I.Introduction

The neuronal interactions within the nervous system facilitate physiological functions (e.g., sustaining life and maintaining homeostasis) and higher-order cognitive functions, such as emotions, thoughts, language, perception, and learning ([Carr & Shepherd, 2010]; [Lundy-Ekman, 2007]). The central nervous system (CNS) diseases involve structural or functional damage to the brain and spinal cord ([Pendleton & Schultz-Krohn, 2013]). Neurological symptoms resulting from CNS damage include paralysis, loss of motor and sensory function, cognitive impairment, and dysphagia ([Radomski & Trombly Latham, 2013]), all of which negatively affect performance of basic and instrumental activities of daily living (ADLs) including functional mobility and self-care activities ([Pendleton & Schultz-Krohn, 2013]).

Recovery phases following CNS injury are typically categorized into acute (< 1 month), subacute (1-6 months), and chronic (> 6 months) stages ([García-Rudolph et al., 2019]). In Korea (‘Korea’ refers to ‘Republic of Korea’), patients in large hospitals often need to transfer to other facilities due to the maximum length of hospital stay policy ([Yang & Min, 2021]), leading to repeated admissions and discharges, which imposes a significant financial burden on patients due to repeated tests and therapies ([Choi, 2019]). Functional recovery is most rapid during the first six months post-injury. Thus, it is crucial to initiate rehabilitation therapy, including occupational and physical therapy, in a timely manner. Appropriate use of functional evaluations can support this rehabilitation process, helping to expedite discharge to home and minimize unnecessary healthcare costs ([Kim et al., 2009]; [Lee, 2017]). Therefore, it is important to develop an assessment tool that can appropriately measure functional outcomes, including the performance of ADLs, for people with CNS injuries.

Client-centered and performance-based evaluations are essential for addressing challenges in performing ADLs and enhancing the quality of life for patients striving for reintegration into daily life and community participation ([American Occupational Therapy Association, 2020]; [Christiansen et al., 2005]; [Kielhofner, 2007]). Commonly used tools for evaluating task performance within the context of clients’ backgrounds and environments include the Canadian Occupational Performance Measure (COPM), Assessment of Motor and Process Skills (AMPS), and ADL-focused Occupation-based Neurobehavioral Evaluation (A-ONE)([Árnadóttir, 2010]; [Fisher & Jones, 2011]; [Law et al., 1990]). Despite their utility, these tools, developed in other countries, may not align well with Korean cultural contexts and can be difficult to implement within the limited evaluation time typically available in clinical settings. Furthermore, tools like the A-ONE and AMPS require significant time and financial investment to train evaluators, with the AMPS also necessitating specialized software for result interpretation. Additionally, COPM relies on interviews or self-reporting rather than direct observation, making them less suitable for assessing actual task performance levels.

The Performance Assessment of Self-care Skills (PASS) is a performance-based scale that evaluates the ability to perform functional mobility, self-care, and ADLs through observation, distinguished by its objectivity and reliability ([Rogers et al., 2016]). It is particularly characterized by its emphasis on the interaction between individuals and their environments, a fundamental principle of occupational therapy ([Wolf et al., 2019]). Studies related to the PASS demonstrate its wide applicability ([Bingham et al., 2018]; [Ciro et al., 2015]; [Eroğlu et al., 2020]). Additionally, the PASS has been adapted to various cultural contexts, including Portuguese and Arabic versions, with studies testing its reliability and applicability ([Ferreira et al., 2021]; [Hamed et al., 2012]).

A review of occupational therapy evaluation tools used in Korea highlights a lack of task performance assessments, such as PASS, compared to the prevalence of tools for assessing motor, perceptual, and cognitive functions ([Song, 2012]; [Yoo et al., 2006]), suggesting a shortage of instruments designed to comprehensively evaluate daily living skills in Korean medical settings. Consequently, there is an urgent need for a culturally adapted Korean version of the PASS. This study aimed to develop and validate the Korean Performance Assessment of Self-Care Skills (K-PASS). The primary objective was to establish the reliability and validity of the K-PASS for evaluating functional mobility, self-care, and ADL performance in Korean patients with CNS diseases. The ultimate goal was to provide a culturally adapted, client-centered, and performance-based assessment tool to support clinical interventions effectively.

II.Methods

2.Research Procedure and Participants

Prior to developing the K-PASS, approval was obtained from the original co-authors, Margo B. Holm and Denise Chisholm, to translate and adapt the PASS in alignment with the specific cultural and societal context of Korea. The study was conducted in accordance with the Declaration of Helsinki, and ethical approval was obtained from the Institutional Review Board of Soonchunhyang University (Approval Number: 1040875-202301-SB-003).

The development of the K-PASS involved a two-phase process. In Phase 1, the PASS was adapted into Korean through a multi-step process: translating the PASS into Korean, validating its appropriateness with an expert panel, testing the comprehensibility of the translation, performing a back-translation, and validating the back-translation. Phase 2 focused on evaluating the validity and reliability of the finalized K-PASS. Content validity was assessed through surveys completed by occupational therapists, who evaluated the appropriateness of the K-PASS scoring criteria, task conditions/instructions, and scoring of each task (hereinafter referred to as “item”). Known-groups validity and internal consistency reliability were tested by administering the K-PASS to study participants (Figure 1).

Figure 1.Flow Diagram of Research Procedure

1)The PASS Adaptation Process

The researcher, a supervising professor, and a professional translator with a background in health sciences and experience living in Canada, conducted the translation of the PASS into Korean. The translation’s appropriateness was evaluated by an expert panel consisting of two occupational therapy professors, three occupational therapists with at least five years of clinical experience, and one bilingual occupational therapist proficient in both Korean and English. None of the panel members had prior experience with the PASS. The evaluation comprehensively assessed the translated items for semantic accuracy in conveying the original English content, alignment with the intended evaluative concepts, and cultural suitability within the Korean context.

Following the expert panel’s evaluation of translation adequacy, 10 healthcare professionals including occupational therapists, physical therapists, and nurses working in healthcare facilities with at least five years of clinical experience, but no prior familiarity with the PASS, assessed the clarity of the translated items. These professionals evaluated whether the translated items were clear, understandable, and free of ambiguity, using a process similar to that employed by the expert panel.

After assessing the comprehensibility of the translation, the Korean version of the PASS was back-translated into English by a professional translator with no prior exposure to the PASS. The back-translation was then reviewed by a bilingual evaluator who had not previously encountered the PASS, resided in the United States, and had completed a doctoral program in occupational therapy at a U.S. university. The evaluator examined the structural and semantic alignment between the original PASS and the back-translated version.

Throughout the validation processes, all items were evaluated using a 4-point Likert scale (4 = very adequate or very comprehensible or very similar, 3 = adequate or comprehensible or similar, 2 = inadequate or incomprehensible or dissimilar, 1 = very inadequate or very incomprehensible or very dissimilar), with those scoring 2 or below flagged for revision. Unrestricted feedback was collected to identify reasons for low scores and provide suggestions for improvement. The results obtained from the expert panel’s assessments of translation adequacy and comprehensibility were converted into validation scores based on the 4-point Likert scale. Following methodologies proposed in previous studies ([Chae et al., 2008]; [Jung et al., 2015]; [Park et al., 2017]), items with an average validation score below 0.80 or individual item scores of 2 or below were iteratively revised until all the necessary criteria required for validation were met.

2)Validity and Reliability Testing of the K-PASS

Once the back-translation validation was completed, the content validity of the finalized K-PASS was evaluated by occupational therapists working in healthcare facilities, all with at least five years of clinical experience and no prior exposure to the PASS or the K-PASS. The number of participants was set at 10, following Lynn’s recommendation that 5-10 experts are sufficient for content validity determination ([Lynn, 1986]). A 4-point Likert scale (4 = very appropriate, 3 = a ppropriate, 2 = inappropriate, 1 = very inappropriate) was used to assess whether the K-PASS items were conceptually aligned with the intended evaluation goals. Items rated 2 or below were supplemented with freely provided feedback, and the content validity index (CVI) was calculated as the proportion of items rated 3 or 4. A CVI cutoff score of 0.78, based on the criteria established by [Lee (2021a)] and [Polit et al. (2007)], was applied.

Known-groups validity testing for the K-PASS was conducted with 30 CNS disease patients and 30 healthy adults (Table 1). Participants diagnosed with CNS diseases by a specialist were assigned to the CNS disease group, while individuals with no history of CNS diseases were placed in the healthy adult group. Based on the central limit theorem, a total sample size of 60 (30 participants per group) was determined to enhance the likelihood of a normal distribution ([Lee, 2000]). Participants who met the inclusion criteria, were capable of communication, and provided informed consent were enrolled in the study after receiving detailed explanations about its purpose, procedures, and methods. The K-PASS was administered to all participants, and the mean summary scores across the 26 items were compared between the CNS disease group and the healthy adult group.

Table 1.Subjects’ General Characteristics (N = 60)

Classification		n (%)
		CNS disease patients (n = 30)	Healthy adults (n = 30)
Sex	Male	13 (43.3)	11 (36.7)
	Female	17 (56.7)	19 (63.3)
Age (year)	< 40	4 (13.3)	9 (30.0)
	40-49	7 (23.3)	7 (23.3)
	50-59	8 (26.7)	9 (30.0)
	≥ 60	11 (36.7)	5 (16.7)
Diagnosis	Stroke	14 (46.7)	-
	Parkinson’s disease	5 (16.7)
	Alzheimer’s disease	6 (20.0)
	Etc.	5 (16.7)
Period of onset (month)	< 1	8 (26.7)
	1-5	6 (20.0)
	≥ 6	16 (53.3)

The sum of the percentages does not equal 100% because of rounding.-: Not applicable, CNS: Central nervous system.

We computed Cronbach’s alpha using the K-PASS scores from the CNS disease group to examine the internal consistency reliability, which indicates whether the items of domains the K-PASS measure the same construct. A Cronbach's alpha of 0.70 or higher was considered acceptable for the study ([Lee, 2021b]).

III.Results

IV.Discussion

This study developed the K-PASS by adapting the original PASS to align with Korean cultural contexts and subsequently validated its reliability and validity.

An analysis of time allocation among Koreans for daily activities revealed that household budgeting, financial planning, and banking are integral components of the IADL domain ([Hong & Lee, 2010]). Koreans dedicate approximately one-third of their daily living time to household management tasks such as budgeting, planning, and accessing financial or public services ([Statistics Korea, 2020]). Furthermore, with rice comprising 87.3% of the annual per capita grain consumption in Korea and kimchi-based dishes being highly popular ([Gallup Korea, 2019]; [Statistics Korea, 2024]), adaptations of the PASS items were tailored to incorporate these cultural aspects. The original evaluative concepts of financial management and meal preparation in the PASS were preserved, ensuring that the modified items were both culturally relevant and grounded in empirical evidence.

During the adaptation process of the PASS, the results from the translation adequacy, comprehensibility, and back-translation evaluations, conducted by an expert panel, showed that all items achieved the validation threshold of 0.80 or higher or a score of 3 or higher. This confirms the adequacy of the finalized K-PASS ([Chae et al., 2008]; [Jung et al., 2015]; [Park et al., 2017]). The 26 items of the K-PASS demonstrated strong content validity, as indicated by an S-CVI of 0.92 and I-CVI scores ranging from 0.80 to 1.00, confirming their alignment with the intended evaluation goals. These results validated the adequacy of the K-PASS items for assessing functional mobility, self-care, and ADLs in CNS disease patients within clinical settings, effectively reflecting the intended evaluative concepts ([Polit & Beck, 2006]; [Polit et al., 2007]).

The known-groups validity testing results for the K-PASS demonstrated that scores for CNS disease patients were significantly lower than those for healthy adults. This finding confirms that the K-PASS effectively distinguishes between the two groups and provides accurate and appropriate measurements ([Polit & Yang, 2015]). The results of internal consistency reliability testing indicated that the all K-PASS items achieved a Cronbach’s alpha of 0.70 or higher. These findings confirm the homogeneity of the K-PASS items and demonstrate that the tasks within each domain consistently measure the same underlying concept ([Lee, 2021b]).

In localized PASS versions across the globe, adjustments have been made to align with cultural contexts. For example, the Arabic version replaced meal preparation tasks with dishes representative of local cuisine ([Hamed et al., 2012]). Similarly, in the Portuguese version, tasks such as ‘Bill paying by check,’ ‘Checkbook balancing,’ and ‘Mailing bills’ were adapted to involve paying bills through ATMs in line with regional practices. Validity and reliability were subsequently established for the localized version ([Ferreira et al., 2021]). These adaptations are analogous to the modifications implemented for the K-PASS, which also demonstrated high validity and reliability.

The significance of this study lies in the development of the K-PASS, a client-centered, performance-based evaluation tool designed for comprehensive or selective task assessment tailored to individual needs. Its design ensures efficient application in clinical settings with limited evaluation time. The K-PASS enables precise performance assessment through direct observation within standardized categories, clearly identifying task performance levels. Adapted to reflect Korean culture, it is well-suited for Korean clinical settings. Furthermore, its validity and reliability were rigorously established through extensive psychometric testing.

This study had limitations. The sample size for known-groups validity and internal consistency reliability testing was relatively small, and participant characteristics (e.g., sex, age, diagnosis, onset timing) were not distributed evenly. Moreover, test-retest reliability (to ensure consistency across repeated measurements) and inter-rater reliability (to assess agreement among evaluators) were not examined during the development process. Future research should address these limitations by including diverse patient groups and larger sample sizes to further validate the tool’s reliability and validity. Moreover, the ongoing refinement of the K-PASS should incorporate activities commonly performed in Korea and include gender- and age-specific activities to maintain its relevance in a changing societal context.

V.Conclusion

This study developed and validated the K-PASS, a Korean adaptation of the original PASS, designed to assess functional mobility, self-care abilities, and ADLs in individuals with CNS diseases in clinical settings. The development process included translation, expert panel assessments of adequacy and comprehensibility, back-translation, and its subsequent review. Reliability and validity testing provided robust evidence of the K-PASS’s content validity, known-groups validity, and internal consistency reliability. These results demonstrate that the K-PASS is a reliable and valid tool for evaluating daily living skills in individuals with CNS diseases. The K-PASS is anticipated to serve as an effective assessment tool and provide a foundation for creating client-centered, performance-based interventions in clinical practice.