A Systematic Review of Interventions for Acalculia Following a Stroke or Brain-injury

Acalculia, an acquired deficit in numerical skills following a brain-injury, is estimated to affect 30%-65% of brain-injury survivors and has negative impact on independence and quality of life. Four previous reviews (two systematic) covered interventions for acalculia, however, all missed some studies.The current work systematically searched Web of Science and ProQuest Dissertation Abstracts for studies describing interventions for acalculia published up until 13th of June 2025. To be included, studies had to be written in English, involve an intervention for acalculia that resulted from a stroke or a brain-injury, directly address numerical difficulties, and report the outcomes of the intervention, with no limit on the type or timing of measures. Sixteen publications describing interventions for acalculia were identified, with a total of N=31 patients. One unpublished study described an app-based intervention with 18 patients. Most interventions (10) targeted relearning of multiplication tables, followed by interventions designed to improve transcoding (4). All interventions were delivered individually (i.e., no group interventions), and most were tailored to individual patients. The most common method used was intense repetition (‘drill’), and the majority of interventions were conducted in French or German. Only one intervention was delivered in a non-European language (Japanese). While all interventions were effective, there were differences in the transferability of improvement from trained to untrained problems. Overall, the review highlights the scarcity of evidence of interventions for acalculia, despite the high prevalence of the condition. We highlight gaps and make suggestions for improving the quality of interventions and outcomes for patients.