Historically, the first neuropsychology scholars maintained that cognitive functions dissociate (that is, they could be selectively altered due to brain damage) and that each of them is made up of different elements that, in turn, also dissociate.
The previous hypothesis, called “the modularity of the mind”supports the idea that the neurological information processing system is formed by an interconnection of several subsystems, each of which includes a number of processing units or modules responsible for supporting the main system.
On the other hand, the fact of that any brain damage can selectively alter One of these components also seems to direct towards another modular organization of brain structure and physiological processes.
Objective of neuroscience in neuropsychological intervention
Thus, the primary objective of neuroscience in this matter is to know to what extent the biological functions of the brain are “broken” in such a way that this division corresponds directly to the decomposition of the processing units that (according to the main postulates of neuropsychology) underlie the performance of a given cognitive function.
In an attempt to achieve the above goal, neuropsychology has tried to advance by leaps and bounds in the knowledge of the structure and functioning of the information processing system through the study and Detailed functional analysis of the behavior of patients with various types of brain damage.
Neurological alterations and disorders
It must be taken into account that, as the main consequence derived from a brain injury, a pattern of altered behaviors and preserved behaviors can be clearly observed in the patient. Curiously, altered behaviors, in addition to being dissociated from the rest of the individual behaviors, can be (in many cases) associated with each other.
If an analysis of the behavioral dissociations derived from brain damage is carried out, on the one hand, and an analysis of the associations, on the other (the latter aimed at determining whether all the associated symptoms can be explained by damage to a single component) , the components of each modular subsystem could be identifiedwithin the global and/or main system, thus facilitating the study of the operation of each of them.
Behavioral dissociations
In the 1980s some authors identified three different types of behavioral dissociations: classic dissociation, strong dissociation and tendency to dissociate.
When classic dissociation occurs, the individual shows no impairment in performing various tasks, but performs others quite poorly (compared to his or her executive abilities before the brain injury).
On the other hand, we speak of strong dissociation when the two compared tasks (which the patient performs for evaluation) appear impaired, but the deterioration observed in one is much greater than that observed in the otherand in addition the results (measurable and observable) of the two tasks can be quantified and the difference between them is expressed. Otherwise, as presented above, we speak of “tendency to dissociation” (it is not possible to observe a significant difference between the executive level of both tasks in addition to not being able to quantify the results obtained in each of them and explain their differences).
Let us know that the concept of “strong dissociation” is closely related to two independent factors: the (quantifiable) difference between the levels of execution in each of the two tasks, and the magnitude of the executive deterioration presented. The greater the first and the lesser the second, the stronger the dissociation presented.
Traditionally, within our field of study, a “syndrome” has been called a set of symptoms (in this case behavioral) that tend to occur together in an individual under various conditions.
Classify patients into “syndromes” has a series of advantages for the clinical psychologist. One of them is that, since a syndrome corresponds to a certain location of the lesion produced, this can be determined by observing the patient’s performance in the tasks for subsequent assignment to a specific syndrome.
Another advantage for the therapist is that what we call “syndrome” has a clinical entity, so, once it is described, it is considered that the behavior of every patient who has been assigned to it is being described.
It is necessary to emphasize that, in fact, rarely does a patient under treatment fit perfectly into the description of a specific syndrome; Furthermore, patients assigned to the same syndrome do not usually resemble each other.
The reason for the above is that, in the concept of “syndrome” that we know, there is no restriction on the causes why the symptoms that comprise it tend to occur together, and these reasons can be of at least three types:
1. Modularity
There is a single altered biological component and/or module and all the symptoms presented in the patient’s behavior derive directly from this alteration.
2. Proximity
Two or more significantly altered components are present (each causing a series of symptoms), but the anatomical structures that keep them functioning and/or serve as support They are very close to each otherso the lesions tend to produce symptoms in all of them together and not in just one in particular.
The direct modification of a neurological element or module as a result of a brain injury, in addition to directly causing a series of symptoms (known as “primary symptoms”), alters the executive function of another element and/or neurological structure whose anatomical support is originally intact, which causes secondary symptoms even without having been the main target of the injury produced.
