Functional neuroimaging studies argue that sensory deficits in hemiplegic cerebral palsy (HCP) are related to deviant somatosensory processing in the ipsilesional primary somatosensory cortex (S1). A ...separate body of structural neuroimaging literature argues that these deficits are due to structural damage of the ascending sensory tracts (AST). The relationship between the functional and structural integrity of the somatosensory system and the sensory performance is largely unknown in HCP. To address this relationship, we combined findings from magnetoencephalography (MEG) and probabilistic diffusion tractography (PDT) in 10 children with HCP and 13 typically developing (TD) children. With MEG, we mapped the functionally active regions in the contralateral S1 during tactile stimulation of the thumb, middle, and little fingers of both hands. Using these MEG-defined functional active regions as regions of interest for PDT, we estimated the diffusion parameters of the AST. Somatosensory function was assessed via two-point discrimination tests. Our MEG data showed: (i) an abnormal somatotopic organization in all children with HCP in either one or both of their hemispheres; (ii) longer Euclidean distances between the digit maps in the S1 of children with HCP compared to TD children; (iii) suppressed gamma responses at early latencies for both hemispheres of children with HCP; and (iv) a positive correlation between the Euclidean distances and the sensory tests for the more affected hemisphere of children with HCP. Our MEG-guided PDT data showed: (i) higher mean and radian diffusivity of the AST in children with HCP; (ii) a positive correlation between the axial diffusivity of the AST with the sensory tests for the more affected hemisphere; and (iii) a negative correlation between the gamma power change and the AD of the AST for the MA hemisphere. Our findings associate for the first time bilateral cortical functional reorganization in the S1 of HCP children with abnormalities in the structural integrity of the AST, and correlate these abnormalities with behaviorally-assessed sensory deficits.
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•Hemiplegic CP exhibits abnormal somatotopy in one or both hemispheres.•Hemiplegic CP shows longer distances between digit somatosensory representations.•Suppressed gamma somatosensory responses are seen in hemiplegic CP.•Altered somatosensory organization is associated with deficient sensory fibers.•Injury of sensory fibers correlates with the severity of sensory deficits.
OBJECTIVES:Widespread sensory deficits resembling hemihypoaesthesia occur in 20-40% of chronic pain patients on the side of pain, independent of pain aetiology, and have been termed nondermatomal ...sensory deficits (NDSD). Sensory profiles have rarely been investigated in NDSD.
METHODS:Quantitative sensory testing (QST) according to the protocol of the German Research Network on Neuropathic Pain (DFNS) was performed in the face, hand and foot of the painful body side and in contralateral regions in chronic pain patients. Twenty-five patients with NDSD and 23 without NDSD (termed pain-only group) were included after exclusion of neuropathic pain. Comprehensive clinical and psychiatric evaluations were done.
RESULTS:NDSD in chronic pain was associated with high burden of disease and more widespread pain. Only in the NDSD group significantly higher thresholds for mechanical and painful stimuli were found in at least 2 of 3 regions ipsilateral to pain. In addition, we found a bilateral loss of function for temperature and vibration detection, and a gain of function for pressure pain in certain regions in patients with NDSD. Sensory loss and gain of function for pressure pain correlated with pain intensity in several regions.
DISCUSSION:This may indicate a distinct sensory profile in chronic non-neuropathic pain and NDSD, probably attributable to altered central pain processing and sensitisation. The presence of NDSD in chronic non-neuropathic pain may be regarded as a marker for higher burden of pain disease.
Objectives: Widespread sensory deficits occur in 20-40% of chronic pain patients on the side of pain, independent of pain aetiology, and are known as nondermatomal sensory deficits (NDSDs). NDSDs can ...occur in absence of central or peripheral nervous system lesions. We hypothesised that NDSDs were associated with cerebral grey matter changes in the sensory system and in pain processing regions, detectable with voxel-based morphometry. Methods: Twenty-five patients with NDSDs, 23 patients without NDSDs ("pain-only"), and 29 healthy controls were studied with high resolution structural MRI of the brain. A comprehensive clinical and psychiatric evaluation based on Diagnostic and Statistical Manual was performed in all patients. Results: Patients with NDSDs and "pain-only" did not differ concerning demographic data and psychiatric diagnoses, although anxiety scores (HADS-A) were higher in patients with NDSDs. In patients with NDSDs, grey matter increases were found in the right primary sensory cortex, thalamus, and bilaterally in lateral temporal regions and the hippocampus/fusiform gyrus. "Pain-only" patients showed a bilateral grey matter increase in the posterior insula and less pronounced changes in sensorimotor cortex. Conclusions: Dysfunctional sensory processing in patients with NDSDs is associated with complex changes in grey matter volume, involving the somatosensory system and temporal regions.
Viewing the body is reported to improve tactile acuity Kennett, S., Taylor-Clarke, M., & Haggard, P. (2001). Non-informative vision improves the spatial resolution of touch in humans. Current ...Biology, 11, 1188–1191. The aim of the present study was to investigate whether this effect might be useful in improving somatosensory deficits of brain damaged patients. To support this proposal, we firstly tested the hypothesis that vision might modulate tactile performance when tactile information is limited. Thirty-two healthy subjects performed a two points discrimination task (2PDT) in three conditions: looking at their stimulated forearm, at a neutral object or at a rubber foot. The results showed that the effectiveness of visual enhancement of touch varies as a function of subjects’ tactile acuity. Moreover, the accuracy in 2PDT was higher when viewing their arm only in subjects with lower tactile sensitivity. To directly demonstrate that viewing the body might ameliorate tactile deficits, the same experiment was conducted on 10 brain damaged patients suffering a reduced somatosensory sensitivity. An amelioration of the performance was found in viewing arm condition. These findings suggest that the interaction between different sensory modalities might be effective in ameliorating deficits in single modalities.
Nondermatomal somatosensory deficits (NDSDs) are large sensory deficits not conforming to dermatomal/root territories, and no structural pathology accounts for them. They can be very mild or very ...dense, highly variable, or extremely fixed over time and may be very disabling. It is now accepted by mainstream pain science that they are the product of a central neurophysiological phenomenon. We demonstrated in this paper through literature review and through multiple clinical cases that NDSDs (a) have a psychobiological substrate at the level of the central nervous system, (b) are very frequently associated with chronic pain and/or psychotraumatic experiences, (c) occur very frequently in the context of conversion disorder, but (d) can also occur in the absence of conversion disorders, (e) can be superimposed on structural neurological deficits, and (f) respond positively, or at least in part, to sodium amobarbital (commonly referred to as the “truth serum”).
Patients with chronic pain disorders often show somatosensory disturbances that are considered to be functional. This paper aims at a more precise clinical description and at a documentation of ...functional neuroimaging correlates of this phenomenon. We examined 30 consecutive patients with unilaterally accentuated chronic pain not explained by persistent peripheral tissue damage and ipsilateral somatosensory disturbances including upper and lower extremities and trunk. The patients were assessed clinically and with conventional brain CT or MRI scan. In the last 11 patients functional neuroimaging was carried out (18-fluordeoxyglucose positron emission tomography=FDG-PET). Depressive symptoms were assessed with the Hamilton depression scale (HAMD-17) and pain intensity was rated with a visual analogue scale for pain (VAS). All patients suffered from mild to moderate depressive symptoms. All patients had experienced a prolonged antecedent phase of severe emotional distress; most of them remembered a “trigger episode of somatic pain” on the affected side. Somatosensory deficits were a replicable hyposensitivity to touch and heat perception of nondermatomal distribution. Conventional imaging procedures (brain CT or MRI scans) showed no structural changes. However, in 11 patients functional imaging with FDG-PET showed a significant hypometabolic pattern of changes in cortical and subcortical areas, mainly in the post-central gyrus, posterior insula, putamen, and anterior cingulate cortex. In summary, pain-related nondermatomal somatosensory deficits (NDSDs) are a phenomenon involving biological as well as psychosocial factors with replicable neuroperceptive clinical findings and a complex neurodysfunctional pattern in the FDG-PET.
Ein 48-jähriger Industrieangestellter wird vorgestellt, welcher im Anschluss an einen Arbeitsunfall eine schmerzassoziierte nicht-dermatombezogene somatosensorische Ausfallsstörung mit ...Halbseitenverteilung erleidet. Schmerzausweitung, Schmerzchronifizierung, halbseitige Hyperalgesie (einhergehend mit ipsilateraler Berührungs- und Wärmehypästhesie) weisen auf maladaptive neuroplastische Vorgänge der schmerzverarbeitenden neuronalen Strukturen hin. Die Stressbelastung des ZNS im Vorfeld oder zum Zeitpunkt des Auslöseereignisses scheint ein massgebender Risikofaktor zu sein.
We present the case of a 48-year old man who, eight years after an industrial accident, presents with chronic right-sided nondermatomal pain and hypaesthesia to heat and touch. During symmetric peripheral touch functional magnetic resonance imaging revealed hypometabolism in the left thalamus, somatosensory cortex, and anterior cingulate cortex. Pain-associated nondermatomal somatosensory deficits (NDSDs) localizing to one side of the body are a frequent clinical entity, which are often triggered by an accident. The tendency of NDSDs to extend to adjunct ipsilateral body parts and to become chronic points to maladaptive adjustment of pain-processing areas in the central nervous system. Psychological stress prior to or around the triggering event seems an important risk factor for NDSDs.
On the Nature of Nondermatomal Somatosensory Deficits Mailis-Gagnon, Angela; Nicholson, Keith
The Clinical journal of pain,
2011-January, 2011, 2011-Jan, 2011-01-00, 20110101, Letnik:
27, Številka:
1
Journal Article
Recenzirano
OBJECTIVESNondermatomal somatosensory deficits (NDSDs) not conforming to the distribution of peripheral nerves or dermatomes, and often present after a minor injury or with no known inciting event, ...have long been associated with “hysteria.” This article reviews the modern literature concerning NDSDs associated with chronic pain with regard to their prevalence, phenomenology and clinical presentation, clinical assessment, etiology and pathophysiology, relationship with Conversion Disorder and psychological factors, and their treatment and prognosis.
METHODSPast research and relevant literature concerning NDSDs are reviewed and summarized. Clinical case reports are presented to illustrate the salient features of NDSDs.
RESULTSThe prevalence of NDSDs varies between 25% and 50% in samples of chronic pain populations. We describe the temporal, spatial, qualitative, motor, sensory, and behavioral characteristics of NDSDs. Illustrative case reports show the remarkable NDSD phenomenology, variability, and reversibility. NDSDs represent intensely dynamic phenomena that are likely associated with supraspinal mechanisms. Recent functional imaging findings show significant alterations in brain activation patterns in these patients. Similar but spatially and temporally restricted phenomena have been shown in experimental studies with healthy controls and pain patients. NDSDs are associated with certain demographic variables, and possibly psychological factors seem to constitute a poor prognostic sign for response to treatment and return to work and can coexist with structural musculoskeletal or nervous system abnormalities.
CONCLUSIONSNDSDs are important and prevalent clinical phenomena associated with chronic pain. Their prevalence in the general population, primary care settings, and non pain patients is unknown. Research needs to be carried out to elucidate these important phenomena.
To review the literature and our current understanding of nondermatomal somatosensory deficits (NDSDs) associated with chronic pain in regards to their prevalence, assessment and clinical ...presentation, cause and pathophysiology, relationship with conversion disorder and psychological factors, as well as their treatment and prognosis.
NDSDs are negative sensory deficits consisting of partial or total loss of sensation to pinprick, light touch or other cutaneous modalities. Although they had been noted more than a century ago and appear prevalent in chronic pain populations, they are poorly studied. They may be very mild or very dense, may occupy large body areas, are often highly dynamic and changeable or, to the contrary, very stable and long lasting. NDSDs may occur in the absence of biomedical pathology or coexist with structural musculoskeletal or nervous system abnormalities. They appear to be associated with psychological factors and a poor prognosis for response to treatment and return to work. Recent brain imaging studies provide a basis for understanding NDSD pathophysiology.
NDSDs represent prevalent phenomena associated with chronic pain. Further, research is needed to elucidate their origin, response to treatment, and prevalence in the general population, primary care settings, and nonpain patients.
The effects of transcutaneous electrical stimulation on deficits of tactile perception contralateral to a hemispheric lesion were investigated in 10 right brain-damaged patients and in four left ...brain-damaged patients. The somatosensory deficit recovered, transiently and in part, after stimulation of the side of the neck contralateral to the side of the lesion, in all 10 patients with lesions in the right hemisphere, both with (six cases) and without (four cases) left visuo-spatial hemineglect, and in one left brain-damaged patient with right hemineglect. In three left brain-damaged patients without hemineglect, the treatment had no detectable effects. In one right brain-damaged patient, the stimulation of the side of the neck ipsilateral to the side of the lesion temporarily worsened the somatosensory deficit. These effects of transcutaneous electrical stimulation are similar to those of vestibular stimulation. The suggestion is made that these treatments modulate, through afferent sensory pathways, higher-order spatial representations of the body, which are pathologically distorted toward the side of the lesion. The modulatory effect is direction-specific: the defective internal representation of the contralesional side may be either partly restored, improving the disorder of tactile perception, or further impoverished, worsening the deficit. The possible neural basis of this modulation is discussed.
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