KTH: An Age-Appropriate Cognitive Screening Tool for the Oldest Old

Very old adults typically retain crystallized abilities (e.g., vocabulary, overlearned skills) but show marked declines in fluid abilities (e.g., processing speed, executive functions), which justifies age-specific norms. Motor and sensory limitations may additionally affect screening outcomes and confound cut-offs. Against this background, the short picture-based cognitive screening instrument Kognitiver Test für Hochbetagte (Cognitive Assessment for Oldest-Old; KTH; Ballasch et al., 2024) was developed for adults aged ≥80 years. This study aimed to evaluate the reliability, validity (convergent, discriminant, and criterion-related), and feasibility of the KTH, and to examine demographic influences on performance. In a cross-sectional design, N= 408 community-dwelling adults aged 60-91 years (M= 69.6, SD= 7.92; 63.2% women) were assessed, including n= 59 participants aged ≥ 80 years (M= 83.64, SD= 3.99) and n= 349 participants aged < 80 years (M= 67.23, SD= 5.72). Group differences were examined using Mann–Whitney U tests as the assumption of normality was not met; reliability was analyzed using Cronbach’s α. Convergent and discriminant validity were assessed using Spearman correlations with established cognitive and affective measures. Participants aged 80 years and older showed significantly lower performance on global cognitive measures and most KTH domains, supporting the necessity for age-sensitive interpretation. Particularly pronounced deficits were found in memory and executive-function-related subtests, while orientation, language comprehension and recognition showed no significant age-group differences. Education was positively associated with performance across many measures, whereas sex showed limited and domain-specific effects. Sensory factors explained only little additional variance beyond age and education. The KTH total score showed weak raw internal consistency (= .55) but acceptable standardized internal consistency (= .74); subscale reliabilities were mostly low. Convergent validity was strongest with the Dementa Detection Test (rs= .546, p< .001). Divergent validity with depressive symptoms was supported by a weak negative correlation with the Geriatric Depression Scale (rs= -.140, p= .005). Overall, the findings support the KTH as a feasible, time-efficient, and age-appropriate cognitive screening instrument with good psychometric properties for very old adults. The study further highlights the importance of separating norms for individuals aged <80 years versus ≥80 years, as age-related performance differences do not necessarily indicate pathology As only cognitively healthy participants were included, the results primarily contribute to the characterization of orthonormative cognitive aging. Nevertheless, establishing age-specific reference groups is clinically relevant to improve interpretation of screening results.