Cognitive Neuropsychology has two basic aims:

1. to explain patterns of intact and impaired cognitive performance in patients with acquired or developmental disorders of cognitive functions

2. to make inferences about the cognitive architecture of intact cognitive processes from the patterns of intact and impaired capabilities seen in patients

The assumption that a cognitive system is composed of multiple subprocesses, which process information independently of each other is known as the modularity assumption. These modules are also distinct in the brain and brain damage may therefore selectively impair modules.

Assertions as to which processes are distinct within a cognitive system are often based on dissociations. If a patient performs poorly on task 1 and has no difficulties in performing task 2, there is a dissociation between these two tasks. If there is another patient who shows a dissociation in the opposite direction (task 1 normal, task 2 impaired), we have a double dissociation. Double dissociations are the basis to claim that there are different subprocesses underlying two tasks.

Cognitive processes (e.g. face recognition, reading, spelling) are complex and involve multiple processing steps, each of which can be selectively impaired. Given that there are many subprocesses that could be disrupted, the possible combination of intact and disrupted processes is enormous. It is thus unlikely to find two patients with the exact same pattern of performance, which is why patients are studied in single case studies rather than groups.

Under the universality assumption there is no qualitative variation across neurologically intact people in the architecture of a cognitive process. This is why studies of single patients can be generalised across people.

Cognitive neuropsychological models are used in clinical settings to examine patients' disorders by testing the functionality of each subprocess involved. The goal of the treatment may be to enhance functioning of the processes found to be impaired. This approach to assessment ensures an accurate target for the treatment.

Recommended References

Caramazza, A., & Coltheart, M. (2006). Cognitive Neuropsychology twenty years on. Cognitive Neuropsychology, 23(1), 3-12.

Ellis, A. W., & Young, A. W. (1986). Human Cognitive Neuropsychology. Hove, UK: Lawrence Erlbaum Publisher.

Rapp, B. (2001). The handbook of neuropsychology. Ann Arbor: Taylor & Francis.

Riddoch, M. J., & Humphreys, G. W. (1994). Cognitive neuropsychology and cognitive rehabilitation. Hove: LEA Publishers.

Temple, C. (1997). Developmental Cognitive Neuropsychology. Hove, UK: Psychology Press.

Fodor, J. A. (1983). The modularity of mind. Cambridge, MA: Bradford Books.

Journals

Cognitive Neuropsychology

Neuropsychological Rehabilitation

Summary Written By

Saskia Kohnen

Macquarie Centre for Cognitive Science (MACCS)