Epilepsy vs Space Weather — Completed Correlation Analysis (2015–2026)

Analysis Complete — First Results Published

This report presents the results of our first full correlation analysis between epilepsy-related Google Trends data and space-weather variables over 4,076 consecutive days (2015-03-18 → 2026-07-15).

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Data: How We Built the Dataset

Google Trends Pipeline

The epilepsy search-interest series was constructed by pulling daily data from Google Trends in overlapping 90-day windows, then stitching the windows together using a normalisation procedure. Each query returns 90 days of relative interest values (0–100 scale), and consecutive windows were aligned at their overlap points to produce a continuous 4,076-day time series.

Space-Weather Variables

Matched to the same 4,076-day date range from public NASA/NOAA sources:

Variable	Source	Resolution
Kp	NOAA SWPC	3-hourly → daily mean
Ap	NOAA SWPC	3-hourly → daily
Dst	WDC Kyoto	hourly → daily mean
Solar wind speed	NASA OMNI	hourly → daily mean
IMF B (average)	NASA OMNI	hourly → daily mean
F10.7 solar flux	NOAA	daily
Sunspot number	SILSO	daily

Preprocessing

• Both series were detrended using STL decomposition (365-day seasonal period) to remove annual cycles and long-term drift
• Outliers were winsorised at ±3 standard deviations
• Final dataset: 4,076 matched daily observations — no missing days, no gaps

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Methodology

1. Cross-correlation function computed at lags τ = −14 to +14 days (Pearson and Spearman)
2. Benjamini–Hochberg FDR correction at α = 0.05 across all lags × variables
3. Surrogate-data validation: 1,000 random permutations per variable to establish empirical significance
4. All code in Python (pandas, SciPy, statsmodels)

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Key Findings

Top 10 Significant Correlations (F10.7)

All top results cluster around F10.7 solar flux at positive lags of +5 to +14 days. This means elevated solar radio flux today is associated with slightly higher epilepsy-related search activity 5–14 days later.

The table below shows the strongest Pearson correlations that survived FDR correction:

Lag (days)	Pearson r	p-value	FDR p-value	Significant
+11	+0.1417	< 0.000001	< 0.000001	✓
+13	+0.1413	< 0.000001	< 0.000001	✓
+12	+0.1407	< 0.000001	< 0.000001	✓
+10	+0.1403	< 0.000001	< 0.000001	✓
+14	+0.1391	< 0.000001	< 0.000001	✓
+9	+0.1377	< 0.000001	< 0.000001	✓
+7	+0.1366	< 0.000001	< 0.000001	✓
+8	+0.1362	< 0.000001	< 0.000001	✓
+6	+0.1362	< 0.000001	< 0.000001	✓
+5	+0.1348	< 0.000001	< 0.000001	✓

Bar Chart — Top 10 F10.7 Correlations

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Surrogate Test — All 7 Variables

The permutation test confirms that all 7 space-weather variables produce signals stronger than random shuffles would generate. However, the effect sizes are small in absolute terms.

Variable	Real r	Empirical p	Significant
Kp	−0.0385	0.0120	✓
Ap	−0.0330	0.0230	✓
Dst	+0.0331	0.0410	✓
Solar wind speed	−0.0419	0.0050	✓
IMF B (avg)	−0.0392	0.0080	✓
F10.7 flux	+0.1333	0.0000	✓
Sunspot number	+0.0741	0.0000	✓

Timeline Chart

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Effect Size Table (All Variables at Optimal Lag)

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Interpretation

The analysis reveals a weak but statistically significant positive association between F10.7 solar radio flux and epilepsy-related search interest, peaking at lag +11 days (r = +0.1417).

Key Points

• Not null, not strong. The signal is real (confirmed by FDR + surrogate tests), but the effect size is modest (r ≈ 0.14)
• Lag structure is smooth. Correlations at lags +5 through +14 are all positive and similarly sized — not a single spike, but a broad elevation
• Other variables show only trace signals. Kp, Ap, Dst, solar wind, and IMF-B show statistically significant but practically negligible associations (|r| < 0.05)
• Compare to literature. Earlier Chizhevsky-era work reported stronger effects in experimental settings; modern clinical EEG studies often find null results. Our finding sits between these extremes

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Limitations

1. Daily resolution — finer-grained (hourly) data may reveal stronger effects
2. Single keyword — "epilepsy" is only one term; a broader health-term panel is needed
3. No geographic breakdown — Google Trends aggregates globally; regional effects may be diluted
4. Observational, not causal — correlation ≠ causation; multiple confounders possible

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Analysis completed: 2026-07-17. Data period: 2015-03-18 → 2026-07-15 (4,076 days). Status: Completed.

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In Plain English — What Does This Actually Mean?

Okay, let's step back from the numbers and tables for a moment and talk like human beings.

We spent several weeks pulling together 11 years of daily data — epilepsy-related Google searches on one side, and a bunch of solar activity measurements (radio flux, sunspots, magnetic storms, solar wind) on the other. We cleaned it up, removed seasonal patterns, and ran every reasonable statistical test we could think of.

So, does space weather cause epileptic seizures?

Short answer: probably not — or at least, not in any strong or obvious way.

The numbers do show a tiny but real connection between F10.7 solar radio flux and epilepsy searches about 11 days later. It's there, it's statistically significant, and it doesn't look like random noise. But the effect is very small. Think of it like this: if you tracked 1,000 people, maybe a handful of them show a pattern that lines up with solar activity — but the other 990+ don't.

The other variables — magnetic storms (Kp, Dst), solar wind speed, sunspot counts — show even weaker signals. Technically significant (because we have 4,076 data points, so even tiny patterns get detected), but practically negligible.

What we can say with some confidence: the Sun is not a major driver of epilepsy-related search behaviour at the daily level. If there's a connection, it's subtle enough that you'd never notice it in everyday life. This is actually a useful finding — it means we can probably stop looking for big, dramatic solar-seizure links and focus on more promising directions.

What's next? We'll test more health-related search terms (not just epilepsy), try hourly-resolution data instead of daily, and look at regional breakdowns rather than global aggregates. If the same weak-but-real pattern shows up across multiple keywords and locations, it becomes more interesting. If it disappears — well, that's science.

Bottom line: no, the Sun doesn't cause seizures. But it might have a whisper of influence worth keeping an ear on. We'll keep digging.