Multimodal learning of clinically accessible tests to aid diagnosis of neurodegenerative disorders: a scoping review

Development of a smartphone screening test for preclinical Alzheimer's disease and validation across the dementia continuum

BACKGROUND

Dementia prevalence is predicted to triple to 152 million globally by 2050. Alzheimer's disease (AD) constitutes 70% of cases. There is an urgent need to identify individuals with preclinical AD, a 10-20-year period of progressive brain pathology without noticeable cognitive symptoms, for targeted risk reduction. Current tests of AD pathology are either too invasive, specialised or expensive for population-level assessments. Cognitive tests are normal in preclinical AD. Emerging evidence demonstrates that movement analysis is sensitive to AD across the disease continuum, including preclinical AD. Our new smartphone test, TapTalk, combines analysis of hand and speech-like movements to detect AD risk. This study aims to [1] determine which combinations of hand-speech movement data most accurately predict preclinical AD [2], determine usability, reliability, and validity of TapTalk in cognitively asymptomatic older adults and [3], prospectively validate TapTalk in older adults who have cognitive symptoms against cognitive tests and clinical diagnoses of Mild Cognitive Impairment and AD dementia.

METHODS

Aim 1 will be addressed in a cross-sectional study of at least 500 cognitively asymptomatic older adults who will complete computerised tests comprising measures of hand motor control (finger tapping) and oro-motor control (syllabic diadochokinesis). So far, 1382 adults, mean (SD) age 66.20 (7.65) years, range 50-92 (72.07% female) have been recruited. Motor measures will be compared to a blood-based AD biomarker, phosphorylated tau 181 to develop an algorithm that classifies preclinical AD risk. Aim 2 comprises three sub-studies in cognitively asymptomatic adults: (i) a cross-sectional study of 30-40 adults to determine the validity of data collection from different types of smartphones, (ii) a prospective cohort study of 50-100 adults ≥ 50 years old to determine usability and test-retest reliability, and (iii) a prospective cohort study of ~1,000 adults ≥ 50 years old to validate against cognitive measures. Aim 3 will be addressed in a cross-sectional study of ~200 participants with cognitive symptoms to validate TapTalk against Montreal Cognitive Assessment and interdisciplinary consensus diagnosis.

DISCUSSION

This study will establish the precision of TapTalk to identify preclinical AD and estimate risk of cognitive decline. If accurate, this innovative smartphone app will enable low-cost, accessible screening of individuals for AD risk. This will have wide applications in public health initiatives and clinical trials.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT06114914, 29 October 2023. Retrospectively registered.

Brief webcam test of hand movements predicts episodic memory, executive function, and working memory in a community sample of cognitively asymptomatic older adults

INTRODUCTION

Low-cost simple tests for preclinical Alzheimer's disease are a research priority. We evaluated whether remote unsupervised webcam recordings of finger-tapping were associated with cognitive performance in older adults.

METHODS

A total of 404 cognitively-asymptomatic participants (64.6 [6.77] years; 70.8% female) completed 10-second finger-tapping tests (Tasmanian [TAS] Test) and cognitive tests (Cambridge Neuropsychological Test Automated Battery [CANTAB]) online at home. Regression models including hand movement features were compared with null models (comprising age, sex, and education level); change in Akaike Information Criterion greater than 2 (ΔAIC > 2) denoted statistical difference.

RESULTS

Hand movement features improved prediction of episodic memory, executive function, and working memory scores (ΔAIC > 2). Dominant hand features outperformed nondominant hand features for episodic memory (ΔAIC = 2.5), executive function (ΔAIC = 4.8), and working memory (ΔAIC = 2.2).

DISCUSSION

This brief webcam test improved prediction of cognitive performance compared to age, sex, and education. Finger-tapping holds potential as a remote language-agnostic screening tool to stratify community cohorts at risk for cognitive decline.

miRNA-137-5p improves spatial memory and cognition in Alzheimer's mice by targeting ubiquitin-specific peptidase 30

BACKGROUND

Alzheimer's disease (AD) is a prevalent neurodegenerative disorder causing progressive dementia. Research suggests that microRNAs (miRNAs) could serve as biomarkers and therapeutic targets for AD. Reduced levels of miR-137 have been observed in the brains of AD patients, but its specific role and downstream mechanisms remain unclear. This study sought to examine the therapeutic potential of miR-137-5p agomir in alleviating cognitive dysfunction induced in AD models and explore its potential mechanisms.

METHODS

This study utilized bioinformatic analysis and a dual-luciferase reporter assay to investigate the relationship between miR-137-5p and ubiquitin-specific peptidase 30 (USP30). In vitro experiments were conducted using SH-SY5Y cells to assess the impact of miR-137-5p on Aβ1-42 neurotoxicity. In vivo experiments on AD mice evaluated the effects of miR-137-5p on cognition, Aβ1-42 deposition, Tau hyperphosphorylation, and neuronal apoptosis, as well as its influence on USP30 levels.

RESULTS

It was discovered that miR-137-5p mimics efficiently counteract Aβ1-42 neurotoxicity in SH-SY5Y cells, a protective effect that is negated by USP30 overexpression. In vivo experiments demonstrated that miR-137-5p enhances the cognition and mobility of AD mice, significantly reducing Aβ1-42 deposition, Tau hyperphosphorylation, and neuronal apoptosis within the hippocampus and cortex regions. Mechanistically, miR-137-5p significantly suppresses USP30 levels in mice, though USP30 overexpression partially buffers against miR-137-5p-induced AD symptom improvement.

CONCLUSION

Our study proposes that miR-137-5p, by instigating the downregulation of USP30, has the potential to act as a novel and promising therapeutic target for AD.