Daniel Ernest Ford, M.D., M.P.H.
- Director, Johns Hopkins Institute for Clinical and Translational Research
- Professor of Medicine
Against the view that psychogenic factors predominate in anosognosia is the rather obstinate fact that anosognosia antibiotics for breeding dogs keftab 375 mg online, like uncomplicated unilateral neglect infection 4 weeks after birth purchase keftab american express, has usually been found to be very much commoner for the left than for the right side of the body antibiotic keflex buy cheap keftab 750mg line. Moreover virus 2014 fall keftab 125mg without a prescription, the lesion virus killing children order keftab 250mg on-line, when focal virus killing children keftab 250mg lowest price, appears to implicate the temporoparietal region rather than the pre-rolandic cortex or lower levels of motor organisation. One complication is that there is no agreed definition of anosognosia, especially where the penumbra of related phenomena are concerned, so assessing prevalence is problematic. This is further complicated in left hemisphere-damaged patients by the presence of aphasia, which might lead to an underestimate of the condition in right hemiplegics (Cutting 1978). The published work on the cerebral localisation of anosognosia has been systematically reviewed by Pia et al. They concluded that while right hemisphere damage is the hallmark, bilateral damage is frequently reported. Furthermore, the deficit seems to be equally frequent when the damage is confined to frontal, parietal or temporal cortical structures, and may also emerge as a consequence of subcortical lesions. Interestingly, the probability of occurrence of anosognosia was noted to be highest when the lesion involved parietal and frontal structures in combination. The rarity of anosognosia and related defects in the right limbs is very hard to explain by any theory. It has been 74 Chapter 2 suggested that since the left limbs are normally subordinate to the right, cerebral lesions merely exaggerate this tendency or, alternatively, that with lesions of the dominant hemisphere intellectual deficits and aphasia readily swamp these more subtle manifestations. Others have attempted to resolve the dilemma by proposing that the non-dominant hemisphere is prepotent where the body image is concerned, or at least that it contains special mechanisms for the recognition of unilateral inequalities. Many unilateral examples are seen with focal brain disturbance, particularly as part of an epileptic aura, and some of the most bizarre instances, including autoscopy, can occur in the course of migrainous attacks. A further group appear in association with static lesions, particularly those which have led to left hemiplegia and anosognosia, but here again the phenomena are usually short-lived even if recurrent. Macrosomatognosia and microsomatognosia consist of feelings of abnormal largeness or smallness of parts, or of half or even the whole of the body. Such changes may be accompanied by sensations of heaviness, distortion or displacement of the part concerned, or features such as these may constitute the sole abnormality. Feelings of swelling, elongation, shortening or twisting may be experienced, rather than a change that preserves the normal proportions of the part. Rarely the experience may be of physical separation of the part from the rest of the body. Autotopagnosia Autotopagnosia refers to an inability to recognise, name or point on command to various parts of the body both on the right and on the left. However, restricted forms are seen in conjunction with many other types of body image disorder, in that a tendency may occur to misidentify certain body parts. Such a defect confined to one body half is seen in patients with unilateral neglect or anosognosia. Most examples which implicate the body bilaterally are explainable in terms of apraxia, agnosia, aphasia or disorder of spatial perception. De Renzi and Scotti (1970) described a case which perhaps illustrates essential mechanisms of another type. The patient, who had a tumour of the left parietal lobe, failed to point to body parts, but in contrast could promptly name all parts pointed to by the examiner. The same dissociation between pointing himself and naming could be seen for parts of objects other than the human body, for example for parts of a bicycle. The defect thus appeared to be a part of a more general disturbance of failure to analyse a whole into parts. Autotopagnosia is usually seen in conjunction with diffuse bilateral lesions of the brain. Lesions of the left hemisphere alone can produce it, but must always involve the parietooccipitotemporal region (Frederiks 1985). An epileptic girl sometimes had a somatic sensory aura during which she felt that: my whole body grows very rapidly almost to the point of bursting. After a few seconds it collapses, like a deflated balloon, and then I lose consciousness and have a turn. A lorry driver discovered to have epilepsy had attacks: when everything seems to run away from me, and then I get the feeling in my eyes that they tear out of their sockets, and rush out from the cabin, till they touch the people and the houses and the lampposts along the road. Then everything rushes towards me again and my eyeballs hurry back into their sockets. At other times I might feel that my hands and arms grow long very rapidly, till they seem to reach miles ahead. A woman with migraine complained: Before the ache I see coloured zig-zag stripes appearing always from the left side. After a while I begin to feel that my head shrinks until it becomes not bigger than a small orange. This sensation lasts about 1 minute and then my head at once comes back to its normal size. This feeling of my head shrinking and expanding goes on for some time, until I get my splitting headache. Illusions of transformation, displacement or reduplication A great variety of body image disturbances may be loosely grouped together under this heading. Some of the less dramatic, such as feelings of heaviness or enlargement of a limb, may occur in healthy subjects in states of extreme exhaustion, sensory deprivation or in the course of falling asleep. A truly delusional or hallucinatory experience is rare in the absence of marked impairment of consciousness or psychotic illness. It is of course hard to discern, in cases such as those just quoted, how far the abnormal experience is due to a primary disturbance of the body schema or how far it represents an imaginative elaboration of simple kinaesthetic and vestibular sensory changes. Derangements of either right or left hemisphere function may lead to such phenomena, and when a focal lesion is responsible the parietotemporo-occipital region is said to be usually involved. Reduplicative phenomena usually involve the limbs, and most often the hand or fingers alone. Many cases occur with anosognosia for left hemiplegia, and may lead to illusions of movement in the paralysed limbs. Insight is again usually preserved in large degree, and when the patient looks at the actual limbs the phantom promptly disappears. However, occasional cases are reported in which enduring phantoms prove an embarrassment and inconvenience, and the patient feels obliged to make the real limb coincide in position with the phantom. More dramatic instances of reduplication may involve the whole-body image (Lukianowicz 1967). One patient with a left hemiplegia claimed to have an extra left hand; one with a left hemiparesis and a fracture of the right leg stated that he had four legs; and one with a severe head injury who had previously had an eye removed claimed to have several eyes. Another patient with a cerebellar astrocytoma and meningitis said that he had three heads and four bodies, one of each with him and the remainder upstairs in a closet. In all four cases the reduplications were accompanied by other forms of reduplication for time, place or person. Usually the image is in front of the patient at a certain distance, mostly fleetingly but very occasionally lasting for days at a time. It may consist of the whole or only a part of the body, but the face is usually included. Cases have been described in which the image occurs to one side of the midline in a hemianopic field of vision. The experience may be extremely realistic but is almost always recognised by the subject to be a pathological event. Usually the experience is visual, as the name implies, but sometimes the body image is experienced as projected into outside space by senses other than vision. A number of subdivisions of this striking phenomenon are recognised, as discussed by Brugger et al. In heautoscopy, somaesthetic elements are additionally projected into peripersonal space so that the subject both sees and feels awareness of the presence of his double. It is endowed with an intense sense of familiarity and affinity, and sometimes it dawns on the subject that the presence is in fact a replica of himself. Phantom limb, which occurs after amputation or peripheral lesions of the nervous system, has a basis quite distinct from the supernumerary phantom that occurs with cerebral disease (Halligan et al. It is nonetheless in some ways the most decisive proof of the existence of the body schema. Phantom limbs are seen most commonly after amputation, but similar phenomena may follow severe nerve plexus lesions or lesions of the brainstem and thalamus. Equivalent phantom phenomena have also been reported after removal of the breast, the genitalia or the eye. Distinction must be made between the perception of the missing limb itself, including its spatial characteristics, and the perception of phantom limb sensations such as paraesthesiae, heaviness, cold, cramp and pain. In the course of time it may appear only sporadically, or it may gradually telescope, the distal portion ultimately approaching the stump and disappearing into it. It is typically paroxysmal, burning or shooting in character, sometimes occurring alone and sometimes with paraesthesiae. As with other phantom limb sensations the pain may be markedly affected by influences such as a change in the weather, use of a prosthesis, use of the contralateral limb, pain elsewhere in the body or firm efforts at mental concentration. A topographically organised sensory representation of the phantom limb may develop (remapping), for example on the face or chest, stimulation of which may be experienced in the phantom and which may be detected using functional neuroimaging in the corresponding sensory cortical region. A psychogenic component thus undoubtedly exists, and has been interpreted in terms of loss of bodily integrity and reaction to disablement. Psychotherapy and hypnosis have accordingly sometimes met with success in treatment, as has sensory distraction. However, a physiological component is also indicated by the efficacy, shortlived though it may be, of surgical procedures. Relief may follow the excision of a stump neuroma, chordotomy, or lesions in the thalamic radiation or sensory cortex. Insight into the unreality of the experiences was commonly retained, though sometimes incompletely expressed. In some cases complex sensory experiences appeared to underlie feelings that the body was changing into that of the opposite sex, likewise in some examples of transformation into Christ or other figures. Care was taken to distinguish as far as possible between mechanisms such as these, in which there was a discernible relationship to corresponding bodily sensations and hallucinations, and the more usual situation in which a delusional belief in a new identity or sex was purely ideational. Feelings of change of position in space included levitation, floating and falling, sometimes as hypnagogic phenomena but sometimes occurring in the full waking state. In epileptic patients equivalent sensations were sometimes observed as a kinaesthetic aura preceding an epileptic attack. Feelings of reduplication and splitting occurred in schizophrenia and in depression. A schizophrenic student had the feeling of: two bodies, one outside the other, only a bit larger than my actual body. A woman when depressed had a feeling: as if my body was split into two halves, like a stem of a tree struck by lightning. They both feel a few inches apart and there is nothing between them, but a black empty hole; black and empty and dead. Disturbances of the shape of the body image were the commonest abnormality and took many forms. Such changes appeared to be based essentially on Again, in epileptic patients such experiences could herald an attack. Experiences of autoscopic doubling were also seen in patients with schizophrenia and depression. Feelings of additional body parts occurred in several bizarre forms, sometimes inviting a psychodynamic formulation which would see them as symbolically representing displaced sexual organs (but see Halligan et al. A man whose potency was dwindling as a result of spinal injury developed recurrent depressive episodes. In one there were visual and haptic hallucinations of spurs and horns growing from his ankles, in another of a ball sticking out of his thigh, and in another of big screws growing from his abdomen and thighs. Neuropsychology in Relation to Psychiatry 77 Change of size sometimes affected the whole body, and sometimes parts only, such as the ears, nose or limbs. Again, displaced sexual symbolism sometimes provided the most ready explanation, though analogous examples occurring in the course of epileptic and migrainous attacks may have rested primarily on disturbed cortical function. Lilliputian experiences were rare in comparison to feelings of enlargement, but one depressed woman had distressing hypnagogic experiences in which she felt her body shrink rapidly to the size of her little finger. Changes in mass were usually manifest as feelings of emptiness and hollowness of body parts, particularly of the head. They were confined to patients with depressive illness or neurotic disorder, and often came close to nihilistic delusions. Non-cognitive disturbances and regional brain dysfunction the forms of disability discussed above have all been more or less closely tied to cognitive or perceptual deficits, even though these have sometimes been of a rather subtle nature. Abnormalities of emotion and personality cannot be assessed with anything like the precision that is usually possible for cognitive defects. It has already been seen how much uncertainty surrounds our understanding of such measurable disorders as memory impairment, and such testable defects as aphasia or apraxia. With the body image disturbances there is an uncertain admixture of physiogenic and psychogenic mechanisms to be considered. Such problems are greatly extended in any analysis of disordered emotion or abnormalities of personality and social behaviour. Despite such difficulties important leads have been obtained, and interesting clinicopathological correlations have emerged in the examples discussed below. A man with an anxiety disorder described a recurrent hypnopompic experience as follows: Just after I wake up, but before I move, I have a terrifying feeling that my whole body consists of skin with nothing inside, like an empty blown-up balloon, or an empty shell, only pretending to be a human body. It is a very frightening feeling, which lasts only a few seconds and disappears immediately when I move any part of my body. In general these various disturbances in psychiatric patients seemed to be an integral part of their mental illnesses, along with the more common hallucinations and related psychotic symptoms.
Walton (1952) commented on the general similarity between such symptoms after subarachnoid haemorrhage and after head injury necroanal infection purchase keftab overnight, an observation that others have made (Hellawell & Pentland 2001) antibiotics used to treat mrsa buy keftab australia. At 3 infection app generic 375 mg keftab with visa, 6 and 12 months every patient was assessed by psychiatric interview and classified according to a somewhat idiosyncratic classification of organic mental disorders developed in Sweden (Lindqvist & Malmgren 1993) antibiotic resistance how does it occur buy cheap keftab online. Thus the excluded patients included six who were diagnosed as suffering a non-organic psychiatric disorder usually on the basis of depressive symptoms that were either present before the haemorrhage or only appeared during the course of the first year antimicrobial metals order keftab 125 mg fast delivery, not having been present at 3 months bacteria phylum keftab 375 mg with amex. Therefore a picture emerges which is reminiscent of that seen in traumatic brain injury. Some neuropsychiatric sequelae, for example personality change with disinhibition or poor motivation, and the amnesic syndrome, are tightly determined by the severity of brain injury. In contrast, patients also suffer a range of symptoms, of which fatigue, headache, dizziness and emotional changes are the commonest, that are less easy to understand simply as a consequence of brain injury, more likely to improve over the early months, and probably more related to psychological factors. This was the finding in a population-based study of over 200 patients, comprising 95% of the target cohort, who were available for telephone interview between 12 and 18 months after haemorrhage; 50% reported memory problems, 40% mood problems and 10% reported being dependent in terms of everyday activities (Hackett & Anderson 2000). Even when studies are restricted to patients with good neurosurgical outcome, many are found to have disabling psychosocial problems that relate to cognitive, emotional and behavioural sequelae. Three studies have restricted their ascertainment to patients rated good or fair outcome on the Glasgow Outcome Scale. They tended to suffer worse headaches than before the haemorrhage, almost one-third were depressed, and almost onethird reported that they had lost their job or been demoted or retired. In a second study, only 3 of 20 patients fully employed at the time of the haemorrhage were still employed at that level 19 months later (Buchanan et al. Common symptoms were high levels of fatigue and intolerance of noise and social contact. Very few reported positive effects of the injury and family members reported that they themselves had high levels of distress and burden. Finally, in their study of 52 patients recruited consecutively and compared with controls matched carefully for age, sex and psychosocial status, Powell et al. On measures of self-organisation and productive employment, over half the patients scored above the 90th centile of the control population scores. There was subtle evidence of cognitive impairment, with greater impairment evident at 3 months than 9 months, by which time only prose recall was impaired. Elevated levels of depressed mood, intrusive thoughts and avoidance were reported (described above). Using the 8-point extended Glasgow Outcome Scale to measure disability on several occasions over the first 5 years, it was possible to demonstrate significant improvements in outcome. However, after 12 months and over the next 4 years patients were as likely to deteriorate one point as they were to improve one point, with the vast majority of patients remaining unchanged. There was a considerable degree of overlap in the symptoms described by the two groups. For example, more than 75% of subjects reported that though they had for several months or years after the haemorrhage suffered fatigue or sleepiness, these had now resolved. The largest study is of over 600 patients most of whom had at most slight disability after a subarachnoid haemorrhage between 2 and 19 years (average 9 years) previously (Wermer et al. One-quarter of patients who had been working before the haemorrhage were no longer working, and a further one-quarter were working reduced hours or in a less demanding position. Almost 60% reported personality change, the commonest changes being increased agitation/ irritability, increased emotionality and apathy. Overall 35% reported memory problems, although the proportion lessened as time since haemorrhage increased. The most frequent symptoms were fatigue, headaches, concentration problems and dizziness, with only one-quarter of patients saying that they had made a complete symptomatic recovery. Thus the pattern and extent of problems, compared to what has been described above in the first months and years after haemorrhage, does not seem to change much in the very long term. Emotional precipitation of subarachnoid haemorrhage Occasional examples are reported of cerebrovascular accidents that show a striking temporal relationship to emotionally stressful events. However, the most dramatic instances appear to involve patients with subarachnoid haemorrhage. Particularly striking examples have been recorded by Storey (1969, 1972), in which the haemorrhage followed immediately upon some emotionally traumatic event, presumably by virtue of the rise of blood pressure engendered. Another woman was watching television when an aeroplane on a test flight was shown exploding in the air; she believed (erroneously as it turned out) that her son was on it, put her hands to her head and had the haemorrhage within seconds of the disaster. Another had a subarachnoid haemorrhage within a minute of being told by her husband that he knew of her adultery and was going to divorce her. Cerebrovascular Disorders 499 Altogether Storey found evidence of a striking emotional precipitant in four of his original 261 patients, and two further less dramatic examples. Such precipitation appeared to be markedly more common in patients with no obvious source for the haemorrhage than in patients with aneurysms demonstrable on angiography. Giant cerebral aneurysms the great majority of aneurysms giving rise to subarachnoid haemorrhage are small, rarely exceeding 1 or 2 cm in diameter. Massive aneurysms are distinctly uncommon, but when present can give rise to much diagnostic confusion and are often not even considered in differential diagnosis. Best known is aneurysm of the intracavernous portion of the internal carotid artery, which may compress surrounding nerves leading to ophthalmoplegias and sensory loss of trigeminal distribution. They most commonly present with diplopia and pain in the face, eye or head (Stiebel-Kalish et al. Those situated on the circle of Willis at the base of the brain rarely rupture, but can produce local pressure effects simulating basal space-occupying lesions. However, in six patients mental changes predominated; dementia was the presenting feature, usually but not invariably accompanied by neurological signs such as cranial nerve deficits or hemiparesis. Morley (1967) reviewed the literature concerning unruptured vertebrobasilar aneurysms, which can lead to a variety of pictures simulating multiple sclerosis, posterior fossa tumours or vertebrobasilar ischaemia. Three of his own five cases had at first been diagnosed as psychiatrically unwell; vague symptoms of headache, nondescript dizziness, slowed speech and a muted facial expression had led to an impression of depressive illness. Sometimes focal neurological signs, including cortical blindness and hemiplegia, may be found but are not usually part of the picture. The disorder evolves rapidly, often within the space of 24 hours, and if untreated progresses to coma with fatal outcome in a high proportion of cases. Patients generally make a full recovery although three cases have been described in which hypertensive episodes in childhood appear to have been followed by temporal lobe epilepsy and hippocampal sclerosis (Solinas et al. Serial images are required to differentiate the acute effects of hypertensive encephalopathy from the ischaemic demyelination of white matter, characteristically in a periventricular distribution, that is associated with chronic hypertension. Another reversible finding is high signal on T2 sequences in white matter, particularly posteriorly in the cerebral hemispheres. Pathological examination may reveal a normal brain, but usually there is marked oedema or petechial haemorrhages and microinfarcts. Byrom (1954) showed in the rat that with hypertension of advanced degree there was intense segmental constriction of cerebral arterioles, attributable to attempts at autoregulation that fail when the pressure exceeds a certain limit. Dilatation occurs between the constricted segments and the vessel wall is damaged, leading to hyperperfusion and cerebral oedema, which may be the essential factors underlying hypertensive encephalopathy (Skinhoj & Strandgaard 1973). Hypertensive encephalopathy this was never a common condition, with less than one in six patients with malignant hypertension suffering encephalopathy (Healton et al. Nevertheless, it is still very occasionally seen, particularly in patients with eclampsia (Becker 2006). Very occa- Migraine Migraine is a common and sometimes severely incapacitating disorder. Migraine is a familial disorder, characterised by recurrent attacks of headache widely variable in intensity, frequency and duration, commonly unilateral, usually associated with anorexia, nausea and vomiting, and sometimes preceded by or associated with neurological and mood disturbances (Critchley 1969). In the presence of aura the diagnosis of migraine headache is usually unmistakable, but headache in the absence of aura may be less easy to diagnose. Although estimates vary quite widely, it is reasonable to conclude that over the previous year about 12% of adults will have had at least one attack of migraine. The male to female ratio is about 1: 3 and the lifetime prevalence about 16% (Hirtz et al. Clinical features Onset is usually in childhood or early adult life, some 25% of cases beginning before the age of 10 and very few after 50. A childhood history of cyclical vomiting with abdominal pain can sometimes be traced as a precursor. This has been studied prospectively in 76 patients who reported having non-headache symptoms that predicted an attack (Giffin et al. Using patient hand-held electronic diaries that were adjusted so that entries could not be retrospectively altered or deleted, patients recorded these symptoms and whether they were in fact followed by migraine. When such symptoms were recorded in the diaries they were followed by migraine within 72 hours on 72% of occasions. The most common premonitory symptoms were tiredness, difficulty concentrating, stiff neck and irritability. In other words, there was not a specific constellation of symptoms that only occurred during the premonitory phase, although yawning, hunger or food cravings, and increased energy were more common before than during the attack. The authors suggested that the presence of non-headache symptoms before, during and after a migraine attack were consistent with a model of migraine as an episodic dysfunction of trigeminovascular regulation, probably mediated at the level of the brainstem (see below). It is mostly unilateral at onset, though tending to become diffuse later in the attack. Anorexia, nausea and vomiting usually develop, also photophobia and intolerance of noise. Autonomic changes may include pallor, facial oedema, conjunctival injection, abdominal distension or the passing of one or more loose stools. Difficulty will be encountered in distinguishing it from tension-type headache in certain cases. Various dramatic neurological symptoms may be seen but the commonest is visual disturbance as the first indication of an impending attack. Other forms consist of moving coils, curving lights or rippling sensations in the visual field. A negative scotoma may follow in their wake, or constitute the whole of the aura in itself. Problems with language may take the form of anomia or difficulty with speaking (Ardila & Sanchez 1988). Body image disturbances, though rare, can take fascinating forms, as discussed in Psychiatric features associated with attacks (later in chapter). Mood changes include irritability and depression, but the occasional person feels refreshed or euphoric after the attack. A not uncommon variant, seen in about 10% of cases, is basilar-type migraine or basilar artery migraine (Bickerstaff 1961a; Kirchmann et al. The attacks begin with a visual aura, sometimes extending to both half-fields and obscuring vision, then proceeding to symptoms of brainstem dysfunction such as vertigo, dysarthria, ataxia, tinnitus, and sensory symptoms distally in the limbs and around the lips and tongue. After several minutes to three-quarters of an hour these give way to throbbing headache usually of occipital distribution. Loss of consciousness may be interposed between the brainstem symptoms and headache, lasting sometimes for up to half an hour and presumably due to ischaemia of the reticular formation. The hemiparesis is always associated with sensory, language or visual disturbances and in one-fifth of cases the attacks are accompanied by confusion or drowsiness. In a proportion, particularly in younger patients and sometimes following a mild head injury, prolonged episodes of an encephalopathic-like illness, lasting days and weeks, may be seen (Ducros et al. The majority of cases have symptoms of basilar migraine, and in 20% of families patients have permanent cerebellar signs. Familial hemiplegic migraine is rare and is largely of interest in view of the genetic findings (see below), which are generally not found in sporadic hemiplegic migraine. The headache may be mild or even totally absent, leading to considerable diagnostic difficulty if a history of more typical attacks is not forthcoming. Thus the visual aura or other neurological disturbance may occur alone, or there may be episodes of nausea and vomiting, abdominal pain or drowsiness. Activation of hypothalamic, rather than brainstem, blood flow is found (May et al. The accompanying editorial described retinal migraine as an oxymoron (Winterkorn 2007) because it is highly unlikely that the pathophysiology underlying migraine aura, involving spreading depression over the cortex (see below), could apply to the retina. Course and outcome Once established, migraine is commonly a lifelong complaint, although spells of relief may occur for years at a time. Some are affected at fairly regular intervals, and a small number of women are especially susceptible around the time of their menstrual periods. The prevalence declines beyond the age of 50 years in both men and women (Steiner et al. Precipitating factors, for example fatigue or sleep, stress, particular foods or drinks, menstruation, weather (Prince et al. However, Broderick and Swanson (1987) were able to find only 20 examples of stroke occurring with an attack among almost 5000 patients at the Mayo Clinic. Good recovery was usual, only two being left with moderate disability and 14 with mild or minimal disability. Those with stroke during an attack were less likely to have cardiovascular abnormalities as potential sources of emboli, and more likely to have a prolonged duration of attack. Such features suggested that strokes which occur during the course of attacks were intimately related to the pathophysiology of the migraine process, i. The conclusion from a review of the relation between stroke and migraine is that the risk of suffering ischaemic stroke is increased in patients with migraine, particularly in young women (Bousser & Welch 2005).
However antimicrobial hand soap discount 750 mg keftab visa, the most common setting for this symptom is severe dementia antibiotics for dogs cephalexin side effects generic 500 mg keftab visa, where perception of the entire visual world is degraded and combined with faulty reasoning and confusion infection 6 months after hysterectomy cheap 750mg keftab fast delivery. A few cases have been described in which impaired self-recognition antibiotics for acne what to expect purchase discount keftab on line, the so-called mirror sign antibiotic gram negative buy 500 mg keftab amex, seemed to be out of proportion to other deficits (Phillips et al antibiotic resistant sinus infection trusted 250 mg keftab. Usually, though, such complaints indicate depersonalisation without concomitant intellectual or neurological dysfunction. On closer questioning, the essence of the complaint, while obviously provoked by gazing at the mirror, is that the individual is unsure of his identity and feels detached from it. Colour agnosia Patients with colour agnosia show defective appreciation of the differences between colours and fail to relate colours to objects correctly, even though their primary colour vision is intact as shown by normal performance on the Ishihara chart. Thus they have difficulty in sorting objects according to colour, ordering them in series or matching colours one with another. A dominant occipital lobe lesion is usually responsible and a right homonymous hemianopia is frequently present. Such problems may be unaccompanied by any other form of language difficulty, representing an unusually clear example of disruption of neural systems that mediate between specific concepts and their corresponding word forms (Damasio & Damasio 1992). The lesion in such cases appears to lie in the temporal segment of the left lingual gyrus. The concept of colour itself is abolished and the world around, though perceived normally in form and depth, is seen in shades of grey. Damage in such cases is situated in the occipital and subcalcarine portions of the lingual gyri bilaterally (Damasio & Damasio 1992). Visuospatial defects After cerebral lesions a number of defects of visuospatial perception may be demonstrated. However, it remains uncertain whether failure to reproduce simple models and drawings depends on dyspraxic difficulties or failure of visuospatial analysis, likewise how far inability to draw from memory may further depend on defective visual imagery. Classic visuospatial agnosia is indeed widely regarded as broadly synonymous with constructional apraxia, as discussed below. Visuospatial agnosia Visuospatial agnosia is identified by failure on tasks which demand explicit analysis of the spatial properties of a visual display. This is most readily tested by asking the patient to reproduce simple designs under visual control: the copying of drawings or the construction of patterns with bricks or sticks. The Block Design and Object Assembly subtests of the Wechsler Adult Intelligence Scale will most readily indicate minor degrees of such a defect. Usually the patient has no difficulty in finding his way about, though an itinerary on a map cannot be indicated and towns cannot be correctly located. In the most severe examples a loss of topographical memory (see later in section) may be present as well. An interesting fact, often noted, is that patients with marked visuospatial defects rarely make specific complaints about them. Thus visuospatial agnosia easily eludes routine examination and special tests are needed for its detection. Drawings made by patients with left parietal lesions tend to be coherent but simplified versions of the model, with omission of details but relative preservation of spatial relationships. Performance is notably improved when the patient is provided with a model to copy. Patients with right parietal lesions produce more elaborate drawings, but made hastily and without care, and the result is typically scattered and fragmented. Disorientation on the page is marked, the left side of the page is relatively neglected, and the drawings are often asymmetrical and show gross disorganisation of spatial relationships. Simultanagnosia Classically the patient fails to recognise the meaning of a complex picture while details are correctly appreciated. However, this is not attributable to difficulty in forming meaningful concepts, since with auditory information there is prompt understanding. Moreover, if plenty of time is given, or every individual feature of the picture is pointed out, the patient ultimately comprehends the meaning. The key problem appears to be with the perception of more than a limited number of units or configurations at a time. Thus tachistoscopic studies have shown that such patients have normal thresholds for the perception of single shapes and letters, but greatly elevated thresholds when more than one stimulus is presented at a time. Coslett and Saffran (1991), in a detailed analysis of a case, suggested that the fundamental difficulty lay in the integration between object identity and information concerning spatial location when multiple items of visual information needed to be processed. Posterior lesions of the dominant lobe have been implicated in patients who display the complete syndrome. Problems in fixating on an object or directing fixation to a part thereof in an array may be regarded as simultanagnosia but tend to be seen more as problems in visuospatial attention. Some evidence has come from studies of patients after section of the corpus callosum that upholds the greater Neuropsychology in Relation to Psychiatry 67 importance of the non-dominant hemisphere in tasks demanding visuospatial analysis. In brief, the left hand often out-performs the right on unimanual construction tasks. Again there is the difficulty in teasing apart constructional (praxic) difficulties from purely perceptual ones (Bogen & Gazzaniga 1965; LeDoux et al. Visual disorientation A further defect of visuospatial ability consists of difficulty in localising objects in space by vision alone. As a result the patient cannot point accurately to an object or estimate its distance. Such difficulty can occur in either half-field of vision alone, contralateral to the side of a lesion, or involve the whole visual field with bilateral lesions. When involving the whole field of vision the patient has difficulty in finding his way around objects or in learning the topography of a room. Visual disorientation is usually seen in conjunction with impairment on more complex visuospatial tasks, and the lesions are situated posteriorly within the hemispheres. Warrington and colleagues have suggested that there may be areas within the occipital lobes that contribute to the absolute localisation in space of a single object, whereas the integration of several spatial stimuli necessary for the appreciation of spatial relations between two or more objects is impaired by unilateral lesions within the right parietal area (see McCarthy & Warrington 1990). Loss of topographical memory Patients with visual object agnosia or visuospatial agnosia may sometimes still be able to visualise familiar scenes or describe familiar routes. However, loss of topographical memory may occur, again in conjunction with lesions in the parietal lobes. While bilateral posterior lesions were common in the group, they concluded that unilateral right-sided posteromedial lesions were critical. Ratcliff and Newcombe (1973) produced especially interesting findings from a study of men with penetrating missile wounds of the brain. Two tests were employed: a visually guided stylus maze task, and a locomotor map-reading task in which the subject was required to trace out a designated route on foot. These were designed to tap visuospatial agnosia and topographical disorientation, respectively. Patients with lesions in the posterior part of the right hemisphere were significantly worse than those with left posterior lesions on the mazelearning test, but a significant deficit on the map-reading test emerged only in those with bilateral posterior lesions. Ratcliff and Newcombe were led to conclude that while the right hemisphere has a special role in the perception of space, it does not bear an exclusive responsibility for the maintenance of spatial orientation. Bilateral lesions appeared to be necessary before route finding was impaired, perhaps because this involves a constant reorientation to stimuli as the subject moves around and alters his frames of reference. Further experiments on the topic are described by De Renzi (1982), along with a detailed discussion of the various deficits that may contribute to topographical disorientation. Visual neglect Unilateral visual neglect (or unilateral spatial agnosia) may be seen in spontaneous drawings, copies, description of pictures, or use of paper when writing. It may also lead the patient to fail to take turnings to the left and consequently he may lose his way on familiar routes. This is an agnosia for space as such, not merely an agnosia for spatial relations between visual objects. It is well confirmed that neglect of the left half of space is very much more common than that on the right, and depends on a right temporoparietal lesion (Heilman et al. Following a right middle cerebral infarction he showed left visuospatial neglect, a left hemiparesis and an inferior homonymous quadrantanopia. On standard line bisection tests, performed with the paper immediately before him, he showed marked displacements to the right, but was able accurately to indicate the midpoint of lines and to direct darts accordingly when these were some 2. This has led to theoretically motivated rehabilitation programmes, for example involving attentional cueing to the 68 Chapter 2 neglected side, for what is a notoriously disabling syndrome (Pierce & Buxbaum 2002). In an elegant yet simple study, Bisiach and Luzzati (1978; described in detail in McCarthy & Warrington 1990, pp. They asked their neglect patients to imagine standing in the Piazza del Duomo in Milan and to describe the scene from two vantage points: with the cathedral behind or in front of them. In either case it was the buildings on their left that were omitted though knowledge of them was clearly preserved. In an added twist, Marshall and Halligan (1988) showed that some implicit knowledge could affect behaviour despite being explicitly neglected. Auditory agnosia and auditory perceptual defects In auditory agnosia hearing is unimpaired, as tested by pure tone thresholds, but the patient fails to recognise or distinguish the sounds that he hears. Typically the onset is with severe dysphasia, which then clears substantially to leave the auditory problem in evidence. The patient is unable to recognise speech, as in pure word-deafness (see earlier in chapter), but in addition cannot recognise non-speech sounds such as the pouring of water, crumpling of paper or jingling of keys. Vignolo (1969) provides a detailed review, both of the phenomena observed and of their relationships to aphasia. Most examples have been associated with bilateral lesions of the posterior parts of the temporal lobes. Less complete difficulty with the processing of auditory information may be demonstrated in some patients with brain lesions. Vignolo (1969) showed that patients with right hemisphere lesions fail relatively on tests of discriminating meaningless sounds, whereas patients with left-sided lesions have greater difficulty in identifying sounds to which meaning can be attached. This indicates that the auditoryreceiving areas of the two hemispheres are to some extent specialised, that of the right being specifically concerned with grasping the acoustic structure of the auditory input. Analogous differences between the hemispheres have more recently been shown for tactile recognition as well (see under Tactile perceptual defects, next). With regard to music, the right temporal lobe appears overall to be more important than the left. Right temporal lobectomy has been found to impair performance on tests of musical aptitude, whereas left temporal lobectomy does not (Kimura 1961; Milner 1962). Shankweiler (1966) played extracts of familiar songs to patients who had had temporal lobectomies and found that the group with left lesions had greater difficulty in recalling the titles or words, whereas the group with right lesions had greater difficulty in reproducing or recognising the melody. Using dichotic listening tasks, words fed to the right ear (and proceeding thence by crossed pathways predominantly to the left hemisphere) are reported better than words fed to the left ear, whereas with fragments of melodies the situation is reversed (Kimura 1961, 1964). Moreover, when dichotic tests are given to lobectomised patients it is found that left temporal lobectomy produces a more severe decrement in the contralateral ear where words are concerned, and right temporal lobectomy for the recognition of musical passages (Shankweiler 1966). Gordon and Bogen (1974) also reported interesting effects when patients were asked to sing familiar songs during the course of unilateral intracarotid amobarbital injections. When the left hemisphere was sedated with the drug the words of the song were severely affected while the melody continued well; in contrast, when the right hemisphere was sedated the words remained relatively intact whereas the pitch and melodic line were severely disrupted. However, detailed analysis of various components of musical perception (pitch, timbre, discrimination and rhythm) have often given conflicting results, suggesting that neither hemisphere alone is specialised for all aspects of musical cognition and that musical training may confound the results. Lezak (1995) reviews the more recent clinical and experimental evidence, indicating that while the right hemisphere is generally the more important in melodic recognition and chord analysis, the left tends to predominate in the processing of sequential and discrete tonal components of music. Early functional imaging work showed changes in cerebral blood flow in the right temporal cortex during the perceptual analysis of melodies and of the right frontal cortex during pitch comparisons but, predictably, more recent work has revealed additional complexities implicating wider and more distributed neural networks depending on the nature of the task. Neuropsychology in Relation to Psychiatry 69 Amusia may be defined as an impairment or loss of musical function deriving from acquired disease of the brain (Henson 1985). Amusia without aphasia has proved to be rare, but examples have been described following right temporal or right frontal lesions. In such examples the deficit usually involves loss of capacity to sing or hum a tune (oral-expressive amusia). Henson (1985) reviews the scattered literature on other amusia syndromes: musical agraphia, musical alexia and musical amnesia, and receptive amusia in which there is failure to discriminate pitch, intensity, timbre and rhythm. This latter disturbance is usually seen only as part of a more widespread auditory agnosia. After listening to tape-recorded sentences, patients were asked to judge either the content or the emotional tone in which each sentence had been spoken (happy, sad, angry or indifferent). Six patients had right temporoparietal lesions (with left unilateral neglect) and six had left temporoparietal lesions (with fluent aphasia). The responses were made by selection from a series of line-drawn pictures appropriate to the sentences and emotions concerned. All subjects achieved perfect scores with respect to content, but those with right hemisphere lesions were significantly impaired in judging affective tone (KucharskaPietura et al. As such it remains a useful venue for the discussion of these disorders, and yields a useful group of simple clinical tests when one is looking for subtle signs of a lesion in the dominant hemisphere. However, the essential clustering together of the defects has been seriously questioned, and it is now clear that they barely constitute a syndrome in the accepted sense of the word. It is known that the four components are not always found together, one or more often being absent when the others can be demonstrated clearly. Similarly, one or more components can occur along with other disorders of cognitive function: dysphasia, dyslexia, constructional apraxia, visual disorientation or generalised intellectual impairment. Benton (1961) examined the intercorrelations on tests of the four Gerstmann symptoms and of three other functions related to the parietal lobes (constructional ability, reading and visual memory) in a large unselected series of brain-damaged subjects; it emerged that the correlations of the Gerstmann abilities with each other was no higher than with the three abilities not included in the syndrome. In a separate analysis of patients with damage restricted to the left parietal lobe, the Gerstmann defects again failed to cluster together. When all four defects did appear together they were usually accompanied by severe impairment of many other functions. It has not seemed possible to establish a common fundamental disturbance underlying each of the four defects.
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