Qualitative analysis for the “ideational apraxia” score from the Alzheimer's disease assessment scale cognitive subscale

Background Various types of cognitive dysfunction could make it difficult to use multiple objects properly in Alzheimer's disease (AD). Aim To observe the qualitative feature of action deficits during a widely used praxis task and to clarify cognitive dysfunctions underlying the deficits. Methods We examined 80 patients with mild cognitive impairment (MCI), 84 patients with AD (69 mild and 15 moderate AD) and 40 healthy controls (HC) using the Alzheimer's Disease Assessment Scale cognitive subscale—Japanese version (ADAS‐J cog) and the Mini‐Mental State Examination (MMSE). Errors in the “praxis task” of ADAS‐J cog were classified into 4 types: apraxic, attentional, visuospatial and writing errors based on their qualitative features. The ratio of each error type was calculated and compared with each other. Results Participants with mild and moderate AD made significantly more errors in the praxis task compared with those in the HC and MCI groups. Qualitative analysis revealed that attentional errors occur more frequently in the MCI group than those in the HC group. For apraxic errors, there were significant differences between the MCI group and the mild/moderate AD groups. The more severe their general cognitive dysfunctions, the greater the variety of errors patients exhibit in the praxis task. Conclusion The results indicate that a main factor affecting the praxis task in MCI patients was attentional deficits, while various cognitive dysfunctions were related to action deficits in patients with AD. Our qualitative analysis for the praxis task revealed difference in action deficits in MCI and AD patients.