Topical diagnosis of lesions of the frontal area of the cerebral hemispheres

Category Diagnostics | August 12, 2017 17:58

defeat of the frontal region, including the premotor, characterized by a number of symptoms.With bilateral lesions of the frontal lobes observed phenomena, indicating a weakening of the inhibitory effect of the cortex on the innate unconditional mechanisms, the activity of which the adult subject to activities of a higher level - the conditioned reflex.

These primarily include the symptoms included in pseudobulbar palsy: a violent laughter and crying, a group of reflexes of oral automatism (sucking, palm-chin).Often when this disinhibited absolute grasp reflex (grasping reflex).Often, this reflex is accompanied by a significant increase in articular reflex Mayer.

essence reflex setting is as follows.Automatism seizure (of the hand), healthy people use every day when carried in the hand clamped object, without thinking about it.Although we can completely forget about this subject, actively holding in his hand clamped happens automatically, and an irritant, causing flexor action is stimulation of the pal
m clamped object.Performing daily work, automatism setting activated and in extreme circumstances, when danger of death suddenly overtakes a person and when proceeding relatively slowly in the crust analysis processes become useless, even when it is necessary to act and more primitive, but shorter devices for self-preservation.

cerebral cortex, especially the frontal brain, slows setting reflex.Consequently, with the defeat of the frontal lobe of the brain and ways of connecting them with the underlying formations, grasping reflex disinhibited.When this setting is turned automatism operated not only by direct stimulation of the subject palm, but even if the object is at some distance from it.

Sometimes the hearth side celebrated the so-called resistance symptom consists in the fact that at any attempt to passively bring one or another part of the patient's body from the rest position (straighten or bend the forearm, raise the upper eyelid, and others.), Automatically tighten antagonists and researchermeets some resistance (weakening denervation).

With the defeat of the field, has bilateral relations with the opposite hemisphere of the cerebellum, there are very similar to the cerebellar coordination disorders in the opposite half of the body.It is about the instability when walking, when promahivaniem paltsenosovoy sample mild symptoms and dizmetrii adiadohokineza (frontal ataxia).Along with this disorder often occurs in the form of so-called astasia-Abaza, when the patient because of the insecurity in the legs at full preservation of movements in them in the supine position can not stand (astasia) or walk (Abaza).In such cases, there is a loss of acquired stereotypes of standing and walking.

important to consider the location of the projection eye movement.When pathological processes that cause irritation adversivnogo front of the field, there is a twist eye, head, and sometimes the trunk in the direction opposite to the hearth.When the processes that destroy this area, the deviation of the head and eyes going towards the fire.

For topical diagnosis of lesions of the basal surface of the frontal lobe is very important condition of olfactory function.Early signs of defeat this area are a violation of smell (single- and double-sided hyposphresia or anosmia);the proximity of the visual pathways creates conditions for involvement in the pathological process at the same time and view (optic nerve damage to one or both sides).With the localization of tumors on the basis of the frontal lobe Topeka-diagnostic role, Foster Kennedy syndrome, comprising a primary atrophy of the optic nerve in one eye and stagnant nipples - in another.With this syndrome with tumors of the anterior cranial fossa is often combined and unilateral anosmia on the side of the optic nerve atrophy.

When a massive violation of the cortex of the frontal region on both sides, when the activity of the motor analyzer is greatly reduced, the patient is no activity (lack of initiative).Externally, the patient gives the impression of complete indifference to the environment.If it does not touch it, he can sit or lie down for hours.But enough to address a question to such a patient to get at laconic, but the correct answer to the question.This contrast between the "spontaneous" activity and the answer to the question, and urged clinicians using psychological concepts, denoted as a weakening of the will - Abul.

Pavlov exposed idealist essence of the concept of free will.He showed that it impulses from the external and internal analyzers are the source of the activities of the motor analyzer, reflected the work of skeletal muscles.In diffuse lesions of the frontal lobes is violated not only the perceiving apparatus of the motor analyzer, and afferent fibers that bring here the impulses from external analyzers.Therefore, the motor analyzer is deprived of the energy necessary for its active work.But here, it found special significance for human second signaling system and the special close relationship between auditory and motor part of the vocal apparatus: the sum of all the usual stimuli does not receive a response, and verbal stimulation causes a verbal response, resulting in an active state of the motor analyzer.

These same phenomena characteristic diffuse lesions of the frontal lobes (the tumor), and should be attributed to the inclination motor perseveration and automatism, difficulties in switching from one movement to another.

It should be noted the peculiarity of disorders arising Jari defeat the frontal area of ​​vascular and neoplastic processes.When vascular processes (for example, in hypertensive patients) there are small lesions that break in the motor analyzer formed communications and fixed stereotypes.As a result, the entire amount of impulses from the external and internal analyzers entering the motor analyzer can operate the individual pieces of a stereotype, the remainder of the extensive system.

Other symptoms of frontal lobe lesions observed in tumor processes.Here in the foreground so-called total workload.The pulses arrive in the motor analyzer, where there are analysis and synthesis processes and implemented dynamic stereotypes, but all the processes are performed with difficulty and poverty of movement does not depend on a lack of activity of the motor analyzer, and the difficulties in the implementation process of the nerve due to a violation of the general brain activity.These differences are, of course, relative.When tumors can be observed phenomena reducing activity of the motor analyzer.With the defeat of the frontal area (tumor) is often marked euphoria, poor judgment and inadequate behavioral reactions.

course, various symptoms in patients with lesions of the frontal region is observed in full in one patient.It depends on the nature of the process, its prevalence, degree of preservation of the rest of the cortex.But some symptoms are so characteristic that gives the doctor a basis for judgments about participation in the frontal lobe.