Slowness in schizophrenia.

Nufferno Speed Test In this investigation we have used only the Nufferno speed test, which is designed to measure speed as distinct from general level of intelligence. It consists of 19 problems of the Thurstone letterseries type in each of which the patient is presented with series of letters and is required to add at the end of the series the letter which is appropriate to the sequence (Furneaux, 1955, 1956). Every patient was tested on two versions of equal difficulty. In the first or unstressed version (AA) the patient is allowed to work at his own rate, but in the second or stressed version (AB) the examiner urges him to complete the task as quickly as possible. The score for each version is the mean of the logarithms of the times spent for the completion of the items correctly solved in each version. The higher the score, therefore, the slower the patient. Several workers have applied this test to schizophrenic subjects and all report a tendency for them to be slower than normals (Nelson, 1953; Ogilvie, 1954; Shapiro and Nelson, 1955a, 1955b; Broadhurst, 1956). The forms of the test used have varied, however, according to the aims in view, so that it is difficult to compare results. For the AA unstressed version the range for an unselected normal population is from 0 6 to 2 1 and for the AB stressed version 0 5 to 1 8. Broadhurst gives the standard deviation for a group of normal adults as 0-32 on the AA version.