Behavioural Neurology

Review Article

Neuropsychological Changes in Complex Regional Pain Syndrome (CRPS)

Table 2

Summary of neuropsychological functions investigated in people with CRPS in research studies published between July 1995 and June 2019.


Neuropsychological function/symptom	Measure/task	Performance of participants with CRPS^a,b	Study details^c

Body representation

Self-reported body perception	Interview	Distorted representation of the affected limb (altered perceptions of size, shape, and weight; desire to amputate; mismatch between sensations and appearance of the limb; erasure of its anatomical parts; poor awareness of its position; and asomatognosia)	Galer et al. [33], ; Lewis et al. [34],
	Neglect-like symptoms questionnaire [35, 36]	Asomatognosia (feelings of foreignness and lack of ownership of the affected limb) (17-90%)	Förderreuther et al. [37], ; Frettlöh et al. [35], , PC; Galer and Jensen [36], ; Kolb et al. [38], , HC, PC†; Michal et al. [39], , PC; Reinersmann et al. [40], , PC†, [41], , PC; Wittayer et al. [42],
	Bath CRPS body perception disturbance scale [43]	Distorted representation of the affected limb (see above)	Brun et al. [44], ; Bultitude et al. [45], ; Kotiuk et al. [46], ; Lewis and Schweinhardt [47], , HC; Tajadura-Jiménez et al. [48],
Objective limb size	Estimation of actual limb size based on enlarged or shrunk images	Overestimation of size of the affected limb	Moseley [49], , PC, AL; Peltz et al. [50], , HC, AL
	Tactile distance judgements following tool use	Perceived lengthening of the unaffected arm and shortening of the affected arm	Vittersø et al. [51], , HC, BL
Limb position sense	Limb position matching	Reduced accuracy in both limbs	Brun et al. [44], , HC, BL; Lewis et al. [52], , HC, BL
	Manual straight-ahead pointing (eyes closed)	Bias towards the affected side of space	Christophe et al. [53], , NC, BL; Jacquin-Courtois et al. [54], , NC, HC, AL
		Normal	Christophe et al. [55], , NC, BL; Kolb et al. [38], , HC, PC, BL
Limb movement sense	Estimation of the extent of actual movement relative to altered visual feedback	Reduced accuracy and precision in the affected limb	Brun et al. [44], , HC, AL
Mental limb rotation/internal representation of limbs	Limb laterality recognition test	Reduced accuracy for the affected vs. unaffected limb images	Johnson et al. [56],
		Longer reaction times for the affected vs. unaffected limb images	Johnson et al. [56], ; Moseley [57], , HC; Reid et al. [58], ; Schwoebel et al. [59], , HC, [60],
		Longer reaction times for images of both limbs in the affected vs. unaffected side of space	Reid et al. [58],
		Longer reaction times for images of both limbs	Bultitude et al. [45], , HC; Kohler et al. [61], , HC; Reinersmann et al. [62], , HC, PC†; Wittayer et al. [42], , HC
		Normal	Breimhorst et al. [63], , HC; Reinersmann et al. [40], , HC, PC
Multisensory integration/body ownership	Rubber hand illusion	Normal	Reinersmann et al. [41], , HC, PC, BL
Bimanual representation of limbs	Artificial finger illusion	Reduced illusion strength for vision-proprioception only (abnormal bimanual representation); normal with tactile input	Wang et al. [64]; , HC, BL

Lateralised spatial cognition

Self-reported motor neglect	Interview/clinical observation	Motor neglect for the affected limb (slower initiation, execution, and decreased amplitude and spatial extent of movements, required directed attention to move the affected limb, and occurrence of involuntary movements)	Galer et al. [33],
	Neglect-like symptoms questionnaire [35, 36]	Motor neglect for the affected limb (see above) (17-90%)	Frettlöh et al. [35], , PC; Galer and Jensen [36], ; Kolb et al. [38], , HC, PC†; Michal et al. [39], , PC; Reinersmann et al. [40], , PC†, [41], , PC; Wittayer et al. [42],
Visuomotor spatial attention	Line bisection	Bias towards the affected relative to unaffected side of space	Christophe et al. [53], , NC, BL; Jacquin-Courtois et al. [54], , HC, NC, AL; Förderreuther et al. [37], , HC, BL
		Bias away from the affected relative to unaffected side of space	Robinson et al. [65], , NC
		Normal	Christophe et al. [55], , NC, BL; Förderreuther et al. [37], , HC, BL; Kolb et al. [38], , HC, PC; Reid et al. [58], , NC, BL; Reinersmann et al. [40], , HC, PC
	Robot-assisted line bisection	Bias towards the left relative to right side of space	Verfaille et al. [66], , HC, UL
	Line bisection on the limbs	Bias away from the affected relative to unaffected side of space (on the affected limb and on both limbs on the affected side of space)	Reid et al. [58], , NC, BL
	Clock drawing test	Normal	Kolb et al. [38], , HC, PC
Egocentric frame of reference	Visual subjective body midline	Bias towards the affected relative to unaffected side of space (only in the dark)	Christophe et al. [53], , NC; Jacquin-Courtois et al. [54], , HC, NC; Sumitani et al. [67], , HC [68], , HC, [69], , NC; Uematsu et al. [70], , PC
		Bias towards the left relative to right side of space (in the dark)	Reinersmann et al. [40], , HC, PC
		Normal (in the dark)	Christophe et al. [55], , NC; Wittayer et al. [42], , HC
Tactile spatial attention	Confrontation test (detection of concurrent stimulation on both limbs)	Omissions of stimuli on the affected side of the body (extinction; 14%)	Cohen et al. [71], , BL
	Temporal order judgements	Bias away from the affected relative to unaffected limb (when tactile stimuli delivered to uncrossed hands)	Reid et al. [58], , NC
	Temporal order judgements	Bias away from the affected limb (when tactile stimuli delivered to uncrossed hands) and from the affected side of space (when tactile stimuli delivered to hands crossed over body midline), relative to the unaffected limb and side of space	Moseley et al. [72], , [73], , HC
		Normal (crossed and uncrossed hands)	Filbrich et al. [74], , NC
Auditory spatial attention	Temporal order judgements	Normal	Reid et al. [58], , NC
Visual spatial attention	Temporal order judgements	Bias away from the affected relative to unaffected side of space and limb (when visual stimuli presented in near space without hands, or on the surface of uncrossed hands, but not when hands were crossed over body midline)	Bultitude et al. [45], , HC
		Bias away from the affected relative to unaffected side of space (when visual stimuli presented near uncrossed hands but not far from the hands)	Filbrich et al. [74], , NC
	Orienting saccades to cued and noncued stimuli in the left and right visual fields	Normal	Filippopulos et al. [75], , HC
	Speeded detection task	Longer reaction times in the right side of space	Kolb et al. [38], , HC, PC
Internal representation of space	Mental number line bisection	Deviation away from the affected relative to unaffected side of space	Sumitani et al. [67], , HC
		Deviation towards the affected relative to unaffected side of space	Christophe et al. [53], , NC; Jacquin-Courtois et al. [54], , NC, HC
Spatially-defined motor control	Rhythmic finger tapping	Normal/no hands asymmetry (with one and both hands, in uncrossed and crossed posture, with and without visual feedback)	Christophe et al. [55], , HC, BL
		Normal/no hands asymmetry (with one and both hands, hands close together or further apart, without visual feedback)	Christophe et al. [53], , BL
	Speeded button pressing	Slower and more variable movements (with the affected vs. unaffected hand in both sides of space, and with both hands in the affected vs. unaffected side of space)	Reid et al. [76], , BL
	Circle drawing task	Reduced accuracy (with the affected vs. unaffected hand in both sides of space, and with both hands in the affected vs. unaffected side of space)	Reid et al. [76], , BL
		Normal/no hands asymmetry	Christophe et al. [55], , HC, BL

Non-spatially-lateralised cognition

Object recognition	Tactile recognition of objects	Astereognosia for the affected hand (64%)	Cohen et al. [71], N=22, HC, BL
	Visual recognition of objects	Normal	Robinson et al. [65], , NC
Face recognition	Benton test of face perception	Prosopagnosia	Robinson et al. [65], , NC
Finger identification	Identification of indicated fingers (verbally, by touch, pointing, or movement)	Finger agnosia on the affected limb (48-59%); longer reaction times, reduced accuracy, and increased variability of finger discrimination (on both hands, but worse on the affected hand)	Cohen et al. [71], , HC, BL; Förderreuther et al. [37], , BL; Kuttikat et al. [77], , HC, BL
		Normal	Robinson et al. [65], , NC, UL
Tactile recognition of writing on the skin	Identification of letters and numbers traced onto one’s palm	Dysgraphaesthesia on the affected hand (36%)	Cohen et al. [71], , HC, BL
Constructional ability	Copying or constructing named geometric figures using drawing or matchsticks	Constructional apraxia for the affected hand (32%)	Cohen et al. [71], , HC, BL
	Kohs block test	Normal	Kolb et al. [38], , HC, PC
Numerical and language processing	Counting, mental arithmetic, reading, repeating, writing, copying, identifying numbers and letters/words, spelling	Dyscalculia (27%); dysgraphia for the affected hand (27%)	Cohen et al. [71], , HC, BL
Speech repetition	Repetition of words and sentences, confrontation naming	Conductional dysphasia (4%)	Cohen et al. [71], , HC
Verbal fluency	Boston Naming test, animal (semantic) fluency, letter fluency	Impaired verbal fluency	Libon et al. [78], , NC
Visuospatial orientation	Rod Orientation test	Normal	Kolb et al. [38], , HC, PC
Knowledge about object orientation	Object orientation judgements, copying, drawing, and reorienting objects into upright position	Agnosia for object orientation	Robinson et al. [65], , NC
Knowledge about order and orientation of numbers and letters/words	Spontaneous and dictated writing and copying	Mirror reversal in writing and reading, horizontal inversion of letters and words, and letters and numbers ordering in writing (cases for the affected hand, both hands, and unaffected hand)	Cohen et al. [71], , HC, BL; Robinson et al. [65], , UL
	Letter orientation recognition	Normal (for standard vs. reflected letters and left vs. right side of space)	Reid et al. [58],
Body sides differentiation	Identification of indicated body parts (verbally, by touch, or pointing)	Left-right disorientation (9%)	Cohen et al. [71], , HC, BL
		Normal	Robinson et al. [65], , NC, UL
Imitation of complex movements	Pantomime of indicated motor acts	Ideomotor apraxia (5%)	Cohen et al. [71], , HC, BL
Temporal acuity	Temporal order judgements	Reduced temporal acuity	Bultitude et al. [45], , HC
Alertness	Test of attentional performance	Normal response readiness	Reinersmann et al. [62], ; HC, PC
Working memory	Digit span	Impaired working memory span	Libon et al. [78], , NC
	Test of attentional performance	Normal continuous updating	Reinersmann et al. [62], , HC, PC
Spatial working memory	Block tapping test	Normal	Kolb et al. [38], , HC, PC, right limb
Episodic verbal memory and learning	California verbal learning test II	Impaired encoding, recall, and recognition	Libon et al. [78], , NC
Global cognitive processing	Digit span, Boston naming test, animal (semantic) fluency, letter fluency, and California verbal learning test II	Global processing impairment (particularly impaired naming, declarative memory, and executive function; 23%) or mild dysexecutive syndrome (particularly impaired working memory and verbal fluency; 42%)	Libon et al. [78], , NC

^aPercentages represent the proportion of individuals with CRPS out of the total CRPS sample who presented with abnormal performance. We reported percentages where available; in other cases, we presented group effects. ^bNormal performance indicates that there were no differences between participants with CRPS and control participants and/or between the affected and unaffected side among participants with CRPS. ^c represents CRPS sample size. Where applicable, we specified which control group was included (HC = healthy/pain-free controls; PC = pain controls; NC = normative data or comparison against zero; † = no significant difference between CRPS and control group) and which limb(s) were tested (AL = affected limb; UL = unaffected limb; BL = both limbs).