<p>Developmental dyslexia (DD) is associated with multiple cognitive deficits. This study examined whether digital training of specific cognitive components is feasible and effective, whether parental involvement increases training intensity, and whether a multi-component intervention yields specific and cumulative benefits for reading fluency, spelling, and reading comprehension. We developed a multi-component digital intervention targeting visual-attentional (VA), auditory-phonological (AP), and cross-modal processes. In a pre-registered multiple single-case (within-subject) intervention study (ClinicalTrials.gov: NCT04028310), 144 children with DD aged 8 to 13 years participated. The first two training components (VA vs. AP) were counterbalanced across participants. Each training phase lasted 2 months, with home-based practice 5 days per week for 15 min per session under parental supervision. Before and after the digital intervention phases, children received conventional remediation once per week for 2 months, serving as a within-subject baseline. Training effects were component-specific: VA training led to greater improvements in visual-attentional skills than AP training, whereas AP training yielded greater gains in phoneme awareness than VA training. Across the full three-stage program, cumulative improvements were observed in reading fluency, spelling, and reading comprehension that exceeded gains during conventional remediation alone. Starting with VA training resulted in larger reading fluency gains than starting with AP training. These findings provide a proof of concept that a scalable, home-based, multi-component digital intervention can induce specific cognitive improvements and cumulative gains in reading and spelling skills in children with DD, while remaining feasible for large-scale implementation.</p>