Methods of Estimating Premorbid Functioning

Abstract

Clinical neuropsychological assessment frequently requires the comparison of obtained scores against some estimate of premorbid level of functioning, but only recently has significant attention been turned to objective methods to accomplish this objective. Clinical judgment, although useful in some circumstances, is generally insufficient. Other methods of estimating premorbid function include demographic regression formulae, such as the Barona formula, subtest scatter methods, such as that suggested by Lezak, and the use of current scores on tests of presumably spared abilities, such as the National Adult Reading Test (NART). Almost all methods predict to some general level of intellectual functioning rather than to specific neuropsychological skills. This paper reviews the suggested methods in terms of the underlying assumptions and the available empirical evidence. Suggestions for future research include the development of skill specific predictors as well as investigations regarding the relation between predictor accuracy and characteristics of the subject, such as high versus low premorbid functioning in the subject. Additionally, there is a great need for methods to predict premorbid functioning in children.

Genetic and Environmental Sources of Covariance Between Reading Tests Used in Neuropsychological Assessment and IQ Subtests

“…Second, that following brain insult, word reading ability is less diminished than other cognitive skills. Third, that as all words are irregular, the application of grapheme-phoneme conversion (gpc) rules yields incorrect pronunciations, and thus correctly read words are part of the reader's internal lexicon (Franzen, Burgess, and Smith-Seemiller, 1997). The contextualization of words is assumed to maximize the correlation between IQ and word reading by providing the best opportunity for word recognition (Beardsall and Huppert, 1994).…”

“…It was the first reading test used to assess premorbid IQ. However, it was realized that as a test designed specifically for children, it yielded a low ceiling when assessing adults (Franzen et al, 1997). The test is composed of both regular and irregular words and is not contextualized.…”

“…The phenotypic correlation of word reading tests with IQ in neurologically intact populations is well established (see Franzen et al, 1997). An estimate of the proportion of variance in WAIS-R Verbal IQ accounted for by the NART was 72% in a large cross-validation sample of participants aged from 16 to 88 years .…”

Review of sports-related concussion: Potential for application in military settings

“…If an athlete was not tested before injury, the neuropsychologist must use demographic information, prior school grades, or current reading level to estimate the athlete's premorbid baseline [47][48]. Then, the athlete's postinjury neuropsychological test performance can be compared with scores from individuals whose abilities are at this expected level (norm-based comparisons).…”

Desempenho de uma amostra de indivíduos com comprometimento cognitivo leve, doença de Alzheimer e idosos saudáveis em tarefa de decisão lexical

“…Para este propósito são utilizados os testes de QI pré-mórbido, portanto, testes que mostram o funcionamento cognitivo geral prévio ou anterior à existência de uma patologia (Franzer et al, 1997).…”