[Kraepelin's calculating test as an indicator of shunt-operation effect for normal pressure hydrocephalus (NPH) (author's transl)].

Many reports have been issued since the first report on NPH by Adams et al. in 1965, and shunting operation is reported as the most efficient procedure for this condition. However, still some problems are remained to be solved, for example we have no generally accepted objective evaluating method for mental activity of NPH--patient in pre- and post-shuntoperation. The author chose Kraepelin's calculating test, which is continuing adding of at random series of one figure numbers and result rate of every minute and correct or erroneous rates are used as the indicator for mental capacity according Yokota's standard. The reproducibility and stability of this test are realized again on the cases of this report. The most essential appreciation for the treatment of NPH is mental activity itself and not size of the ventricle nor improving of EEG. This report has proved that the Kraepelin's calcuculating test with Yokota's standard is stable objective indicator for mental activity of NPH--patient, and pre- and post-shuntoperation evaluation was mentioned.