Reduced cue-context modulation of Fz/Cz theta in children with developmental dyscalculia.

Developmental dyscalculia (DD) may involve difficulty using prior context during cognitive control. We tested whether children with DD showed reduced cue-context modulation of theta recorded at Fz and Cz. Single-trial electroencephalographic data were analyzed from 143 children aged 6-11 years, including 71 with DD and 72 typically developing (TD) children. The task was a Cue/Uncue Go/No-Go paradigm. The primary contrast compared S6 and S8, two no-response conditions with the same current stimulus category but different preceding cue contexts. To address the original montage asymmetry, all revised analyses used the same 19-electrode montage and reference. The primary EEG sample included 128 children with identifiable Fz and Cz channels and at least 20 artifact-free epochs in each condition. Three-cycle Morlet wavelets quantified the S6-minus-S8 log-power contrast at 5-7 Hz and 200-400 ms. Total-theta modulation was smaller in DD than TD, F(1,124) = 15.86, p < .001, partial η2 = 0.113. The effect remained after removal of condition-averaged event-related potentials, F(1,124) = 11.66, p < .001, partial η2 = 0.086. It also remained after S8 trial-count matching and joint adjustment for technical variables and task performance. Greater modulation showed modest associations with more hits and faster responses. These findings indicate reduced S6-minus-S8 theta modulation at Fz/Cz in this DD cohort. The contrast is not specific to arithmetic, DD, or a single control process, and it should not be interpreted as a source-localized or individual diagnostic marker.