Background: Delirium is a common and serious condition in hospitalized patients that often leads to extended hospital stays and increased healthcare costs. Accurate and timely detection is essential for optimal patient outcome.

Aims: This study aimed to adapt the internationally recognized 4 AT Delirium Diagnosis Scale to Turkish and to evaluate the validity and reliability of this tool for the Turkish patient population.

Design: This study was structured and conducted at a state hospital from March to June 2023.

Methods: The study included 188 participants, determined through a power analysis. The 4AT Delirium Test and additional assessment tools were used to ascertain the delirium status of the patients. Comprehensive statistical evaluations were conducted using SPSS 25.0, which included analyses, such as item difficulty indices, item discrimination, and chi-square tests. Ethical approval for this study was granted by the Non-Interventional Ethics Committee, ensured full compliance with the ethical standards set by the World Medical Association's Declaration of Helsinki. All participants provided informed consent before participation. Additionally, our results strictly adhered to the guidelines of the STROBE Checklist.

Delirium is a common occurrence in healthcare settings, leading to extended hospital and intensive care stays, and negatively impacting mortality and morbidity rates [1,2]. Previously seen as an unavoidable outcome, delirium is now understood as a preventable condition [3,4]. The delirium incidence in postoperative recovery units fluctuates between 3% and 54%, contingent upon the diagnostic method, patient demographics, and timing of the assessment [6,7,8,9].

Although a myriad of approaches and scales are employed to detect delirium, some may inadequately or erroneously define the condition. Overlooking delirium in its early stages increases healthcare expenses, extends hospitalization, burdens healthcare staff, and interrupts therapeutic plans [3,10,11]. Additionally, the importance of credible and efficient evaluation methods for delirium detection in postoperative recovery units has been underscored [6]. Both the Anesthesia Association and the European Anesthesia Association emphasize the significance of early delirium identification in these units [12,13]. Delirium onset in recovery units correlates with its emergence in general wards or intensive care units [14]. Thus, patients should not be discharged from the recovery units without undergoing a delirium assessment.

A comprehensive psychiatric evaluation remains a benchmark for diagnosing delirium. However, given the extensive training this method demands and its lengthy process [15,16] , there is a need for more streamlined and promptly applicable tests for routine delirium screening in postoperative recovery units. While many scales used for delirium assessment require specialized training and are time intensive [17,18], tools such as the delirium risk determination scale, confusion assessment method [CAM] [19], confusion assessment scale for the ICU [CAM-ICU] [20], 3D confusion assessment method [3D-CAM], delirium index [DI], and confusion assessment method importance [CAM-S] have gained acceptance. However, many of these tools are unwieldy [9,17,18]. In response, the 4 At Delirium screening scale [4 AT] was formulated for more rapid and dependable delirium screening [21,22].

The 4AT is a concise assessment tool, comprised of four items designed to evaluate delirium. Healthcare professionals can administer this test in less than 2 minutes, eliminating the need for specialized training [21]. The efficacy of 4AT has been validated in numerous studies involving various populations [21,23,24]. Despite its global recognition and adoption as a clinical instrument, there is a noticeable gap in research on its application within postoperative recovery units, or "awakening units," using the 4AT scale.

Screening for delirium, particularly following surgery, is crucial for timely identification because of its significant impact on long-term patient outcomes. Thus, there is an undeniable demand for reliable and streamlined assessment instruments. Many current tools require specialized knowledge and can be unwieldy in applications. A notable gap exists within Turkey's postoperative recovery setting for efficient and trustworthy delirium screening methods. Against this backdrop, our research aims to tailor the internationally recognized 4 AT Delirium Diagnosis Scale to the Turkish landscape and confirm its effectiveness. The primary objective of this study was to adapt the 4 AT Delirium Diagnosis Scale for Turkish use and ascertain its validity and reliability in a Turkish patient cohort. Within this framework, we address the following questions.

1. What is the validity of the 4 AT Delirium Test for the Turkish patient population?
2. What is the reliability of the 4 AT Delirium Test for the Turkish patient population?

Inclusion Criteria:

• Our study cohort comprised patients who satisfied certain prerequisites. These included being aged 18 years or older, possessing the capability to communicate, scoring between -3 and +4 on the Richmond Agitation-Sedation Scale [RASS], achieving a minimum score of 10 on the Glasgow Coma Scale [GCS], and no neurological or psychiatric backdrop that might skew a delirium assessment. If any participant opted to exit the study, their associated data were omitted.

Exclusion Criteria:

• Individuals who encountered acute post-anesthesia complications, were diagnosed with advanced cognitive deficits or dementia, lost communication abilities entirely, or displayed reluctance or inability to furnish information during the study were excluded. Moreover, patients diagnosed with an alternate neurological or psychiatric ailment after delirium assessment were also included. Participants or their guardians, who either declined involvement or retracted prior consent, were excluded from the study.

The study population consists of adult patients admitted to the ICU for surgery. Participants were selected based on preoperative cognitive status assessments, with those showing normal evaluations included in the study. The population exhibits diversity in terms of age, gender, and types of surgery. Post-operative patients in the recovery room were evaluated for consciousness and sedation agitation levels using established scales such as RASS and GKS. The study specifically focuses on screening for post-anesthesia emergence delirium, making the population representative of typical ICU surgical cases where delirium assessment is critical

"In this study, we do not plan to share individual participant data with other researchers. The decision not to share IPD is based on concerns related to participant privacy and confidentiality. The data collected in this study are sensitive and disclosing them, even in a de-identified format, could pose risks to participant privacy. Therefore, in accordance with our ethical obligations and institutional guidelines, we have decided to maintain the confidentiality of the data and not make it available for external access.