Chapter 13: Neuropsychological assessment in SA

AUTHOR: M. Lucas

ABSTRACT: Neuropsychology is frequently defined as the relationship between brain functioning and behavior but with the collapse of Cartesian dualism, this focus has been expanded.  With the mind today seen as the output of the brain it is therefore available to objective consideration as well.  Modern Neuropsychology thus encompasses not only the understanding and interpretation of structural/functional brain systems but includes broader understandings such as the subjective experience of self (Solms, 2006). There have been two traditions in Neuropsychology: A syndrome based approach, dependent upon a clinic-anatomical analysis, which we will refer to as the clinical approach; and a cognitive neuroscientific approach, with close links to information processing and artificial intelligence.  The former approach has its origins in the times of cortical localization beginning with Broca, Wernicke and Charcot, but more recently is based upon integrated theories of brain function; while the latter approach is based on principles of cognitive psychology and assumes that mental activities operate in terms of specialized sub-systems or modules.  It has primarily researched cognitive systems that can be separated out (dissociated) from each other.  Both approaches are complementary, use case studies, experimental designs and quantitative analysis.  Each adds valuable information to the study of the brain and mind and currently they are moving towards a more unified model.

Clinical neuropsychology is primarily concerned with anatomical brain variants and pathology and uses the syndrome-based medical model as its theoretical basis.  Typically this discipline is concerned with assessment, diagnosis, management and rehabilitation of people who have neurocognitive impairment.  Deficits are usually acquired as a result of illness and injury to the nervous system; may be temporary or permanent but measurable by subjective complaints (e.g. I am forgetful) and objective measures (e.g. psychometric tests, neuro-imaging studies). Further, clinical neuropsychology is concerned not only with the cognitive impairments but the emotional and behavioural consequences of such illness and injury.  Most importantly, these areas are assessed within the framework of person’s social and cultural background. Thus, neuropsychological assessment must take place through use of triangulation using firstly, personal narratives, collateral information, medical records and investigations such as neuro-imaging and secondly, extensive knowledge on the part of the psychologist of mind/brain issues, neuroanatomy, pathology and physiology, and thirdly, careful administration, scoring and interpretation of appropriate measures of cognitive, emotional and behavioural functioning.  Test measures may be in the form of appropriate standardised or individualised batteries. In South Africa, Neuropsychologists have typically used the standardized norms supplied by test manufacturers for their middle-class, usually white, clients and made judgements on levels of function using standardized scores and statistical analyses (e.g. standard deviations, z scores, t scores, percentile ranks etc.).  However, this group forms a small part of the South African population, making this approach an invalid one for most South Africans.  There have been attempts to standardize various tests for the local population but this has met with only limited success (e.g. Nell, 1999).  The general failure to produce working norms has been for several reasons: i) population heterogeneity in terms of language, education, socio-economic status and cultural stance ii) a dynamic and emerging population, thus tests standardized for a group have limited life as members become better educated iii) changes in level of test sophistication as communities move from pre-modern (rural) to modern (urban) lifestyles. In the face of these challenges, it has been recommended that neuropsychologists use a more hypothesis driven approach first promulgated by Luria (Solms, 2008) as a basis.  Test scores can be then interpreted from a differential score or pattern analytical approach (Zilmer, Spiers & Culbertson, 2008).

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