BRAIN ATROPHY: CHARACTERISTICS, SYMPTOMS AND CAUSES - GEOGRAFÍA - 2025

The brain atrophy is a pathological process in which a progressive death and elimination of neurons in the brain, occurs and neural connections and nerve structures. When we speak of brain atrophy, we refer to a degenerative process characterized by the loss of functionality of the brain regions.

This pathology can affect different regions of the brain, depending to a large extent on the factors that cause the atrophy. As each region of the brain is responsible for processing different cognitive functions, the symptoms of brain atrophy can vary significantly in each case.

Cerebral atrophy in brain affected by Alzheimer's

Despite the fact that this alteration is usually pathological, it should be noted that the normal aging process can also generate brain atrophy, in these cases being considered a benign condition linked to age.

Characteristics of brain atrophy

CT scan of a brain with atrophy. Source: «Cognitive function in very old men does not correlate to biomarkers of Alzheimer's disease». BMC Geriatrics

Atrophy refers to a decrease in the size of an organ due to loss of protoplasmic mass; involves a decrease in the size of the brain.

In this sense, the brain atrophy process implies the presence of a series of basic characteristics. These are:

It is an acquired alteration

Unlike hypoplasia (a condition in which the functional decline of the organ is due to an arrest in development without the organ reaching normal size), atrophy is about a reduction in acquired size.

This means that subjects with cerebral atrophy have presented an optimal development and functionality of their brain structures.

However, due to different factors, at a certain moment the brain begins to reduce its activity. Neurons die and the connection between them is lost, thus causing a gradual degeneration of brain structures.

It can occur at different levels of organization.

Not all cases of brain atrophy have the same damage or degenerative processes in the brain. For this reason, the symptoms can vary remarkably in each subject.

Brain atrophy can originate in isolated neurons, in larger tissues or even in the organ in a globalized way.

One of the most common cases of cerebral atrophy is that characterized by closeness between the cortical and epindymal surfaces, widening of the cerebral sulci, and thinning of the convolutions of the frontal lobes.

The atrophy affects the parenchyma of the organs.

In atrophy, the loss of protoplasmic mass mainly affects the parenchyma of the organs, which is why in atrophic organs the stroma is usually prominent and appears with an increased shape.

It is a progressive condition.

The loss of protoplasmic mass in cerebral atrophy develops slowly and progressively, through a process of imbalance between anabolism and catabolism.

Not all atrophies are pathological.

Finally, it should be noted that although the term brain atrophy is often used to refer to pathological conditions, not all are.

In fact, aging implies a progressive reduction of brain connections and structures. In order to distinguish pathological atrophy from benign age-related atrophy, it is important to carry out an adequate neuropsychological examination that specifies the characteristics of cognitive impairment.

Symptomatology

Brain magnetic resonance imaging showing atrophy of the cortex and the white matter of the frontal lobes. Source: Mikhail Kalinin

According to the National Institute of Strokes and Neurological Disorders, brain atrophy is one of the most common neurological conditions in the population.

It originates due to the death of some neurons in the brain, as well as the loss of connection between them. It is important to bear in mind that this alteration can affect the entire brain or only some specific sector or area.

The symptoms of cerebral atrophy can vary remarkably in each case, depending mainly on the brain areas involved in the condition. Likewise, the causes that originate the appearance of brain atrophy also play an important role in determining its symptoms.

For example, brain atrophies caused by neurodegenerative pathologies such as Alzheimer's disease or Huntington's disease generate progressive deterioration.

In these cases, brain degeneration usually begins by involving specific regions and producing specific symptoms. However, with the passage of time the atrophy tends to spread and show a much broader symptomatology.

Thus, it is highly complex to determine the symptoms of cerebral atrophy, since they differ in each case. However, the National Institute of Strokes and Neurological Disorders specifies that the most typical manifestations of cerebral atrophy are:

Memory problems

Memory loss is one of the most typical symptoms of pathologies such as Alzheimer's, Lewy body dementia, frontotemporal dementia, Huntington's disease or any other condition that can cause a dementia syndrome.

Normally, cerebral atrophies that imply a deterioration in the person's memory function are characterized by affecting the hippocampal regions of the brain, as well as the structures adjacent to the temporal lobe.

The language

Closely linked to memory, brain atrophy usually causes a progressive degeneration of the individual's language ability.

The alteration that learning competences experience, as well as the processes of attention, concentration and perception, usually results in a gradual deterioration of the person's language.

Psychological disturbances

When atrophy affects subcortical regions of the brain, such as the thalamus, amygdala, or hypothalamus, psychopathological changes can be experienced.

Depression, apathy, motivational deficits, and anxiety disorders are the most prominent symptoms in this type of brain atrophy.

Behavioral disturbances

Although they are usually rare, cerebral atrophy that affects the frontal lobe of the brain can cause behavioral changes and changes in the personality traits of the person.

Movement disturbances

Another of the most typical symptoms of cerebral atrophy generated in the subcortical regions of the brain are alterations in movement.

Pathologies such as multiple sclerosis or Parkinson's disease usually motivate the appearance of these types of manifestations, since they affect the brain structures responsible for generating such functions.

Physical problems

When cerebral atrophy affects the medulla oblongata (a structure in the brain stem), a person can experience a wide variety of physical changes.

Respiratory problems, disorders in the digestive system and alterations in the cardiovascular system are the most prevalent. Likewise, brain atrophies that affect the cerebellum usually cause ataxia (lack of coordination) and decreased muscle tone.

Finally, when the midbrain (midbrain) is compromised, violations of metabolic processes and thermoregulation can be experienced, and when atrophy affects the forebrain, the reflex reaction is drastically reduced.

Causes

Head CT with normal pressure hydrocephalus (left image) and head MRI (right image), in the coronal plane at the level of the posterior commissure. Source: "Neuroimaging in normal pressure hydrocephalus". Dementia & Neuropsychologia, Benito Pereira Damasceno.

At present, a large number of pathologies that can generate brain atrophy have been documented. The most prevalent in society are neurodegenerative diseases, since these are mainly characterized by degenerating different regions of the brain and therefore causing brain atrophy.

However, many other situations can cause this condition, even non-pathological conditions such as aging are strongly related to brain atrophy. The pathologies that have been most associated with this alteration are:

Multiple sclerosis

Multiple sclerosis is a disease characterized by the appearance of demyelinating, neurodegenerative and chronic lesions in the central nervous system.

This pathology usually causes a dysfunction of the blood-brain barrier (system of capillaries that protects the entry of substances into the brain through the blood).

In this way, macrophages and lymphocytes can cross the blood-brain barrier of patients with multiple sclerosis and access the brain, causing brain damage and causing symptoms such as tingling, weakness, lack of coordination, muscle stiffness, speech disorders or visual disturbances.

Alzheimer disease

Alzheimer's is considered the neurodegenerative disease par excellence. It usually affects the elderly and is characterized by a gradual and progressive death of neurons.

The most typical symptoms of Alzheimer's are memory loss, since brain atrophy occurs initially in the hippocampus (a structure that is responsible for developing memory processes).

However, with the progression of the disease the atrophy extends to the other brain regions, producing many more cognitive deficits.

Encephalitis

Encephalitis is a group of pathologies that occur due to an inflammation of the brain. They usually occur through infections by bacteria, parasites, fungi or viruses.

The condition usually causes the appearance of focal or diffuse lesions of the gray matter or the white matter of the central nervous system. The most typical symptoms caused by the cerebral atrophy of this disease are: acute febrile syndrome, headache, altered consciousness, seizures, language alterations and sensory disorders.

Huntington's disease

Huntington's disease is a serious and rare disorder characterized by being hereditary and degenerative. It is due to the specific mutation of the huntingtin protein and usually causes psychiatric and motor disorders.

It presents a very slow progression (between 15 and 20 years). In the initial phases, the pathology affects the antero-medial areas of the caudate nucleus and the dorsal areas of the putamen nucleus, causing alterations in the joint and spontaneous language.

Later, in intermediate stages, the person usually experiences a notable reduction in their linguistic ability. In advanced disease, Huntington's chorea usually causes Wernicke's aphasia, a marked reduction in verbal fluency, dysgraphic writing, and alterations in visuespatial processing.

Pick's disease

Pick's disease is a neurodegenerative pathology characterized by causing atrophy in the temporal and frontal lobes of the brain. This condition causes the progressive destruction of nerve cells in the brain, causing the proliferation of substances called Pick's bodies.

By affecting the temporal and frontal lobes of the brain, this pathology often causes personality changes, impaired social skills, behavioral disinhibition, emotional dullness, irritation, apathy, depressive symptoms, and memory loss.

HIV virus

The human immunodeficiency virus (HIV) is a lentivirus that causes HIV infection and eventually leads to the development of acquired immunodeficiency syndrome (AIDS).

This disease is characterized by affecting the immune system, a fact that allows opportunistic infections to develop in different regions of the body, including the brain.

HIV can cause brain atrophy, leading to a demented syndrome that begins subtly but progresses steadily, causing manifestations such as slow thinking and expression, apathy, difficulty concentrating and impaired coordination.

Vitamin B12 deficiency

Korsakkof syndrome is a condition that arises from a deficiency of vitamin B12. It is a common pathology among people with alcoholism and subjects with Wernicke's disease.

Korsakoff syndrome causes cerebral atrophy in the cranial nerves, in the periventricultar gray matter, in the hypothalamus and in the thalamus due to the deficiency of vitamin B12. This cerebral atrophy usually causes alterations such as anterograde amnesia, retrograde amnesia and learning difficulties

Aging

Finally, aging constitutes a normal and non-pathological situation that is related to brain atrophy. Over the years, as with most organs in the body, the brain diminishes its functionality.

The connections between neurons are weakened and brain structures decrease their activity, causing slight cognitive failures such as: impaired memory, decreased learning ability, decreased attention, etc.

Treatment

The treatment of cerebral atrophy must be based on the intervention of the pathology that causes the deterioration of the brain regions.

However, most of the conditions that cause this pathology are characterized by being chronic and incurable. Exercising the brain through cognitive stimulation programs is recommended to enhance the functioning of preserved abilities.

References

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