MCI-AD, Early Stage Alzheimer's Disease
Conditions
Brief summary
As populations age, Alzheimer's disease (AD) is increasing while disease-modifying drugs remain elusive, making early diagnosis and intervention essential. Building on advances in neuromodulation and virtual reality (VR), we target amnestic mild cognitive impairment (aMCI)-the prodromal stage of AD-as a key window for prevention. Preliminary evidence shows disrupted theta-delta phase-amplitude coupling in prefrontal and temporal cortices in aMCI, whereas olfactory enrichment can enhance hippocampal synaptic function, improve cognition, and potentially lower AD risk. We will conduct a large-scale clinical cohort study to test the neural mechanisms and clinical efficacy of multi-site, cross-frequency transcranial alternating current stimulation (tACS) combined with multisensory (visual-olfactory-auditory) VR. A comprehensive database spanning demographic, neuropsychological, biochemical, neuroimaging, and neuromodulation parameters will guide optimal protocols and provide objective evidence for non-pharmacological interventions, informing development of a microcurrent brain stimulator and a portable VR device.
Detailed description
With the accelerating pace of population aging, the prevalence of Alzheimer's disease (AD) continues to rise, yet effective disease-modifying pharmacotherapies remain unavailable. Early diagnosis and intervention are critical to slowing cognitive decline and reducing disease burden. In recent years, rapid advances in neuromodulation and virtual reality (VR) have opened new avenues for mechanistic studies and functional brain rehabilitation in AD and other neurodegenerative disorders. Amnestic mild cognitive impairment (aMCI) is widely regarded as the prodromal stage of AD and represents a key window for prevention and treatment. Developing innovative non-pharmacological therapies for individuals at this early stage has therefore become an urgent clinical priority. Preliminary studies indicate that people with aMCI exhibit a significant loss of phase-amplitude coupling (PAC) between theta and delta rhythms in the prefrontal cortex and temporal lobe, whereas olfactory-enriched environmental stimulation can enhance hippocampal synaptic function, improve cognition, and lower AD risk. Accordingly, we propose a large-scale clinical cohort study to investigate the neural-circuit mechanisms and clinical efficacy of multi-site, cross-frequency transcranial alternating current stimulation (tACS) and multisensory VR integrating visual, olfactory, and auditory inputs for the treatment of aMCI. We will establish a comprehensive database encompassing demographic, neuropsychological, biochemical, neuroimaging, and neuromodulation parameters. Ultimately, this work will provide optimal theoretical parameters and objective evidence to guide the development of non-pharmacological interventions for AD-specifically, a microcurrent brain stimulator and a portable VR device.
Interventions
BEHAVIORALOlfactory stimulation
Olfactory stimulation were set as follows: Essential oil types: yuzu, lavender, lemon, and mint. Concentration: 158 μL of essential oil + 50 mL of water. The mixed solution was poured into the test tubes of the olfactory instrument, ensuring that the liquid levels of the four solutions were kept at the same height. Each scent was released for 30 seconds, followed by a 10-second air interval, with each cycle lasting 20 minutes.
BIOLOGICALTemporal Interference,TI
During stimulation, the parameters were set as follows: Δf=40Hz (2000Hz vs. 2040Hz) 2mA Stimulation duration: 20min We fixed the stimulation protocol and used a standard head to simulate stimulation of the entorhinal region.
COMBINATION_PRODUCTOlfactory-TI Stimulation
During stimulation, the parameters were set as follows: Δf=40Hz (2000Hz vs. 2040Hz) 2mA Stimulation duration: 20min We fixed the stimulation protocol and used a standard head to simulate stimulation of the entorhinal region. Olfactory stimulation were set as follows: Essential oil types: yuzu, lavender, lemon, and mint. Concentration: 158 μL of essential oil + 50 mL of water. The mixed solution was poured into the test tubes of the olfactory instrument, ensuring that the liquid levels of the four solutions were kept at the same height. Each scent was released for 30 seconds, followed by a 10-second air interval, with each cycle lasting 20 minutes.
COMBINATION_PRODUCTSham Control
During stimulation, the parameters were set as follows: Δf=0Hz (2000Hz vs. 2000Hz) 2mA Stimulation duration: 20min. Olfactory stimulation were set as follows: Essential oil types: air. lasting 20 minutes.
Sponsors
Shanghai Mental Health Center
Yuan Shen
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
60 Years to No maximum
Healthy volunteers
Yes
Inclusion criteria
Baseline screening inclusion criteria: a) Age ≤ 65 years and ≤ 85 years; b) Education duration ≥ 1 year; c) Normal cognitive function at enrollment: MMSE total score: non-illiterate (primary school or below) ≥ 20 points, primary school or above ≥ 24 points; d) Corrected vision and hearing are basically normal, and able to complete cognitive assessment.
Exclusion criteria
Baseline screening
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Path Integration - Angle Deviation | Baseline; 5 minutes after Session 1; 5 minutes after Session 5; 5 minutes after Session 10. | Absolute angular error during the path-integration task. Lower values indicate better performance. Unit of Measure: Degrees (°); lower is better. |
| Path Integration - Composite Accuracy (M_ROC_AUC) | Baseline; 5 minutes after Session 1; 5 minutes after Session 5; 5 minutes after Session 10. | Area under the ROC curve computed from multivariate PI features to quantify task accuracy/reliability across sessions. Unit Measure: AUC, 0.00-1.00 (higher values indicate better accuracy/stability). |
| Change in Cognitive Performance (MoCA-B) | Baseline; 5 minutes after Session 10. | Change in global cognition using the Montreal Cognitive Assessment-Basic (MoCA-B). Unit of Measure: MoCA-B score, 0-30 (higher scores indicate better cognition). |
| Change in Olfactory Sensitivity (TDI score) | Baseline; 30 minutes after Session 1; 30 minutes after Session 5; 30 minutes after Session 10; 1 week after Session 10. | Change in olfactory function measured with the Sniffin' Sticks Threshold-Discrimination-Identification (TDI) composite score. Unit of Measure: TDI score, 1-48 (higher scores indicate better olfactory function). |
| Path Integration - Distance Deviation | Baseline; 5 minutes after Session 1; 5 minutes after Session 5; 5 minutes after Session 10. | Difference between actual and ideal path length during the path-integration task. Lower values indicate better performance. Unit of Measure: Meters (m); lower is better. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Adverse Events Related to Intervention | Baseline; 5 minutes after Session 1; 5 minutes after Session 5; 5 minutes after Session 10. | Incidence of device- or procedure-related adverse events (e.g., skin irritation, headache, dizziness, nausea). Unit of Measure: Number of participants with ≥1 adverse event (count). |
| Activities of Daily Living (ADL - Barthel Index) | Baseline; 30 minutes after Session 1; 30 minutes after Session 5; 30 minutes after Session 10; 1 week after Session 10. | Change in functional ability using the Barthel Index. Unit of Measure: Barthel Index, 0-100 (higher scores indicate greater independence). |
Outcome results
None listed