A set of related medical disorders that lack a proper classification system and diagnostic criteria is like a society without laws. The result is incoherence at best, chaos at worst. For this reason, the International Classification of Headache Disorders (ICHD) is arguably the single most important breakthrough in headache medicine over the last 50 years. The ICHD identifies and categorizes more than a hundred different kinds of headache in a logical, hierarchal system. Even more important, it has provided explicit diagnostic criteria for all of the headache disorders listed. The ICHD quickly became universally accepted, and criticism of the classification has been minor relative to that directed at other disease classification systems. Over the 20 years following publication of the first edition of the ICHD, headache research has rapidly accelerated despite sparse allocation of resources to that effort. In summary, the ICHD has attained widespread acceptance at the international level and has substantially facilitated both clinical research and clinical care in the field of headache medicine.

International Classification of Headache Disorders

A complex regional pain syndrome (CRPS)—multiple system dysfunction, severe and often chronic pain, and disability—can be triggered by a minor injury, a fact that has fascinated scientists and perplexed clinicians for decades. However, substantial advances across several medical disciplines have recently improved our understanding of CRPS. Compelling evidence implicates biological pathways that underlie aberrant infl ammation, vasomotor dysfunction, and maladaptive neuroplasticity in the clinical features of CRPS. Collectively, the evidence points to CRPS being a multifactorial disorder that is associated with an aberrant host response to tissue injury. Variation in susceptibility to perturbed regulation of any of the underlying biological pathways probably accounts for the clinical heterogeneity of CRPS.

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Clinical features and pathophysiology of complex regional pain syndrome

Background: Phantom limb and complex regional pain syndrome type 1 (CRPS1) are characterized by changes in cortical processing and organization, perceptual disturbances, and poor response to conventional treatments. Graded motor imagery is effective for a small subset of patients with CRPS1. Objective: To investigate whether graded motor imagery would reduce pain and disability for a more general CRPS1 population and for people with phantom limb pain. Methods: Fifty-one patients with phantom limb pain or CRPS1 were randomly allocated to motor imagery, consisting of 2 weeks each of limb laterality recognition, imagined movements, and mirror movements, or to physical therapy and ongoing medical care. Results: There was a main statistical effect of treatment group, but not diagnostic group, on pain and function. The mean (95% CI) decrease in pain between pre- and post-treatment (100 mm visual analogue scale) was 23.4 mm (16.2 to 30.4 mm) for the motor imagery group and 10.5 mm (1.9 to 19.2 mm) for the control group. Improvement in function was similar and gains were maintained at 6-month follow-up. Conclusion: Motor imagery reduced pain and disability in these patients with complex regional pain syndrome type I or phantom limb pain, but the mechanism, or mechanisms, of the effect are not clear.

http://specialistpainphysio.com/wp-content/uploads/2011/11/Graded-Motor-CRPS.pdf

Graded motor imagery for pathologic pain A randomized controlled trial

Many people with recurrent low back pain (LBP) have deficits in postural control of the trunk muscles and this may contribute to the recurrence of pain episodes. However, the neural changes that underlie these motor deficits remain unclear. As the motor cortex contributes to control of postural adjustments, the current study investigated the excitability and organization of the motor cortical inputs to the trunk muscles in 11 individuals with and without recurrent LBP. EMG activity of the deep abdominal muscle, transversus abdominis (TrA), was recorded bilaterally using intramuscular fine-wire electrodes. Postural control was assessed as onset of TrA EMG during single rapid arm flexion and extension tasks. Motor thresholds (MTs) for transcranial magnetic stimulation (TMS) were determined for responses contralateral and ipsilateral to the stimulated cortex. In addition, responses of TrA toTMS over the contralateral cortex were mapped during voluntary contractions at 10% of maximum. MTs and map parameters [centre of gravity (CoG) and volume] were compared between healthy and LBP groups.The CoG of the motor cortical map of TrA in the healthy group was » 2c m anterior and lateral to the vertex, but was more posterior and lateral in the LBP group.The location of the CoG and the map volume were correlated with onset of TrA EMG during rapid arm movements. Furthermore, the MT needed to evoke ipsilateral responses was lower in the LBP group, but only on the less excitable hemisphere. These findings provide preliminary evidence of reorganization of trunk muscle representation at the motor cortex in individuals with recurrent LBP, and suggest this reorganization is associated with deficits in postural control.

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Reorganization of the motor cortex is associated with postural control deficits in recurrent low back pain.

The complex regional pain syndrome (CRPS) is a disabling neuropathic pain condition that may develop following injuries of the extremities. In the present study we sought to characterize motor dysfunction in CRPS patients using kinematic analysis and functional imaging investigations on the cerebral representation of finger movements. Firstly, 10 patients and 12 healthy control subjects were investigated in a kinematic analysis assessing possible changes of movement patterns during target reaching and grasping. Compared to controls, CRPS patients particularly showed a significant prolongation of the target phase in this paradigm. The pattern of motor impairment was consistent with a disturbed integration of visual and proprioceptive inputs in the posterior parietal cortex. Secondly, we used functional MRI (fMRI) and investigated cortical activations during tapping movements of the CRPS-affected hand in 12 patients compared to healthy controls (n = 12). During finger tapping of the affected extremity, CRPS patients showed a significant reorganization of central motor circuits, with an increased activation of primary motor and supplementary motor cortices (SMA). Furthermore, the ipsilateral motor cortex showed a markedly increased activation. When the individual amount of motor impairment was introduced as regressor in the fMRI analysis, we were able to demonstrate that activations of the posterior parietal cortices (i.e. areas within the intraparietal sulcus), SMA and primary motor cortex were correlated with the extent of motor dysfunction. In summary, the results of this study suggest that substantial adaptive changes within the central nervous system may contribute to motor symptoms in CRPS.

The motor system shows adaptive changes in complex regional pain syndrome

To investigate neglect, extinction, and body-perception in patients suffering from complex regional pain syndrome (CRPS). So-called 'neglect-like' symptoms have been reported in CRPS, however no studies have yet analyzed this phenomenon which might substantiate the theory of the central nervous system involvement in the pathophysiology of CRPS. A total of 114 patients with CRPS of the upper limb underwent bedside neurological examination. 'Neglect-like' symptoms were determined by asking all patients what kind of feeling they had toward the affected hand (feeling of foreignness). Hemispatial neglect was tested with the line bisection task in 29 patients and sensory extinction to simultaneous stimulation in 40 patients. The ability to identify fingers after tactile stimulation was tested in 73 patients. Independently of the affected side and disease duration, 54.4% of the patients reported that their hand felt 'foreign' or 'strange'. The ability to identify fingers was impaired in 48% on the affected hand and in 6.5% on the unaffected hand ( X(2) = 33.52, df = 1, p < 0.0001). These findings were related to pain intensity, illness duration and the extent of sensory deficits. No typical abnormalities indicating neglect were found in the line bisection test. Sensory extinction was normal in all patients. A large proportion of CRPS patients have disturbances of the self-perception of the hand, indicating an alteration of higher central nervous system processing. There are no indicators that classic neglect or extinction contribute to these findings. Physical therapy of such patients should take this observation into consideration.

Impaired self-perception of the hand in complex regional pain syndrome (CRPS)

Objective.—To investigate the incidence and characteristics of seizure-associated headaches and the modalities of treatment.



Background.—Systematic investigations of the characteristics of seizure-associated headaches are rare. Although data in the literature on the incidence of postictal headaches range between 37% and 51%, experiences with their treatment are limited and pathophysiological concepts do not exist.



Methods.—One hundred ten epileptic outpatients from an epilepsy referral center participated in a semi-standardized interview about headaches associated with epileptic seizures. The characteristics of these patients and of 15 additionally recruited patients with known postictal headaches were analyzed.



Results.—The incidence of seizure-associated headaches was 43% (n = 47). Forty-three patients had exclusively postictal headaches. One patient had exclusively preictal headaches. Three patients had both pre- and postictal headaches. The duration of postictal headaches was longer than 4 hours in 62.5% of the patients. In the majority of patients, postictal headaches occurred in more than 50% of the seizures. Postictal headaches were treated by self-medication in 19 patients (30%). No patient treated headaches according to a medical prescription. In 11 patients, postictal migraine was untreated. Postictal headaches were associated with focal seizures in 23 patients and/or with generalized seizures in 54 patients. According to the headache classification of the International Headache Society, headaches were classified as migraine-type in 34% of patients and as tension-type headache in 34% of patients. Headaches could not be classified in 21% of patients. Patients with and without postictal headaches did not differ as to localization of the epileptogenic zone or to the number of prescribed antiepileptic drugs. There was no relationship between the localization of the epileptogenic focus, localization of the headache, or the headache classification.



Conclusions.—Headaches associated with partial and generalized seizures are frequent and undertreated. Treatment should consider both the headache syndrome and the general guidelines for treating primary headaches. The pathophysiology of seizure-associated headaches cannot be explained by the epileptic syndrome.

Headache Associated with Epileptic Seizures: Epidemiology and Clinical Characteristics

TMS motor cortical brain mapping in patients with complex regional pain syndrome type I.

In 1988 the International Headache Society defined the diagnostic criteria of Tolosa-Hunt syndrome (THS) to include episode(s) of unilateral orbital pain for an average of 8 weeks if untreated, with associated paresis of one or more of the third, fourth, and sixth cranial nerves. Cranial nerve paresis may coincide with the onset of pain or follow it within a period of up to 2 weeks, and the pain must be relieved within 72 h after the initiation of corticosteroid therapy. Other causative lesions must be excluded by neuroimaging. On the basis of the history and neuroradiological findings of six patients we show the pitfalls in diagnosing THS with these criteria. We propose a revision of the criteria: Other causative lesions must be excluded by neuroimaging, especially of the region of the cavernous sinus and the orbita, and by blood and CSF examinations. Since imaging techniques have dramatically improved, it is now possible to visualize the inflammatory tissue in THS. Positive magnetic resonance imaging or computed tomography findings compatible with inflammatory tissue neither exclude nor confirm THS and remain suspect until a malignant tumor or inflammation other than THS is excluded. Clinical and radiological follow-up examinations must be performed for at least 2 years, even in patients with negative findings on magnetic resonance imaging at onset.

The criteria of the International Headache Society for Tolosa-Hunt syndrome need to be revised

To determine if recently reported changes in sensory thresholds during migraine attacks can also be seen in cluster headache (CH), we performed quantitative sensory testing (QST) in 10 healthy subjects and in 16 patients with CH. Eight of the patients had an episodic CH and the other eight a chronic CH. The tests were performed on the right and left cheeks and on the right and left side of the back of the hands to determine the subjects' perception and pain thresholds for thermal (use of a thermode) and mechanical (vibration, pressure pain thresholds, pin prick, von Frey hairs) stimuli. Six patients were examined in the attack-free period. Three were also willing to repeat the tests a second time during an acute headache attack, which was elicited with nitroglycerin. The healthy subjects performed the experiments in the morning and evening of the same day to determine if sensory thresholds are independent of the time of day. If they were, this would allow estimation of the influence of the endogenous cort...

A. Straube

Papers

Impaired self-perception of the hand in complex regional pain syndrome (CRPS)

Headache Associated with Epileptic Seizures: Epidemiology and Clinical Characteristics

TMS motor cortical brain mapping in patients with complex regional pain syndrome type I.

The criteria of the International Headache Society for Tolosa-Hunt syndrome need to be revised

Quantitative Sensory Testing in Cluster Headache: Increased Sensory Thresholds: