The Hierarchic Dementia Scale: conceptualization.

The Hierarchic Dementia Scale is an instrument for measuring the severity of mental impairment based on Piagetian concepts, neuropsychological findings, and the hierarchic nature of decline in mental function. Performance of 20 specific functions such as orienting reflexes and comprehension can be rapidly pinpointed over a wide range of impairment. The scale is reliable, valid, responsive, safe, inexpensive, and easy to use.