Introduction
Neuropsychology is an applied science which investigates the relationship between brain and behavior. In particular, it is the study of cognitive effects of neurological illness or brain injury with an aim of inferring normal functioning models of the brain. Current theories of brain functioning describe the brain as a variety of complex, localized and connected systems with a certain degree of redundancy and plasticity.
Historically, neuropsychology involved the evaluation of brain damage in adults and primarily dealt with the physical nature of damage to a mature nervous system. Cognitive neuropsychology has made important contributions to cognitive theorizing and has become a part of the mainstream psychology. Other related disciplines assimilated with neuropsychology are cognition, perception and development psychology. Cognitive neuropsychology measures the progress in terms of collecting fascinating individual patient and describing their patterns of dissociation with respect to increasingly detailed box-and-arrow diagrams.
Recently, much controversy arose regarding this method on how exactly the boxes and arrows function (Robertson et al. 1993). Cognitive neuropsychology calls for studying the neuropsychological patient together with brain information processing.
The research involves behavioural studies with functions and structural neuroimaging of intact subjects and patients. This has shed light on the area of theoretical basis of cognitive neuropsychology as it made researchers to understand how each area of the brain function since each part of the brain is unique. In addition, brain injury was more understood in explicit terms as impairment in the information processing abilities of larger cognitive system (Robertson et al. 1993). The major goals of cognitive neuropsychology are; lesion localization; assessment of deficit; model building and localization of function.
Lesion localization
Lesion method involves the understanding of what an individual can no longer do and match this with the knowledge of which part of the brain is damaged. This will definitely deduce a functional relationship that was previously undiscovered. In addition, lesion localization helps a person to know whether a talent is handled by a single cognitive process or a multiple of several working together. For instance, if a theory states that walking and sitting are different skills that arise from a single cognitive process, it is not possible for a person, after brain injury, to walk and not sit or to sit and not walk. This kind of scenario suggests that different parts of the brain are specialized for different skills and the cognitive systems are separable (Shallice 1988).
Localization of function
According to Franz Gall (1900), certain people differences in intelligence and personality could be measured by noting the bumps and indentations of the skull. Therefore, the size of a given area determines the psychological capacity of the individual. In addition, the concept of localization of function also expanded to include connections between the brain regions. The explanations of loss of functioning can easily confuse symptoms with localization of function.
This involves the ability to form new episodic memories associated with damage to the hippocampus and therefore the hippocampus is where episodic memories are stored. In explaining the localization of functions in cognition, Luria notes that “in order to progress from establishment of the symptom (loss of a given function) to the localization of the corresponding mental activity, a long road has to be traveled” (1973). The correct methodology and convergence evidence helps in progression process across multiple disciplines and methods including animal models and computational simulations.
Model Building
Neuropsychologists should participate in model building with an aim of interpreting patterns of impaired and preserved cognitive (dyslexia). This should be in terms of an open model of the normal operation of those functions. Model building led to the surfacing of cognitive neuropsychological whereby the cognitive models of normal cognitive function provided a hypothetical foundation for explaining cognitive deficits (Robertson et al. 1993).
Assessment of deficit
A better understanding of the cognitive deficits is to provide a basis for improved diagnosis and treatment. In most occasions, deficits are best characterized in terms of damage to, or abnormal development of normal cognitive mechanisms. For instance, in diagnosing reading deficits for purposes of selecting appropriate treatment strategies, one need to determine which aspects of the normal reading process are disrupted and the nature of the disruptions. Typically, characterization of deficit categories and diagnostic tests not grounded in well articulated theories of normal cognition.
Deficit types such as Broca’s aphasia, non-fluent speech and impaired repetition have not been defined primarily on the basis of clinical observations suggesting that certain symptoms often co-occur. In other instances, the function such as receptive and expressive aphasia has grounded in very coarse grained analyses of normal cognitive functions. Recent studies on cognitive theory concerning diagnosis and remediation have received considerable attention.
Conclusion
Cognitive neuropsychology has made and continues to make major contributions to the area of normal cognition. However, the exciting results in cognitive science are coming from studies of deficits. Moreover, the lesion-deficit correlation method is a major source of knowledge about localization of cognitive process in the brain (Shallice 1988). Finally, cognitive neuropsychological research has advanced our understanding of cognitive deficits and holds as a valuable in development of treatments.
References
Luria, A. R. (1973). The working brain: an introduction to neuropsychology. London: Allen Lane.
Robertson, L. C., Knight, R. T., Rafal, R. et al. (1993). Cognitive neuropsychology is more than single-case studies. Journal of Experimental Psychology: Learning, Memory and Cognition, 19(3), 710-717.
Shallice T. (1988). From Neuropsychology to Mental Structure. New York: Cambridge University Press.