Reliability and validity of a rating scale for post-stroke psychiatric symptoms

Reliability and validity of a rating scale for post-stroke psychiatric symptoms were examined by the videotape method. The scale comprised 10 items categorized into two symptom domains of decreased spontaneity and impaired emotion. Also, two items for global assessment of the two symptom domains were added. Each item had seven anchor points from 0, representing no impairment, to 6, corresponding to complete impairment. Face validity of the scale was confirmed through the questionnaire survey. Nine neurologists independently assessed psychiatric symptoms in 30 videotaped post-stroke patients. Weighted kappa coefficients of more than 0.5 were noted for all the items except for one item. Data from three cerebral metabolism enhancers trials were used to examine the validity. Changes in severity in the Global Change Scale (GCS) from the baseline to the final assessment was assessed by raters' impression in these trials. Factorial validity of the scale was confirmed by the factor analysis. GCS in the three trials were considerably related to the summed scores of the items in the two categories. Namely, in the box plot figures, boxes of the middle 50% of data well differentiated the adjacent categories of GCS. However, overlap from vertical bars was observed. These results suggest reliability and validity of the scale.