I read with great interest the article by Hashimoto et al. 1, which identifies the Noise Pareidolia Test (NPT) as an independent predictor of delirium in older adults requiring emergency hospitalization. The authors elegantly demonstrate that visual-perceptual vulnerability, quantified by NPT scores, correlates significantly with the onset of delirium, offering a novel perspective for bedside nursing assessments. This approach is particularly commendable as it shifts the focus from general cognitive decline to specific perceptual deficits, potentially enabling more targeted interventions. While I applaud this innovative approach to early risk stratification, I believe there are two critical methodological issues regarding potential confounding factors that warrant further discussion to clarify the specificity of the findings. First, the inclusion of patients with dementia without differentiation of subtypes may introduce a significant selection bias. As the authors noted, the NPT was originally developed to detect pareidolia, a core clinical feature of Dementia with Lewy Bodies (DLB) 2. Given that DLB is frequently underdiagnosed in clinical practice and is inherently associated with a high risk of delirium and fluctuating cognition, there is a possibility that the high NPT scores in the delirium group merely reflect a higher prevalence of undiagnosed DLB patients within that cohort. Furthermore, since both DLB and delirium share cholinergic deficits as a pathophysiological basis, the NPT might be detecting this underlying neurochemical substrate rather than an acute risk state per se. If the predictive value of the NPT is driven primarily by its sensitivity to DLB pathology rather than a general vulnerability to delirium, its utility in older adults with other forms of cognitive impairment (e.g., Alzheimer's disease or vascular dementia) might be overestimated. Controlling for core features of DLB, such as parkinsonism or REM sleep behavior disorder, would be essential to validate the NPT as a universal predictor. Second, the influence of acute pharmacological interventions in the emergency setting requires more rigorous scrutiny. Although the study adjusted for the use of benzodiazepine receptor agonists, it appears this referred to chronic or baseline prescriptions rather than acute administration immediately preceding the test. Patients requiring emergency admission often receive acute doses of opioids, anticholinergics, or sedatives for pain relief or agitation management prior to ward transfer. These agents can induce transient visual-perceptual alterations or acute confusion within minutes to hours. Given that the median age of the participants was 85 years, pharmacokinetic clearance is often reduced, prolonging the visual side effects of even single doses administered in the ambulance or emergency room. Without excluding patients who received such psychotropic medications within the 24 h prior to NPT administration, it is difficult to distinguish whether a high NPT score represents an intrinsic “visual vulnerability” or simply a transient drug-induced neurotoxicity. This distinction is vital, as the latter would render the NPT a measure of current intoxication rather than a predictor of future risk 3. Despite these limitations, Hashimoto et al.'s study underscores the critical importance of visual-perceptual assessment in delirium prevention. I strongly encourage future research to replicate these findings in larger cohorts with stricter exclusion criteria for recent acute medication use and more detailed phenotyping of dementia subtypes. Clarifying these distinctions is not merely academic but holds profound implications for clinical management—differentiating between a patient who needs environmental modification for delirium versus one requiring specific pharmacotherapy for Lewy body pathology. Addressing these confounders will be instrumental in establishing the NPT not only as a research tool but as a robust, specific clinical instrument for safeguarding vulnerable older adults in acute care settings. The author has nothing to report. The author has nothing to report. The author has nothing to report. The author declares no conflicts of interest. Data sharing not applicable to this article as no datasets were generated or analysed during the current study.
Lanping Zhang (Sun,) studied this question.