Qualitative changes in vocabulary test performance after lobotomy and selective frontal operations

Abstract

The vocabulary performance of 40 neurotic patients before and after lobotomy and three types of selective frontal operations has been analysed in various ways. After lobotomy there was a significant decrease in quantitative (conventional) scores and a significant lowering of the quality of the word defintions. After the selective operations there was no significant decrease in quantitative scores but a marked lowering of the quality of the word definitions. The findings justify warnings against accepting conventional vocabulary scores as a measure of premorbid intelligence in brain-injured patients. They also support the Yacorzynski hypothesis that the stability of the vocabulary test in some cases of mental impairment is only apparent. The traditional dichotomous scoring of vocabulary tests, being too crude, may conceal important losses in finer word discriminations in such cases. The importance of adequate analysis and quantification of qualitative aspects of test performances in experimental clinical testing is stressed.