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

Psychology is a constantly expanding science, and one of its many branches is forensic neuropsychology.

In this article, we will explore this sub-discipline, which links the functioning of the brain to events that can be dealt with in the legal field.

    Definition of forensic neuropsychology

    Forensic psychology is the part of psychology devoted to any question that goes through the judicial forum, And can be in many different areas (custody of minors, disability, prison license, credibility of testimony, etc.). In this area, forensic neuropsychology seeks to explain human behavior from its brain structures.

    The goal of the forensic neuropsychologist would always be investigate whether there are possible neurocognitive disorders, which underlie a certain behavior related in some way to a trial, Be able to translate it into a psychological expert report which serves as a reference for the judge when making a decision and to render a verdict in the case which motivated the consultation.

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

    The application of neuropsychology in the forensic field is relatively new, as it has only been carried out since the 1980s. However, in the desire to use increasingly scientific and standardized methodologies, “augurs d ‘a great journey and a rapid short-term growth of this discipline, as it allows us to establish a measurable and contrastable basis for certain human behaviors likely to be the subject of an important judicial decision which often have significant consequences, such as a possible prison sentence.

    Fields of action

    Forensic neuropsychology can provide valuable service in different areas of justiceOf which we can highlight three, which would cover the vast majority of interventions.

    1. Labor law

    In the first place, we would find cases related to labor law, because a forensic report is often necessary to determine the consequences that a worker may have suffered due to an accident at work or an occupational disease. The neuropsychologist will examine the existence and extent of these sequelae, So that legal services have a basis on which to make a decision on possible disability or compensation.

    2. Civil law

    Another area would be civil law, which is very broad and therefore very diverse areas of expertise can be found. The most common have to do with the capacities of persons to exercise the guardianship of a minor, as well as to study a possible incapacity of a subject. But other questions are sometimes consulted in which the abilities of individuals to perform certain activities are assessed, such as conducting or receiving certain treatments.

    3. Criminal law

    Of course, the last field in which forensic neuropsychology would act would be that of criminal law, since their task is fundamental to assess the possible criminal liability of a person or even his procedural capacity.

    Expertises are common in which we study whether the person has impaired cognitive and volitional capacities due to a neuropsychological cause that limits his responsibility.

      neurocognitive disorders

      We have already seen that the goal of forensic neuropsychology is to study the existence of possible neurocognitive alterations that may be at the origin of certain behaviors. These alterations can come from very different causes. Let’s take a look at some of the most common.

      • Brain damage of external origin, usually due to a traumatic brain injury.
      • Internal brain injury. They usually come from a tumor or stroke, although other causes, such as hydrocephalus, can occur.
      • Neurodegenerative pathologies. The most common are dementias (including Alzheimer’s disease) and other illnesses, such as sclerosis.
      • The consumption of toxic substances, such as alcohol and other drugs, consumption in high doses and / or sustained over time can be harmful and irreversible.
      • Epilepsy disorder, because the electrical imbalance between neurons can cause different psychological alterations.
      • Developmental disorders, which can be very different in nature, involving some type of cognitive and / or behavioral problem.
      • Cerebral palsy, whatever its origin (oxygen deprivation, cerebral infarction, etc.).

      • Severe mental disorders, such as schizophrenia.
      • Normal aging process, as it also involves deterioration of certain structures of the nervous system.

      Cognitive functions you explore

      In the field of forensic neuropsychology, many abilities of the subject can be assessed. Let’s take a look at the most frequently examined cognitive functions in this discipline to assess whether they are affected by a neurological condition.

      1. Attention

      Attention is the ability that it allows us to discriminate all the stimuli of the environment and to collect only the information that interests us at a given moment, By focusing in this way on what is relevant to us and rejecting a huge amount of data that would otherwise saturate our brains.

      Therefore, alterations in attention would make it difficult or unable to focus their senses on a particular stimulus or series of stimuli.

      2. Praxis

      Another capacity studied is praxis. These are the movements that we perform for a purpose. Their alterations would be apraxias, and we can establish three types:

      • Ideation: difficulty in designing the sequence of movements to achieve the goal.
      • Ideomotor: in this case, the subject can conceive the sequence, but he is not able to transmit it to the motor system, so that he cannot achieve it or he does it with difficulty.
      • Motor: affects complex movement sequences. The individual has an inability to perform them.

      Each of these apraxias is caused by an injury in a very specific area of ​​the brain.

      3. Gnosias

      The ability to perceive and recognize certain stimuli through the senses is known as gnosis. There will therefore be a gnosis relating to each of the information channels (visual, auditory, etc.). As in praxis, each of them is generated at a certain place in the brain, so depending on the site of the lesion, this will cause one agnosia or another, and therefore difficulties in perceiving the information in a concrete way.

      4. Memory

      Another of the fundamental abilities of human beings is, of course, memory, which in turn is made up of different types (sensory, short and long term memory). They involve the retention of data in our brain for a certain period of time, And 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 major faculty within us is language, a method by which we are able to communicate fluently through sounds and symbols. If this ability is impaired, we will speak of aphasia, Which can be very different in nature, depending on the specific language ability that is hampered, and would be caused by damage to a very specific place in the brain, as in the previous examples, each ability would depend on a given structure.

        6. Executive functions

        Executive functions they are responsible for our ability to perform a series of complex behaviors. They would represent the coordination of many other abilities that, working together, allow us to perform behaviors that do not occur in any other species, so this would be one of the abilities that makes us human. They would depend, basically, on the frontal lobe, which is extremely developed in our species, and also on the system. limbic. Injury to these structures can cause drastic changes in the personality of the subject.

        7. Metacognition

        Finally, we would meet metacognition, another of the abilities inherent in human beings. It would refer to knowing our own cognition, that is, our ability to know our own abilities and also to be able to regulate them. If this perception is altered, we may find it difficult to realize that we are having difficulty or are unable to use a particular skill..

        the simulation

        There is one 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 that the forensic neuropsychologist faces is the question of if the subject really has an illness or on the contrary is pretending. This question is often not easy to answer.

        A recurring problem is the memory problems alleged during a trial. For this, diagnostic tests are continuously designed which measure the capacities studied at the same time as the simulation, to obtain an indicator which verifies whether one can rely on the subject’s answers or on the contrary is likely to try to deceive . Our.

        To give us an idea of ​​the magnitude of this problem, it is estimated that in Spain 40% of victims of head trauma lie, exaggerate or somehow distort their testimony about the consequences that they undergo. .

        Therefore, simulation is a concept that is taken into account and should be identified throughout the process of evaluating expert reports in forensic neuropsychology.

        Bibliographical references:

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

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