A.  How to derive the mental status information

1. Most of the data for judging the patient’s (Pt’s) mental status emerge as a natural consequence of the questions posed during the standard medical history, which this text does not cover. Although you do the basic Neurologic Examination (NE) by a set routine, you should probe the Pt’s mental status unobtrusively and flexibly. If you blurt out questions obviously designed to test the mental status, such as, “Do you hear voices?” the Pt may respond with annoyance, sullen silence, or outright anger. Nevertheless, just such a question, introduced at the proper time, encourages the disclosure of distressing thoughts. The Pt then may describe the voice that repeats, “You have a duty to kill your family.” Because your personal characteristics and interview techniques condition what the Pt can and will disclose, you must remain flexible, empathetic, and nonjudgmental. This is the first point: the interview technique is everything.

2. By monitoring the Pt’s responses, you determine which questions to use and how far to pursue any particular line of inquiry. As long as the Pt talks productively, continue the line of inquiry. If the Pt changes the subject or becomes evasive, flustered, or silent, you have pressed too hard. The Pt is not ready to talk about that. Try another tack. A mentally ill Pt may permit a full NE but completely resist inquiries obviously designed to disclose thoughts. Patients will talk about whatever problems and anxieties occupy their thoughts, if they can tolerate the thought and its communication. This is the second point: Pts will disclose their mental state, particularly their worries and concerns, if you provide a free opportunity.

3. We have highlighted the two most important statements. With these in mind, you may find it useful to re-read Chapter 1, Section I E.

B.  Categories of the mental status examination

1. The examiner (Ex) must know and explore each category of the mental status examination (Arciniegas and Beresford, 2001; Strub and Black, 2000). Learn Table 11-1.

TABLE 11-1 • Outline of Mental Status Examination

2. Because much of the mental status examination belongs to the psychiatric history, this text focuses on the sensorium because:

a. Sensorial testing uses questions that require more or less objective answers for passing or failing, for example, either you know what day it is, or you do not know what day it is.

b. Sensorial deficits are sensitive to organic impairment of the brain.

C.  The nature of the sensorium

The sensorium is that place where you are aware that you are aware.

1. We all intuitively recognize our awareness of ourselves and our environment. Without consciousness, no other categories of the sensorium are tenable or testable. But consciousness requires a content. At any moment we are conscious of objects, the state of our bladder, the time of day, our feelings, etc. We call our awareness the sensorium.

2. Functions of the sensorium:

a. Registers current internal and external contingencies.

b. Relates current internal and external stimuli to our memories and to our future hopes and desires.

c. Invests the streams of afferent stimuli with emotion, determines their significance, and assigns priority that results in neglect or attention.

d. Proposes various actions and their consequences.

e. Directs the motor system in the actual behaviors that achieve personal survival and satisfaction.

f. Allows us to experience life as a conscious process with a past, present, and future and to respond appropriately (Fig. 11-1).

3. Examples of sensorial responses to internal or external contingencies

a. Internal contingencies: Anxiety about academics: “Maybe I better study tonight.” Hunger: “Maybe I better eat something.”

b. External contingencies: Fire: “I better get away from here.” Meeting another person: “Mmmm, I would like to know that person better” or “Mmmm, I should avoid that person.”

c. The sensorium is ever vigilant and somewhat suspicious in order to avoid harm and gain advantage.

D.  The sensorium commune: the common sense of all human kind

1. The ancients recognized that every person who is sound of mind has a sensorium commune, a sense in common of:

a. Who they are, their role, and station in life: parent, child, student.

b. Where they are: at home, school, hospital, the bathroom.

c. When it is: It is noon. It is today, a particular date. Yesterday has passed. Tomorrow will come. It is winter, not spring, summer, or fall.

d. What is happening: It is snowing. The house is on fire. A dog is barking.

e. How the wise and prudent person should behave: Thus, we have the common sense to come in out of the snow, to get out of a burning house, and to yell at the dog to stop yapping, because we all sense these circumstances as dangers or nuisances.

2. What is uncommon sense (unshared sense)?

a. The uncommon senses or perceptions that we do not share are our personal political, religious, and moral beliefs, for example, there is a God/there is no God.

b. Hence, we avoid specific questions about these topics and most of all avoid debating them in the medical setting because they generate argument, not medical data. Questions on such topics lack quantifiable, objective end points that test the organic condition of the brain, as do questions about the sensorium.

E.  Testing for acute dysfunction of the sensorium after a concussion

1. Patient analysis: A blow to the head has rendered a 21-year-old athlete unconscious for 2 minutes. As the Ex reaches the player, who still lies on the playing field, consciousness appears to have returned. The Ex’s quick neurologic appraisal shows normal breathing, pupils, eye movements, and spontaneous movements of all extremities. These findings exclude a major catastrophe such as spinal cord transection or a large cerebral lesion. To quickly, but effectively, evaluate the athlete’s sensorium, the Ex asks a series of who, where, when, and what questions, posing them seriatim because of the urgent circumstances (Table 11-2).

TABLE 11-2 • Questions to Detect Acute Sensorial Dysfunction After a Head Injury

2. By correctly answering all questions, the athlete demonstrates the first four sensorial functions: consciousness; attention span; orientation for time, person, and place; and recent memory (Table 11-1).

3. Asking the Pt to learn three unrelated items, a color, an address, and an object, and then repeat them after 5 minutes adds another useful test, as does spelling the word world backward or reciting the months backward (McCrea et al, 1998).

4. The Ex then asks about neurologic symptoms such as blurred vision, double vision, numbness, and so forth and completes a Standard NE.

5. As an exercise, try to select from Table 11-2 the single most, symbolic, generic question that best tests the athlete’s sensorium if you were limited to one question.

a. We submit, “What is the score of the game?” as the best question, although you may feel differently.

b. Basically, the sensorial tests determine whether the person knows the score, or in street-talk expressing the same thing when meeting someone, we say, “Hey man, what’s coming down?” “What’s happening?” Asking “What’s the score?” subsumes all of these statements that invite newly met persons to display their sensorium.

6. Here is a marvelous, true anecdote of a mother who brought her 8-year-old child into the Emergency Room for examination after a hard fall on concrete had caused severe scalp bleeding:

a. When asked whether the fall had stunned the child. The mother said: “Oh no. I knew she wasn’t stunned ‘cause I asked her who was she and who was I and where was she and what had just happened to her, and she knew all that.”

b. The Ex said: “Those are certainly the right questions. Where did you learn that?” She said: “Why? anybody knows that.” In other words, she posed her perfectly scripted questions from an intuitive appreciation of “common sense” as a test of brain function, the matching of one brain’s perceptions against those of another’s.

F.  Testing for chronic dysfunction of the sensorium in the brain-impaired or demented patient

The principle is the same as in acute concussion but the form of the questions differs. Avoid machine-gunning the Pt with a series of simplistic questions: “What is your name? Where are you? What is the day, date, and week? Do you hear voices? Who is the president? Can you remember an item, a color, and an address?” If you ask questions that crudely, the Pt, especially if somewhat demented or mentally ill, will quickly realize that you are probing their mental status. Often they will reply (not a little piqued): “What’s the matter, Doc; do you think I’m crazy?” The Ex ultimately must derive answers to the questions in Table 11-3, but derive them artfully in the natural course of the interview. The Pt should experience it all as an ordinary conversation, not as an inquisition.

TABLE 11-3 • Questions to Detect Chronic Sensorial Dysfunction in Dementia

G.  An operational definition of the sensorium

These deliberations allow us to hazard an operational definition: The sensorium consists of those brain functions tested by a standard set of questions that elicit more or less objective answers about the person’s past, present, and future.

For clinical purposes, we judge “objectivity” and “normality” by matching the Pt’s answers against the answers that standard persons with common sense would make.

H.  Where does the sensorium reside within the body?

1. The sensorium cannot be in the limbs and other parts of the body. Their destruction does not alter the sensorium. The two historical contenders for the site have been the heart and the brain.

2. Many ancient savants and scholars located the sensorium in the heart (Keele, 1957; Gross, 2009). After all, the heart races when you are frightened, and when the heart stops, the sensorium stops.

a. The ancient Egyptians seemed to favor the heart because in their embalming practices, they always preserved the heart in a canopic jar or by returning it to the thorax, but they discarded the brain.

b. Aristotle, a Greek (384–322 BC), advocated the heart. In his De Partibus Animalum, he asserted:

For the heart is the first of all the parts to be formed; and no sooner is it formed than it contains blood. Moreover, the motions of pleasure and pain, and generally of all sensations plainly have their source in the heart and find in it their ultimate termination.

3. But dissenters throughout time raised their voices. Hippocrates (5th century BC) said:

And men should know that from nothing else but from the brain came joys, delights, laughter and jests, and sorrows, griefs, despondency and lamentations. And by this, in especial manner, we acquire wisdom and knowledge, and see and hear and know what are foul and what are fair, what sweet and what unsavory.

4. Aristotle’s view of the heart as the site of life and consciousness has persisted in our popular culture, and until the 1960s persisted also in medicine in the very definition of death.

a. In our vernacular, the heart remains the site of consciousness and emotion.

  i. We say that a person with no feeling or compassion has no heart. Or the person may be faint-hearted or lion-hearted.

 ii. We still speak of love as an affair of the heart, and the heart remains the Valentine’s Day symbol of love. (Can we ever change our vocabulary from sweetheart to “sweetbrain” and declare, “I love you with all of my brain,” rather than, “I love you with all of my heart”?)

b. The Aristotelian view, even though acknowledged as wrong, determined the very definition of death into the 1960s. Medically and legally, death was defined as irreversible cessation of the heartbeat and breathing. We still record the time of death as when the heart stops, even though the brain died long before.

I.   Where does the sensorium reside within the brain?

1. Indisputable evidence from clinicopathologic studies clearly places the sensorium in the brain. No contrary evidence exists, now that the critical and decisive experiment, heart transplantation, has once and for all excluded the heart as the site of the sensorium.

2. Although not localizing as specifically as sensorimotor functions, certain parts of the sensorium appear to localize to particular brain regions.

a. Consciousness and attention span to some degree co-localize through the ascending reticular activating system.

b. Recent memory and orientation to person, time, and place are impaired after lesions of the medial temporal lobes and the closely related hippocampal-fornix-mamillary body circuit and basal forebrain (Fig. 11-10), but diffuse cortical or white matter lesions also impair these functions.

c. Calculation has a nodal point in the left angular gyrus region.

d. Insight, judgment, and planning are in large measure executive functions of the frontal lobes.

3. Functional brain imaging undoubtedly will localize sensorial functions, affective states, and thought processes better than the clinicopathologic correlation studies of the past.

4. To end the preliminaries poetically, we may regard the sensorium as the place of knowing, that place where we know what we see, hear, and feel; or, ironically in Aristotelian terms, it is where the heart is, where we have our perceptions, feelings, and priorities.

J.  The sensorium and sensory deprivation

The notion that the sensorium knits all of the individual sensory impressions into a stream of consciousness anticipated modern studies in sensory deprivation. A person confined to a stimulus-free, totally dark, totally soundproof, constant-temperature chamber devoid of environmental fluctuations and human contact finds that the sensorium weakens. Boredom alternates with fright. The thoughts become loose and detached, and hallucinations follow. Continued isolation causes complete disintegration. The sensorium requires incessant change—the interplay of light and dark, sound and silence, pain and pleasure—to function. The philosophic ideal of pure thought, free from the fetters of the flesh and its environment, is therefore exposed as a fraud. The sensorium functions not floating free as a cloud but with respect to the ever-changing stream of internal and external stimuli. Thus, you behave differently in a classroom than in a swimming pool, and you survive in both.

K.  Detailed examination of the sensorium

1. Consciousness: Because you obviously cannot respond consciously when asleep, the sensorium is a property of the waking state. For the moment, we define consciousness intuitively as awareness of self and environment. (Chapter 12 discusses operational tests of consciousness.) Does the Pt make responses that prove awareness of self and environment?

2. Attention span: After consciousness comes attentiveness, the attention span of the individual. Can the Pt attend to stimuli long enough to comprehend and respond to them, or attend to a task long enough to complete it? For a simple, effective test, ask the Pt to recite the months backward or spell the word world backward (McCrea et al, 1998).

3. Orientation: If conscious and attentive, does the Pt comprehend who and where he or she is and when it is? This orientation as to person, place, and time requires ongoing sensory impressions. Have you ever awakened from a deep sleep momentarily disoriented as to the day, the hour, or even where you were? If so, you had to process different afferent stimuli, until all of the pieces of the puzzle suddenly fell into place. Judge the Pt’s orientation:

a. As to person: Does the Pt recognize him- or herself and his or her role, the other people present, and their roles?

b. As to place: Does the Pt recognize that he or she is in a clinic or hospital, its name, and the name of the city and state?

c. As to time: Can the Pt recite the time of day, day of the week, the month, and the year?

4. Memory: Orientation, attention span, and memory intertwine inextricably. Screen for memory this way:

a. Note how well the Pt recalls and relates the events of the medical history.

b. Inquire, “Does your memory work all right?” Or more bluntly, “Do you have trouble with your memory?” If you suspect a memory disturbance, say to the Pt, “Suppose we try out your memory?” Ask the Pt to name the presidents backward from the present one. Although also requiring a long attention span, this task requires more attention and memory than reciting the months backward.

c. Next provide the Pt with an address, a color, and an object to remember, three nonsense items that have no special relation: 5330 Broadway, orange, and table. Have the Pt repeat the items to ensure that they have registered. Then, at the end of the NE, ask the Pt to recite them.

d. Determine whether the Pt differs in the ability to recall recent or remote events. Can the Pt remember what he or she ate for breakfast? Recent memory suffers most in aging or brain diseases in general. To easily remember this difference, recall that grandfather cannot remember where he just laid his glasses, but he can wax eloquently about the events of long ago.

5. Fund of information: The oriented, attentive Pt with a good memory knows what is happening in the world. Ask about current activities or events. If unable to discuss current activities and events, the Pt has organic brain disease, cultural deprivation, or is so withdrawn as to need psychiatric care.

6. Insight, judgment, and planning: Simply ask what the Pt plans to do. Do the proffered goals and plans match the Pt’s physical and mental capabilities? The Pt with quadriplegia who expects to work as a carpenter or the individual with a borderline IQ who expects to become a chemist lacks insight, judgment, and planning. Does the Pt recognize the illness and its implications?

7. Calculation: Test calculation by asking whether the Pt can balance a checkbook, make change, do formal paper-and-pencil calculations, and subtract 7’s serially from 100.

L.  Affective responses

Besides being conscious, attentive, and oriented, having a good memory, a fund of information, insight, judgment, and planning, the standard person reacts emotionally to ongoing events. Imagine your reaction to a hand grenade thrown onto your table or merely to a cockroach. Your alarm or aversion differs in the two cases. Affective responses should have the appropriate quality and quantity.

1. Assay affective responses not by blunt questions, but by comparing the observed with the expected reactions. What affect would you expect as a Pt discusses her paralyzed arm? What affect would you expect if the Pt complains that the “apparatus” plots to kill him? A blunted, bland, or indifferent affect occurs most commonly with hysteria, schizophrenia, and bifrontal lobe lesions.

2. If you have cause to cry or laugh, how much provocation does it take to make you start and how much time does it take you to get over it? If the Pt cries for 15 seconds and then starts to laugh when you ask him to tell you a funny story, the Pt has affective lability, the opposite of affective blunting. Affective lability, on-and-off laughing and crying, commonly accompanies bilateral upper motoneuron (UMN) disease, as we have seen in pseudobulbar palsy and diffuse brain diseases.

M.  Perceptual distortions: illusions, hallucinations, and delusions

1. Illusions: Everyone has experienced the illusion of water shimmering on a hot highway on a summer’s day. The water is an illusion. An illusion is a false sensory perception based on natural stimulation of a sensory receptor. The healthy person recognizes the illusory nature of such an experience, but the sick person may not.

2. Hallucinations: Observe that sweating, tremulous man cowering on the bed, screaming about dogs and snakes in the corner of his room. Or observe this calm woman with an expressionless face who tells you in a flat voice that she hears God’s voice ordering her to drown her baby. Both Pts display characteristic hallucinations: the man has delirium tremens, and the woman schizophrenia. Before an epileptic seizure, many Pts experience visual, auditory, or somatic hallucinations. An hallucination is a false sensory perception not based on natural stimulation of a sensory receptor (Videos 11-1 and 11-2). The mentally ill Pt usually does not recognize the hallucination as a false representation of reality, whereas the Pt with epilepsy does.

Hypnagogic and hypnopompic hallucinations are not true hallucinations. A hypnagogic hallucination represents wakeful dreaming while falling asleep, while a hypnopompic hallucination represents wakeful dreaming immediately after waking up.

3. Delusions: This Pt, eyeing a nurse carrying a tray into the room, says to you sotto voce, “There is one of them now. She is trying to poison me.” You err in responding to this remark if you try to reason with him that she has merely come to take his temperature. Somehow, his psychic economy needs to misperceive the nurse as a conspirator, and all the reason in the world will not dispel his belief. A delusion is a false belief that reason cannot dispel.

4. Literary geniuses frequently depict illusions, hallucinations, and delusions. Try to identify these perceptual distortions (and get reaccustomed to the programming that follows in the next section):

a. Here, Macbeth muses alone after murdering Duncan:

b. This exemplifies an illusion/ an hallucination/ a delusion, which is defined as________________________________________________________________

_________________________________________________________________. (hallucination) (a false sensory perception not based on natural stimulation of a sensory receptor)

c. Here is a passage from Gérard De Nerval poem The Dark Blot:

He who has gazed against the sun everywhere he looks thereafter, palpitating on the air before his eyes, a smudge that will not go away.

d. This exemplifies an illusion/ a hallucination/ a delusion which is defined as __________________________________________________________________. (illusion) (a false sensory perception based on natural stimulation of a sensory receptor)

e. Here, lawyer Porfiry Petrovitch, in Fyodor Dostoyevsky Crime and Punishment, discusses a client:

“Yes, in our legal practice there was a case almost exactly similar, a case of morbid psychology,” Porfiry went on quickly. “A man confessed to murder and how he kept it up! It was a regular hallucination; he brought forward facts, he imposed upon every one and why? He had been partly, but only partly, unintentionally the cause of a murder and when he knew that he had given the murderers the opportunity, he sank into dejection, it got on his mind and turned his brain, he began imagining things, and he persuaded himself that he was the murderer. But at last the High Court of Appeals went into it and the poor fellow was acquitted and put under proper care.”

  i. Was lawyer Petrovitch correct in stating that his client suffered from “a regular hallucination”? Yes/ No. (No)

 ii. Is the client’s mental aberration an illusion/ a delusion? (delusion)

iii. Define a delusion. (A delusion is a false belief that reason cannot dispel.)

5. Localizing significance of hallucinations: Although hallucinations may accompany a variety of mental illnesses or diffuse metabolic diseases, repetitively experienced hallucinations may indicate a lesion of the appropriate sensory cortex. A lesion in the occipital cortex might cause hallucinations of vision; in the uncus, of smell; and in the postcentral gyrus, of somatic sensation. Such hallucinations often constitute part of the aura, or forewarning, of an epileptic seizure produced by a focal epileptic discharge in one of these areas.

BIBLIOGRAPHY  ·  The Mental Status

Arciniegas DB, Beresford TB. Neuropsychiatry. New York, NY: Cambridge Univ. Press; 2001.

Gross CG. A Hole in the head. More Tales in the History of Neuroscience. Cambridge, Massachusetts, London, England: The MIT Press; 2009.

Keele K. Anatomics of Pain. Springfield, IL: Charles C. Thomas; 1957.

McCrea M, Kelly JP, Randolph C, et al. Standardized assessment of concussion (SAC): on site mental status evaluation of the athlete. J Head Trauma Rehabil. 1998;13:27–35.

Strub RL, Black FW. The Mental Status Examination in Neurology. 4th ed. Philadelphia, FA: Davis; 2000.

A.  Introduction to agnosia, apraxia, and aphasia

Fate foredooms every medical student to address the deficits signified by these three mystifying Greek terms. Despite the fascinating subject, the name-plagued literature on agnosia, apraxia, and aphasia discourages even the hardiest scholar. Aphasiologists, in particular, are a contentious lot. Each one, compulsively it seems, must disagree with the methods, concepts, and nomenclature of their predecessors. Philosophy and polysyllabic words prevail, resulting in considerable humbug, hence, the quote from Brecht. For salvation, we shun the rhetoric and simply ask: By what operations do we discover the signified deficits?

B.  Agnosia

1. Review of agnosia: Agnosia means literally not knowing. A root of a word when attached to –agnosia or –ognosia then specifies what the Pt does not know. As a review from Chapter 10, list some common agnosias tested in the Standard NE.

____________________________________________________________________

______________________________________ (Astereognosia, agraphognosia, atopognosia, anosognosia, and tactile agnosia.)

2. General definition of agnosia: Knowing the operations that disclose agnosia (eg, give the Pt certain stimuli to identify) justifies a general definition. Agnosia is the inability to understand the meaning, import, or symbolic significance of ordinary sensory stimuli even though the sensory pathways and sensorium are relatively intact. Learn this definition. Agnosias affect various modalities, visual, auditory, or tactile. The Pt may fail to recognize stimuli in one modality but then recognize them in another.

3. An optimal definition not only states what something is but what it is not and the conditions necessary to diagnose it. The necessary conditions to diagnose agnosia are:

a. The Pt’s sensory pathways are relatively intact.

b. The Pt’s sensorium and mental status are relatively intact.

c. The Pt previously understood the symbolic significance of the stimulus, that is, was familiar with it.

d. An organic cerebral lesion causes the deficit.

4. These conditions exclude Pts with interrupted sensory pathways, intellectual developmental disorders, overt dementia, and functional mental illnesses such as somatic symptom disorders and negativistic personality disorders.

5. Agnosias beyond the scope of this text include associative visual agnosia (modality-specific inability to recognize and name previously known objects or their pictures or to demonstrate their use), apperceptive visual agnosia (impaired perception of patterns and inability to recognize shapes; Giannakopoulos, 1999), and color agnosias.

C.  Agraphognosia (agraphesthesia)

1. Technique for testing: With the Pt’s eyes closed, trace letters or numbers between 1 and 10 on the skin of the palm or fingertips. Use any blunt tip, such as the cap end of a ballpoint pen.

a. Normal educated people rarely miss the traced figures, but a normal person unpracticed in numbers may sometimes err.

b. In testing for agraphognosia in the left hand, you test the right/ left _______________________ lobe of the brain. (right; parietal)

2. For a Pt unable to recognize letters written on the skin and whose lesion had destroyed sensory pathways, the correct term would be __________________. (graphanesthesia)

3. The same pathway from the periphery to the somatosensory cortex that detects the direction of movement of a stimulus across the skin also mediates graphognosia (Bender et al, 1982).

D.  Prosopagnosia

1. Prosopagnosia means the inability to recognize faces in person or in photos (Video 11-3).

2. Technique to test for prosopagnosia: The Ex asks someone known to the Pt to enter the room. The Pt cannot recognize the person’s face but does recognize the individual immediately by the voice sound when the person speaks. When looking at a facial photo of family or a well-known celebrity, the Pt can see the face and can even describe the parts but fails to recognize who the person is. It probably should be noted that this syndrome is not just limited to recognizing human faces, but to recognizing items with specific historical significance within a class of objects. As such, patients with prosopagnosia also have trouble identifying their car among a series of cars, their own clothing, etc.

3. The lesion usually occupies the inferomedial temporo-occipital region, irrigated by cortical branches of the posterior cerebral artery (Damasio and Damasio, 1989; Hudson and Grace, 2000; Tranel and Damasio, 1996). The lesion is usually bilateral, but if unilateral, it is usually right-sided (Wada and Yamamoto, 2000). Lesions in this region also cause an acquired type of color agnosia (achromatopsia or chromatagnosia).

E.  Technique to test for agnosias of the body scheme: autotopagnosia (asomatognosia)

1. The concept of a body scheme: One’s brain knows one’s anatomic parts, boundaries, and postures as a grand gestalt called the body scheme or somatognosia (Castle and Phillips, 2002; Coslett et al, 2002; Miller et al, 2001). Even a puppy knows its parts and separates self from nonself. The normal body scheme, such as finger localization (finger gnosia) and right-left orientation, only becomes formally testable in 4- to 6-year-old children and thus illustrates a definite developmental timetable (Reed, 1967).

2. Neuropsychiatric disorders may cause body scheme delusions (Castle and Phillips, 2002). In anorexia nervosa, the person perceives herself as too fat, no matter how emaciated she actually becomes. A person may erroneously perceive normal body parts, such as the nose, breasts, or, in cases of gender dysphoria, the genitalia, as misshapen.

3. Several terms express the concept of somatognosia or its antonym somatagnosia. Topagnosia is the inability to localize skin stimuli. Autotopagnosia means the inability to locate, identify, and orient one’s body parts, that is, body scheme agnosia.

4. Technique to test for two autotopagnosias: tactile finger agnosia and right-left disorientation

a. For identifying the fingers, assign the numbers 1 to 5 to the digits of each of the Pt’s hands, beginning with the thumb, or use names. Then, with the Pt’s eyes closed, randomly touch a digit on the right or left hand and ask the Pt to identify the finger by number or name and whether it is the right or left hand (Reitan and Wolfson, 1993).

  i. If the Pt seems to have right-left disorientation, give further commands such as, “Touch your right hand to your left ear,” to verify the deficit.

 ii. To further explore right-left disorientation, ask the Pt to point out your own right and left hands and digits by number or name.

iii. The lesion usually occupies the region of the left angular gyrus (posterior parasylvian area). See Gerstmann syndrome, Section III O.

b. Also test the Pt for autotopagnosia by placing a part in one position and asking the Pt to duplicate the position with the opposite extremity, with the eyes closed. For example, elevate the Pt’s arm to a position on one side and ask the Pt to hold it there and to duplicate the position with the opposite extremity.

F.  Left-side hemispatial inattention

1. Patients with right parietal lesions often fail to attend to the entire left half of space. Evidence for this unilateral neglect comes from observing that the Pt ignores persons, objects, or any stimuli from the affected side, fails to dress that side, and fails to eat the food from that half of the plate. Such Pts, at least early after an acute lesion, often have anosognosia (see Section G).

2. Technique to test for left-side hemispatial inattention

a. Ask the Pt to draw a cross or any symmetrical figure such as a bicycle wheel with spokes or the face of a clock (Freedman et al, 2000). The Pt will draw the right half of the figure accurately but make mistakes in completing the drawing on the opposite side (Fig. 11-4; Critchley, 1953; Stone et al, 1991).

b. The line bisection test demonstrates left-side inattention better than drawing a clock face (Ishiai et al, 1993). Draw a straight line 20 cm long across a sheet of paper and ask the Pt to make a pencil mark exactly in the center. The Pt with a right parietal lobe lesion makes the mark considerably to the right of the true center because of neglect of the left half of space (Tegner and Levander, 1991).

G.  Anosognosia

1. Definition: Josef Babinski (1857–1932) introduced anosognosia to describe a Pt who had a left hemiplegia and left-side sensory loss but who was unaware of his neurologic deficits. Some authors now use anosognosia generically for lack of awareness of any bodily defect. Although highly characteristic on the left side after right parietal lesions, it can affect the right side after left parietal lesions, particularly in the acute phase of the lesion (Stone et al, 1991).

2. Technique to test for anosognosia

a. The Ex, noting a left hemiplegia, asks the Pt whether anything is wrong with the side. The Pt replies No. If the Ex asks whether the Pt can move the left arm, the Pt will reply Yes despite complete hemiplegia (Levine et al, 1991).

b. The most dramatic test for anosognosia is this: Stand on the left side of the Pt’s bed and place the Pt’s hemiplegic arm on the bed alongside the Pt. Lay your own left arm across the Pt’s waist. Ask the Pt to reach over and pick up his own left hand. He will grope across his abdomen, grasp your hand, and hold it triumphantly aloft, never realizing the error.

H.  Inattention to double simultaneous cutaneous stimuli

1. Synonyms include sensory suppression, sensory extinction, and sensory inattention. As with agnosias, the sensory pathways from the periphery to and including the primary sensory cortex must be intact, making the phenomenon a test of association cortex. Inattention to bilateral double stimuli occurs with vision (Chapter 3, Section I B 2), hearing (Chapter 8, Section IV H), and touch.

2. Technique to test for tactile inattention to simultaneous bilateral stimuli (double simultaneous stimulation)

a. Inform the Pt that you may touch one or both sides. With the Pt’s eyes closed and using light pressure, brush one or simultaneously both cheeks randomly with the tips of your index finger or wisps of cotton.

b. The Pt reports whatever is felt and should perceive one or both stimuli. Similarly test the dorsum of the hands and then the feet.

c. If the Pt reports only one stimulus after the Ex has applied simultaneous stimuli, the Ex again states, “I may be touching you in more than one place. Don’t let me fool you.” Then alternate, randomly touching only one or both sides, until you determine whether the Pt consistently does or does not feel bilateral simultaneous stimuli.

d. Inattention to simultaneous bilateral stimuli is most prominent after right parietal lobe lesions, in which case the Pt fails to attend to the stimulus on the left (Bender, 1952; Critchley, 1953; Meador et al, 1998; Weinstein and Friedland, 1977). Occasionally, with left parietal lesions, the Pt will not attend to the right side on simultaneous stimulation. After simultaneous stimulation of both sides, the Pt with a right parietal lesion inattends to stimuli from the right/ left side. (left)

3. Technique to test for inattention to simultaneous unilateral stimuli

a. On one side, simultaneously touch the face and hand several times, and then the foot and hand and face and foot. The person normally reports both stimuli. Parietal lobe lesions impair recognition of both stimuli.

b. Learning-disabled children without gross structural lesions of the brain often suppress double stimulation on one side. Usually the Pt feels the face or foot stimulus and suppresses the hand stimulus.

I.   Review of localization of agnosias and loss of discriminative sensory modalities

1. Recite the definition of agnosia and the qualifying requirements.

2. Agnosias generally signify lesions of the association areas that extend from the primary sensory receptive areas or of the thalamocortical circuits of the association areas. The cortex works by thalamocortical and corticothalamic feedback circuits. The association nuclei of the thalamus project to the association areas of the cortex, just as the sensory nuclei of the thalamus project to the respective sensory cortices. The thalamic projections to primary sensory cortex run courses different from those for the association pathways and can be preserved when lesions interrupt the association circuitry. Interruption of a feedback circuit at any point may cause defects similar to lesions of only the cortical component of the circuit. Thus thalamic lesions may cause hemineglect, some agnosias, and aphasia (Bruyn, 1989). In these instances, the sensory pathways are at least partly preserved, as the definition requires.

3. Although right parietal lesions most commonly cause contralateral hemiinattention, lesions of either parietal lobe regularly cause loss of discriminative modalities contralaterally, such as astereognosis, agraphognosia, atopagnosia, and loss of two point discrimination (Fig. 11-9). The primary modalities of touch, pain and temperature, and vibration remain more or less intact with cortical lesions. Lesions of infracortical pathways or in the periphery more commonly significantly impair these modalities.

4. For autotopagnosias such as finger agnosia and right-left disorientation, the relevant association area is the left posterior parasylvian area. In this case, a unilateral lesion causes bilateral deficits of the body scheme. Lesions of the left posterior parasylvian area cause, in addition to bilateral finger agnosia and right-left disorientation, dyscalculia and dysgraphia (see Gerstmann syndrome).

5. In summary, lesions of either parietal lobe may cause contralateral loss of astereognosis and other discriminative modalities, but hemispatial inattention and anosognosia are more common with right/ left parietal lobe lesions. (right)

6. In contrast, finger agnosia and right-left disorientation are more common with right/ left posterior parasylvian lesions. (left)

BIBLIOGRAPHY  ·  Agnosia

Bender M. Disorders in Perception, with Particular Reference to the Phenomena of Extinction and Displacement. Springfield, IL: Charles C Thomas; 1952.

Bender M, Stacy C, Cohen J. Agraphesthesia: a disorder of directional cutaneous kinesthesia or a disorientation in cutaneous space. J Neurol Sci. 1982;53:531–555.

Bruyn RPM. Thalamic aphasia: a conceptual critique. J Neurol. 1989;236:21–25.

Castle DJ, Phillips Ka. Disorders of Body Image. Petersfield, United Kingdom: Wrightson Biomedical; 2002.

Coslett HB, Saffran EM, Schwoebel J. Knowledge of the human body. A distinct semantic domain. Neurology. 2002;59:357–363.

Critchley M. The Parietal Lobes. London: Edward Arnold & Co; 1953.

Damasio H, Damasio AR. Lesion Analysis in Neuropsychology. New York, NY: Oxford Univ. Press; 1989.

Freedman M, Leach L, Kaplan E, et al. Clock Drawing: A Neuropsychological Assessment. New York, NY: Oxford Univ. Press; 1994.

Hudson AJ, Grace GM. Misidentification syndromes related to face specific area in the fusiform gyrus. J Neurol Neurosurg Psychiatry. 2000;69:645–648.

Ishiai S, Sugishita M, Ichikawa T, et al. Clock-drawing test and unilateral spatial neglect. Neurology. 1993;43:106–110.

Levine DN, Calvanio R, Rinn WE. The pathogenesis of anosognosia for hemiplegia. Neurology. 1991;41:1770–1780.

Meador KJ, Ray PG, Day L, et al. Physiology of somatosensory perception. Cerebral lateralization and extinction. Neurology. 1998;51:721–727.

Miller BL, Seeley WW, Mychak P, et al. Neuroanatomy of the self. Evidence from patients with frontotemporal dementia. Neurology. 2001;57:817–821.

Reed J. Lateralized finger agnosia and reading achievement at ages 6 and 10. Child Dev. 1967;38:213–220.

Reitan RM, Wolfson D. The Halstead-Reitan Neuropsychological Test Battery. Theory and Clinical Interpretation. 2nd ed. Tucson, AZ: Neuropsychology Press; 1993.

Stone SP, Wilson B, Wroot A, et al. The assessment of visuo-spatial neglect after acute stroke. J Neurol Neurosurg Psychiatry. 1991;54:345–350.

Tegner R, Levander M. The influence of stimulus properties on visual neglect. J Neurol Neurosurg Psychiatry. 1991;54:882–887.

Tranel D, Damasio AR. Agnosias and apraxias. In: Bradley WG, Daroff R, Fenichel GM, Marsden CD, eds. Neurology in Clinical Practice. Principles of Diagnosis and Management. 2nd ed. Boston, MA: Butterworth Heinemann; 1996, Chap. 16, 119–130.

Wada Y, Yamamoto T. Selective impairment of facial recognition due to a haematoma restricted to the right fusiform and lateral occipital region. J Neurol Neurosurg Psychiatry. 2000;71:254–257.

Weinstein EA, Friedland RP, eds. Hemi-attention Syndromes and Hemisphere Specialization. Advances in Neurology. Vol 18. New York, NY: Raven; 1977.

J.  Apraxia

1. Definition of apraxia: The ability to execute a voluntary act is called praxia (praxis = action, as in practice). By negating praxia, the ability to act, we describe apraxia, the inability to act. Apraxia means the inability to perform a voluntary act even though the motor system, sensory system, and mental status are relatively intact. Learn this definition.

2. Formal criteria to distinguish apraxia from other motor defects

a. The Pt’s motor system is sufficiently intact to execute the act.

b. The Pt’s sensorium is sufficiently intact to understand the act.

c. The Pt comprehends and attempts to cooperate.

d. The Pt’s previous skills were sufficient to perform the act.

e. The Pt has an organic cerebral lesion as the cause of the deficit.

f. In summary, the Pt must comprehend the act, cooperate in attempting it, and have a motor system sufficiently intact to execute the act. These requisites exclude Pts with paralysis or functional mental illnesses, such as hysteria or negativism, profound dementia, and mental retardation, to whom apraxia is not meant to apply.

g. If the definition and conditions for diagnosing apraxia causes the strange feeling of repeating a previous experience (the déjà vu of anterior temporal lobe lesions), we are on the right track. Review frame II B 2 that defines agnosia.

3. Distinction between apraxia and other motor deficits: Apraxic Pts are often unaware of their deficits and may do an act automatically that they cannot do on command. For example, apraxic Pts may fail to stick out their tongue and lick their lips on command but may then lick their lips automatically. The Pt may fail to make a fist when asked in close the fingers but may automatically grasp an object, such as a spoon.

a. With pyramidal lesions, the paralysis precludes doing the act voluntarily or automatically, thus violating a necessary condition that the motor system be fairly intact. The paralyzed Pt may also have apraxia, but the paralysis prevents its recognition.

b. The Pt with a cerebellar lesion retains the ability to perform an act but cannot perform it smoothly.

c. With basal motor nuclei lesions, involuntary movements or rigidity impede down the act, but the sequence of the act remains possible.

K.  Technique to test for common apraxias

1. The Ex tests for apraxia almost inadvertently in giving routine commands such as: “Stick out your tongue.” “Make a fist.” “Walk across the room.” These commands disclose tongue, hand, and gait apraxias, respectively.

2. For formal testing, the Ex makes special verbal requests and, if that fails, demonstrates acts for the Pt to pantomime.

3. Face-tongue (bucco-facial) apraxia: Ask the Pt to protrude the tongue and move it up, down, right, and left and lick the lips. Ask the Pt to act as if blowing out a match or sucking on a straw. If verbal instruction fails, try miming.

Related posts:

Clinical and Laboratory Tests to Distinguish Conversion Disorder (Functional Neurologic Symptom Disorder) from Organic Disease Examination of the Central Ocular Motor Systems Ancillary Neurodiagnostic Procedures—Lumbar Puncture and Neuroimaging Examination for Cerebellar Dysfunction Examination of the Motor Cranial Nerves V, VII, IX, X, XI, and XII Examination of the Somatic Motor System (Excluding Cranial Nerves)

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