Alzheimer's disease and mild cognitive impairment: Effects of shifting and interference in simple arithmetic

Laura Zamarian, Carlo Semenza, Frank Domahs, Thomas Benke, Margarete Delazer

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The present study investigated arithmetic processing in patients with mild dementia of Alzheimer's type (DAT) and patients with mild cognitive impairment (MCI) without dementia. Arithmetic processing (e.g., 2 + 3 = ?, 3 × 4 = ?) was evaluated in (1) 'blocked' condition (without extra load on attentional and executive functions), in (2) 'mixed' condition (shifting between different operations was required), and in (3) 'Stroop-like' condition (executive control and inhibition of automatic retrieval processes were needed). Both DAT and MCI patients showed intact arithmetic knowledge retrieval from long-term memory in the blocked condition. However, DAT patients were compromised whenever load was put on executive functions, whereas MCI patients succeeded to shift between operations (mixed condition) but had difficulties to inhibit overlearned associations (Stroop-like condition). In line with previous studies, these findings point to the contribution of attentional and executive functions in arithmetic. The present investigation is also of clinical relevance: it suggests that it may be important to assess arithmetic processing not only in blocked presentation but also in mixed presentation. The mixed condition has a high ecological value because it mimics daily-life arithmetic activities (e.g., checking the grocery bill). As indicated by the present results, DAT and MCI patients who are in the normal range at routine neuropsychological (blocked) arithmetic assessments may experience difficulties by extra requirement of non-numerical resources. That means, they possibly process arithmetic not efficiently in daily-life situations.

Original languageEnglish
Pages (from-to)79-88
Number of pages10
JournalJournal of the Neurological Sciences
Issue number1-2
Publication statusPublished - Dec 15 2007



  • Calculation
  • Daily-life activities
  • Dementia
  • Ecological test
  • Executive functions
  • Fact retrieval

ASJC Scopus subject areas

  • Ageing
  • Clinical Neurology
  • Surgery
  • Developmental Neuroscience
  • Neurology
  • Neuroscience(all)

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