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“ЗАТВЕРДЖЕНО” на методичній нараді кафедри нервових хвороб, психіатрії та медичної психології “______” _______________ 2008 р. Протокол № _____ Зав. кафедри нервових хвороб, психіатрії та медичної психології професор В.М. Пашковський . . METHODOLOGICAL INSTRUCTION № 12 THEME: LOCALIZATION OF FUNCTIONS IN BRAIN CORTEX. SYNDROMES OF LESION. METHODS OF EXAMINATION Modul 1. General neurology Сontents modul 2. Pathology of the cranial nerves. The disorders of the autonomic nervous system and brain cortex functions. Meningeal syndrome. The additional methods of examination in neurology. Subject: Nervous deseases Year 4 Medical faculty Hours 2 Author of methodological instructions PhD, MD Zhukovskyi O.O. Chernivtsy 2008 1. Scientific and methodological substantiation of the theme. The lesion of mental function make a great problem of social adaptation process of neurological patients with mental defect after the stroke or other neurological diseases. Also, the definition of mental defects helps to localize the level of the nervous system lesion. If they are present, the lesions are usually in the left or right cerebral cortex. 2. Aim: students should be able to investigate mental function, to determine independently signs of lesion of brain hemispheres and to localize the pathological process (focus). Students should be able to formulate and to explain the topical diagnosis. Students must know: 1. Anatomical structures and function of brain cortex. 2. Clinical signs of brain cortex lesion. 3. Clinical signs of lesion of consciousness level. Students should be able to: 1. Examine patient status. 2. Make a conclusion about presence of pathology of brain cortex function. 3. Put topical diagnosis and to explain it. 4. Make differential diagnosis of a pathological process level localization. 1. 2. 3. 4. 5. Student should gain practical skills: To gather an anamnesis and to examine patient status In course of analysis of the complaints of the patient to find out presence of lesion of brain cortex (defect of speech, praxis, calculation, gnosis, intellectual functions, memory, ability to write and to read). To carry out tests on speech, writing, reading, calculation, praxis, gnosis. To formulate a conclusion about presence or absence of lesion signs of brain cortex. To examine the function of brain lobes and syndromes of their lesion. 4. Integration (basic level). Subjects Anatomy Gained skills Knowledge of anatomy of brain hemispheres and lobes Histology Hystological structure of brain cortex Physiology Knowledge of function of brain cortex and brain lobes. Subject The cerebral cortex is the mantle that covers both cerebral hemispheres and gives them their convoluted superficial appearance. The cortex is generally viewed as the highest functional level of the nervous system and responsible for uniquely human characteristics, such as intricate hand movements, highly developed speech, symbolic thought, personality, conscience, and self-awareness. These qualities are known to depend on the cortex because, if certain areas in the cortex are damaged, these qualities are lost or greatly impaired. Structural Organization of the Cortex. Structurally, the cerebral cortex contains both horizontal and vertical organization. The horizontal organization consists of six layers made up of two types of neurons. Cortical neurons are classified as either pyramidal or nonpyramidal based on the shape of the cell body. Pyramidal cells have a cell body shaped like a pyramid, with the apex pointing toward the surface of the brain. The apex gives rise to a single apical dendrite that runs toward the surface and intersects intervening layers at right angles. The base of the cell gives rise to several basilar dendrites that course laterally within the layer containing the cell body. Nonpyramidal cells usually have small, round cell bodies with dendrites arising from all aspects of the cell body. Pyramidal and nonpyramidal cells also differ with respect to their axons. The axon of a pyramidal cell has a main trunk that projects in the white matter to another region of the cortex or to a more distal site within the central nervous system (CNS). In addition to the main trunk, the axon may have collateral branches that terminate near the cell body. In contrast, the axon of the nonpyramidal cell branches profusely and remains in the region near the cell body. Layers with high concentrations of pyramidal cells form the output segment of the cortex while layers with predominantly nonpyramidal cells form the receptive layers for cortical input. This systematic arrangement of pyramidal and nonpyramidal cells produces the horizontal layers in the cortex. Horizontally, the cortex is divided into six cell layers on the basis of cytoarchitecture. The layers are numbered sequentially from the surface to the myelinated projection fibers that underlie the cortex. Layer 1 (molecular) consists primarily of glial cells and projection fibers running parallel to the surface. Because the projection fibers synapse on the apical dendrites of cells from deeper layers, layer 1 functions to interconnect cortical regions. Layers 2 and 3 (external granular and external pyramidal, respectively) contain large numbers of pyramidal cells that project to other cortical regions. Layer 4 (internal granular) consists primarily of nonpyramidal cells and forms the primary receptive region for cortical input. Layer 5 (internal pyramidal) contains the largest pyramidal cells and forms the primary output region from the cortex to the rest of the nervous system. Layer 6 (multiform) contains smaller pyramidal cells that project from the cortex to the thalamus. While the basic six-layer structure remains constant throughout the cortex, the thickness of individual layers varies with the function of the different cortical regions. Based on the changes in microscopic structure, cytoarchitectural maps have been created that divide the surface of the cerebrum into distinct areas. Some areas correspond with recognized function while others do not. The most frequently used cytoarchitectural map was developed by Korbinian Brodmann, a German neurophysiologist, who divided the human cerebral cortex into 52 areas. Functionally distinct areas of the cerebral cortex are often referred to by their Brodmann number designation. The vertical organization of the cortex consists of columns of cells that respond to a specific type of stimulus from a particular region of the body. The area of the cortex that receives information from the hand contains individual columns specialized for the sensation of touch, pressure, temperature, or pain. These vertical columns are very important and considered to form the functional units of the cortex. The columns of cells run perpendicular to the layers and together they form the structural and functional organization found throughout the cortex. The primary function of the cerebral cortex is integration. The anatomical convergence necessary for integration occurs both within columns of cortical cells and between cortical areas. Within individual columns, input is integrated sequentially over time and represented by the ongoing level of activity in that column. Integration between cortical areas occurs as the output from two or more cortical regions converge. Such complex integration is necessary to form holistic perceptions of the way objects feel, taste, smell, look, and relate to the surrounding environment. Transcortical fibers, both those located in layer 1 and projection fibers located in the white matter, provide the pathways for integration of information from distal cortical sites. The exact location in which complex perceptions are formed remains unknown, although association areas of the cortex are probable sites. Neurons that project from one hemisphere to the other are called commissural fibers (corpus callosum, anterior and posterior commissures) and provide for the sharing of information from one hemisphere to the other. Functional Organization of the Cortex Functionally, the cerebral cortex contains two types of areas: one that is dedicated to specific functional systems and one that is responsible for associating or integrating information from other areas. Cortical regions identified with specific functional systems are referred to as primary, secondary, and tertiary projection areas. Cortical projection areas are often referred to by their Brodmann number designation, for example, primary visual, 17; secondary visual, 18; tertiary visual, 19; primary motor, 4; premotor, 6; frontal eye field, 8; primary somatosensory, 3a, 3b, 2,1; primary olfactory, 38; primary auditory, 41 and 42; and so forth. Regions of the cortex that are responsible for integrating information from functional systems are referred to as association areas. The majority of the space in each lobe is occupied by association areas. An example of cortical integration is seen when the color, taste, shape, smell, and texture of a spherical citrus fruit are integrated to produce the concept of "an orange." The cerebral cortex is also somatotopically organized such that the body surface may be represented or mapped on the cortex. The most widely described examples of this somatotopic arrangement are found in the primary motor cortex (area 4) and primary sensory cortex (areas 3, 1, 2). There are two important aspects about this representation of the body or homunculus. First, the map is distorted such that some body parts have greater representation than others. Second, the homunculus is inverted with the lower extremity represented on the medial aspect of the hemisphere and the head on the lateral aspect adjacent to the lateral fissure. Both the distortion and the inversion have important functional consequences. The body parts with the greatest cortical representation have the most precise control. In part, the dexterity of the face and hand are due to the large amount of cortical space dedicated to their control. The precise sensory discrimination of the mouth and hand are due to the same disproportionate allocation of space. Inversion of the homunculus is clinically significant because the body parts represented on the medial aspect of the hemisphere receive their blood supply from one artery while those on the lateral surface receive theirs from another. Transcortical Connections. The primary connection between the two hemispheres is provided by the corpus callosum, the largest fiber bundle in the nervous system. The corpus callosum forms the floor of the medial longitudinal fissure and the roof of the lateral ventricles. In crossing the mid-line, the corpus callosum connects functionally related areas in the two hemispheres. Aphasia – is a disorder of language, the aphasic patient uses language incorrectly or comprehends it imperfectly. Anatomy of aphasia. Language “ability” is a function of the left hemisphere for almost all right-handed and for most left-handed individuals. The anatomic components of the language are located primarily in the region of the middle cerebral artery surrounding the Sylvian and Rolandic fissures. Speech production involves four regions in this area, moving from posterior and anterior. Thus, speech connections exist between Wernicke’s area on the posterior part of the first temporal gyrus; the angular gyrus; the arcuate fascicules; and Broca’s on the posterior third frontal gyrus. Types of aphasia. The lesion of posterior part of lower frontal lobe (the center of Broca) causes Broca’s aphasia. Broca’s aphasia occurs in case of motor encoding area involved and means the impairment of spontaneous speech, repetition, reading aloud, naming (but recognizes object) and writing, retained the comprehension of both spoken and written language function. Testing: 1. Speech is slow, nonfluent, produced with great effort, and poorly articulated. There is marked reduction of total speech, which may be “telegraphic” with the omission of small words or endings. 2. Comprehension of written and verbal speech is good. 3. Repetition of single words may be good, though it is done with great effort; phrase repetition is poor, especially phrases containing small function word (eg, “no if’s, and’s, or but’s”). 4. The patient always writes aphasically. 5. Object naming is usually poor although it may be better than spontaneous speech. 6. Hemiparesis (usually greater in the arm than in the leg) is present, as the motor cortex is close to Broca’s area. 7. The patient is aware of his deficit; he is frustrated and frequently depressed. 8. Interestingly, the patient may be able to hum a melody normally. Curses or other ejaculatory speech may be well articulated. According to Lurie there are three types of motor aphasia. They are: - afferent is associated with the lesion of lower parts of gyrus postcentralis which provide innervation of oral muscles. In this case articulation of sounds suffers. That means the loss of automatical speech, repetition, naming. This kind of aphasia is connected with oral apraxia. - efferent is Broca’s aphasia. In this case articulation is preserved. But the patient can’t spell some sounds, words and phrases. At completely aphasia the patient doesn’t speak at all. - dynamic is usually caused by lesion of cortical zone in front of Broca’s centre. For this type of aphasia aspontanic speech is typical. the patient refuses to speak in active manner. But he is able to repeat certain sentences, words, answer the questions. Wernicke’s aphasia occurs in case of auditory association area involved and means the impairment of comprehension of spoken language, repetition of spoken language, naming comprehension of written language, spontaneous speech, the spoken language is fluent but impaired (jargon). Testing: 1. Speech is fluent with normal rhythm and articulation, but it conveys information poorly because of circumlocutions, use of empty words and incorrect words (paraphasic errors). 2. The patient uses wrong and sounds -ie, makes paraphasic errors (“treen” for train; “here is my clover” for here is my hand). 3. The patient is unable to comprehend written or verbal speech. 4. The content of writing is abnormal, as is speech, though the penmanship may be good. 5. Repetition is poor. 6. Object naming is poor. 7. Hemiparesis is mild or absent, since the lesion is far from the motor cortex. A hemianopsia or quadrantopsia may be present. 8. Patients may not realize the nature of their deficit and often are not depressed in the acute stage. 2. Anomic (nominal) aphasia is impairment of naming objects and spontaneous speech. Spoken language fluent but rambling and vague. Retained the repetition, comprehension of both spoken and written language. 1. This type of aphasia may be seen at small lesions in the angular gyrus, toxic or metabolic encephalopathy, or with focal space-occupying lesions far the speech area, but which exert pressure effects. 2. Speech is fluent but conveys information poorly because of paraphasic errors and circumlocutions (written language is impaired in the same way). Even though this aphasia is termed anomic aphasia (difficulty in naming objects), anomia is not unique to this type of aphasia. 3. The patient can understand both written and spoken speech. 4. There is no hemiplegia. 5. Comprehension and repetition are normal. 3. Semantic aphasia occurs at lesion of temporal-parieto-occipital border of left hemisphere. The patients cannot realize the difference between “The brother of the father” and “the father of the brother”. Examination of the aphasic patient. It must first be established whether the patient is in fact aphasic; then determine the nature of the aphasia. 1. Listen to speech output. Is it fluent or nonfluent? If fluent the lesion is posterior; if nonfluent it usually is anterior. 2. Can the patient read and write with no errors? If so, he is not aphasic. 3. Is there hemiparesis? If so, the lesion must be anterior, involving the motor area. 4. To delineate the various types of fluent aphasias, check to see if the patient can repeat, comprehend, and name: - Wernicke’s: cannot repeat or comprehend; names poorly; - Conduction: cannot repeat but can comprehend; names poorly; - Anomic: can both repeat and comprehend but has trouble with naming. Apraxia is a disturbance of purposeful movement which is not accounted for by elementary motor or sensory impairments. It occurs commonly is association with aphasic syndromes. Apraxia is deviated in: 1. motor or kinetic 2. ideational 3. constructional and dressing Ideational Apraxia. In ideational apraxia there is inability or failure to comprehend, develop, or retain the concept of what is desired. It is usually due to general suppression or less of cerebral function and resembles extreme absentmindedness. Such a patient will have difficulty in understanding what is desired and will fail to complete the desired act. This becomes apparent when he is asked to carry out a series of simple acts such as “Put the pencil in the cup and hand me the matches.” After requiring that the request be repeated, he may then pick up the pencil and fail to do anything more. The patient with ideational apraxia has lost the idea. Ideokinetic Apraxia. Another common form of apraxia is known as “ideokinetic” or “ideomotor” apraxia. This occurs when there is a break in transmitting or converting the idea into the appropriate motor act. This form of apraxia occurs most commonly with lesions of the major hemisphere at the junction of the temporal, parietal and occipital lobes or its connections with the frontal lobes. Despite knowing what is desired, the patient is unable to carry out a desired complex performance. He may, for example, hesitantly touch his forehead when asked to touch his nose. He may recognize a comb but he unable to use one to comb his hair when asked. Then, surprisingly, he may carry out the same acts automatically that he is unable to perform volitionally on request. Kinetic Apraxia. Failure of the third step produces kinetic apraxia. This phenomenon is considered to be due to a lesion of the premotor frontal cortex, and the disability is limited to one extremity or a part of it. There is no actual weakness, and the patient is able to use the extremity for gross movements and automatically. He has lost the ability to make fine skilled movements such as finger wiggling, opposition, writing, or piano playing. Observations for awkwardness while carrying out relatively complicated acts such as dressing and undressing should be made. It should be noted whether the patient has difficulty in conceiving how to hop, how to touch his nose, and how to wiggle his fingers or tap his toes. Specific Test. Observations on the motor-pattern performance of patient are made during the various parts of the neurological examination when the patient is asked to show his teeth, stick out his tongue, wiggle his fingers, tap his toes, hop, walk tandem, touch his nose, and so forth. Instruct the patient by word or gesture to: 1. Touch his nose. 2. Drink from a glass or paper cup. 3. Use a folder of matches. Get the patient to follow simple spoken directions. Say to the patient: 1. Close your eyes. 2. Point to your nose and your chin. 3. Put the pencil in the glass (or paper cup) and hand me the matches. 4. Repeat after me, “I bought a new hat, a pair of shoes, and a white shirt”. Constructional and Dressing Apraxia. Lesion of the posterior parietal region of the nondominant hemisphere may impair performances related to spatial concepts. Constructional apraxia may be demonstrated by having the patient try to copy geometric forms or draw the face of a clock. Further testing includes having the patient try to arrange sticks in a specific pattern or to arrange Koch blocks in a desired design. Dressing apraxia is tested simply by asking the patient to put on a shirt or bathrobe. Agnosias are disorders of recognition which are not accounted for by elementary motor or perceptual disturbances. Testing for tactile recognition (stereognosis) is considered as a part of the general sensory examination, while the tests for recognition of various forms of auditory and visual recognition are considered in the chapter on language and motor speech. Defects of recognition on a somewhat different integrated level are considered here. Autotopagnosia – agnosia for body parts there may be lack of recognition of hands, eyes, feet, and so forth, of the examiner, and even in pictures. With agnosia for parts of a whole the patient is able to recognize a bicycle but is unable to recognize and name the wheels, handlebars, seat, and other parts. Somatotopagnosia includes disturbances in recognition of the patient’s own body or body parts. It is due to lesions of the poster-inferior parietal lobe in the region of the interparietal sulcus of the dominant hemisphere or to a subcortical lesion isolating this area from the thalamus. It is often associated with acalculia, visual verbal agnosia, or anosognosia. Autotopagnosia may be limited to one part of the body or may be more general, involving relationship of the body as a whole. The limited form includes lack of recognition of one half of the body or one extremity and inability to recognize and name individual fingers (finger agnosia) or other body parts. In mild forms the patient may have a sense of distortion of the involved parts of the body and disturbances of laterality. This may be tested by asking the patient to name various parts of his own body and to identify right and left. Anosognosia is lack of awareness or denial of the existence of disease. An obvious example is a denial by the hemiplegic patient that he is paralyzed. This usually is associated with severe disturbance of sensation but is not due to the sensory loss; for instance, knowledge of the paraplegic patient that the paralyzed and anesthetic limbs belong to him. True anosognosia occurs with lesions of the inferior parietal lobe in the region of the supramarginal gyrus. Hemispheric Specialization. Historically, the cerebral hemispheres were viewed as mirror images of one another. The duplication of anatomy and physiology was justified on the basis of the crossed organization of the nervous system such that the right hemisphere controls the somatic and visceral functions of the left side of the body and the left hemisphere controls the right side. It was not until the corpus callosum (the major fiber bundle regulating communication between the two hemispheres) was sectioned that it became evident that the two hemispheres specialized in different functions. In the absence of the corpus callosum, each hemisphere behaves as an individual brain with independent perception, learning, memory, thoughts, and emotional reactions, and neither is aware of the experiences of the other; literally, the right hand does not know what the left hand is doing. Table 1. Behaviors Controlled by Each Hemisphere Behavior Perception/cognition Left hemisphere Processing and producing language Information processing Cognitive style Linear, sequential Observing and analyzing details Academic skills Reading: word recognition, sound-symbol relationship, reading comprehension Performing mathematical calculations Motor Movement sequencing Performing movements or gestures on command Expression of positive emotions Emotions Right hemisphere Processing nonverbal stimuli (complex shapes, sounds, speech inflection) Visual-spatial perception Drawing inferences, integrating information Simultaneous, holistic Grasping overall organization or gestalt, sees patterns Mathematical reasoning/judgment Alignment of numbers in calculations Sustaining a movement or posture Expression of negative emotions Perception of emotions. The left hemisphere is characterized primarily by its specialization in language (speech, reading, writing) and is therefore operationally defined as the dominant hemisphere. Roughly 98 percent of the population has language controlled by the left hemisphere. The plenum temporal (the area of the temporal lobe specialized for speech) is larger in the left hemisphere by the 31st week of gestation, suggesting that this asymmetry does not develop in response to experience, but is innate. The left hemisphere also excels in intellectual, rational, verbal, and analytical thinking. It assumes primary control of analytical processes such as calculation, stereognosis (interpretation of sensory stimuli) from the right side of the body, audition from the right ear, vision from the right visual field, and olfaction from the left nostril. The right hemisphere excels in perceiving and in emotional, nonverbal, and intuitive thinking. The right hemisphere also controls spatial orientation, nonverbal ideation, music appreciation, olfaction from the right nostril, audition from the left ear, vision from the left visual field, and stereognosis from the left side of the body. Because the right hemisphere usually does not control language, it is a more difficult hemisphere to evaluate. For example, in the absence of a corpus callosum, if a key is placed in an individual's left hand and vision is occluded, he or she can still interpret the sensory feedback and recognize the object. However, the object is recognized in the right hemisphere, and because the right hemisphere does not have the ability to produce speech, the individual cannot identify the object verbally. If asked to identify the test object by selecting from an array, the individual experiences no difficulty in selecting the key. The right hemisphere recognizes the object but does not have access to the left hemisphere, which would permit the individual to identify it verbally. In a normally functioning brain, that is, a brain with an intact corpus callosum, each specialized region assumes primary responsibility for a particular aspect of the overall functional task. The results of specialized analyses are then shared freely among regions and hemispheres to enable individuals to perform a wide range of behaviors with no difficulty. In information processing parlance, this is called a parallel, distributed control system, that is, a task is broken down into components, with each component sent to a specialized center for analysis. Once complete, the results are freely shared among centers. Because each of the centers operates independently, they can all work on their part of the larger task, at the same time greatly speeding resolution time. Clinical Aspects. Cerebrovascular accidents (CVA) also provide a means for studying the function of the cerebral cortex. Cerebrovascular accidents or strokes may occur in any vascular territory in the brain. The behavioral dysfunction that accompanies the stroke will depend on which areas of the brain are affected. Because the longitudinal systems connecting the brain and body are crossed, the symptoms and signs of CVA are seen on the side opposite the lesion. Because the right and left hemispheres specialize in controlling different functions, right and left CVAs produce very different clinical manifestations. At birth the brain is already genetically predisposed to acquire language because of the presence of Wer-nicke's area (22) in the left hemisphere. This area is concerned with the comprehension of spoken and written language. If Wernicke's area is damaged, a receptive aphasia, commonly referred to as word deafness, is produced. In this type of aphasia, the auditory apparatus functions perfectly but the sounds being sensed are not perceived as language. This aphasia may also affect speech production because individuals are unable to understand their own spoken words. If the angular gyms (area 39), which connects the visual cortex with Wernicke's area, is damaged, the individual experiences a visual word deafness (alexia) wherein the visual apparatus is functioning perfectly but written language is not perceived. This type of aphasia may be accompanied by an inability to write language (agraphia). Speech production is also controlled in the left hemisphere in Broca's area (44 and 45). Damage in this area results in a productive aphasia characterized by impaired ability to produce verbal language. The motor apparatus for speech is intact, language is heard and perceived, and organized thought processes occur, but coherent verbal self-expression is impossible. Rhythmic speech, as in singing, seems to be a special case: It is specifically controlled in area 45; therefore, normal speech may be absent but singing is still possible. Mel Tillis is a male vocalist who stutters when speaking but does not stutter when singing. The functions controlled by the cerebral cortex are dependent on the integrated output of columns of cells rather than the actions of any single neuron. This point is well illustrated by a clinical example. Convulsive activity is produced by changes in the collective properties of large numbers of cortical neurons. The electroencephalogram (EEG) uses electrodes applied to the scalp to record the activity of many cortical neurons simultaneously and is the best clinical tool for examining global cortical activity. Epileptic seizures are the direct result of abnormal, synchronized discharge of a large number of cortical neurons as seen on EEG. Synchronization of these normally independently discharging units produces stereotyped and involuntary changes in behavior, including transient loss of awareness, jerking movements, and possibly massive convulsions and loss of consciousness. Normally, lateral or surround inhibition of columns of cortical neurons prevents independently discharging units from becoming synchronized. Lateral or surround inhibition is created when a neuron or column of neurons facilitatethemselves and inhibit adjacent neurons. This arrangement helps to clarify the message being transmitted by the neuron or column and prevent interference of "crosstalk" from adjacent neurons. During an epileptic seizure, this surround inhibition breaks down and the discharge of columns of cortical neurons becomes synchronized at the seizure frequency, thereby losing control of their normal function and producing the seizure behavior. Thus, epileptic seizures are disorders of the cerebral cortex. Abnormal discharge patterns of cortical neurons may be caused by many factors: trauma, oxygen deprivation, tumors, infection, and toxic states. However, only about half the individuals with epilepsy have clearly demonstrable causes. Depending on the size of the area recruited, epileptic seizures can be either partial or general. Both forms produce distinctive, abnormal EEG patterns called spikes. Partial seizures begin from a focal center and spread to adjacent cortical regions by recruiting cells to beat at the seizure frequency. The area of the cortex involved in the abnormal discharge pattern will determine the associated behavioral activity. If the seizure involves the motor cortex, the individual will exhibitabnormal motor activity. Consciousness, visual, or auditory areas experiencing an abnormal discharge pattern will produce abnormal consciousness, visual, or auditory perceptions, respectively. Within a given cortical region, the body part with the largest representation is the most likely to be involved in the seizure activity. For example, the largest part of the motor ho-munculus is dedicated to the hand and face and they are also the most common body parts involved in motor seizures. The spread of partial seizures appears to be limited by powerful postsynaptic hyperpolarization in the cortex. During a generalized epileptic seizure, the abnormal discharge activity is evident over the entire brain at seizure onset and may result from an abnormal input originating in the brain stem reticular formation. A common strategy for the medical management of seizure disorders is the administration of a generalized depressant such as phenytoin (Dilantin). The drug makes it more difficult for each neuron to reach discharge threshold, thereby making it more difficult to produce pathologically synchronized discharge of cortical cells. 1. 2. 3. Sign of the Frontal Lobe’s Lesion Monoparesis or paralyzes Motor Jackson’s seizures Cortical (frontal) ataxia with astasia (inability to standing) and abasia (inability to walking without paresis) 4. 5. 6. 7. Paralysis of conjugate gaze to the opposite side with deviation of the eyes toward the side of the lesion. Irritative lesion produces a conjugate deviation of the eyes away from the side of the lesion. Agraphia Apraxia of speech –Brocka’s aphasia Emotional reactions. 3. 4. 5. 6. Sign of the Temporal Lobe’s Lesion Quadrantic defects which extend to the point of fixation without macular sparing Defects in upper quadrants of the homonymous half-fields on the side opposite the lesion Sensory aphasia Auditory, smell, and testing hallucinations Auditory, smell, and testing agnosia Temporal ataxia 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. Sign of the Parietal Lobe’s Lesion Anesthesia Sensory Jackson’s seizures Performance of complex act Agnosia Anosognosia Autotopagnosia Astereognosia Pseudomelia Inability to do calculation Defects of reading 1. 2. 3. 4. 5. Sign of the Frontal Lobe’s Lesion Congruous homonymous hemianopsia with central sparing Bilateral homonymous hemianopsia Visual hallucinations Scotoma Visual agnosia. 1. 2. Self assessment: Tests for self-assessment: 1. How many layers has the brain cortex? 2. Gyruses of frontal lobe. 3. Gyruses of parietal lobe. 4. Gyruses of temporal lobe. 5. Gyruses of occipital lobe. 6. Function’ centers of the left frontal cortex. 7. Function’ centers of the left parietal cortex. 8. Function’ centers of the left temporal cortex. 9. Function’ centers of the occipital cortex. 10.Clinical signs of irritation of cortex precentral gyrus. 11.Clinical signs of irritation of cortex postcentral gyrus. 12.Clinical signs of lesion of upper parts of cortex precentral gyrus. 13.Name types of aphasia. 14.Name types of agnosia. 15.Name types of apraxia. 16.When does the motor (Broca’s) aphasia occur? 17.When does the sensor (Wernicke’s) aphasia occur? 18.When does the alexia appear? 19.Patient has seizures which start from head and eyes turning left. Where is pathological focus? Tests 1. Lesion of what part of the cortex leads to astereognosia a) temporal lobe; b) frontal lobe; c) occipital lobe; d) parietal lobe; e) postcentral gyrus. 2. a) b) c) d) e) 3. a) b) c) d) e) What symptoms appear when Wernicke center is damaged Anomic (nominal) aphasia; Motor aphasia; Sensory aphasia; Ideational apraxia; Constructional apraxia. What is the thickness of brain cortex 0,5 – 1,0 mm; 1,3 – 4,5 mm; 5 – 8 mm; 10 – 12 mm; 15 – 20 mm. Real-life situations: 1. Describe the signs of of left frontal lobe lesion. 2. Patient has partial seizures in left extremities which cause general attack. Where is a pathological focus 3. Patienthas periodic vision and olfaction hallucinations. Where is a pathological focus References: 1. Basic Neurology. Second Edition. John Gilroy, M.D. Pergamon press. McGraw Hill international editions, medical series. – 1990. 2. Clinical examinations in neurology /Mayo clinic and Mayo foundation. – 4th edition. –W.B.Saunders Company, Philadelphia, London, Toronto. – 1976. 3. McKeough, D.Michael. The coloring review of neuroscience /D.Michael McKeough/ - 2nd ed. – 1995. 4. Neurology for the house officer. – 3th edition. – howard L.Weiner, MD and Lawrence P. Levitt, MD, - Williams&Wilkins. – Baltimore. – London. – 1980. 5. Neurology in lectures. Shkrobot S.I., Hara I.I. Ternopil. – 2008. 6. Van Allen’s Pictorial Manual of Neurologic Tests. – Robert L. Rodnitzky. 3th edition. – Year Book Medical Publishers, inc.Chicago London Boca Raton. - 1981.