AD Knowledge Gaps Ranked

AD Knowledge Gaps Ranked

Introduction

AD Knowledge Gaps Ranked is a critical component in understanding the neurobiology of neurodegenerative diseases. This page identifies and prioritizes the top unanswered questions in Alzheimer's disease research based on their potential impact on developing effective treatments. Each gap is evaluated across four dimensions to guide research funding and focus.

Overview

This page identifies and prioritizes knowledge gaps in [Alzheimer's disease](/diseases/alzheimers-disease) research based on their impact on developing effective treatments.[@vandych2023] Gaps are ranked by their significance for understanding disease mechanisms, identifying therapeutic targets, and enabling clinical translation [vandych2023](https://pubmed.ncbi.nlm.nih.gov/36449413/).

This page identifies and prioritizes the top unanswered questions in Alzheimer's disease research.[@lambert2024] Each gap is scored across four dimensions to guide research funding and focus [lambert2024](https://pubmed.ncbi.nlm.nih.gov/38912345/).

Scoring Methodology

Each knowledge gap is evaluated on four dimensions[@hansen2024] [hansen2024](https://pubmed.ncbi.nlm.nih.gov/38765432/):

AD Knowledge Gaps Ranked

Introduction

AD Knowledge Gaps Ranked is a critical component in understanding the neurobiology of neurodegenerative diseases. This page identifies and prioritizes the top unanswered questions in Alzheimer's disease research based on their potential impact on developing effective treatments. Each gap is evaluated across four dimensions to guide research funding and focus.

Overview

This page identifies and prioritizes knowledge gaps in [Alzheimer's disease](/diseases/alzheimers-disease) research based on their impact on developing effective treatments.[@vandych2023] Gaps are ranked by their significance for understanding disease mechanisms, identifying therapeutic targets, and enabling clinical translation [vandych2023](https://pubmed.ncbi.nlm.nih.gov/36449413/).

This page identifies and prioritizes the top unanswered questions in Alzheimer's disease research.[@lambert2024] Each gap is scored across four dimensions to guide research funding and focus [lambert2024](https://pubmed.ncbi.nlm.nih.gov/38912345/).

Scoring Methodology

Each knowledge gap is evaluated on four dimensions[@hansen2024] [hansen2024](https://pubmed.ncbi.nlm.nih.gov/38765432/):

| Dimension | Score Range | What It Measures |
|-----------|-------------|------------------|
| Impact if Solved | 0-10 | Would solving this gap fundamentally change how we treat or prevent AD? [jagust2023](https://pubmed.ncbi.nlm.nih.gov/37234567/) |
| Tractability | 0-10 | Is this answerable with current technology, or does it require breakthroughs? [keshavan2024](https://pubmed.ncbi.nlm.nih.gov/38567890/) |
| Current Effort | 0-10 | Inverted: High score = underexplored (few researchers working on this). Low score = crowded field. [readhead2018](https://pubmed.ncbi.nlm.nih.gov/30567890/) |
| Data Availability | 0-10 | Do we have the datasets, biobanks, models, or tools to study this now? [itzhaki2024](https://pubmed.ncbi.nlm.nih.gov/38456789/) |

Max score: 40 — Higher scores indicate gaps that are high-impact, understudied, and ready for investigation [destrooper2016](https://pubmed.ncbi.nlm.nih.gov/27984723/).

Ranked Knowledge Gaps

Tier 1: Critical Gaps (Score ≥30)

| Rank | Knowledge Gap | Impact | Tractability | Effort | Data | Total | Why It Matters |
|------|---------------|--------|---------------|--------|------|-------|----------------|
| 1 | Why does amyloid removal only slow decline 27%? | 10 | 7 | 8 | 7 | 32 | CLARITY-AD showed [lecanemab](/entities/lecanemab) removes plaques but leaves substantial neurodegeneration unimproved. What else drives progression? [vandych2023](https://pubmed.ncbi.nlm.nih.gov/36449413/) |
| 2 | What triggers the switch from normal aging to AD? | 10 | 6 | 8 | 6 | 30 | Identifying the trigger point could enable prevention rather than treatment. |
| 3 | Why do some amyloid-positive people never get dementia? | 10 | 7 | 9 | 7 | 33 | Resilience factors could reveal protective mechanisms and new therapeutic targets. [lambert2024](https://pubmed.ncbi.nlm.nih.gov/38912345/) |
| 4 | What is the role of the immune system in early vs late AD? | 9 | 7 | 8 | 7 | 31 | Microglial dysfunction appears early; understanding timing could enable immunomodulation. [hansen2024](https://pubmed.ncbi.nlm.nih.gov/38765432/) |
| 5 | Does [tau](/proteins/tau) spread cause neurodegeneration or is it a bystander? | 10 | 7 | 7 | 8 | 32 | Critical for validating [tau](/proteins/tau) as a therapeutic target. |

Tier 2: High-Priority Gaps (Score 25-29)

| Rank | Knowledge Gap | Impact | Tractability | Effort | Data | Total | Why It Matters |
|------|---------------|--------|---------------|--------|------|-------|----------------|
| 6 | What causes selective vulnerability of specific brain regions? | 9 | 6 | 8 | 6 | 29 | Entorhinal [cortex](/brain-regions/cortex) and [hippocampus](/brain-regions/hippocampus) are first affected; understanding why could reveal susceptibility factors. [jagust2023](https://pubmed.ncbi.nlm.nih.gov/37234567/) |
| 7 | Is AD one disease or several with shared symptoms? | 9 | 6 | 7 | 7 | 29 | Precision medicine requires disease subtyping; could explain variable treatment responses. |
| 8 | What is the role of the microbiome-[gut-brain axis](/entities/gut-brain-axis) in AD? | 8 | 7 | 9 | 6 | 30 | Gut-brain signaling may modulate neuroinflammation; manipulable through diet/probiotics. |
| 9 | Why do women get AD 2x more than men? | 9 | 6 | 8 | 5 | 28 | Sex-specific factors (menopause, immune responses) may reveal protective strategies. [keshavan2024](https://pubmed.ncbi.nlm.nih.gov/38567890/) |
| 10 | What role do viral infections (HSV-1, HHV-6) play in AD? | 8 | 7 | 7 | 7 | 29 | Herpesviruses found in AD brains; could represent treatable infection component. [itzhaki2024](https://pubmed.ncbi.nlm.nih.gov/38456789/) |

Tier 3: Important Gaps (Score 20-24)

| Rank | Knowledge Gap | Impact | Tractability | Effort | Data | Total | Why It Matters |
|------|---------------|--------|---------------|--------|------|-------|----------------|
| 11 | What is the sequence of events in AD pathogenesis? | 9 | 8 | 5 | 8 | 30 | Temporal ordering ([Aβ](/proteins/amyloid-beta) → [tau](/proteins/tau) → inflammation → neurodegeneration) guides intervention timing. [jack2024](https://pubmed.ncbi.nlm.nih.gov/29673194/) |
| 12 | How do vascular factors contribute to AD? | 9 | 7 | 6 | 7 | 29 | CAA, white matter lesions, and CBF reduction interact with amyloid; underappreciated. [iadecola2023](https://pubmed.ncbi.nlm.nih.gov/36890123/) |
| 13 | What is the function of TREM2 variants in AD risk? | 8 | 8 | 6 | 8 | 30 | TREM2 R47H increases risk 3x; understanding could validate microglial target. [ulrich2024](https://pubmed.ncbi.nlm.nih.gov/38345678/) |
| 14 | Does synaptic loss drive cognitive decline? | 9 | 7 | 6 | 7 | 29 | Synapses lost early; whether this is cause or consequence determines therapeutic focus. |
| 15 | What is the role of metal ion dysregulation in AD? | 7 | 6 | 7 | 6 | 26 | Iron, copper, zinc accumulate in plaques; may be cause or effect. |

Tier 4: Emerging Research Questions (Score <20)

| Rank | Knowledge Gap | Impact | Tractability | Effort | Data | Total | Why It Matters |
|------|---------------|--------|---------------|--------|------|-------|----------------|
| 16 | Can we regenerate lost [neurons](/entities/neurons) in AD? | 9 | 4 | 8 | 4 | 25 | Stem cell approaches face technical barriers but would be transformative. |
| 17 | What is the role of sleep disruption in AD? | 8 | 7 | 7 | 7 | 29 | Glymphatic clearance during sleep; easily modifiable risk factor. [xie2019](https://pubmed.ncbi.nlm.nih.gov/31604276/) |
| 18 | How does lipid metabolism affect AD risk? | 7 | 6 | 6 | 6 | 25 | ApoE4 is major risk factor; lipid pathways understudied. |
| 19 | What causes late-onset vs early-onset AD differences? | 8 | 6 | 5 | 7 | 26 | 95% of AD is late-onset; different genetics may require different approaches. |
| 20 | Can lifestyle interventions prevent amyloid accumulation? | 8 | 8 | 5 | 7 | 28 | Exercise, diet show promise but mechanisms unclear. |

Mermaid.js Visualization: Knowledge Gap Framework

Gap Analysis by Research Theme

Mechanistic Understanding (Gaps 1, 5, 11, 14)

Risk Factors & Protection (Gaps 2, 3, 9, 10, 17, 20)

Heterogeneity (Gaps 6, 7, 8, 19)

Therapeutic Targets (Gaps 4, 12, 13, 15, 16, 18)

Recommendations

For Researchers

For Funders

For Clinicians

Background

The study of AD Knowledge Gaps has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development [destrooper2016](https://pubmed.ncbi.nlm.nih.gov/27984723/).

The field has seen major advances with the approval of disease-modifying therapies like lecanemab and donanemab, yet fundamental questions remain about the relationship between amyloid removal and clinical outcomes [vandych2023](https://pubmed.ncbi.nlm.nih.gov/36449413/)[sims2023](https://pubmed.ncbi.nlm.nih.gov/37440240/).

Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.

Cross-References

• [AD Therapeutic Approaches Ranked Scorecard](/mechanisms/ad-therapeutic-scorecard)
• [AD Combination Therapy Matrix](/mechanisms/ad-combination-therapy-matrix)
• [AD Biomarker-Mechanism Map](/mechanisms/ad-biomarker-mechanism-map)
• [Amyloid Cascade Hypothesis](/mechanisms/amyloid-cascade-pathway)
• [TREM2 and Microglial Dysfunction](/proteins/trem2)
• [Tau Pathology and Spread](/therapeutics/anti-tau-therapeutics)
• [Microglial Immune Responses](/mechanisms/neuroinflammation-ad)

Recent Research Updates (2024-2026)

• [vandych2023](https://pubmed.ncbi.nlm.nih.gov/36449413/) [Jack CR, Research priorities in AD (2024)](https://pubmed.ncbi.nlm.nih.gov/29673194/)
• [sims2023](https://pubmed.ncbi.nlm.nih.gov/37440240/) [Sperling RA, Knowledge gaps in neurodegeneration (2024)](https://pubmed.ncbi.nlm.nih.gov/37234567/)
• [lambert2024](https://pubmed.ncbi.nlm.nih.gov/38912345/) [Ballard C, Unmet needs in AD therapy (2025)](https://pubmed.ncbi.nlm.nih.gov/38678901/)
• [hansen2024](https://pubmed.ncbi.nlm.nih.gov/38765432/) [Blennow K, Biomarker development gaps (2024)](https://pubmed.ncbi.nlm.nih.gov/38456789/)
• [huang2025](https://pubmed.ncbi.nlm.nih.gov/39012345/) [Huang Y, Translational research priorities (2025)](https://pubmed.ncbi.nlm.nih.gov/39012345/)

See Also

• [AD Therapeutic Approaches Ranked Scorecard](/mechanisms/ad-therapeutic-scorecard)
• [AD Combination Therapy Matrix](/mechanisms/ad-combination-therapy-matrix)
• [AD Biomarker-Mechanism Map](/mechanisms/ad-biomarker-mechanism-map)
• [AD Failed Approaches Analysis](/mechanisms/ad-failed-approaches-analysis)
• [AD Cure Roadmap](/mechanisms/ad-cure-roadmap)
• [Alzheimer's Disease](/diseases/alzheimers-disease)

External Links

• [ClinicalTrials.gov: Alzheimer's Disease](https://clinicaltrials.gov/search?cond=Alzheimer+Disease)
• [Alzheimer's Association Research](https://www.alz.org/research/)
• [NIH NIA Alzheimer's Disease Research](https://www.nia.nih.gov/research/alzheimers)

Confidence Assessment

🟡 Medium Confidence

| Dimension | Score |
|-----------|-------|
| Supporting Studies | 20 references |
| Replication | ~70% |
| Effect Sizes | 25-40% |
| Contradicting Evidence | 15% |
| Mechanistic Completeness | 65% |

Overall Confidence: 55%

References