Qualitative Analysis of Constructional Errors in Neurodegenerative Conditions: A Systematic Review.

Background/Objectives: Constructional apraxia (CA) is an impairment in combining simple elements into coherent spatial configurations without basic motor deficits. Although common in neurodegenerative disorders, the qualitative features of visuo-constructional errors and their role in differentiating dementia types remain unclear. This systematic review aimed to synthesize patterns of visuo-constructional errors in dementia and mild cognitive impairment (MCI), exploring distinctive qualitative features associated with different neurodegenerative conditions. Methods: A systematic literature search was conducted in PubMed, Scopus, and Web of Science for studies published between January 1990 and January 2026, following PRISMA guidelines. Studies on adults with dementia or MCI assessing drawing/copying abilities through standardized tasks and qualitative error analysis were included. Reviews, meta-analyses, case reports, non-English articles, and studies not explicitly assessing constructional apraxia were excluded. The quality of evidence was assessed using an adapted version of the Newcastle-Ottawa Scale. Results: A total of 25 studies were included, showing heterogeneous and condition-specific visuo-constructional deficits. Spatial errors and simplifications were the most common across disorders, while perseverations, rotations, and closing-in phenomena were less frequent. Alzheimer's disease was mainly associated with spatial disorganization, omissions, and conceptual errors linked to temporo-parietal dysfunction; frontotemporal dementia with executive deficits such as perseverations and planning impairments; Lewy body and Parkinson's disease dementias with visuospatial and attentional alterations; and Huntington's disease with simplifications and executive dysfunction related to fronto-striatal involvement. Conclusions: No single error pattern was pathognomonic, but qualitative assessment of constructional errors may provide clinically useful information when integrated with the broader neuropsychological profile.