Operation-specific ERP dynamics of arithmetic processing in children with developmental dyscalculia

Developmental dyscalculia (DD) is associated with persistent arithmetic difficulties, but the temporal dynamics of operation-specific arithmetic processing remain unclear. This study examined operation-locked event-related potentials (ERPs) during addition, subtraction, and multiplication in 76 children aged 8-12 years, including 37 children with DD and 39 typically developing (TD) controls. ERPs were time-locked to the onset of the second operand, when the complete arithmetic expression became available. Children with DD showed lower accuracy and longer reaction times across all operations. ERP analyses revealed prolonged N1, P2, and N2a latencies, together with reduced N1 and N2a amplitudes and increased frontal P2 amplitude. Subtraction produced the most evident delay, particularly in early latency measures. Across the full sample, longer N2a latencies were associated with slower reaction times, although within-group correlations were not significant. These findings indicate that DD is characterized by a temporal processing inefficiency that begins during early symbolic encoding and extends to intermediate monitoring and updating of arithmetic information, especially when procedural computation demands are high.