Cognitive screening in older autistic adults: Evaluating the performance of the RUDAS

Older Autistic adults are underrepresented in dementia research, and few studies have examined how standard cognitive screening tools perform in this population. The Rowland Universal Dementia Assessment Scale (RUDAS) may be useful for detecting cognitive impairment in older Autistic adults. This study aimed to evaluate the diagnostic accuracy of the RUDAS in differentiating cognitively healthy Autistic older adults from those with mild cognitive impairment (MCI) or dementia. In this cross-sectional diagnostic accuracy study, 78 Autistic adults aged 65 to 88 years (62% female) were recruited through a memory clinic. Participants were classified as cognitively healthy (Montreal Cognitive Assessment score > 26 and no reported cognitive concerns) or as having MCI, Alzheimer’s disease (AD), or frontotemporal dementia (FTD) based on clinical diagnoses by a neurologist. All participants were Autistic adults with a confirmed diagnosis of an autism spectrum condition, documented in medical records or diagnostic reports. RUDAS performance was evaluated against clinical diagnoses. The influence of autistic traits (assessed using the AQ-10) on RUDAS scores was also examined. Group sizes were as follows: 24 healthy Autistic older adults, 19 Autistic older adults with a diagnosis of MCI, 23 with AD, and 12 with FTD (see Table 1 for demographic characteristics). The RUDAS showed good overall discrimination between diagnostic groups, though AUC values varied slightly across conditions. For discrimination between cognitively healthy individuals and any cognitive impairment, the RUDAS showed high diagnostic accuracy (AUC = 0.84), though this was slightly lower than typically reported in neurotypical populations. At the optimal cut-off, sensitivity and specificity ranged from 72% to 80%. Autistic traits (AQ-10 scores) showed a slight association with RUDAS scores (β = -0.18, p = 0.04), indicating a small but statistically significant relationship, with higher AQ-10 scores modestly linked to lower RUDAS performance. The RUDAS shows promise as a cognitive screening tool for older Autistic adults. However, variability in diagnostic accuracy across subgroups (Table 2) and relatively small subgroup sample sizes, particularly for FTD, indicate that further research is needed to develop or adapt dementia screening measures for Autistic adults, ideally co-designed with Autistic communities to ensure relevance and appropriateness.