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VITENSKAP A Rasch analysis of the Sunnaas ADL Index for stroke survivors Av Kristin S. Loxley & Ann-Kristin G. Elvrum Abstract Sunnaas ADL Index’s internal scale validity Kristin S. Loxley is an occupational thera- pist, MSc, working at Sunnaas Rehabilitation Hospital and affiliated with Department of In- terdisciplinary Health Sciences, Faculty of Medicine, University of Oslo, Norway. Email: kristin.loxley@ sunnaas.no Ann-Kristin G. Elvrum is an occupational th- erapist, ph.d., working at Clinic of Rehabi- litation, St. Olav’s Hospital, Trondheim University Hospital, Trondheim and De- partment of Neurom- edicine and Movement Science, Norwegian University of Scien- ce and Technology, Trondheim. Artikkelen ble mottatt 23.03.2023 og godkjent 22.07.2023. Det er ingen interessekonflikter. Background : The Sunnaas ADL Index (SADL) is a generic outcome measure that evaluates indepen- dence in activities of daily living (ADL). Acceptable reliability of SADL for patients with stroke has been confirmed, while information concerning construct validity is lacking. Aims/Objectives : The objective of our study was to evaluate SADL’s internal scale validity and aspe- cts of reliability for stroke survivors. Material and Methods : Data from 200 patients (136 men, mean age 58 years) admitted to the stro- ke unit at Sunnaas Rehabilitation Hospital (2012- 2017), was included in the Rasch measurement model analyses to evaluate internal scale validity and item and person reliability of SADL. Results : SADL was found to be unidimensional with an item fit of 91.8 percent and excellent person (0.91) and item reliability (0.99). Only one item, communication, showed misfit, but was retained, as removal did not improve fit statistics. The scoring categories functioned well, but mean person ability was higher than mean item difficulty with nine per- sons reaching maximum scores. Conclusion : The SADL is a valid measure of inde- pendence in daily activities for stroke survivors and seems most appropriate for those with moderate to severe disabilities. It should be considered to revise the scoring criteria for the item communication. Keywords : Outcome Measures; Model, Statistical; Psychometrics; Activities of Daily Living 32 Ergoterapeuten 5–2023
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Introduction Loss of independence in activities of daily living (ADLs) is a devas- tating consequence for many persons who experience stroke and other brain related injuries (1, 2). It affects their possibility to live independently and safely at home and to participate in work and leisure activities. Regaining independence in daily activities is associated with higher quality of life, reduced caregiver burden and less use of healthcare resour- ces (3, 4). Occupational Thera- pists (OTs) are especially concer- ned with enabling performance and participation in everyday activities (5). Therefore, assess- ments of activity performance are essential for OT’s working with rehabilitation of people with acquired brain injuries. Evaluat- ing the performance and level of independence in both primary self-care activities (PADLs) such as eating and dressing and instru- mental activities (IADLs) such as cooking and shopping, provide a starting point for goal-setting and planning of interventions and adaptations to promote indepen- dence in ADLs (1). To evaluate individual treatment effect, as well as measuring the level of independence, safety, required level of assistance and potential for rehabilitation, assessments of ADL with sounds psychometric properties are crucial (3, 6). In addition, valid and reliable outco- me measures that are sensitive to change, are important to provi- de evidence-based knowledge concerning efficacy of various interventions (1, 3, 7). The Sunnaas ADL Index (SADL) is commonly used by occupational therapists in Nor- way to evaluate independence in ADLs (8, 9). In addition, the Figure 1. Scoring sheet for the Sunnaas ADL Index. Barthel Index and Functional Independence Measure (FIM) are frequently used to measure ADL outcomes (3). The SADL asses- ses the level of independence in completing twelve daily activities as well as how much assistance and/or adaptation is needed to complete them (10). Unlike Barthel Index or FIM, the SADL includes items evaluating instru- mental ADLs that are relevant for OT interventions (cooking, housework and outdoor mobi- lity) (11). The scoring sheet also provides a visual overview over the level of assistance and adap- tations needed to perform the included activities (Figure 1) (12). This enables the therapist to ea- sily illustrate for the patient what steps are needed to become in- dependent in these activities and discuss possible interventions. Although originally created for patients with stroke, the SADL has also been used for geriatric patients and patients with condi- tions such as spinal cord injuries, multiple trauma, poliomyelitis and osteogenesis imperfecta (8, 10, 13-18). Earlier studies have inves- tigated the psychometric proper- ties of SADL for the joint groups Ergoterapeuten 5–2023 33
