Mapping the Cognitive Constructs Assessed by the Allen Cognitive Level Screen: A Scoping Review

Despite widespread clinical use for over four decades, the precise cognitive constructs assessed by the Allen Cognitive Level Screen (ACLS) remain unresolved. This scoping review examines quantitative relationships between ACLS scores and standardized cognitive assessments to clarify which cognitive abilities the ACLS captures and inform its integration alongside traditional cognitive evaluations.

Following Arksey and O'Malley's framework, we searched five databases (PubMed, Embase, Web of Science, CINAHL, PsycINFO) from inception through December 2025. Studies were included if they reported empirical data from clinical populations, used any ACLS version, included standardized cognitive measures, and reported correlation analyses. Two independent reviewers screened 222 records. Cognitive measures were classified into nine domains based on Lezak's neuropsychological taxonomy. Correlation strength was categorized according to Cohen's conventions: weak (r < 0.30), moderate (0.30 ≤ r < 0.50), or strong (r ≥ 0.50).

Twenty-four studies, encompassing 1951 participants across six diagnostic groups, met the inclusion criteria. Of 117 quantitative relationships examined, 73.5% were statistically significant. The ACLS showed the strongest associations with global cognition, social cognition, and executive function, with significance rates ranging from 81.5% to 94.7%. Associations were comparatively weaker across memory, visuospatial, and orientation domains, ranging from 33.3% to 50.0%. Correlation patterns varied across populations and ACLS versions, with only one study examining the current ACLS-6.

The ACLS demonstrates reliable associations with integrated cognitive processes, particularly global functioning, executive abilities, and attention-processing capacities, rather than discrete cognitive components. These findings suggest the ACLS may reflect observable patterns of sensorimotor information processing during purposeful activity. Clinicians should therefore interpret ACLS results as a complement to, rather than a substitute for, traditional domain-specific cognitive assessments, particularly when precise differentiation of cognitive deficits is required for treatment planning. Critical gaps in structural validity research and ACLS-6 which currently constrain definitive conclusions regarding the instrument's construct validity.