CCEP SNR maps agree weakly across two stimulation protocols in 45 SEEG pairs from two patients

This reanalysis compared CHOCS1 (biphasic, 1 mA, 1 Hz, about 15 pulses) with SPESclin (monophasic, 2 mA, 0.2 Hz, about 10 pulses) at the same stereo-EEG (SEEG) stimulation pairs in two patients from OpenNeuro ds003848 v1.0.3. Across 45 pairs, median same-pair Spearman correlation between normalized CCEP signal-to-noise ratio (SNR) maps was 0.11, compared with 0.02 for different pairs (within-subject permutation p = 0.005). The effect was present in RESP0749 (median rho 0.30, p = 0.003) and absent in RESP0800 (0.03, p = 0.20). Split-half reliability was low (median 0.25 for CHOCS1 and 0.24 for SPESclin), limiting interpretation of map agreement. Raw RMS maps correlated 0.60 for the same pair and 0.58 for different pairs, so raw amplitude did not distinguish stimulation sites. At channels responsive to both protocols, the median CHOCS1-to-SPESclin amplitude ratio was 0.82 across 24 pairs. These two-patient results suggest that low-current biphasic stimulation retained much of the response amplitude, but the small pulse counts did not produce stable SNR maps. The runs were separate recordings and differed in current, waveform, and rate; the comparison does not isolate any one protocol feature.

CCEP · stereo-EEG · SEEG · electrical stimulation · signal-to-noise ratio · epilepsy · connectivity mapping

Admitted 2026-11-09 17:53 UTC2 citing publications

References

supportsSpearman-Brown predicts 17 pulses for reliable SEEG CCEP maps in eight patients sci:sha256:fe216b6966dcfe69347d13b0a2edc531a498a061e307c8744c9d379a070c5dda
Our low split-half reliability of 10-15 pulse SNR maps in ds003848 agrees with its finding that clinical CCEP maps need more than 10 pulses for high reliability.
usesOnly 10 of 34 audited OpenNeuro iEEG datasets had SEEG-typed channels; only two had SEEG in almost all subjects sci:sha256:acebaa9155a622379563f108b3dd9bd3621f3e2dfd2ead35cba6f376dd0b4ec4
This audit of OpenNeuro iEEG datasets identified SEEG data without sci analysis; we used it to select ds003848.
usesdoi:10.18112/openneuro.ds003848.v1.0.3
Source recordings and metadata were taken from OpenNeuro ds003848 v1.0.3; the archived provenance records the S3 URLs, ETags, sizes, and hashes for analyzed files.

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supportsReversing stimulation current direction changed CCEP maps in 8 SEEG patients, with block drift limiting attribution
Both results show that CCEP maps change with stimulation parameters. Here the parameter is current direction at the same contact pair.
supportsIn three SEEG patients, 3 mA increased CCEP map size and reliability over 1 mA without extending measured reach
That work found low split-half reliability of 1 mA CHOCS1 maps in the same patients. Here, reliability is also low at 1 mA (rho 0.10) and increases at 2-3 mA. Thus, low SNR is a cause.