Three socio-demographic equations for the estimation of the (premorbid) intelligence quotients according to Wechsler

Within each neuropsychological assessment, estimation of a patients premorbid level of functioning is central to the diagnosis of deficits and to realistic treatment planning. The biographical case history indispensable for that purpose can be supplemented by more formalized methods, whose respective advantages and disadvantages are outlined. In particular, purely socio-demographic formulae permit estimation of premorbid intelligence independent of current disease processes. Since no "social formulae" of that kind have been available in Germany so far, 612 healthy subjects, representatively stratified for age, sex and school education, were interviewed for their socio-demographic characteristics.An intelligence test (HAWIE-R; German adaptation of theWAIS-R), a vocabulary test(MWT-B) and a reading test (LECTOR) were also carried out. Socio-demographic prediction models for the full, verbal and performance IQ were developed by means of regression analyses and then successfully cross-validated. Despite an unavoidable regression to the mean, precision of estimation was sufficient, at least for the full and the verbal IQ. The formulae are applicable for residents of the former Federal Republic of Germany as well as for East-Germans born after 1985 A case example and the calculation sheet contained in the appendix, together with the discussion of relevant indication and interpretation issues, facilitate usage of the formulae.