Disability after encephalitis: development and validation of a new outcome score.

OBJECTIVE To develop a simple tool for assessing the severity of disability resulting from Japanese encephalitis and whether, as a result, a child is likely to be dependent. METHODS A new outcome score based on a 15-item questionnaire was developed after a literature review, examination of current assessment tools, discussion with experts and a pilot study. The score was used to evaluate 100 children in Malaysia (56 Japanese encephalitis patients, 2 patients with encephalitis of unknown etiology and 42 controls) and 95 in India (36 Japanese encephalitis patients, 41 patients with encephalitis of unknown etiology and 18 controls). Inter- and intra-observer variability in the outcome score was determined and the score was compared with full clinical assessment. FINDINGS There was good inter-observer agreement on using the new score to identify likely dependency (Kappa = 0.942 for Malaysian children; Kappa = 0.786 for Indian children) and good intra-observer agreement (Kappa = 1.000 and 0.902, respectively). In addition, agreement between the new score and clinical assessment was also good (Kappa = 0.906 and 0.762, respectively). The sensitivity and specificity of the new score for identifying children likely to be dependent were 100% and 98.4% in Malaysia and 100% and 93.8% in India. Positive and negative predictive values were 84.2% and 100% in Malaysia and 65.6% and 100% in India. CONCLUSION The new tool for assessing disability in children after Japanese encephalitis was simple to use and scores correlated well with clinical assessment.