a Late-Onset Frontal Lobe Syndrome Cohort

BACKGROUND

The criteria for behavioral variant frontotemporal dementia (bvFTD) incorporate MRI and [18F]-FDG-PET. Cerebrospinal fluid (CSF) analysis is merely advised for excluding Alzheimer's disease.

AIMS

We aimed to assess the impact of biomarkers on diagnostic certainty and contingent changes of bvFTD diagnosis within the clinically relevant neuropsychiatric differential diagnosis of subjects with a late-onset frontal lobe syndrome (LOF).

METHODS

We included 137 patients with LOF, aged 45-75 years, 72% males. Biomarker disclosure was considered contributing after any substantial difference in diagnostic certainty or a diagnostic change. Percentages of contributing biomarkers were compared between three major diagnostic groups (bvFTD, psychiatry, other neurological disorders). Certainty levels in stable diagnostic groups were compared to those with a diagnostic change.

RESULTS

Biomarkers contributed in 53, 60 and 41% of the LOF patients for MRI, [18F]-FDG-PET and CSF, respectively. Biomarkers changed the diagnosis in 14% of cases towards bvFTD and in 13% from bvFTD into an alternative. Those that changed had a lower level of a priori diagnostic certainty compared to stable diagnoses.

CONCLUSION

Our study not only supports the widely accepted use of MRI and [18F]-FDG-PET in diagnosing or excluding bvFTD, but also shows that CSF biomarkers aid clinicians in the diagnostic process.

Lower cerebral blood flow is associated with impairment in multiple cognitive domains in Alzheimer's disease

INTRODUCTION

We examined the association between decreased cerebral blood flow (CBF) and cognitive impairment in Alzheimer's disease (AD), mild cognitive impairment (MCI), and subjective cognitive decline (SCD).

METHODS

We included 161 AD, 95 MCI, and 143 SCD patients from the Amsterdam Dementia Cohort. We used 3-T pseudo-continuous arterial spin labeling to estimate whole-brain and regional partial volume-corrected CBF. Neuropsychological tests covered global cognition and five cognitive domains. Associations were investigated using linear regression analyses.

RESULTS

In the whole sample, reduced overall and regional CBF was associated with impairment in all cognitive domains. We found significant interactions between diagnosis and CBF for language and between diagnosis and parietal CBF for global cognition and executive functioning. Stratification showed that decreased CBF was associated with worse performance in AD patients but not in MCI or SCD.

DISCUSSION

Our results suggest that CBF may have potential as a functional marker of disease severity.

Lower cerebral blood flow is associated with faster cognitive decline in Alzheimer's disease

Objective

To determine whether lower cerebral blood flow (CBF) is associated with faster cognitive decline in patients with Alzheimer’s disease (AD).

Methods

We included 88 patients with dementia due to AD from the Amsterdam Dementia Cohort. Mean follow-up was 2 ± 1 years. Linear mixed models were used to determine associations of lower whole brain and regional pseudo-continuous arterial spin labelling measured CBF with rate of cognitive decline as measured with repeated mini-mental state examination (MMSE). Model 1 was adjusted for age, sex, and education. Model 2 was additionally adjusted for normalized gray matter volume, medial temporal lobe atrophy, white matter hyperintensities, microbleeds, and lacunes. Analyses were repeated after partial volume correction (PVC) of CBF. Statistical significance was set at p ≤ 0.05.

Results

Patients were 65 ± 7 years old, 44 (50 %) were women, and mean baseline MMSE was 22 ± 4. Annual decline (β[SE]) on the MMSE was estimated at -2.11 (0.25) points per year. Lower whole brain (β[SE]-0.50[0.25]; p ≤ 0.05) and parietal (β[SE]-0.59[0.25]; p < 0.05) CBF were associated with faster cognitive decline. PVC cortical CBF was not associated with cognitive decline.

Conclusions

Lower CBF, in particular in the posterior brain regions, may have value as a prognostic marker for rate of cognitive decline in AD.

Key points

• In AD, lower CBF is associated with more rapid cognitive decline.

• Decreasing CBF does not reach a plateau early in AD.

• PcASL-CFB has additive value to conventional structural MRI measures in AD.

Schizophrenia as a mimic of behavioral variant frontotemporal dementia

Recently, the diagnostic criteria for the behavioral variant of frontotemporal dementia were revised. Although these criteria offer a relatively high sensitivity, their specificity is yet unknown. We describe a 54-year-old woman fulfilling criteria for both late-onset schizophrenia and probable behavioral variant frontotemporal dementia. Following an initial presentation with psychosis, she developed progressive apathy, compulsiveness, and executive dysfunction. Moreover, bilateral frontotemporal hypometabolism was seen on [(18)F]fludeoxyglucose-positron emission tomography. A post-mortem diagnosis of schizophrenia was established, given the clinical picture combined with the pathological exclusion of a neurodegenerative cause. Our case suggests that patients with other brain disorders may meet the current diagnostic criteria for probable frontotemporal dementia. Further clinicopathological validation of these criteria is needed to determine their exact specificity.

Identifying bvFTD Within the Wide Spectrum of Late Onset Frontal Lobe Syndrome: A Clinical Approach

OBJECTIVE

The behavioral variant of frontotemporal dementia (bvFTD) can be difficult to diagnose because of the extensive differential diagnosis, including many other diseases presenting with a frontal lobe syndrome. We aimed to identify the diagnostic spectrum causing a late onset frontal lobe syndrome and examine the quality of commonly used instruments to distinguish between bvFTD and non-bvFTD patients, within this syndrome.

METHODS

A total of 137 patients fulfilling the criteria of late onset frontal lobe syndrome, aged 45 to 75 years, were included in a prospective observational study. Diagnoses were made after clinical and neuropsychological examination, and neuroimaging and cerebral spinal fluid results were taken into account. Baseline characteristics and the scores on the Mini-Mental State Exam (MMSE), frontal assessment battery (FAB), Frontal Behavioral Inventory (FBI), and Stereotypy Rating Inventory (SRI) were compared between the bvFTD and the non-bvFTD group.

RESULTS

Fifty-five (40%) of the patients received a bvFTD diagnosis (33% probable and 7% possible bvFTD). Fifty-one patients (37%) had a psychiatric disorder, including 20 with major depressive disorder. Thirty-one patients received an alternative neurological, including neurodegenerative, diagnosis. MMSE and FAB scores were unspecific for a particular diagnosis. A score above 12 on the positive FBI subscale or a score above 5 on the SRI were indicative of a bvFTD diagnosis.

CONCLUSION

A broad spectrum of both neurological and psychiatric disorders underlies late onset frontal lobe syndrome, of which bvFTD was the most prevalent diagnosis in our cohort. The commonly used MMSE and the FAB could not successfully distinguish between bvFTD and non-bvFTD, but this could be achieved with the more specific FBI and SRI.

White Matter Hyperintensities Relate to Clinical Progression in Subjective Cognitive Decline

BACKGROUND AND PURPOSE

In patients with subjective cognitive decline, we assessed whether small vessel disease was associated with clinical progression and cognitive decline.

METHODS

We included 334 patients with subjective cognitive decline. Follow-up was 3±2 years.

RESULTS

Fifty-three (16%) patients progressed clinically to mild cognitive impairment or dementia. White matter hyperintensities were associated with clinical progression and with annual decline on memory, attention, executive functioning, and global cognition. Microbleeds and lacunes were not associated with clinical progression or cognitive decline.

CONCLUSIONS

In patients with subjective cognitive decline, patients with white matter hyperintensities are at increased risk of clinical progression and cognitive decline.

Cerebral perfusion in the predementia stages of Alzheimer's disease

Objectives

To investigate arterial spin-labelling (ASL) cerebral blood flow (CBF) changes in predementia stages of Alzheimer’s disease (AD).

Methods

Data were obtained from 177 patients with subjective complaints, mild cognitive impairment and AD from the Amsterdam Dementia Cohort. AD stages were based on diagnosis and cerebrospinal fluid biomarkers amyloid-β (Aβ) and total-tau (tau). General-linear-models were used to assess relationships between AD stages and total and regional CBF, correcting for age and sex.

Results

Decreasing CBF was related to more advanced AD stages in all supratentorial regions (p for trend < 0.05). Post-hoc testing revealed that CBF was lower in AD compared to controls and stage-1 predementia patients (i.e. abnormal Aβ and normal tau) in temporal and parietal regions, and compared to stage-2 predementia patients (i.e. abnormal Aβ and tau) in temporal regions. CBF values of stage-2 predementia patients were numerically in between those of stage-1 predementia patients and AD.

Conclusion

The continuing decrease of CBF along the continuum of AD indicates the potential of ASL-CBF as a measure for disease progression.

Key Points

• Decreasing CBF relates to more advanced AD stages in all supratentorial regions.

• The reduction of CBF does not reach a bottom level.

• ASL-CBF has potential as a measure for disease progression in AD.

Trajectories of cognitive decline in different types of dementia

BACKGROUND

To investigate trajectories of cognitive decline in patients with different types of dementia compared to controls in a longitudinal study.

METHOD

In 199 patients with Alzheimer's disease (AD), 10 with vascular dementia (VaD), 26 with dementia with Lewy bodies (DLB), 20 with behavioural variant frontotemporal dementia (bvFTD), 15 with language variant frontotemporal dementia (lvFTD) and 112 controls we assessed five cognitive domains: memory, language, attention, executive and visuospatial functioning, and global cognition (Mini-Mental State Examination, MMSE). All subjects had at least two neuropsychological assessments (median 2, range 2-7). Neuropsychological data were standardized into z scores using baseline performance of controls as reference. Linear mixed models (LMMs) were used to estimate baseline cognitive functioning and cognitive decline over time for each group, adjusted for age, gender and education.

RESULTS

At baseline, patients with dementia performed worse than controls in all cognitive domains (p < 0.05) except visuospatial functioning, which was only impaired in patients with AD and DLB (p < 0.001). During follow-up, patients with AD declined in all cognitive domains (p < 0.001). DLB showed decline in every cognitive domain except language and global cognition. bvFTD showed rapid decline in memory, language, attention and executive functioning (all p < 0.01) whereas visuospatial functioning remained fairly stable. lvFTD declined mostly in attention and executive functioning (p < 0.01). VaD showed decline in attention and executive functioning.

CONCLUSIONS

We show cognitive trajectories of different types of dementia. These estimations of natural disease course have important value for the design of clinical trials as neuropsychological measures are increasingly being used as outcome measures.