http://exhibits.library.stonybrook.edu/mfp/files/original/9cd1485c72c87cfe41a9b822584a53cf.pdf 399d53acd860a7f8f327c824ea2685e0 PDF Text Text Reprinted from the A. M. A. Archives of Neurology and Psychiatry October 1952, Vol. 68, pp. 481-490 Copyright, 1952, by American Medical Association EXOSOMESTHESIA OR DISPLACEMENT OF CUTANEOUS SENSATION INTO EXTRAPERSONAL SPACE MORTIMER F. SHAPIRO, M.D. MAX FINK, MD. AND MORRIS B. BENDER, M.D. NEW YORK phenomena that may be apparent during examination of patients with AMONG disease of the sensory pathways is mislocalization of a sensory stimulus. 'It has long been known that a person with a sensory defect, as seen in the common varieties of cerebral hemiplegia, may inaccurately localize stimuli applied on the paretic side. Such point mislocalizations are apparent in examinations using a single stimulus and have been described in detail by Head.1 These mislocalizations can be accentu— ated by the use of double simultaneous stimulation techniques.2 In addition, when these techniques of examination are employed, other varieties of mislocalization, such as displacement,3 become apparent. Displacement is the patterned mislocalization of one of two stimuli simultaneously applied to difi’erent body areas. The direction of displacement is in a definite pattern, which is dependent upon the parts of the body stimulated. Characteristic of mislocalization so far reported has been the fact that their extent was within the limits of the patient’s body. In the course of studies. of cutaneous perception, we observed a new form of displacement in which the patient consistently and in a predictable fashion mislocalized stimuli into extrapersonal space. This type of displacement we have termed “exosomesthesia.” 4 Exosomesthesia is not a commonly observed phenomenon. More than 400 patients with brain disease were examined at Psychiatric Pavilion of Bellevue Aided by a Fellowship from the National Foundation for Infantile Paralysis (Dr. Fink). This investigation was supported in part by research grant #MH-139 from the United States Public Health Service, National Institutes of Health. From the Department of Neurology and Psychiatry, New York University College of Medicine, and the Neurological Service of the Mount Sinai Hospital and Bellevue Hospital Center. 1. Head, H.: Studies in Neurology, London, Oxford University Press, 1920, Vol. 2. 2. Bender, M. B.; Shapiro, M. F., and Schappell, A. W.: Extinction Phenomenon in Hemiplegia, Arch. Neurol. & Psychiat. 62:717-724 (Dec.) 1949. Bender, M. B.: The Advantages of the Method of Simultaneous Stimulation in the Neurological Examination, M. Clin. North America 32:755—758 (May) 1948. 3. Bender, M. B.: The Phenomenon of Sensory Displacement, A. M. A. Arch. Neurol. & Psychiat. 65:607—621 (May) 1951. 4. The term was derived by Dr. Judah A. Jofie (Hinsie, L. E., and Shatzky, J.: Psychiatric Dictionary, New York, Oxford University Press, 1940) from the Greek 3w, out of ; mind, body, and al’dfiww, perception by the senses. �2 Hospital Center by routine and specialized sensory tests. Exosomesthesia was observed in only 15 cases, an incidence of about 3%.5 The following case reports illustrate the phenomenon and demonstrate some of the conditions under which it was observed. CASE REPORTS CASE 1.—H. M., a man aged 64, was admitted to the Psychiatric Pavilion of Bellevue Hospital with a history of progressive mental changes of six years’ duration. The first four years of illness were marked by slowly progressive impairment of memory, concentration, and other intellectual functions and by increasing apathy to his environment. In the last two years there was rapid exacerbation of this condition, resulting in the loss of his job as a store manager. During this period his speech became increasingly garbled and stammering. He vacillated between irritability and complete apathy. He was occasionally incontinent, ceased bathing, had difficulty in dressing, and was sometimes so forgetful and confused as to wander into the street without his trousers. Routine Neurologic Examination—In walking, the trunk was tilted to the right, and there was a tendency to drag the right lower extremity. However, there was no significant motor weakness, reflex change, or tonus abnormality. Coordination tests were well performed. The cranial nerve functions were intact. Vibration sense was correctly perceived only in the clavicles and the head, while position sense was lost in the fingers, wrists, toes, and ankles bilaterally. Temperature differences were poorly perceived except in the face area. His responses to touch and pinprick stimulation will be described later. A mild degree of “mixed aphasia” was present. This speech difficulty was evident only by special testing or when the patient was fatigued by prolonged examination. There was a fluctuating dyspraxia of moderate severity. Occasionally he had difficulty in dressing, being unable to handle buttons and sleeves. However, he could perform such functions as feeding himself, combing his hair, and other routine daily tasks. He was usually unable to mimic the more complicated patterns of the hand—praxis tests. An electroencephalogram showed bilateral diffuse abnormality, with decrease in amplitude and intermittent suppression of activity over the parietal regions. A pneumoencephalogram dis— closed bilaterally dilated ventricles and moderate “cortical atrophy,” particularly in the left temporal lobe. PsychiatricStatus—Although the patient was oriented for place and situation, he made errors as to date and time of day. There were defects in recent memory, concentration, calculation, and ability to assume the abstract attitude. He usually sat placidly staring into space or wandered aimlessly about the ward. He did not mix with other patients. When approached by members of the staff, he was friendly and passively cooperative. Testing procedures were approached with cheerful indifference. When, however, he was pushed into test situations greater than his capacity, he reacted with increasing irritability and tension, eventually culminating in a “catastrophic reaction.” At such times he would become red in the face, shout that he knew the answers but did not want to continue, and suddenly begin to weep. Body Schema—He was able to distinguish the right side of his body from the left, but was unable to make this distinction on the examiner’s body. He had no difficulty either in locating midline structures of his body, such as the nose, mouth, chin, umbilicus, and penis, or in pointing to his eyes. With eyes open he readily found both ears; but when his eyes were closed he groped about his face for several seconds before locating them. He could point to his thighs, knees, ankles, and toes but could not point to any specific toe other than the big toe. He frequently had difficulty in locating portions of his upper extremities. If asked to point to his shoulders, he correctly located one shoulder but then groped behind his neck looking for the other. This defect was even more noticeable in trying to find the “other” elbow and wrist, and greatest in trying to find the “other” hand. His search for the “other” hand or wrist was bizarre. He would look under the pillow or rummage under the mattress, becoming tense and ' Fink, M.; Green, M., and Bender, M. B.: The Face-Hand Test as a Diagnostic Sign of Organic Mental Syndrome, Neurology 2:46—58 (Jan-Feb.) 1952. 5. �3 insisting it was lost. It should be emphasized that, despite the great difficulty in locating parts of his body, the patient was able to name the body parts, except the fingers and toes. This was true whether the part pointed to was on the patient’s or on the examiner’s body. Sensory Stanton—(w) Single Stimulation: He had difficulty in differentiating between the sharp and the dull end of a pin. This defect was present throughout the body, although he made significantly fewer errors in the face and hands. Touch stimulation was poorly perceived. Usually he could not state whether or not he had been touched. Again, there seemed to be relatively better preservation of this modality in the hands and face. Except under special conditions of examination of the hands, to be described later, the patient was able to locate the site of a pinprick by pointing. However, if the pin was repetitively and rapidly applied to one region, or if the prick was steadily maintained at that one place, he could not locate the point of stimulation. He would make frantic, random searching movements over his body, and not infrequently around the bedclothes, grimacing as though in pain and exclaiming that he was trying to- remove the pin. If asked where he was being pricked, he disregarded the question and continued to try to remove the stimulus. This phenomenon occurred on stimulation of any portion of the body but was most apparent when the hand was tested. (17) Double Simultaneous Stimulation: The phenomena of extinction and displacement were frequently observed in tests of different body areas by simultaneous tactile stimulation. On stimulation of the face and hand, stimuli to the hand were not perceived or were mislocalized to the cheek. In tests of homologous body areas (as hand-hand) extinction of one percept was common. The side on which the stimulus was not perceived fluctuated, so that at one moment only a right—sided stimulus was perceived and a few moments later only a left-sided stimulus was perceived. Exosomesthesia.——Whenever his palm was in contact with a portion of his body or any other object, and the dorsum of that hand was pricked with a pin, the patient consistently mislocalized the stimulus. This mislocalization was to whatever object the palmar surface of the hand was touching. For example, if the patient’s hand was resting on his thigh and the dorsum of the hand was pricked, he insisted that the thigh had been touched, and not the hand. This mislocalization —exosomesthesia—occurred to the thigh, abdomen, leg, or face and was present with stimuli to either hand. It was observed even when the patient was urged to look at the hand during the application of the pin. Exosomesthesia could not be elicited, however, by stimulation of the palm or palmar surface of the fingers when the dorsum of the hand was resting on a portion of the body. Furthermore, localization of stimuli to the dorsum of the hand was correct if the hand was held in space. Mislocalization also occurred to objects external to his body. If his palm was resting on a table or on his bed, and the dorsum of the hand was pricked with a pin, he would point to these objects and state that the pin had been applied “there.” When questioned, he stated that the hand had been touched but continued to point to the bed or table. Frequently, however, he insisted that it was the bed or table that had been touched, and not his hand. If asked how he could feel the bed being pricked with a pin, he would become tense, avoid the question, and insist, “You touched the bed, not me.” Displacement into extrapersonal space was not eliminated by simultaneous stimulation, even when extinction of one of the percepts occurred. For example, if pins were simultaneously applied to the dorsa of the hands while the palms were resting on a table, he would report feeling only one pinprick, that on the left (or right, as dominance fluctuated) and point to the place where the left hand had been resting, saying. “You touched the bed there.” This phenomenon of displacement into extrapersonal space occurred daily during a period of more than two months. Comment—In this patient a requisite to displacement into space was that the palm of the hand be in contact with an external object. In other words, there were two cutaneous stimuli simultaneously in operation, namely, the pinprick on the dorsum of the hand and the pressure of the object in contact with the palm or fingers. A single stimulus, such as pricking the dorsum of a hand held in space, did not elicit the displacement. �4 Exosomesthesia was elicited only on stimulating the hands. This occurred even though single pinprick was perceived more sharply in the hands than in any other area except the face. Although this patient showed inability to locate correctly parts of his own and the examiner’s body, it does not necessarily mean that exosomesthesia is determined by this particular type of disorder in body scheme. The following case illustrates the phenomenon of exosomesthesia in the presence of the patient’s ability to locate body parts. CASE 2.-—E. K., a woman aged 52, was admitted to the neurologic service of the Mount Sinai Hospital in August, 1950, with a history of grand mal seizures. She had been in good health until 1947, when there appeared sporadic, momentary sensations of “blacking out.” About two years before admission she began to suffer monthly grand mal seizures. There was no aura. Routine examination on admission showed that her status was within normal limits except for anosmia in the right nostril. There was no organic mental syndrome. X—ray studies revealed evidence of a subfrontal neoplasm. On August 12 a craniotomy was done, and after amputation of a portion of the right frontal lobe, a large bilateral subfrontal meningioma was excised. Her postoperative course was stormy. For two weeks she was semistuporous. She responded only to massive, painful stimulation, and these responses were limited to vague, ineffective attempts to push away the stimulus. In this period she lapsed several times into coma and showed Cheyne—Stokes respiration. The Babinski response was obtained bilaterally. Her pupils did not react to light. From about Aug. 23, 1950, the patient improved slowly and steadily. She began to respond verbally, and contact could be maintained for short periods. Vision, which had apparently been absent, began to return, although right homonymous hemianopsia remained for some time. A marked organic mental syndrome characterized by confusion, disorientation, and anosognosia, was present. Routine Neurologic Examination—Neurologic examination in September, 1950, disclosed right homonymous hemianopsia, severe impairment of visual acuity with bilateral secondary optic nerve atrophy, nystagmus in all directions of gaze, a bilateral Babinski sign, and a mild degree of aphasia. Position sense, vibration sense, and temperature perception were unimpaired. There were difliculties in perception of touch and pinprick stimuli, as described below. Psychiatric Statue—The patient was usually friendly and cooperative. However, she was frequently irritable and would not permit examination. She was disoriented as to time and occasionally to situation, but not to place. There were defects in retention and recall, covered by confabulation. She was euphoric and displayed little self-restraint or concern in social situations. Usually she would lie with her body fully exposed. Not infrequently she ,soiled herself or wet the bed. Anosognosia was prominent. Body Schema—On command, the patient was able to identify and locate correctly parts of her own and the examiner’s body, such as the ears, eyes, feet, and parts of the upper extremities. She exhibited some confusion about the right and the left side of the body. Sensory Status.—(a) Single Stimulation: The patient perceived single pinprick stimuli well, although she made occasional nonpatterned errors in localization. These errors were more frequent on the left side. (b) Double Simultaneous Stimulation: On simultaneous application of pinprick to the two sides of the body, except the hands, extinction on the left or displacement on the left toward the level of the right-sided stimulus was the usual response. Homolateral simultaneous stimulation on the right side of the-body showed no extinction, but stimulation on the left side elicited frequent extinction and displacement. Exosomesthesia.——Displacement into extrapersonal space occurred when the left hand was pricked at the same time that either the right hand or the right cheek was stimulated. The phenomenon could also be elicited when the left hand and any other area of the left side of the body were simultaneously stimulated. Under these conditions the patient mislocalized the stimulus to the left hand into space near that hand, or to the object on which the hand was lying. For example, if pinpricks were �5 simultaneously applied to the right cheek and the left hand, the patient indicated she had been pricked on the right cheek and the arm of the chair on which her left hand had been resting. As a rule she answered by pointing. If asked to verbalize, she would say, “The right cheek and about here,” (pointing to the chair arm or into space near her left hand). If asked directly. “Was your hand touched?” she would avoid the question, responding only, “Here,” pointing at the same time to the left chair arm or into space. It is to be noted that, except under the special condition of simultaneous stimulation, the patient was always able to point to or to name her left hand on demand. If pricked simultaneously on the dorsa of the left and right hands, she correctly localized only the stimulus on the right, both by pointing and by stating, “My right hand.” The stimulus on the left, however, was localized only by pointing to the chair arm and saying, “Here.” If asked whether the chair arm and not her left hand, had been touched, she answered, “No, here,” pointing to the chair arm. When pinpricks were applied to the left hand and, at the same time, to another area on the left side of the body, a similar displacement into space was evident. Usually the stimulus to the left hand was mislocalized onto whatever structure the hand was resting or else into contiguous space. The other stimulus on the left side was usually correctly localized, though this stimulus, too, was occasionally displaced into space. When this double displacement occurred, the patient would state that she felt two stimuli and would point into space to the left of the arm, stating, “Here and here.” These mislocalizations were repeatedly observed during a period of a month and were not always limited to the left side. They were occasionally observed to occur on the right side. At these times localization on the left was always correct, as indicated by pointing and by verbalization. C 0mment.——Exosomesthesia was elicited in this patient only under the condition of multiple simultaneous stimulation. It could not be elicited by single—stimulation methods. Also significant is the fact that exosomesthesia was apparent even though there was no gross disorder in body scheme on routine testing. Furthermore, it is evident that her errors in localization were not simply inability to point to or identify parts of her body by name, as ordinarily she experienced no difficulty in doing this on command. Both patients mislocalized percepts to parts of the body, to objects, or into space contiguous with the area stimulated. Occasionally, we have also observed displacement of a stimulus to the person of the examiner. Usually such percepts are mislocalized to a homologous portion of the examiner’s body; e. g., a stimulus applied to the patient’s hand is reported by him as though it had been applied to the examiner’s hand. Rarely, the mislocalization is to any part of the examiner’s body. This type of displacement is illustrated in the following case. CASE 3.—R. M., a man aged 52, was admitted to the Psychiatric Pavilion of Bellevue Hospital with the complaint that he had become confused and depressed. For about a year he had been disoriented and confused as to date and his relationship to people and had wandered about the city aimlessly. He had been admitted to the Farm Colony about a half-year before and had worked as a barber until the week before his admission to the hospital. Routine N euro'logic Examination—Neurologic examination showed normal gait and station. Coordination tests were well performed. The reflexes were active bilaterally, with normal plantar and abdominal responses. Cranial nerve functions were normal. The sensory status showed changes, but only with special methods of testing. A pneumoencephalogram demonstrated moderately dilated ventricles, without shift or deformity, and some dilated cerebral sulci. Psychiatric StaWs.——-A severe organic mental syndrome was evident. In the ward he sat quietly for hours by his bedside, taking little interest in his surroundings. When approached by members of the staff, he appeared perplexed but was affable. During the testing procedures he was cooperative unless confronted by a test situation in which the examiner demanded tasks �6 , beyond his ability. At such times he showed a “catastrophic” reaction, became excited, and discontinued his efforts in the examination. He was disoriented for time, place, and situation. However, he was able to find his‘way about the ward, locating his bed, the nurses’ desk, the doctor’s office, and the lavatory. Severe difficulties in intellectual function were observed. He was unable to give an adequate history. He could not recall the examiner’s name or the events of several hours before but did not confabulate. Calculation and symbol-identification tests were poorly performed. Severe aphasic difficulties were evident. He was unable to name common objects, clothing, or most parts of the body. He could not comprehend written commands, nor could he write, but he was able 'to follow simple verbal commands. Mild dyspraxia was demonstrated in his attempts to imitate finger and mouth movements. However, he was able to dress, feed, and otherwise care for himself. Body Image.——He had difficulty both in naming body parts and in locating them by pointing. The defects were severest in the fingers, wrists, and elbows, and occasionally the feet. There was difficulty in right-left orientation. Sensory Statute—(a) Single Stimulation: Routine sensory studies of touch, pinprick, and vibration stimuli showed no consistent impairment. These stimuli were usually correctly localized and described. Occasionally a single stimulus to the hand or forearm was displaced to a contiguous object or to space about the upper extremity. (b) Double Simultaneous Stimulation: On double simultaneous [touch] stimulation the patient displayed extinction and displacement of tactile stimuli. This was most evident in trials of the face-hand test 6 but was seen in tests of other body parts as well. For example, on simultaneous stimulation of the cheek and the opposite hand, he would either report only the stimulus to the cheek (extinction of the hand stimulus) or report a stimulus to each cheek (displacement of the hand stimulus). The pattern of sensory dominance was that usually seen in diffuse cerebral disease, the face being most dominant, the hand least.5 There was no lateral dominance. ,Exosoimestheyiat—Displacement into extrapersonal space was occasionally observed on single stimulation. This displacement was from the hand, forearm, or elbow to space contiguous to the part touched. Exosomesthesia was, however, markedly exaggerated when double simultaneous stimulation was employed. Again, the areas from which the phenomenon was most frequently'observed were the hands, forearms, and elbows. For example, when stimuli were applied to the dorsa of the hands as they were lying on the patient’s lap, he pointed to space in front of his knees. If asked to state where he had been touched, he would say, “The hands,” but would continue to point to the space in front of his knees. Exosomesthesia was rarely noted when other body parts, such as the cheeks or shoulders, were simultaneously stimulated. Occasionally it was found that on tests with double simultaneous stimulation the patient mislocalized a stimulus from his body to the homologous region of the examiner’s body. For instance, when the hands were simultaneously touched, he would grasp the examiner’s hands and affirm he had been touched “there.” Despite the examiner’s insistence that the stimulus had been to the patient’s hands, the patient would persist in pointing to the examiner’s hands. When asked to name the parts touched, he would say “There, there.” The same phenomenon was occasionally observed on simultaneous stimulation of the two elbows or cheeks. It was significant that this mislocalization to the examiner’s body occurred even when the patient was urged to look at the stimulations. It was observed that emotional tension, increase in the rate of testing or undue prolongation of the examination increased the incidence of exosomesthesia. For example, to initial application of pinprick to the right hand and the left cheek, the patient reported only the face percept, omitting the hand stimulus. Later, he localized the two stimuli to the cheeks. As the examination progressed and the physician speeded up the testing, the patient became tenser. He then localized the face percept correctly but insisted that the hand stimulation was into space in front of the hand. Finally, both stimuli were displaced into space or to the examiner’s body. These phenomena were observed daily over a period of 2% months. Bender, M. B.; Fink, M., and Green, M.: Patterns in Perception on Simultaneous Tests of Face and Hand, Tr. Am. Neurol. A. 75:250-252 (June) 1950; Patterns in Perception On Simultaneous Tests of Face and Hand, A. M. A. Arch. Neurol. & Psychiat. 66:35-5-262 6. (Sept) 1951. ' - - �7 Comment—While single stimulation occasionally produced exosomesthesia in this patient, the phenomenon was more pronounced under conditions of double simultaneous stimulation. This patient also mislocalized stimuli to the examiner’s body. Emotional tension, prolonged examination, or increase in the rate of testing. exaggerated the phenomenon of exosomesthesia. GENERAL COM MENT On consideration of these cases, it is immediately apparent that exosomesthesia is associated with a severe organic mental syndrome. Therefore, it might be argued that exosomesthesia is merely a manifestation of the patient’s mental confusion; that the patient simply points into space because he is confused. However, we have examined many severely confused patients and found exosomesthesia only rarely. Moreover, exosomesthesia is a patterned phenomenon, demonstrable in each patient under defined conditions, predictable as to the area from which it will occur and the extrapersonal spatial region to which the sensation will be projected. For example, in Case 1 exosomesthesia could be elicited only from the hand, and only when the dorsum was stimulated at the same time that the palm or fingers were in contact with another object. Displacement under these circumstances was usually not haphazard. As a rule it occurred to the object touching the palm or fingers. In Case 2 exosomesthesia could be elicited only by double simultaneous stimulation. It was seen most clearly in the hand and could be elicited only unilaterally at any oneexamination. Again, the displacement was not haphazard; the stimulus as a rule was localized to extrapersonal space contiguous to the area actually stimulated. In Case 3 the phenomenon was observed again under conditions of double simultaneous stimulation, and the displacements were either to space contiguous to the stimulated area or to homologous areas of the examiner’s body. It is significant that these displacements could be elicited even when the patient was urged to look at the application of the stimuli. Moreover, even when the examiner pointed out the error in localization and emphasized the implausibility of the response, the patient characteristically insisted on the correctness of the mislocalization. Factors Influencing Exosomesthesia.—Many factors influence the appearance of exosomesthesia. Except in children under special conditions, it has been observed exclusively in patients with severe mental changes resulting from disease of the brain. It is influenced by the type of stimulus used and the rate of stimulation, as well as by the element of simultaneity of stimuli. Moreover, the emotional state of the patient has a significant effect on the phenomenon, as does the part of the body stimulated. In some cases exosomesthesia has been made apparent by administration of small doses of amobarbital sodium. These factors will be discussed. (a) Bilateral Cerebral Disease: The symptom background in everycase of exosomesthesia is an organic mental syndrome secondary to bilateral cerebral disease. We have not been able to demonstrate exosomesthesia in an adult unless there were severe mental changes. But, as previously noted, it is a rare phenomenon, and only a few patients with severe organic mental syndrome show it. In 400 patients with organic cerebral disease, of varying severity, exosomesthesia was observed in approximately 3%.5 Even in these patients it was not manifest in every examination, and its frequency was readily altered by changes in the conditions of testing. It is therefore evident that severe bilateral cerebral disease in itself is not sufficient to produce exosomesthesia. �8 Effect of Simultaneous Stimuli: That simultaneous stimulation may elicit sensory phenomena not apparent on single stimulation has previously been demonstrated.2 For example, a hemisensory syndrome in a hemiplegic patient may not be discernible except under conditions of double simultaneous stimulation. Thus, single stimulation may be well perceived and localized by the patient, but the addition of a second stimulus simultaneously applied may so affect integration that the phenomena of extinction, obscuration, and displacement become apparent. Similarly, simultaneous stimulation elicited exosomesthesia when it was absent on single-stimulus examination, or exaggerated it when it was occasionally manifest on routine stimulation. In Cases 1 and 2 simultaneous stimulation was a necessary condition for eliciting the phenomenon. It could not be demonstrated by single stimulation. In Case 3 exosomesthesia could occasionally be elicited on single stimulation, but with simultaneous stimulation the phenomenon was demonstrated with much greater frequency. (6) Type of Stimulus Most Effective: Of the various stimuli used in these examinations, such as single touch, single pinprick, repetitive touch, and repetitive pinprick, it was noted that repetitive touch stimuli were most effective in eliciting nexosomesthesia. This was especially true on double simultaneous stimulation. (d) Effect of the Patient’s Emotional State: Exosomesthesia was exaggerated by alterations in the test situation which made performances more difficult. Increasing the rate of stimulation or unduly prolonging the examination increased the displacements to extrapersonal space. If the examiner was deliberately critical of the patient’s errors, the phenomenon also appeared with greater frequency. These factors increased the emotional tension of the patient and if carried further produced a “catastrophic” reaction. (e) Effect of Drugs: It has previously been demonstrated that difficulties in perception may be exaggerated by barbiturate intoxicants.5 Amobarbital sodium was administered intravenously in doses of 3 to 7 grains (0.2 to 0.45 gm.) to patients with diffuse cerebral disease. Prior to administration of the drug, these patients manifested the phenomena of extinction and displacement of percepts on simultaneous tests, but not exosomesthesia. While under the influence of the barbiturate;'three patients showed exosomesthesia, in addition to extinction and displacement. In two other patients, in whom exosomesthesia had been elicited only after a protracted testing period, the administration of amobarbital sodium elicited exosomesthesia at the onset of testing and exaggerated the phenomena of extinction and displacement. Relation of Exosomest‘hesia to Extinction, Obscumtvian, and Displacement—In our experience, whenever exosomesthesia has been observed, the phenomena of extinction, obscuration, and displacement are also present. Exosomesthesia, however, is a rare phenomenon, whereas extinction, obscuration, and displacement are commonly observed. Moreover, whereas extinction, obscuration, and displacement are frequently seen in adult patients with mild cerebral dysfunction,5 displacement into extrapersonal space is present only in cases of severe mental changes due to disease of the brain. It may therefore be concluded that exosomesthesia in adults represents a severer type of cerebral dysfunction than other simultaneous stimulation phenomena. (13) �9 Relation of Exosomesthle'sia to- Body I wage—It might be said that exosomesthesia is a pathologic extension of the body image. The normal person is continually of cites the Head of examples For this boundaries example, the image. extending the woman with a feather in her hat who “feels” when the feather is touched, and the surgeon who handles his probe as though it were an extension of his fingers.1 In the normal person, however, these extensions of the body image are fluid, immediately reversible, and clearly recognized by the subject as artificial. The surgeon, for example, is able at any moment to redefine correctly his body image. He “knows” that the probe is not his finger. In the group of patients described above, however, the extension of the body image seems to operate in a pathologic, rigid form. Under certain conditions these patients lose the ability to maintain a realistic definition of the limits of their body. They behave as though portions of the contiguous external world are concretely incorporated into the inner image of their body’s extent. Although we may consider exosomestheisa as a specialized body-image disturbin identification difficulties show do who be not that noted should it patients ance, and location of body parts still may show mislocalization into extrapersonal space. On the other hand, patients with an inability to identify or locate their body parts on command do not necessarily manifest exosomesthesia. In similar fashion, there is no necessary relationship between exosomesthesia and of manifested who dis-placement A difficulties. 3) (Case patient position-sense sensation into extrapersonal space did not make errors in routine tests of position made by observations with is consistent previously This in extremities. the sense Head1 that localization of single stimuli is not functionally related to sense of position of the extremities. Role of the Hand—Although displacement into extrapersonal space has been elicited from various areas of the body, it has been observed to occur most frequently from the hand. Moreover, in no case has it been elicited from another area and been absent from the hand. This predilection for the hand is consistent with the manner in which other the when As functioning reflected. rule, of a the are nervous system dysfunctions of one side of the body is impaired through cerebral disease, the disorder is most manifest in the hand. Thus, in the usual hemiplegia resulting from a capsular lesion the paresis, body-image disturbance, and sensory loss are most prominent in the hand and fingers. of the cerebral diffuse disease, with phenomena in others and these In patients, extinction, obscuration, and displacement are also best elicited when the hand is tested. Furthermore, studies of the order of sensory dominance of various areas of the body demonstrate that the hand is in the lowest rank. This is true of the dominance order of patients with cerebral disease,5 and also of normal subjects, both adults and children.6 Similarly, when allesthesia is observed, it is seen most clearly in the hand. Ben7 described a case in which the clinical course was reflected in a Nathanson and der Bender, M. B., and Nathanson, M.: Patterns in Allesthesia and Their Relation to Disorder of Body Scheme and Other Sensory Phenomena, Arch. Neurol. & Psychiat. 64:501-515 7. (Oct) 1950. �10 waxing and waning allesthesia. As this patient improved, the areas from which the phenomenon could be elicited diminished, until finally allesthesia was demonstrable only in the hand. In autotopagnosia the hands are more profoundly affected than other regions. Finger agnosia, possibly the earliest sign of body-image disturbance, is frequently seen in the absence of other gross disturbances of the body schema. Furthermore, phantom limb, anosognosia, causalgia, and synesthesia are phenomena in which the role of the hand is especially prominent. Just as these pathologic phenomena are manifest in tests of other body parts, but are most clearly demonstrable in the hand, so, too, exosomesthesia, though occasion— ally demonstrable elsewhere, is most apparent in examination of the functions of the hand. Exosomesthesia in the Normal Child.—-It has been observed that sensory phenomena which occur in patients with cerebral dysfunction may be found in the nor— mal young child.6 Similarly, exosomesthesia, which we have never found in adults except when there is severe cerebral disease, can be readily observed in children up to the age of 4 years. In examination of a large series of normal children it was noted that the initial responses of children to double simultaneous stimulation frequently included exosomesthesia, although the commoner responses were extinction and displacement. Exosomesthesia was rare, however, after the initial few trials. The frequency with which exosomesthesia may be seen in children up to the age of 4 years suggests that it may represent, in the child, a “normal” developmental stage in the organization of perception. Its appearance in adults with severe brain disease may possibly be, as with other pathologic phenomena, a regression in function to a previous level of sensory integration. SUMMARY The patterned mislocalization of tactile stimuli into extrapersonal space is described and termed exosomesthesia. Exosomesthesia is observed in patients with severe organic mental syndromes. It is apparent only rarely on single tactile stimulation and is more readily elicited by the technique of double simultaneous stimulation. It is exaggerated by fatigue, rapid testing, and increased emotional tension. Barbiturate intoxication also may elicit or exaggerate the phenomenon. Exosomesthesia is most apparent in stimulation of the hand but has been observed in tests of other body parts. While it may be considered a pathologic extension of the body image, it is not dependent upon concomitant body-image disturbances. Although exosomesthesia has been observed chiefly in patients with severe mental changes, it is not a manifestation of confusion, but is a patterned, predictable phenomenon. It may be a regression, in patients with cerebral dysfunction, to a previously “normal” stage in sensory development, as suggested by the fact that it is readily observed in simultaneous tactile tests of young children. , Printed and Published in the United States of America � Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Published Works Text A resource consisting primarily of words for reading. Examples include books, letters, dissertations, poems, newspapers, articles, archives of mailing lists. Note that facsimiles or images of texts are still of the genre Text. Dublin Core The Dublin Core metadata element set is common to all Omeka records, including items, files, and collections. For more information see, http://dublincore.org/documents/dces/. Title A name given to the resource Exosomesthesia; the displacement of cutaneous sensation into extra-personal space. Trans Am Neurol Assoc. 1952;56 (77th Meeting):260-2. Type The nature or genre of the resource Text Identifier An unambiguous reference to the resource within a given context mfp-02-01-001-6b-009 Date A point or period of time associated with an event in the lifecycle of the resource 1952 Creator An entity primarily responsible for making the resource <a title="Fink, Max, 1923-" href="http://id.loc.gov/authorities/names/n79039548" target="_blank">Fink, Max, 1923-</a> Subject The topic of the resource Published Works -- Articles and Reviews Relation A related resource The Max Fink Collection Description An account of the resource Reprinted from the A.M.A. Archives of Neurology and Psychiatry, October 1952, Vol. 68, pp. 481-490 Rights Information about rights held in and over the resource <a title="IN COPYRIGHT - EDUCATIONAL USE PERMITTED" href="http://rightsstatements.org/vocab/InC-EDU/1.0/" target="_blank">IN COPYRIGHT - EDUCATIONAL USE PERMITTED</a> Source A related resource from which the described resource is derived Special Collections and University Archives, University Libraries. Stony Brook University Libraries (State University of New York). Language A language of the resource en-US Format The file format, physical medium, or dimensions of the resource application/pdf Publisher An entity responsible for making the resource available Contributor An entity responsible for making contributions to the resource Published