Abstract

We have investigated the relation between the scores on the WAIS scale and the error score on a reading test (TIB, Test di Intelligenza Breve) that has been constructed as an Italian equivalent of the National Adult Reading Test (NART; Nelson, 1982). Because of the significant correlation between the two measures, the IQ score on the WAIS can be estimated from a score on the TIB. The TIB, as the NART, is based on a list of words with an irregular pronunciation, that can be named correctly only consulting the stored pronunciation in the mental lexicon. We investigate the predictive abilities of the TIB in three phases. In the first, 127 participants were presented with the TIB and the WAIS tests and the regression equations for predicting IQ scores from TIB errors were constructed. In the second phase, the same tests were presented to a group of 20 DAT (Dementia of Alzheimer Type) patients in order to evaluate whether TIB is resistant to intellectual deterioration, at least in the first stage of dementia, and can therefore be used as a measure of premorbid IQ in dementia. The third phase is a cross-validation study, conducted on a new group of 104 normal participants. In the final part of the study the limits and advantages of the TIB test as a diagnostic tool are discussed.