Developing and validating a language assessment tool to diagnose aphasia in a Sri Lankan Sinhala speaking context

Abstract

Aphasia is an acquired communication disorder commonly present in stoke survivors. No standardized tests are currently available to identify aphasia in the Sri Lankan context. The objectives of this study were to identify language functions in Sinhala to be used as tasks in the tool; to identify the reliability of the developed tool and to identify the validity of the developed tool. Face validity and construct validity were achieved based on the Delphi-method. External validity was identified with concurrent and criterion validity. Data from 200 participants without aphasia (age ranges of 20-40, 41-60, 61-80, 80+ years) and 251 participants with strokes (PWS) were analyzed in the validation process. The reliability was achieved by reliability measures of internal reliability (IR) as Cronbach alpha (CA), split half reliability(SHR), test-retest (TR) and inter-examiner reliability (IER) using a sample of 30 participants with aphasia (PWA) and 60 PWS. No correlation was observed among total scores with age, educational or economy for participants without aphasia, but significant correlation was observed for PWA for age (-758) and education (0.490). The Delphi method resulted with 12 tasks and 69 items for the tool. IR for each task was calculated and CA was within the expected range (0.70-0.90) for 8 tasks and (04) four tasks needed revision. IER reliability was 0.99. TR reliability was 0.90. Two tests correlation was 0.86. ROC curve for 60 SWS was analyzed and that score (140) was used among another 251 PWS to diagnose aphasia and the results indicated sensitivity as 01 and specificity as 0.91 with gold-standard comparisons. In conclusion, the developed tool could be used as a clinically valid and reliable tool to diagnose aphasia in the Sri Lankan context.