Forensic neuropsychology: what it is, functions and what it investigates

Psychology is a science in continuous expansion, and one of its many branches is forensic neuropsychology.

In this article we will explore this subdiscipline, which connects the functioning of the brain with the events that can be dealt with in the legal field.

• Related article: "What is a forensic expertise in Psychology?"

Forensic Neuropsychology Definition

Forensic psychology is the part of psychology dedicated to any matter that passes through the judicial forum, being able to be of very diverse fields (custody of minors, incapacity, prison permits, credibility of the testimony, etc.). Within this scope, forensic neuropsychology tries to explain human behavior from their brain structures.

The goal of the forensic neuropsychologist would always be Investigate whether there are possible neurocognitive alterations that support a certain behavior related in one way or another to a judicial process, to be able to translate it into a psychological expert report that serves as a reference for the judge when making a decision and issuing a verdict in the matter that has motivated the consultation.

In other words, the judge would need the collaboration of the neuropsychologist to find out if there is a basis biological (neurological lesion, alteration or disease) that explains a certain behavior with a high degree of probability.

The application of neuropsychology in the forensic field is something relatively new, since it has only been carried out since the 80s. However, in an effort to use increasingly scientific and standardized methodologies, augurs a great path and rapid growth in the short term of this discipline, since it allows us to establish a measurable and verifiable basis for certain human behaviors that are susceptible to an important judicial decision which on many occasions imply important consequences, such as a possible prison sentence.

Areas of action

forensic neuropsychology can provide a valuable service in different judicial fields, among which we can highlight three, which accounted for the vast majority of the interventions.

1. labor law

In the first place we would find the cases related to labor law, since a report is frequently required coroner that determines the consequences that a worker may have suffered as a result of an accident at work or illness professional. The neuropsychologist will investigate the existence and scope of said sequelae, so that legal services have a basis on which to make a decision about possible disability or compensation.

2. Civil law

Another area would be civil law, which is very broad and therefore very diverse objects of expertise can be found. The most common have to do with the capacities of people to exercise guardianship of a minor, and also to study a possible incapacity of a subject. But sometimes other matters are consulted in which the abilities of individuals to carry out certain activities are evaluated, such as driving or receiving a certain treatment.

3. Criminal law

Of course, the last field in which forensic neuropsychology would operate would be that of criminal law, since His work is essential when evaluating the possible criminal responsibility of a person or even their procedural capacity.

Expert opinions are common in which it is studied whether the person has altered their cognitive and volitional abilities due to some neuropsychological cause that limits their responsibility.

• You may be interested in: "In what cases is it necessary to go to a forensic psychologist?"

Neurocognitive alterations

We have already seen that the objective of forensic neuropsychology is to investigate the existence of possible neurocognitive alterations that may be causing certain behaviour. These alterations can come from very different causes.. Let's see some of the most common.

• Brain injury from an external cause, generally due to a head injury.
• Internal brain injury. They usually come from a tumor or a stroke, although other causes may occur, such as hydrocephalus.
• Neurodegenerative pathologies. The most common are dementia (including Alzheimer's) and other diseases, such as sclerosis.
• Consumption of toxic substances, such as alcohol and other types of drugs, whose consumption in large doses and/or sustained over time can be harmful and irreversible.
• disorder of epilepsy, since the imbalance at the electrical level between the neurons can cause different alterations at the psychological level.
• Developmental disorders, which can be of a very different nature, involving some type of cognitive and/or behavioral problem.
• Cerebral palsy, regardless of its origin (oxygen deprivation, stroke, etc.).
• Serious mental disorders, such as schizophrenia.
• Normal aging process, since it also implies a deterioration of certain structures of the nervous system.

Cognitive functions explored

Within the field of forensic neuropsychology there are many capacities of the subject that can be evaluated.. Let's see the most frequently reviewed cognitive functions through this discipline to estimate if they are being affected by any neurological condition.

1. Attention

Attention is the ability allows us to discriminate between all the stimuli in the environment and collect only the information that interests us at all times, thus focusing on what is relevant to us and discarding a huge amount of data that would otherwise clutter our brains.

Therefore, alterations in attention would cause the subject to have difficulties or be unable to focus their senses on a specific stimulus or series of stimuli.

2. Praxias

Another capacity studied is praxias. They are the movements that we carry out with a purpose.. Its alterations would be apraxias, and we can establish three types:

• Ideatory: difficulties in devising the sequence of movements to achieve the objective.
• Ideomotor: in this case the subject can devise the sequence, but is unable to transmit it to the motor system, so it is not carried out or is done with difficulty.
• Motor: affects complex movement sequences. The individual presents an inability to perform them.

Each of these apraxias is caused by a lesion in a very specific brain area.

3. gnosis

The ability to perceive and recognize certain stimuli through the senses is known as gnosias.. Therefore, there will be a relative gnosia for each of the information access routes (visual, auditory, etc.). As in the praxies, each one of them is generated in a certain place in the brain, so depending on the place of the injury, it will be causing one agnosia or another, and therefore difficulties for the perception of information through one sense concrete.

4. Memory

Another of the fundamental capacities of the human being is, of course, memory, which in turn is made up of different types (sensory, short-term and long-term memory). They suppose the retention of data in our brain during a certain period of time, and therefore its alteration can cause us to have difficulties, either to recover memories, or to generate them, or both at the same time.

• You may be interested in: "Memory psychopathologies: characteristics, types and symptoms"

5. Language

Another primordial faculty in us is language, the method by which we are able to communicate fluently through sounds and symbols. If this capacity is altered we would be talking about aphasias, which can be of a very different nature, depending on the specific language ability that is being impeded, and would be caused by a damage to a very specific place in the brain, because as in the previous examples, each capacity would depend on a structure determined.

6. Executive functions

executive functions They are responsible for us being able to carry out a series of complex behaviors. They would represent the coordination of many other capacities that, working together, allow us to carry out carry out behaviors that do not occur in any other species, so it would be one of the capacities that makes us humans. They would depend, fundamentally, on the frontal lobe, which is tremendously developed in our species, and also of the limbic system. Lesions in these structures can cause drastic changes in the subject's personality.

7. metacognition

Finally we would find metacognition, another of the inherent abilities of the human being. It would refer to the cognition of one's own cognition, that is, to our ability to know our own abilities and also to be able to regulate them. If this perception is altered, we may have trouble realizing that we have difficulties or are unable to use a particular skill..

the simulation

There is a problem that is, by far, the most studied in the field of forensic neuropsychology, and it is none other than simulation. No less than 85% of the studies published in this field refer to this phenomenon, and it is that one of the greatest difficulties facing the forensic neuropsychologist is the question of if the subject really has an ailment or on the contrary is faking. On many occasions it is not easy to answer this question.

A recurring issue is the memory problems alleged during a judicial process. For this purpose, diagnostic tests are continuously devised that measure the capacities studied at the same time as the simulation, in order to obtain an indicator that verifies if we can trust the answers of the subject or, on the contrary, it is probable that he is trying to deceive us

To get an idea of ​​the scope of this problem, it is estimated that in Spain, 40% of trauma victims cranioencephalic, lie, exaggerate or in some way distort their testimony about the consequences they are experiencing as a result of the event.

Therefore, simulation is a concept that is taken into account and is tried to be identified throughout the evaluation process for expert reports in forensic neuropsychology.

Bibliographic references:

• Jarne, A. and Aliaga, A. (2011). Manual of forensic neuropsychology. Madrid. Herder.
• Larrabee, G. J. (2011). Forensic Neuropsychology: a scientific approach. New York. Oxford University Press.
• Tirapu, J., Ríos, M., Maestú, F. (2008). Neuropsychology Manual. Barcelona. beam.