Quantitative electroencephalography (qEEG) provides non-invasive, cost-effective biomarkers for Alzheimer's disease detection and monitoring. EEG alterations occur early in the disease process and correlate with cognitive decline. This page covers EEG biomarkers across different frequency bands, event-related potentials, and their clinical applications.
EEG changes in AD reflect: [1]
These changes manifest as: [2]
| Parameter | Early AD | Moderate AD | Controls | [3]
|-----------|----------|-------------|----------| [4]
| Delta power | ↑ 20-50% | ↑ 50-100% | Baseline | [5]
| Temporal delta | ↑ 30-60% | ↑ 80-150% | Low | [6]
| Parameter | Early AD | Moderate AD | Controls | [7]
|-----------|----------|-------------|----------| [8]
| Theta power | ↑ 30-70% | ↑ 80-150% | Baseline | [9]
| Frontal theta | ↑ 50-100% | ↑ 100-200% | Low | [10]
| Parameter | Early AD | Moderate AD | Controls | [11]
|-----------|----------|-------------|----------|
| Alpha power | ↓ 20-40% | ↓ 40-60% | Baseline |
| Alpha frequency | ↓ 0.5-1.5 Hz | ↓ 1-2 Hz | 10 Hz |
| Posterior alpha | ↓ 30-50% | ↓ 50-70% | Highest |
| Parameter | Early AD | Moderate AD | Controls |
|---|---|---|---|
| Beta power | ↓ 10-30% | ↓ 30-50% | Baseline |
| Beta coherence | ↓ 15-25% | ↓ 30-40% | Normal |
| Parameter | AD vs. Controls | Notes |
|---|---|---|
| Gamma power | ↓ 20-40% | Impaired cortical processing |
| Gamma coherence | ↓ 15-30% | Disrupted integration |
| Parameter | AD | MCI | Controls |
|---|---|---|---|
| P3 latency | ↑ 20-50 ms | ↑ 10-20 ms | Baseline |
| P3 amplitude | ↓ 20-40% | ↓ 10-20% | Normal |
| Band | AD vs. Controls | Regional Pattern |
|---|---|---|
| Alpha | ↓ 20-35% | Posterior regions |
| Beta | ↓ 15-25% | Parietal-occipital |
| Theta | Variable | Frontal increase |
| Group | Mean PAF |
|---|---|
| Controls | 10.2 Hz |
| MCI | 9.3 Hz |
| Mild AD | 8.7 Hz |
| Moderate AD | 8.1 Hz |
| EEG Marker | Conversion Prediction | Evidence |
|---|---|---|
| Elevated theta power | 2-3x higher risk | Strong |
| Reduced alpha power | 1.5-2x higher risk | Strong |
| Slowing index elevation | High predictive value | Moderate |
| P3 latency prolongation | Moderate predictive value | Moderate |
| Technology | FDA Status | Cost (USD) | Accessibility |
|---|---|---|---|
| Standard EEG | Standard care | $200-500 | Clinical available |
| qEEG analysis | Cleared (some) | $300-700 | Specialist required |
| Portable EEG | Cleared | $100-300 | Home possible |
| High-density EEG (256+) | Research | $1,000+ | Research only |
Quantitative EEG (qEEG) analysis involves transforming raw EEG signals into frequency components:
Topographic mapping reveals spatial patterns:
Key qEEG metrics:
P300 is a widely studied ERP in AD:
Additional ERPs in AD research:
Advanced spectral decomposition:
Quantitative measures:
EEG studies in Asian cohorts:
EEG biomarker performance:
Economic considerations:
Multi-modal approaches:
| Feature | EEG | MRI |
|---|---|---|
| Temporal resolution | High | Low |
| Spatial resolution | Low | High |
| Cost | Low | High |
| Accessibility | High | Medium |
| Invasiveness | Non-invasive | Non-invasive |
| Feature | EEG | PET |
|---|---|---|
| Metabolic information | Indirect | Direct |
| Amyloid detection | No | Yes |
| Tau imaging | No | Yes |
| Cost | Low | High |
| Radiation | None | Present |
| Feature | EEG | Blood |
|---|---|---|
| p-tau detection | No | Yes |
| Aβ detection | No | Yes |
| Accessibility | High | High |
| Cost | Low | Medium |
EEG changes over time:
Therapeutic response tracking:
ML approaches in EEG:
Current status:
Cassani et al. EEG theta for AD detection (2018). 2018. ↩︎
Moretti et al. Alpha alterations in MCI/AD (2009). 2009. ↩︎
Papaliagkas et al. P300 in Alzheimer's disease (2011). 2011. ↩︎
Ruzzoli et al. MMN in Alzheimer's disease (2019). 2019. ↩︎
Stam et al. EEG coherence in Alzheimer's disease (2009). 2009. ↩︎
Gómez et al. Spectral entropy in AD (2013). 2013. ↩︎
Jelic et al. EEG predictors of MCI conversion (2000). 2000. ↩︎
Huang et al. EEG and MCI progression (2020). 2020. ↩︎
Kobayashi et al. qEEG in Japanese AD patients (2005). 2005. ↩︎
Kim et al. EEG in Korean MCI/AD (2012). 2012. ↩︎
Zhou et al. EEG biomarkers in Chinese AD (2016). 2016. ↩︎