A Validation of an Examination Protocol for Cerebral Visual Impairment Among Children in a Clinical Population in India

Introduction: Cerebral Visual Impairment (CVI) is a leading cause of vision impairment in developed and developing countries due to and increased survival of preterm and low birth weight infants. There are few data concerning the validity of protocols available to diagnose CVI. Aim: This study aimed to document the face, content and construct validity of an assessment protocol namely, a 15-domain, Structured Clinical Question Inventory (SCQI), which is based on structured history taking and clinical examination, for the diagnosis of CVI in a clinical population of India. Materials and Methods: This study was a retro-spective chart analysis of all children below the age of 18years, referred to the CVI clinic of a tertiary care teaching hospital in Southern India from March 2011-Feb 2012. Clinical case-notes including the SCQI findings of all children referred to the clinic were reviewed. The data were extracted after Institutional Review Board approval. Statistical Analysis: Pearson correlation coefficient, Cronbach's alpha and exploratory factor analysis were used to document the content and construct validity of the examination protocol. Results: A total of 342 children (35.7% male, 64.3% female), with a mean age of 3.8 years (range 0-17 years, the median was 3 years) were included in the study and their data were examined. The internal consistency of the SCQI was 0.93 suggesting it as an excellent tool to characterise and profile CVI and a 2-factor model (Dorsal Stream Dysfunction and Ventral Stream Dysfunction) based on a biologically plausible model explained 63% of the variance. Conclusion: The results of using the SCQI affirm published data and endorse a theoretical construct similar across cultures. The potential diagnostic accuracy, reliability and utility of this measure for CVI needs to be studied further. The clinical use of a short version of the SCQI may be helpful to contribute to the identification of CVI, especially for middle and low-income countries.