Brain lesions and behavioral disturbances

After the injury, regardless of the cause of the acquired brain damage, the patient may experience different alterations, both in his behavior and emotions, which may turn him into a different person.

Whenever we talk about behavioral alterations we must always mention the frontal lobe, the area of the brain located in the most anterior part of the skull, which is responsible for the main forms of mental activity such as:

  • Intelligence.
  • Creativity.
  • Abstract reasoning.
  • Conceptual abilities.

It is also what makes us human, intelligent and sensitive, as well as being able to learn from experiences and regulate our behavior according to the situation.

To get an idea of its importance in humans, the frontal lobe occupies 33% of the brain, while in chimpanzees it represents 15% and in cats 3%.

The frontal lobes connect with deep brain structures and with the temporal lobe, areas involved in emotional, hormonal, visceral, sensory and autonomic functions. The correct meshing of these systems results in the individual being able to regulate his or her behavior according to each situation, taking into account previous experiences, and to be goal-directed and productively involved in different facets of the human experience.

Thus, a malfunction of this regulatory system causes in the sufferer a state of disinhibition of behavior and alteration of emotions, which manifests itself with a tendency to irritability, sudden mood swings, impulsivity, inappropriate behavior in the social or family environment and, in more severe cases, verbal or physical aggression.

Causes of acquired brain damage

Brain injury is not only caused by trauma, but also by stroke (hemorrhage or infarction of cerebral arteries), tumors, encephalitis and anoxic encephalopathy (lack of oxygen to the brain). We must bear in mind that these lesions differ from each other in factors such as the area of the brain affected or the extent of the lesion; some of them are localized, while others affect very large areas or even the whole brain. In this sense, the manifestations, evolution and prognosis between the different types of brain damage are not comparable.

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Finally, there are patient-specific factors that can negatively condition the evolution of behavioral alterations. These factors are a history of habitual consumption of alcohol and toxic substances, advanced age and the previous existence of psychiatric pathology, mental retardation, developmental or learning disorders or brain injury.

What changes may the patient have in behavior or emotions?

  • Alteration of affect.
  • Loss of impulse control.
  • Aggressiveness.
  • Apathy.
  • Cognitive inflexibility.


The repercussions depend on factors such as the frequency and severity of the changes presented by the patient, as well as the degree of coexistence with the patient. In the hospital setting and rehabilitation centers, behavioral disorders can alter or impede the development of activities, negatively affecting the use of therapy and cognitive performance. Disturbed behavior is often the cause of occupational, social and family dysfunction. In the long term, it causes rejection, stigma and progressive isolation, mainly of the person who suffers from it, but sometimes also of family members. For those closest to the patient, it is a cause of overload and emotional suffering.