Semantic dementia: causes, symptoms and treatment

Like many other brain processes, human memory cannot be defined as a single function responsible for storing, encoding, preserving and retrieving everything around us. But it is divided into different types depending on how it works. When these systems fail, alterations such as semantic dementia appear, Which we will discuss throughout this article.

But first of all and to clarify the terms, what is semantic memory? Semantic memory gives us the ability to store everything in our long-term memory. Specifically, it refers to the memory of meanings, understandings, and other conceptual knowledge.

Impairment of this type of memory causes disorders such as semantic dementia. Which manifests itself by language difficulties, or by the recognition of objects or faces. However, people suffering from this type of disease can lead relatively normal lives.

    What is semantic dementia?

    Semantic dementia is a progressive neurodegenerative disorder whose action is focused on language. This disorder is unique to present with a progressive loss of semantic memory, both verbally and non-verbally.

    People who suffer from it gradually lose their language and show an impoverishment of semantic knowledge.. This causes great difficulty in naming, understanding and recognizing objects, as well as in remembering names and faces.

    the causes

    The main cause of semantic dementia is frontotemporal lobe degeneration (DLFT).; being one of the three clinical syndromes most often associated with this degeneration.

    To clarify these terms a little, the main functions of the temporal lobe are related to memory, the temporal lobe being the dominant lobe involved in the memory of words and names of objects; and the non-dominant in charge of our visual memory.

    This injury can have its origin in:

    • Cerebral atrophy
    • multiple heart attacks
    • Excess alcohol
    • Intracranial tumors
    • Normotensive hydrocephalus
    • Chronic drug poisoning
    • multiple sclerosis
    • Brain trauma
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    Semantic dementia is characterized by two main symptoms:

    1. Perception disorder: associative agnosia and prosopagnosia

    The person suffering from this disorder is unable to recognize or understand visual stimuli, especially faces, objects or names.

    This makes it difficult for the patient to interact with others and to be able to lead a normal life in society.. Which is an additional risk of social exclusion. It is not difficult to understand the frustration you may feel at not being able to recognize the people around you; including, of course, your loved ones.

    2. Linguistic deficit: everyday language but empty

    At the onset of the disorder, the patient has difficulty finding the right words to express himself; compensate by using other related terms. For example, if I meant pen, I could say ink or pen.

    As the disease progresses, the meanings of the most common words are also lost.. So I could no longer use ink to refer to the pen, but use more generic words like utensil or instrument.

    Gradually the language will become much poorer; ending up presenting an incomprehensible speech. In addition, all these difficulties will also be presented in the written language, so that the communication of the patient with his environment will be more and more complicated.

    In addition, semantic dementia can have many characteristics:

    • Anomie
    • Lack of attention
    • Episodic and verbal memory alterations
    • Difficulties matching objects
    • Changes in mood and social behavior

    Diagnosis and prognosis

    Although there is no cure for semantic dementia, early diagnosis and drug treatment are essential for the patient to function properly and, therefore, to improve the patient’s prognosis; giving it a better quality of life.

    Since dementia is difficult to diagnose, it is essential to take into account the history of the disease and supplement the patient’s information with interviews with relatives, and thus to study in depth changes in behavior and behavior. personality.

    There are three most successful forms of diagnosis. They are as follows.

    1. Neuropsychological tests

    These tests include both verbal and non-verbal tasks, and are embodied in the Concrete and Abstract Synonym Test of Warrington or the Pyramid and Palm Test of Howard and Patterson (1992).

    2. Neuroimaging techniques

    Through the use of magnetic resonance imaging, a characteristic pattern of atrophy in the temporal lobes (especially on the left) can be observed, affecting the lower and anterior areas to a greater extent.

    Using these techniques, semantic dementia can be differentiated from other subtypes of lobular degeneration such as frontotemporal dementia or progressive non-fluid aphasia.

    3. Histopathology

    Almost all patients diagnosed with this type of dementia show positive results for ubiquitin and for TDP-43.


    As stated above, there is no cure for this disorder. But if usual, the administration of drug therapy to compensate for the effects associated with this disease. Some of these drugs are:

    1. Atypical neuroleptics

    Also called atypical antipsychotics. They act on serotonin receptors, as well as on dopaminergic receptors; used in this case to treat aggressive behavior and agitation of the patient.

    2. Serotonin reuptake inhibitors

    Commonly called antidepressants. This drug increases serotonin levels by inhibiting their collection, thus relieving depressive symptoms, compulsions, etc. that the person can present.

    3. Benzodiazepines

    This drug is a psychotropic drug (acts on the central nervous system), and is characterized by its sedative, anxiolytic and hypnotic effects, among others. In semantic dementia, it is used to alleviate anxiety, anxiety, and insomnia.

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