Die Empfehlungen der Swiss Memory Clinics für die Diagnostik der Demenzerkrankungen

PET Imaging in Dementia: Mini-Review and Canadian Perspective for Clinical Use

PET imaging is increasingly recognized as an important diagnostic tool to investigate patients with cognitive disturbances of possible neurodegenerative origin. PET with 2-[18F]fluoro-2-deoxy-D-glucose ([18F]FDG), assessing glucose metabolism, provides a measure of neurodegeneration and allows a precise differential diagnosis among the most common neurodegenerative diseases, such as Alzheimer's disease, frontotemporal dementia or dementia with Lewy bodies. PET tracers specific for the pathological deposits characteristic of different neurodegenerative processes, namely amyloid and tau deposits typical of Alzheimer's Disease, allow the visualization of these aggregates in vivo. [18F]FDG and amyloid PET imaging have reached a high level of clinical validity and are since 2022 investigations that can be offered to patients in standard clinical care in most of Canada.This article will briefly review and summarize the current knowledge on these diagnostic tools, their integration into diagnostic algorithms as well as perspectives for future developments.

Salivary Proteomics Identifies Transthyretin as a Biomarker of Early Dementia Conversion

Background:

Alzheimer’s disease (AD) remains to date an incurable disease with a long asymptomatic phase. Early diagnosis in peripheral biofluids has emerged as key for identifying subjects at risk and developing therapeutics and preventative approaches.

Objective:

We apply proteomics discovery to identify salivary diagnostic biomarkers for AD, which are suitable for self-sampling and longitudinal biomonitoring during aging.

Methods:

57 participants were recruited for the study and were categorized into Cognitively normal (CNh) (n = 19), mild cognitive impaired (MCI) (n = 21), and Alzheimer’s disease (AD) (n = 17). On a subset of subjects, 3 CNh and 3 mild AD, shot-gun filter aided sample preparation (FASP) proteomics and liquid chromatography mass spectroscopy (LC-MS/MS) was employed in saliva and cerebrospinal fluid (CSF) to identify neural-derived proteins. The protein level of salivary Transthyretin (TTR) was validated using western blot analysis across groups.

Results:

We found that 19.8% of the proteins in saliva are shared with CSF. When we compared the saliva and CSF proteome, 24 hits were decreased with only one protein expressed more. Among the differentially expressed proteins, TTR with reported function in amyloid misfolding, shows a significant drop in AD samples, confirmed by western blot showing a 0.5-fold reduction in MCI and AD compared to CNh.

Conclusion:

A reduction in salivary TTR appears with the onset of cognitive symptoms. More in general, the proteomic profiling of saliva shows a plethora of biomarkers worth pursuing as non-invasive hallmarks of dementia in the preclinical stage.

[Biomarkers for the diagnosis of cognitive impairment - Recommendations from the Swiss Memory Clinics]

Biomarkers for the diagnosis of cognitive impairment - Recommendations from the Swiss Memory Clinics Abstract. Molecular cerebrospinal fluid (CSF) biomarkers of neurodegenerative diseases are now part of the established diagnostic tools for the clinical investigation of cognitive disorders in the elderly. Biomarkers allow for earlier and more accurate differential diagnosis, and are recommended by the Swiss Memory Clinics as an additional investigation based upon individual indication. Information and counselling are needed both before and after biomarker-supported diagnosis. The procedures for diagnostic lumbar punctures and pre-analytical sample handling should follow published recommendations. The results must be interpreted in the context of the other available history and assessment outcome. Thanks to recent research progress, blood-based biomarkers and other non-invasive markers are expected to become available for clinical practice in the near future. This trend will likely lead to a much broader utilisation of biomarkers and may accelerate the development of effective and individually tailored prevention and treatment approaches. This review article provides an overview over the current state of biomarkers and provides the recommendations of the Swiss Memory Clinics for their use in clinical practice.

Appropriate use criteria for dementia amyloid imaging in Switzerland - mini-review and statement on behalf of the Swiss Society of Nuclear Medicine and the Swiss Memory Clinics

While FDG-PET imaging of the brain for the differential diagnosis of dementia has been covered by the compulsory health insurance in Switzerland for more than a decade, beta-amyloid-PET just recently has been added to the catalogue of procedures that have been cleared for routine use, provided that a set of appropriate use criteria (AUC) be followed. To provide guidance to dementia care practitioners, the Swiss Society of Nuclear Medicine and the Swiss Memory Clinics jointly report a mini-review on beta-amyloid-PET and discuss the AUC set into effect by the Swiss Federal Office of Public Health, as well as their application and limitations.

[Recommendations for the Diagnosis and Therapy of Psychotic Disorders in the Elderly]

Recommendations for the Diagnosis and Therapy of Psychotic Disorders in the Elderly Abstract. Psychotic disorders in the elderly cover a wide range of causes and manifestations. They often occur as part of a depression, dementia, substance abuse or delirium. While psychosis can occur with a first manifestation in advanced age, many patients with chronic psychotic disorders reach a high age. Many elderly individuals are also affected by cognitive impairment and somatic conditions, making a third-party history most relevant. The associated changes in life and the complexity of the individual situation needs to be integrated into the diagnosis and treatment. The presented recommendations have been developed under the lead of the Swiss Society of Old Age Psychiatry (SGAP) in collaboration with the Swiss Association of Nurses (SBK) and the subcommittees for gerontological and psychiatric nursing of the association of nursing science (VFP) as well as further professional societies. We aim to make current knowledge concerning diagnosis and treatment available to the interprofessional teams working in in- and outpatients' settings.

Cross-cultural adaptation and validation of the Amsterdam Instrumental Activities of Daily Living questionnaire short version German for Switzerland

Background

Instrumental Activities of Daily Living (IADL) limitations are associated with reduced health-related quality of life for people with mild cognitive impairment (MCI). For these people, the assessment of IADL is crucial to the diagnostic process, as well as for the evaluation of new interventions addressing MCI. The Amsterdam IADL Questionnaire Short Version (A-IADL-Q-SV) is an established assessment tool with good psychometric properties that has been shown to be robust to cultural differences in Western countries. The aims of this study were to: (1) cross-culturally adapt and validate the A-IADL-Q-SV for the German-speaking population of Switzerland; (2) investigate its cultural comparability; and (3) evaluate further psychometric properties.

Methods

The A-IADL-Q-SV German was pretested on clinicians and participants in a memory clinic setting. The psychometric properties and cultural comparability of the questionnaire were investigated in memory clinic settings including participants with MCI or mild dementia, as well as participants with normal cognition recruited from the community. Item response theory (IRT) was applied to investigate measurement invariance by means of differential item functioning to assess item bias. Additionally, the test–retest reliability on scale level, the construct validity through hypothesis testing and the discriminant validity of the A-IADL-Q-SV German were evaluated.

Results

Ninety-six informants of participants with normal cognition, MCI or mild dementia completed the A-IADL-Q-SV German. The basic assumptions for IRT scoring were met. No meaningful differential item functioning for culture was detected between the Swiss and Dutch reference samples. High test–retest reliability on scale level (ICC 0.93; 95% CI 0.9–0.96) was found. More than 75% of the observed correlations between the A-IADL-Q-SV German and clinical measures of cognition and functional status were found to be in the direction and of the magnitude hypothesized. The A-IADL-Q-SV German was shown to be able to discriminate between participants with normal cognition and MCI, as well as MCI and mild dementia.

Conclusions

The A-IADL-Q-SV German is a psychometrically robust measurement tool for a Swiss population with normal cognition, MCI and mild dementia. Thus, it provides a valuable tool to assess IADL functioning in clinical practices and research settings in Switzerland.

Trial registration This study was registered retrospectively in July 2019 on ClinicalTrials.gov (NCT04012398).

Informant Questionnaires in Dedicated Memory Clinics: How Much Do They Contribute?

BACKGROUND/OBJECTIVES

The diagnostic process in a university memory clinic is based largely on cognitive testing. However, input from informants, acquired through interview or questionnaires, may significantly impact diagnosis. We sought to evaluate whether informant questionnaires for basic and instrumental activities of daily living, or for identifying progressive cognitive decline would improve diagnostic predictability of neurodegenerative disorders compared with either the Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuropsychological test battery or the Mini-Mental State Examination score alone.

DESIGN

Retrospective data analysis using logit models.

SETTING

University hospital outpatient memory clinic.

PARTICIPANTS

A total of 394 patients with dementia, mild cognitive impairment (MCI), depression, or subjective cognitive impairment were assessed.

MEASUREMENTS

Bristol Activities of Daily Living Scale, Functional Activities Questionnaire, Informant Questionnaire on Cognitive Decline in the Elderly, and the Physical Self-Maintenance Scale questionnaires were obtained. Analyses through logit models were performed to predict outcome diagnoses, based on cognitive scores alone or in combination with one or more informant questionnaires.

RESULTS

The four questionnaires were highly correlated (.31-.86). The addition of informant questionnaires improved diagnostic predictability between differential diagnoses of MCI and dementia, or dementia and depression. However, the misprediction rate was reduced by up to 6 percentage points only. Adding more than one questionnaire or all CERAD subtests instead of their sum score never improved prediction in regularized logit models to a clinically relevant extent.

CONCLUSION

Although questionnaires contribute to a statistically better prediction of the outcome diagnosis, for some sets of differential diagnoses, the benefit may not be clinically pertinent when routine semistructured informant interviews are used by trained personnel. However, standardized assessment, particularly when patients are seen longitudinally, should not be underestimated.