Construct and ecological validity of the Occupational Therapy Adult Perceptual Screening Test (OT-APST)

Abstract

This paper reports on the construct validity (scale design and convergent validity) and ecological validity of the Occupational Therapy Adult Perceptual Screening Test (OT-APST). The performance of 208 participants following stroke on the OT-APST and a reference tool (either the Loewenstein Occupational Therapy Cognitive Assessment (LOTCA) or the LOTCA-Geriatric version (LOTCA-G)) was compared. The OT-APST performance of the stroke sample was compared with a healthy normative sample (n = 356). The relationship between the OT-APST performance and the Functional Independence Measure (FIM) score of the participants following stroke was also examined. Factor analysis and internal consistency results supported the scale design of the OT-APST. Significant correlations between the performance of the participants following stroke on the OT-APST and the reference tool supported the convergent validity of the OT-APST. The ability of the OT-APST to separate the two participant groups provided further evidence of its construct validity. Significant correlations between OT-APST and FIM scores supported the ecological validity of this tool. This study shows that the OT-APST is an ecologically valid tool with demonstrated construct validity in the assessment of visual perception.

Convergent validity of the Occupational Therapy Adult Perceptual Screening Test (OT-APST) with two other cognitive-perceptual tools in a South African context

“…Although the LOTCA does not have a subscale specifically for unilateral neglect, the authors added the LOTCA Puzzle and Clock items to their analysis as they were thought to be comparable with the OT-APST Unilateral Neglect subscale 19 . They also found the highest correlations to be with the Constructional Skills (rho= 0.802) and Unilateral Neglect subscales (rho= 0.640) 12 .…”

“…Cooke et al found that the LOTCA had several subscales which could be compared to the OT-APST and Spearman's rho correlations were used to determine convergent validity between these items which showed statistically significant correlations with p < 0.01 20 . In the same research on the OT-APST and LOTCA/LOTCA-G, Cooke et.al, did not compare the OT-APST Acalculia and Functional skills subscales to the LOTCA as the LOTCA did not have an item evaluating arithmetical skills or functional skills 12 . Although the LOTCA does not have a subscale specifically for unilateral neglect, the authors added the LOTCA Puzzle and Clock items to their analysis as they were thought to be comparable with the OT-APST Unilateral Neglect subscale 19 .…”

“…This includes the completion of addition and subtraction questions. In a study by Cooke et al 20 , to determine the convergent validity of the OT-APST, results were compared and correlated with the LOTCA and the LOTCA-G (Geriatric) 21 which were used as a "gold standard" 12 . Cooke et al found that the LOTCA had several subscales which could be compared to the OT-APST and Spearman's rho correlations were used to determine convergent validity between these items which showed statistically significant correlations with p < 0.01 20 .…”

“…It is furthermore time efficient for the occupational therapist to quickly identify which patients require more help, particularly when the therapist has several patients to manage. Further, occupational therapists need to use valid and reliable screening tools in order to correctly identify patients with cognitive and perceptual impairments 16 and to substantiate the need for in-depth assessments and guide appropriate intervention 12,17 . The aim of this study was to investigate the convergent validity of the Occupational Therapy Adult Perceptual Screening Test (OT-APST) 18 with two other cognitive-perceptual tools used in South Africa to inform the suitability of a cognitive-perceptual screening tool for therapists practising in the South African context.…”

“…A number of measuring instruments are available that include both cognitive and visual perceptual skills such as visuospatial abilities 7 . In South Africa, occupational therapists often use the Loewenstein Occupational Therapy Cognitive Assessment (LOTCA) 11 which is considered the gold standard in terms of visual perceptual tests 12 and the Rivermead Perceptual Assessment Battery 13 . However, these tools are time consuming, costly and have not been standardised on the SA population.…”