Forensic neuropsychology: what is it, functions and what does it investigate?

These are the functions and areas of application of forensic neuropsychology.

Psychology is an ever-expanding science, and one of its many branches is forensic neuropsychology. one of its many branches is forensic neuropsychology..

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

• Related article, "What is forensic expertise in psychology?"

Definition of forensic neuropsychology

Forensic psychology is the part of psychology dedicated to any matter that passes through the judicial forum.It can be in many different areas (child custody, incapacity, prison permits, credibility of testimony, etc.). Within this field, forensic neuropsychology tries to explain human behavior from its brain structures.

The aim of the forensic neuropsychologist would always be to to investigate if there are possible neurocognitive alterations, which are the basis for a certain behavior related in one way or another to a judicial processThe forensic neuropsychologist's objective would always be to investigate whether there are possible neurocognitive alterations, which are the basis of a certain behavior related in one way or another to a judicial process, in order to be able to translate it into a psychological expert report that will serve the judge as a reference 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 know if there is a Biological basis (injury, alteration or neurological disease) that explains a certain behavior with a high degree of probability.

The application of neuropsychology in the forensic field is something relatively new, as it has only been carried out since the 1980s. However, in the eagerness to use increasingly scientific and standardized methodologies, this discipline is expected to have a great future and rapid growth in the short term, since it allows us to establish a measurable and verifiable basis for certain human behaviors that are susceptible to an important judicial decision. a measurable and contrastable basis for certain human behaviors that are susceptible to an important judicial decision, which in many cases involve important consequences that in many occasions imply important consequences, such as a possible prison sentence.

Fields of action

Forensic neuropsychology can provide a valuable service in different judicial areasAmong these, we can highlight three, which account for the vast majority of interventions.

1. Labor law

In the first place we would find cases related to labor law, since a forensic report is frequently required to determine the sequelae that a worker may have suffered as a result of an accident at work or an occupational disease. The neuropsychologist will investigate the existence and extent of these sequelae, so that the legal services have a basis on which to make a decision about possible disability or compensation.The neuropsychologist will investigate the existence and extent of these sequelae, so that the legal services have a basis on which to establish a decision about a possible disability or compensation.

2. Civil law

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

3. Criminal law

Of course, the last field in which forensic neuropsychology would act would be that of criminal law, since their work is essential when assessing the possible criminal liability of a person or even his or her procedural capacity..

It is common to find out if the person's cognitive and volitional capacities are altered due to some neuropsychological cause that limits his or her responsibility.

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 behavior. These alterations can come from very different causes.. We are going to see some of the most frequent ones.

• Brain injury of external cause, generally due to a cranioencephalic trauma.
• Brain injury of internal cause. They usually come from a tumor or a stroke, although there may be other causes, such as hydrocephalus.
• Neurodegenerative pathologies. The most frequent are dementias (including Alzheimer's) and other diseases, such as sclerosis.
• Consumption of toxic substances, such as alcohol and other drugs, whose consumption in large doses and/or maintained over time can be harmful and irreversible.
• Epilepsy disorder, since the electrical imbalance between neurons can cause different alterations at a psychological level.
• Developmental disorders, which can be of a very different nature, involving some kind of cognitive and/or behavioral problem.
• Cerebral palsy, regardless of its origin (oxygen deprivation, cerebral infarction, etc.).
• Severe mental disorders, such as schizophrenia.
• Normal aging process, since it also involves a deterioration of certain structures of the nervous system.

Cognitive functions explored

Within the field of forensic neuropsychology, there are many abilities of the subject that can be evaluated.. Let us look at the cognitive functions most frequently reviewed through this discipline to estimate whether they are being affected by a neurological condition.

1. Attention

Attention is the ability that allows us to discriminate between all the stimuli in the environment and to collect only the information that interests us at any given moment, thus focusing on what we are interested in.Thus, focusing on what is relevant to us and discarding a huge amount of data that would otherwise saturate our brain.

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

2. Praxias

Another ability studied are the praxias. These are the movements that we perform with a purpose. Its alterations would be apraxias, and we can establish three types:

• Ideational: difficulties in devising the sequence of movements to achieve the goal.
• Ideomotor: in this case the subject can devise the sequence, but fails to transmit it to the motor system, so it does not get to perform it or does so with difficulty.
• Motor: affects sequences of complex movements. The individual presents an inability to perform them.

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

3. Gnosias

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

4. Memory

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

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 aphasia.These can be of a very different nature, depending on the specific language capacity that is being impaired, and would be caused by damage to a very specific part of the brain, since, as in the previous examples, each capacity would depend on a specific structure.

6. Executive functions

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

7. Metacognition

Lastly, we would come across metacognition, another of the abilities inherent to human beings. It would refer to the cognition of one's own cognition, that is, to our ability to know our own capacities and also to be able to regulate them. If this perception is altered, we may have problems in realizing that we have difficulties or are unable to use a particular ability..

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 make reference to this phenomenon, and one of the greatest difficulties faced by the forensic neuropsychologist is the issue of whether the subject really has an ailment or whether he is faking it.. In many cases it is not easy to answer this question.

A recurring issue is memory problems alleged during legal proceedings. For this reason, diagnostic tests are continually devised to measure the abilities studied at the same time as the simulation, in order to obtain an indicator that verifies whether we can trust the subject's answers or whether he is probably trying to deceive us.

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

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

Bibliographical references:

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