w w w . e l s e v i e r . c o m / l o c a t e / p a i n

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Clinical note

A case of complex regional pain syndrome with agnosia for object orientation

Gail Robinson a,b,⇑, Helen Cohen c,d, Andreas Goebel e,f

a Department of Neuropsychology, National Hospital for Neurology and Neurosurgery, Queen Square, London, UKb School of Psychology, University of Queensland, St. Lucia, Brisbane, Australiac The Royal National Hospital for Rheumatic Diseases, Bath, UKd The Royal National Orthopaedic Hospital, Stanmore, UKe Pain Management Centre, National Hospital for Neurology and Neurosurgery, Queen Square, London, UKf Pain Research Institute, University of Liverpool and the Walton Centre NHS Trust, Liverpool, UK

Sponsorships or competing interests that may be relevant to content are disclosed at the end of this article.

a r t i c l e i n f o

Article history:Received 6 October 2010Received in revised form 27 January 2011Accepted 2 February 2011

Keywords:Agnosia for object orientationComplex regional pain syndromeCortical reorganisationCRPS

0304-3959/$36.00 Crown Copyright � 2011 Publishedoi:10.1016/j.pain.2011.02.010

⇑ Corresponding author. Address: School of PsyQueensland, St. Lucia, Brisbane, QLD 4072, Australia+61 7 3365 4466.

E-mail address: g.robinson@psy.uq.edu.au (G. Rob

a b s t r a c t

This systematic investigation of the neurocognitive correlates of complex regional pain syndrome (CRPS)in a single case also reports agnosia for object orientation in the context of persistent CRPS. We report apatient (JW) with severe long-standing CRPS who had no difficulty identifying and naming line drawingsof objects presented in 1 of 4 cardinal orientations. In contrast, he was extremely poor at reorientingthese objects into the correct upright orientation and in judging whether an object was upright or not.Moreover, JW made orientation errors when copying drawings of objects, and he also showed featuresof mirror reversal in writing single words and reading single letters. The findings are discussed in relationto accounts of visual processing. Agnosia for object orientation is the term for impaired knowledge of anobject’s orientation despite good recognition and naming of the same misoriented object. This defecthas previously only been reported in patients with major structural brain lesions. The neuroanatomicalcorrelates are discussed. The patient had no structural brain lesion, raising the possibility that nonstruc-tural reorganisation of cortical networks may be responsible for his deficits. Other patients with CRPSmay have related neurocognitive defects.Crown Copyright � 2011 Published by Elsevier B.V. on behalf of International Association for the Study of

Pain. All rights reserved.

1. Introduction perception disturbance in CRPS (eg, [7]). One study reported a

Complex regional pain syndrome (CRPS) is a chronic pain condi-tion which usually arises after trauma to a limb or, more rarely,spontaneously or after cerebrovascular accidents [6]. It is charac-terised by limb-confined sensory, motor, and autonomic abnormal-ities and is often accompanied by localized osteoporosis and skindystrophy [5]. The causes of CRPS are unknown, but both periphe-ral and central mechanisms are implicated. Neuroplastic corticalreorganisation has been demonstrated [19]. The pain intensity inCRPS has been correlated to the degree of cortical reorganisation(size and location) of the affected limb; reorganisation has alsobeen demonstrated to return to baseline in recovered CRPS [20].

The neurocognitive correlates of CRPS are little investigated.One study reported poor emotional decision making using theIowa Gambling Task in a CRPS patient group, which the authorsinterpret as consistent with the notion that chronic pain engagesthe prefrontal cortex [2]. There is increasing evidence of body

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chology, The University of. Tel.: +61 7 3365 6401; fax:

inson).

transient shift towards the unaffected side in terms of subjectivebody midline judgements [31], whilst another documented fingeragnosia in chronic CRPS [9]. CRPS patients have also self-reporteda ‘neglect-like’ state towards their affected limb whereby the limbis perceived as strange, disordered, or not belonging to the body[11]. When described in detail, the affected limb may be perceivedas much larger, shrunken, or with areas missing from the bodyschema [16].

The current study is, to our knowledge, the first systematicinvestigation of the neurocognitive correlates of CRPS in a singlepatient. We found a number of deviations from normal; unexpect-edly, the patient had agnosia for object orientation, a rare neuro-cognitive defect, which had previously only been described inpatients with structural brain damage [10,12,14,33–35].

2. Methods and results

2.1. History and earlier examination, investigation, and treatment

The patient JW is a 56-year-old, right-handed former police offi-cer and heating engineer. He completed 10 years’ formal education

rnational Association for the Study of Pain. All rights reserved.

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and later obtained a degree as a mature student. His medical his-tory includes neck and spinal injuries from a road traffic accidentin 1983. These physical injuries resulted in a medical retirementfrom the police force, after which he started a heating engineeringand installation business; he ran this business until the followingevent. Before this event, he had fulfilled his obligations at homenormally, including memorisation of appointments, and therehad been no concerns with his job performances. He has notworked since the start of the current difficulties in 2004, and hehas learned to write with his left hand.

In 2004 JW experienced an inferior myocardial infarct andunderwent a coronary artery stenting procedure. When the cathe-ter from the right arm was removed, he perceived pain in the rightarm; later that same day, the arm became swollen and blue. Hewas readmitted and provided antibiotics. The symptoms clearedup completely within a month. In 2005 he found a lump in theright axilla and underwent biopsy under general anaesthesia. Dur-ing the week after surgery he was aware of intense pain developingin his right arm and right side of his face with numbness and par-aesthesia. His speech was slow and dysprosodic. The pain did notsubsequently resolve. He noted colour changes, sweating, andswelling intermittently in the affected areas, more in the arm thanin the body.

JW underwent physical examination of the affected arm twice(2005 and 2008) by a consultant neurologist and a rheumatologist,respectively. On both occasions the arm was found to be swollenand profusely sweating, and to have blue discolouration. There

Fig. 1. Stimulations at distinct areas on the patient’s right leg

was sensory impairment to pinprick and light touch in the painfularea, and exquisite allodynia to touch. He was provided a diagnosisof CRPS in 2006. During a neurological examination in 2006, bodyperception was noted to be distorted. When the patient closed hiseyes he perceived his right arm to have shrunk in length comparedto the left, the right forearm was very slight with a massive hand atthe end of it, there was no elbow, and there was a grossly swollenshoulder and upper arm. Further, the right side of his face was per-ceived to be grossly swollen, and his right ear was stated to be ‘red.’No close examination was possible, but a very restricted range ofmovement on the right side was noted, and his posture was alteredso that his shoulders were hunched, and he protected his right armas much as possible. Detailed sensory examination in 2007 re-vealed dramatic referral (as previously reported in CRPS [21]) ofsensations from the right leg to the right upper body, suggestiveof extensive cortical remapping (Fig. 1).

From May 2005, the patient underwent multiple investigationsand treatments. No alternative diagnoses were suggested to ex-plain for his pain, apart from an initial note of possible Parson-age-Turner syndrome (neuralgic amyotrophy); however, thissyndrome is not reported to be associated with swelling, sweating,and colour changes, and this alternative was later excluded by aconsultant neurologist at a tertiary referral centre.

A brain magnetic resonance imaging (MRI) scan in 2006 wasinitially reported to be normal, and this was confirmed at repeatexamination of the images and discussion with a consultant neuro-radiologist in preparation for this report. There was no evidence of

cause pain in overlapping areas on the right upper body.

Table 1Baseline cognitive tests.

Cognitive test Score (percentile)

Intellectual abilitiesWAIS-III Verbal IQ 90

Vocabularya 8Similaritiesa 10Arithmetica 10Digit Spana 5Performance IQ 67Picture Completiona 6Block Designa 1 (not score)

Picture Arrangementa 7

Memory functionRecognition Memory Test Words 34/50 (<5th

percentile)Faces 32/50 (<5th

percentile)

Executive functionWeigl Sorting Test . . . PassPhonemic Fluency ‘S’ 11 (10–25th

percentile)Semantic Fluency Animals 7 (<10th

percentile)Stroop Test . . . <5th percentile

Language and arithmetic abilitiesGraded Naming Test 22/30 (50–75th

percentile)National Adult Reading Test . . . 26/50 (50–75th

percentile)Oral Graded-Difficulty Spelling

Test. . . 23/30 (50–75th

percentile)Oral Graded-Difficulty

Arithmetic Test. . . 10/24 (25–50th

percentile)

Praxis functionLimb Praxis (left hand) Meaningless

gestures9/10

Meaningful gestures 5/5Object use 5/5

Visual Object and SpacePerception Battery

Incomplete letters 20/20Dot counting 10/10Positiondiscrimination

19/20

Cube analysis 9/10Bell cancellation 90 seconds—

Impaired

Face perceptionBenton Test of Face Perception . . . <37—Severely

Impaired

Body perceptionRight-left orientation . . . 10/10Finger agnosia (left hand) . . . 19/20

Mental rotationFlags Test . . . 9/10Little Man Test . . . 26/32

WAIS-III, Wechsler Adult Intelligence Scale—Third Edition.a Age-scaled score (10 = average, 50th percentile).

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a previous infarct or any other pathology. He had 2 stellate gan-glion blocks which helped temporarily, and a third which aggra-vated symptoms. He had a cervical spinal cord stimulator withan electrode paddle at C3 and C4 in 2007. One programme gavestimulation around the right ear, the whole of the right arm, axilla,right upper torso, and top of the right leg; the other was limited tothe right ear, the whole of the right arm and axilla. His initial re-sponse was positive with significant pain relief, but unfortunatelythis was not sustained. High-dose corticosteroid treatment in 2007had no effect on pain. JW reported his pain intensity throughoutthese years as severe on a 4-point rating scale (none, mild, moder-ate, severe).

The neurocognitive investigation reported here was initiatedbecause the patient and his family had reported both difficultieswith certain activities of daily living and some bizarre cognitive de-fects. The patient reads by covering up words and lines because hefinds that the words move around. When drawing, he is unaware ofreproducing items in a rotated manner until his wife or daughterpoint it out. When reaching for the handle of a coffee cup or pot,he often notices that it is not there. His wife then finds that hehas reached for the wrong side of the cup. These problems manifestintermittently. In addition, he cannot reliably write cheques be-cause he is unable to correctly order numerals and recognise mis-takes, resulting in cheques being bounced.

2.2. Cognitive baseline

The following cognitive investigations were conducted over 2sessions in April and May 2008. Further investigation was not pos-sible because of the geographic distance of his home from Londonand the symptoms associated with his pain condition. JW’s presen-tation was unusual because he was unable to focus on the exam-iner’s face. He reported the observation of movements of speechdisturbed him and elicited pain, the latter also elicited by suddenmovements or noise in the nearby vicinity. With minimal eye con-tact and fixation on the table, he was able to apply himself well tothe following tests, although attention was noted to fluctuate.

JW was assessed on a shortened form of the Wechsler AdultIntelligence Scale—Third Edition (WAIS-III; [39]; see Table 1 forall cognitive tests). Verbal intellectual abilities were in the averagerange. This was consistent with the estimated premorbid level ofoptimal functioning based on occupational and educational back-ground, as well as reading performance on the National AdultReading Test (NART [23]). By contrast, nonverbal intellectualabilities were severely impaired, and he did not score on the BlockDesign subtest; the patient completed the first 3 block designs, butinverted each one (ie, rotated 180�; for scores, see Table 1). Whenthe examiner put the designs in the correct orientation, the patientreported his original inverted design and the current uprightdesign were both the same, suggesting difficulty distinguishingbetween the different orientations. Performance was very pooron verbal and visual recognition memory tests [37]. Because thepatient was fully oriented to person, place, and time, the poormemory performance was thought to be partly underpinned byattentional fluctuation and not indicative of a pure memoryimpairment. Performance on tests of executive ability was variable.The patient passed the Weigl Sorting Test [40]. Phonemic wordfluency [29] was mildly reduced with 1 repetition. Semantic wordfluency [29] was significantly reduced, and his performance on theStroop Test [30] was errorless but slow. Language function waswell preserved, apart from very mildly slow and dysprosodicspontaneous speech. Thus, nominal [22], reading [23], and spelling[3] abilities were in the upper end of the average range, andarithmetic ability [13] was average. Limb praxis with his good lefthand was relatively intact. The patient’s copy of meaningless andmeaningful gestures was normal.

2.3. Perception (form, space, body, and face), drawing, reading,writing, and mental rotation

Visual form and space perception was normal as JW passed 4subtests from the Visual Object and Space Perception Battery(Incomplete Letters, Dot Counting, Position Discrimination, CubeAnalysis; [38]). In addition, no visual errors were made on the pic-ture-naming task that contained black-and-white line drawings.Body perception was relatively intact as there was no evidencefor left/right disorientation (assessed using his left hand to pointto left and right body parts) or finger agnosia with JW’s good lefthand (right hand too painful to be assessed). By contrast, face

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perception was impaired [4]. On a Line Bisection test, the patienthad a tendency to mark the centre of a line as being to the left, sug-gesting some inattention to the right side [27]. However, there wasno further evidence for visual neglect on the Bells Test (Gauthierand Joanette 1992, cited in [17]) despite evidence of general inat-tention (9 omissions across the whole page).

JW’s drawing was accurate but generally positioned in a differ-ent orientation from the target. First, the patient was asked to copy4 simple drawings of objects aligned horizontally long the top halfof an A4 sheet of paper. Although each drawing was quite accurate,each target was copied in the inverted orientation (ie, 180�; Fig. 2).When asked to copy the Rey complex figure [26] again, the copywas almost fully inverted with some evidence for disorganisation.After a short delay (5 min), the patient’s drawing from memorywas rotated to the left (ie, �90�), although the coherence of theoverall structure was again maintained (Fig. 3). When he addedspecific times to a predrawn clock face, there was clear evidenceof rotation (Fig. 4).

To investigate single-letter form and orientation knowledge, thepatient was given several tasks from the Psycholinguistic Assess-ments of Language Processing in Aphasia (PALPA; [15], tasks 18–20). JW was able to accurately match capital and small letters flaw-lessly (100%; Small-Capital letter matching 26/26, Capital-Smallletter matching 26/26). By contrast, his ability to discriminatewhether a single letter was in the correct or mirror-reversed orien-tation was virtually at floor (correct orientation 1/18, reverse 1/18;correct for g and f in the correct and mirror reversed orientations,respectively). In fact, his performance suggests his internal repre-sentation of letter orientation is reversed because he virtually per-formed flawlessly if this was the case (ie, 94.4%).

JW was asked to write 24 high-frequency 3–6-letter words fromthe PALPA in both the left and right hemispace, similar to a task de-vised by Buxbaum and colleagues [8]. JW was only able to write 7of 24 words correctly (fox, door, book, horse, ghost, church,square). Interestingly, he produced no single-letter mirror rever-sals for any target. By contrast, he produced a significant numberof whole-word reversals (17 of 24 words; eg, kcud for duck). JW

Fig. 2. The patient was instructed to copy target objects

did, however, produce 3 single-letter errors that were all last-lettersubstitutions for words written in the mirror reverse direction (eg,efine for knife, tseirt for priest). There was no difference betweenperformance when writing in the left or right hemispace; errorswere consistent to both sides. Despite reporting that he ‘always100% knows’ when he writes backwards, when asked to checkhis work for mirror reversal in writing, the patient only markedsquare as being written the wrong way, and this was a word hehad correctly written.

Mental rotation ability was poor. JW made several errors on theFlags and Little Man tests [25,32]. Specifically, on the Little ManTest, which requires mental reorientation of either upright or in-verted figures in order to report whether a black disc is locatedin either the left or right hand, the patient made 6 errors only forinverted figures (disc in both the left- and right-hand positions).

2.4. Summary

JW presented with normal verbal intellectual, language, visualperceptual, and some executive abilities. By contrast, he presentswith nonverbal intellectual underfunctioning, particularly whentasks comprise a visuospatial construction component, and perfor-mance was poor on tests of memory, face perception, and mentalrotation. Copies of drawings and his inverted block design con-structions showed features of agnosia for object orientation, andthere was some evidence for mirror reversal in writing of singlewords and reading of single letters. These were the focus of the fol-lowing experimental investigations.

3. Experimental investigations: object recognition andorientation

3.1. Task 1: Naming and orienting known objects

The aim of this task was to establish whether object recognitioncould be achieved even when the correct canonical upright orien-tation could not be provided. Each of 32 line drawings was placed

(top). His reproduction is provided in the lower half.

Fig. 3. Rey complex figure.

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in front of the patient with the canonical upright in 1 of the 4 car-dinal orientations (0�, +90�, 180�, �90�). The patient was asked tocomplete 3 tasks: name the object, respond ‘yes’ or ‘no’ as to

Fig. 4. We advised JW to add both long and short arms to pred

whether the object was in the canonical upright position, and ori-ent each drawing into the upright canonical position if not alreadyin this orientation.

JW named 97% of items correctly (31/32, all except for piano;Fig. 5). The patient had accurate knowledge of the canonical up-right for only 53% of the items (17/32). Upon further analysis, JWhad accurate knowledge when objects were rotated to the rightor left (ie, +90� or �90�), because his performance was 100% (16/16). By contrast, JW’s canonical upright knowledge was virtuallynonexistent when items were already upright (1/8) or upside down(ie, rotated 180�; 0/8). JW was impaired because he was only ableto place 25% (8/32) of the objects in the canonical upright position.For these 8 correct, the original orientation was left (n = 4), right(n = 3), and upright (n = 1).

JW’s performance indicated a preservation of object recognitionand naming despite impaired object orientation knowledge. Uponfurther investigation, it was clear that JW’s impairment was mostprominent for objects either in the correct canonical position or in-verted 180� from this (ie, orientation along the horizontal x-axisrather than the vertical y-axis).

3.2. Task 2: Copying misoriented drawings

A subset of 8 line drawings of objects from the previous taskwas used for this task, similar to [35] (camel, dustbin, frying pan,kangaroo, kettle, lamp, shirt, shoe). The patient was asked to copyeach drawing that was rotated in 1 of the 4 cardinal orientations.

JW was able to copy each object with reasonable accuracy, buthe rotated all 8 drawings. When the target drawing was rotated tothe left (ie, �90�; camel and dustbin), JW copied the camel in thesame orientation but mirror reversed, and the dustbin was drawnin the inverted orientation (180�). For target drawings rotated tothe right (ie, +90�; frying pan, kangaroo), the patient inverted thefrying pan (ie, 180�), and the kangaroo was drawn in the canonicalupright orientation (ie, rotated +90� and mirror reversed). Whenthe target drawing was in the canonical upright (kettle, shirt), JWdrew the inverted image (ie, rotated 180�). When the targetdrawing was inverted (ie, 180�; shoe, lamp), JW drew the invertedimage (ie, canonical upright orientation). In summary, 3 of thepatient’s copies were in the canonical upright orientation, 3 wereoriented left or right, and 2 were inverted.

JW’s performance confirms good visual perception of form and alack of orientation knowledge when copying drawings in either thecorrect or incorrect canonical orientation. The fact that miscopies

rawn clock faces to indicate 2 time points, 7:45 and 6:20.

Fig. 5. The patient was given 32 line drawings with 8 drawings each oriented into 1 of the 4 cardinal orientations (0, +90, 180, �90; the + sign indicates rotation to the right).He was asked to name each drawing (dark grey), provide information on whether or not drawings were shown upright (ie, without rotation; light grey), and reorient the eachdrawing into the upright position (ie, 0�; medium grey).

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were not placed in the correct orientation suggests little preserva-tion of orientation knowledge, including top-bottom orientationalong the horizontal x-axis.

3.3. Task 3. Discriminating object orientation

JW was asked to judge which of 3 objects was misoriented com-pared to the other 2 (ie, find the odd one out). JW had no difficultychoosing the object with a different orientation, and he performedflawlessly on this task (10/10).

These results suggest that JW has no difficulty discriminatingobject orientation in a task that does not require canonical uprightknowledge of an object.

4. Discussion

To our knowledge, this is the first reported systematic neuro-cognitive examination, and the first account of agnosia for objectorientation in a patient with CRPS. Dissociation between knowl-edge of object identity and object orientation has been docu-mented in only a few patients with severe brain damage. Forexample, Turnbull et al. [34] reported a patient, LG, who was ableto recognise and name line drawings of objects but was poor inidentifying the correct canonical orientation of these objects. Bycontrast, patient DM was poor in recognising and naming objectsbut was able to orient the drawings into the correct canonical up-right position [33]. A lack of knowledge about the orientation of anobject, despite preserved recognition and naming even when ob-jects are misoriented, has been termed agnosia for object orientation(eg, [10,12,14,33–35]). Agnosia for object orientation has been doc-umented after a number of brain injuries. These included injuriesdue to ischemic stroke with both major clinical motor or visual de-fects, and MRI-confirmed parietal lobe damage (RU—[10]; KB—[14]; LG, NL, and SC—[33–35]), gunshot-induced parietal lobe dam-age (cited after [14]), closed head injury (DM—[33]), and probableAlzheimer disease with particular damage to the parietal lobes(EL—[12]).

Our patient is similar to previous cases of agnosia for object ori-entation with respect to the classic dissociation between objectrecognition and orientation knowledge. Thus, JW showed a pre-served ability to recognise and name line drawings of objects thathad unambiguous upright orientations presented in 1 of 4 orienta-tions (0�, +90�, 180�, and �90�). In contrast, his ability to reorient

objects into their canonical upright position was impaired. This isdespite a good ability to discriminate between several objectsplaced in different orientations. Interestingly, when asked to judgewhether an object was upright or not, performance was accuratewhen objects were oriented to the left or right (ie, +90�) but grosslyinaccurate for objects already upright or inverted (ie, orientedalong the horizontal x-axis). In addition, his copying of rotateddrawings of objects demonstrated the internal structure was main-tained but orientation knowledge was absent, as copies wereplaced in cardinal but incorrect orientations. His mental rotationability was equally poor and comparable to a right posteriorbrain-damaged group reported by Ratcliff [25]. A highly unusualfeature of JW’s presentation is evidence for orientation difficultieson verbal as well as nonverbal tasks, although it was not possibleto complete a detailed investigation. Written language has notbeen investigated in other patients presenting with object orienta-tion agnosia, which may be due to either the absence of deficit orthe severity of pathology in all previous patients, precluding aninvestigation of written language. To our knowledge, this is thefirst documented case of agnosia for object orientation with addi-tional features of mirror reversal in writing of single words andreading of single letters. These cannot be accounted for by other vi-sual and/or cognitive deficits because the patient does not presentwith neglect or visual or space perceptual impairments on stan-dard cognitive tests, and examination did not reveal a visual fielddefect. Notably, on standard oral reading and spelling tests, the pa-tient performed in the average range.

How can we account for JW’s pattern of deficits? We suggestthat JW has lost significant spatial orientation knowledge, most se-verely impacting the top-bottom horizontal x-axis with only par-tial orientation knowledge remaining for the vertical y-axis (ie,left-right). This partial knowledge may explain why mirror reversalfeatures in writing are mixed in with writing in the correct direc-tion, and why judgement of object orientation is preserved whenobjects are oriented along the y-axis.

What are the neuroanatomical correlates? Agnosia for objectorientation has been reported in patients after major ischemicstroke, closed head injury, and probable Alzheimer disease. All re-ported patients experienced structural damage to their parietallobes. Classic mirror writing is usually documented in focal lefthemisphere pathology [28]. Our patient does not have anyMRI-detectable focal cortical (or otherwise) brain lesion. Further,we found no clusters of neurocognitive deficits, which are other-

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wise typical for localized brain damage after stroke or consistentwith a progressive neurodegenerative disorder. Cognitive disordersafter stroke affecting the parietal region may include spatialimpairments, visual neglect, visual agnosia, and language disorderssuch as conduction aphasia, dysgraphia, and dyscalculia [36].Although JW performed poorly on tests of episodic memory, thiswas attributed to attentional problems because he was not amne-sic in daily life, nor was he generally disoriented in person, place, ortime. With regard to a neurodegenerative disorder, the patient’scognitive profile is not consistent with typical or atypical demen-tias (eg, Alzheimer disease or posterior cortical atrophy); he hasa number of well-preserved abilities (eg, object naming, abstractreasoning on similarities, arithmetic, visual and spatial perception)in the context of the very selective impairments which are the fo-cus of this report. Further, a dementia is inconsistent with both thefamily and medical reports that his difficulties were relatively sta-ble and not progressively worsening. A neuropsychiatric explana-tion cannot be excluded, but this is less likely to be theunderlying causal factor, given the consistency of the features doc-umented and the absence of this as an explanation during thenumerous medical investigations.

We suggest that JW has undergone significant cortical reorgani-sation, a well-documented hallmark of CRPS, and that this isresponsible for his defects. The results from an earlier QST exami-nation and spinal cord stimulation had already suggested exten-sive reorganisation in the somatosensory cortex (Fig. 1). Wesuggest that reorganisation of neurons involved with the codingof information about the orientation of objects in space may bethe cause of his orientation agnosia. Given that those patients,who were previously reported to have agnosia for object orienta-tion, had experienced damage to their parietal lobes, such neuronsmay be located in this area; their precise role and interaction withneurons which code for object recognition is currently not known[14,35]. Additional evidence for an important role of the parietallobes in maintaining visuospatial functions comes from neuroim-aging investigations, which have documented a correlation be-tween parietal lobe activation and performance in visuospatialtasks. For example, a positron emission tomographic study ofhealthy volunteers demonstrated that during the mental rotationof alphanumeric stimuli, the left parietal region was specificallyactivated [1]; a functional MRI study of patients with Alzheimerdisease revealed that the magnitude of the functional MRI signalin the left parietal cortex was positively correlated with the perfor-mance on a task that taps visuoconstructive ability (clock drawing)[24]. In CRPS, recently a specific pattern of motor impairment(changes in the movement patterns during reaching and grasping)was demonstrated, which was consistent with a disturbed integra-tion of visual and proprioceptive inputs in the parietal cortex [18];this was associated with motor cortex reorganisation and abnor-mal activation assessed with functional MRI.

In summary, this is to our knowledge the first report of a patientwith CRPS presenting with agnosia for object orientation; JW alsoshowed some features of mirror reversal in writing and reading.These deficits were not underpinned by classical cortical lesions.This raises the possibility that cortical reorganisation associatedwith CRPS plays a role in causing JW’s neurocognitive defects.JW’s deficits affect his daily living and are relevant to his qualityof life. Other patients may experience related problems, and wesuggest that patients with CRPS should be assessed for evidenceof these bewildering and debilitating deficits.

Conflict of interest statement

The authors declare no conflict of interest in relation to thisstudy.

Acknowledgments

We would like to thank the patient. Dr Candy McCabe and ProfDavid Blake provided important suggestions to earlier investiga-tions in this patient and discussions about preliminary outcomes.We thank Dr Adam Woo for practical support. HC was supportedby Arthritis Research UK Clinical Research Fellowship Grant 17573.

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