Publications by authors named "Remi Bouchard"

Introduction: Alzheimer's disease (AD) cerebrospinal fluid (CSF) biomarkers are promising tools to help identify the underlying pathology of neurocognitive disorders. In this manuscript, we report our experience with AD CSF biomarkers in 262 consecutive patients in a tertiary care memory clinic.

Methods: We retrospectively reviewed 262 consecutive patients who underwent lumbar puncture (LP) and CSF measurement of AD biomarkers (Aβ1-42, total tau or t-tau, and p-tau181).

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Objective: We aimed to validate the (DCQ; www.dcqtest.org), a new cognitive screening tool for atypical degenerative syndromes, in the oldest old.

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Introduction: It is well known that some patients with Alz-heimer's disease (AD) have atypical, nonamnestic presentations. While logopenic aphasia and posterior cortical atrophy are well-characterized atypical variants of AD, the behavioral/dysexecutive variant remains a controversial entity, lacking consensus regarding its distinctive clinical and imaging features.

Methods: We present a case series of 8 patients with biomarker confirmation of AD (cerebrospinal fluid [CSF] analysis or amyloid positron emission tomography [PET]) and a progressive frontal syndrome, defined as prominent behavioral and/or executive deficits at initial presentation.

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Background/aims: The logopenic variant of primary progressive aphasia (lvPPA) is characterized by impaired word-finding and sentence repetition with phonologic errors but spared motor speech and grammar and semantic knowledge. Although its language deficits have been well studied, the full spectrum of cognitive changes in the lvPPA remains to be defined. We aimed to explore the neurocognitive profile of the lvPPA using a newly developed cognitive screening tool for atypical dementias, the Dépistage Cognitif de Québec (DCQ).

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Article Synopsis
  • PCC hypometabolism is a key diagnostic marker in late-onset Alzheimer's disease but its value in young-onset, non-amnestic variants is uncertain.
  • A study analyzed 60 young-onset atypical dementia patients and found that 65% showed significant PCC hypometabolism, while it was only 28% for frontotemporal dementia variants.
  • The research concluded that PCC hypometabolism does not effectively differentiate between non-amnestic Alzheimer's and frontotemporal dementia and should be considered carefully in young-onset cases.
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Introduction: Early recognition of atypical dementia remains challenging partly because of lack of cognitive screening instruments precisely tailored for this purpose.

Methods: We assessed the validity and reliability of the Dépistage Cognitif de Québec (DCQ; www.dcqtest.

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Objective: To estimate the prevalence of amyloid positivity, defined by positron emission tomography (PET)/cerebrospinal fluid (CSF) biomarkers and/or neuropathological examination, in primary progressive aphasia (PPA) variants.

Methods: We conducted a meta-analysis with individual participant data from 1,251 patients diagnosed with PPA (including logopenic [lvPPA, n = 443], nonfluent [nfvPPA, n = 333], semantic [svPPA, n = 401], and mixed/unclassifiable [n = 74] variants of PPA) from 36 centers, with a measure of amyloid-β pathology (CSF [n = 600], PET [n = 366], and/or autopsy [n = 378]) available. The estimated prevalence of amyloid positivity according to PPA variant, age, and apolipoprotein E (ApoE) ε4 status was determined using generalized estimating equation models.

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Background: The Mini-Mental State Examination continues to be used frequently to screen for cognitive impairment in older adults, but it remains unclear how to interpret changes in its score over time to distinguish age-associated cognitive decline from an early degenerative process. We aimed to generate cognitive charts for use in clinical practice for longitudinal evaluation of age-associated cognitive decline.

Methods: We used data from the Canadian Study of Health and Aging from 7569 participants aged 65 years or older who completed a Mini-Mental State Examination at baseline, and at 5 and 10 years later to develop a linear regression model for the Mini-Mental State Examination score as a function of age and education.

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Objective: This study aimed to validate and provide normative data for the Dépistage Cognitif de Québec (DCQ; www.dcqtest.org), a new cognitive screening tool for atypical dementias.

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Background: Accumulating evidence points to the superiority of the MoCA over the MMSE as a cognitive screening tool. To facilitate the transition from the MMSE to the MoCA in clinical and research settings, authors have developed MMSE-MoCA conversion tables. However, it is unknown whether a conversion table generated from Alzheimer's disease (AD) patients would apply to patients with other dementia subtypes like vascular dementia or frontotemporal dementia.

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Article Synopsis
  • The finger-to-nose test, commonly used to evaluate cognitive impairments and cerebellar dysfunction, reveals potential cognitive indicators in Alzheimer's disease (AD) patients.
  • Researchers identified two specific signs during the test in AD patients: the "second finger syndrome" and the "distal pressure sign."
  • A review of 461 patient records showed that these signs are frequently found in AD but not in patients with vascular dementia or subjective cognitive impairment.
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Few studies have explored the rate of cognitive decline and caregiver burden within the context of a specialized memory clinic. When this was done, the focus was largely on functional decline related to Alzheimer's disease (AD). Our goal was to compare the longitudinal decline of AD patients to those with Vascular Dementia (VaD) on Mini-Mental State Examination (MMSE).

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Recent studies have supported a role for amyloid positron emission tomography (PET) imaging in distinguishing Alzheimer's disease (AD) pathology from other pathological protein accumulations leading to dementia. We investigated the clinical utility of amyloid PET in the differential diagnosis of atypical dementia cases and its impact on caregivers. Using the amyloid tracer 18F-NAV4694, we prospectively scanned 28 patients (mean age 59.

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Diagnosis of atypical/unclear dementia is often difficult and this delays treatment initiation. Several authors have shown that beyond standard dementia workup, 18F-fluorodeoxyglucose positron emission tomography (FDG-PET) reduces the number of unclear diagnoses, leads to earlier treatment, and has a beneficial impact on families. However, it is not uncommon that the FDG-PET findings are equivocal in this setting.

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Objective: Amnestic mild cognitive impairment (aMCI) and late-life depression (LLD) both increase the risk of developing Alzheimer disease (AD). Very little is known about the similarities and differences between these syndromes. The present study addresses this issue by examining the nature of semantic memory impairment (more precisely, object-based knowledge) in patients at risk of developing AD.

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Semantic deficits have been documented in the prodromal phase of Alzheimer's disease, but it is unclear whether these deficits are associated with non-cognitive manifestations. For instance, recent evidence indicates that cognitive deficits in elders with amnestic mild cognitive impairment (aMCI) are modulated by concomitant depressive symptoms. The purposes of this study were to (i) investigate if semantic memory impairment in aMCI is modulated according to the presence (aMCI-D group) or absence (aMCI group) of depressive symptoms, and (ii) compare semantic memory performance of aMCI and aMCI-D groups to that of patients with late-life depression (LLD).

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Cerebellar contribution to non-motor functions has been supported by several animal, human and functional neuroimaging studies. Which cognitive skills and to what extent the cerebrocerebellar loops contribute remain unclear, however. Among other reasons, this may be explained by the fact that authors have studied patients with extracerebellar lesions.

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This retrospective study examined the role of [(18)F]fluorodeoxyglucose positron emission tomography (FDG-PET) in the diagnosis of atypical/unclear dementias in a memory clinic setting. A total of 94 patients with a diagnosis of mild cognitive impairment (MCI) or dementia, who had a PET study within 2 months of their diagnosis, were reevaluated at 5 and 18 months. Results showed that PET was associated with a change in diagnosis in 29% of patients and a 64% increase in the use of cholinesterase inhibitors (ChEIs).

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Background: Patients with cognitive impairment no dementia (CIND) are at an increased risk of progression to Alzheimer's disease (AD). Whether subtle impairments in functional or social abilities at the CIND stage can predict progression to AD is not yet fully determined. We evaluated whether impairments on the Disability Assessment for Dementia (DAD) and Functional Rating Scale (FRS) can predict progression to AD.

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This article critically considers current diagnostic criteria for dementia and reports recommendations approved by at least 80% of experts attending the Third Canadian Consensus Conference on the Diagnosis and Treatment of Dementia (CCCDTD3). There was consensus that many of the features proposed as essential to a diagnosis of dementia in the 1980s no longer are relevant (for example, the requirements for memory impairment, electroencephalogram and cerebrospinal fluid studies, age-specific exclusions). In addition, other syndromes such as frontotemporal dementia have been recognized and need to inform new dementia criteria.

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In the past two decades there has been a tremendous effort among clinicians and searchers to improve the diagnostic criteria of the dementias on the basis of the differential neurological and neuropsychological profiles. This was an obligatory requirement for clinical trials and the development of treatments. Over the years it became rapidly evident that the cohorts of patients in studies had some degree of heterogeneity, making it difficult to interpret the results of some studies, particularly in the vascular dementias and the mild cognitive impairment (MCI) group.

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Background And Purpose: Empirical studies to clarify the outcomes in Vascular Cognitive Impairment (VCI) are needed. We compared cognitive, functional, and behavioural outcomes in patients with VCI to patients with no cognitive impairment (NCI), and Alzheimer's disease (AD).

Methods: Secondary analysis of the Consortium to Investigate Vascular Impairment of Cognition (CIVIC), a multi-centre Canadian memory clinic 30-month cohort study.

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Background: People who are cognitively impaired not demented (CIND) can be at an increased risk for developing dementia, but little is known about the natural history of CIND in clinical settings.

Method: We examined the 2-year outcome of CIND subjects in the Canadian Cohort Study of Cognitive Impairment and Related Dementias.CIND was diagnosed when at least one positive item was endorsed on the DSM-III-R dementia criteria, but not all criteria were met.

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Background And Purpose: There is a need for empirical studies to define criteria for vascular cognitive impairment (VCI) subtypes. In this paper, we report the predictive validity of a subtype classification scheme based on clinical and radiographic features.

Methods: Nine Canadian memory clinics participated in the Consortium to Investigate Vascular Impairment of Cognition.

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Structures of the medial temporal lobes are recognized to play a central role in memory processing and to be the primary sites of deterioration in Alzheimer disease (AD). Mild cognitive impairment (MCI) represents potentially an intermediate state between normal aging and AD. Proton magnetic resonance spectroscopy (MRS) was used to examine brain metabolic changes in patients with AD and MCI in the medial temporal lobes (MTLs), parietotemporal cortices (PTCs) and prefrontal cortices (PFCs).

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