Presence Of Allodynia Research Articles

Possible relationships between headache–allodynia and nocturnal sleep breathing

Sleep and headache are linked in a bidirectional way. Breathing quality during sleep may be a possible link between them. The objective of this study were to evaluate the prevalence of headache--and of allodynia--in a population of subjects who underwent cardiopulmonary monitoring during sleep for presumed respiratory problems; to evaluate the possible relationships between the presence of headaches--and of allodynia--and respiratory parameters. We studied 181 subjects, 112 without headache (mean age 59.4 ± 13.1 years, 97 men and 15 women); 69 with history of headache (42 men and 27 women; 41 migraineurs and 28 with tension type headache). Headache diagnosis was made according to ICHD-II criteria. A semi-structured ad hoc questionnaire was used to evaluate the presence of allodynia. Full cardiopulmonary monitoring was performed by SOMNO check(®) effort (WEINMANN) with SaO(2), T90 and AHI determination. Headache and headache-associated allodynia were particularly frequent in this population, suggesting a positive correlation between breathing problems during sleep and head pain, and allodynia. The observation that better respiratory parameters were found among headache sufferers with respect to those without headache, even in allodynic subjects, seems to reverse this point of view: headache and allodynia may possibly have an allostatic function preventing deep sleep and, in turn, avoiding prolonged apneas.

Neuronal disinhibition in the trigeminal nucleus caudalis in a model of chronic neuropathic pain

The mechanisms underlying neuropathic facial pain syndromes are incompletely understood. We used a unilateral chronic constriction injury of the rat infraorbital nerve (CCI-IoN) as a facial neuropathic model. Pain-related behavior of the CCI-IoN animals was tested at 8, 15 and 26 days after surgery (dps). The response threshold to mechanical stimulation with von Frey hairs on the injured side was reduced at 15 and 26 dps, indicating the presence of allodynia. We performed unitary recordings in the caudalis division of the spinal trigeminal nucleus (Sp5C) at 8 or 26 dps, and examined spontaneous activity and responses to mechanical and thermal stimulation of the vibrissal pad. Neurons were identified as wide dynamic range (WDR) or low-threshold mechanoreceptive (LTM) according to their response to tactile and/or noxious stimulation. Following CCI-IoN, WDR neurons, but not LTM neurons, increased their spontaneous activity at 8 and 26 dps, and both types of Sp5C neurons increased their responses to tactile stimuli. In addition, the on-off tactile response in neurons recorded after CCI-IoN was followed by afterdischarges that were not observed in control cases. Compared with controls, the response inhibition observed during paired-pulse stimulation was reduced after CCI-IoN. Immunohistochemical studies showed an overall decrease in GAD65 immunoreactivity in Sp5C at 26 dps, most marked in laminae I and II, suggesting that following CCI-IoN the inhibitory circuits in the sensory trigeminal nuclei are depressed. Consequently, our results strongly suggest that disinhibition of Sp5C neurons plays a relevant role in the appearance of allodynia after CCI-IoN.

Correlation between presence of allodynia and sleep quality in migraineurs

Cutaneous allodynia is a frequent complaint in migraine patients, possibly induced by central sensitisation of trigeminal nucleus. The objective of this study is to investigate if sleep quality is related to the presence of migraine-associated allodynia. A total of 175 consecutive migraineurs were included, 124 with episodic and 51 with chronic forms. As control group, 73 subjects free from any kind of headache were included (HC). The presence of allodynia and sleep disturbances was assessed by a set of semi-structured questions. Chi-square test was applied to compare frequencies among groups. Sleep quality was worse among migraineurs with respect to controls for each sleep item analysed. This difference was significant for all items but one (i.e. frequency in drug use to induce sleep). The frequency of sleep disturbances was higher than in controls in both allodynic and non-allodynic migraineurs, although statistical analysis showed that all these differences were still significant in allodynic migraineurs (also in this case for all the sleep items but one, i.e. frequency in drug use to induce sleep), whilst non-allodynic migraineurs were significantly different from controls only for one item (frequency of initial insomnia). These results suggest that allodynia is strongly related to sleep quality, in a bi-directional way: sleep disturbances may favour central sensitisation, and, in turn, allodynia may impair sleep.

Dynamic mechanical (brush) allodynia in cluster headache: a prevalence study in a tertiary headache clinic.

Cutaneous allodynia (CA) has been described in migraine and has been related to treatment failure. There are little data about the incidence of CA in other primary headache syndromes such as cluster headache (CH). The objectives of this study are to evaluate the prevalence of dynamic mechanical (brush) allodynia (BA) in CH patients attending a tertiary headache clinic, and to assess its relation to disease characteristics. Adult patients with episodic or chronic CH were recruited. We obtained demographic data and data on disease characteristics through a structured questionnaire, and tested the patients for brush allodynia BA by applying a 4 × 4 gauze pad over the V1, C2/C3 and C8 skin areas bilaterally. The prevalence of allodynia in the entire study population and in the different sub-groups was calculated. We also examined the association between CA and demographic parameters, and its association with disease characteristics. Forty-one patients were recruited (22 men, 19 women; mean age 44.9 years). Twenty-two had chronic CH (CCH) and 19 had episodic CH (ECH). Mean disease duration was 14.1 years (12.3 the CCH group and 15.7 in the ECH group). Overall, 20 (49%) patients were allodynic. There was no statistically significant association between the presence of allodynia and age, gender, diagnosis (episodic vs. chronic CH), disease duration or disease severity. In conclusion, BA was common in this CH patient sample. The therapeutic implications of the presence of BA in CH need to be further studied.

Is allodynia influenced by psychological profile in headache patients?

Cutaneous allodynia is a frequent complain in headache patients, particularly in those with migraine. A stronger association is present in patients with migraine with aura and with chronic or transformed migraine. The aim of the present study was to investigate if the psychological profile may be related to the presence/absence of allodynia in a sample of headache patients. The psychological profile of patients was assessed by the SCL90R; the presence of allodynia was assessed by a set of semi-structured questions used in previous studies. For the purpose of the study, patients were divided into subgroups according to the headache type (ICDH-II diagnoses), as well as to the temporal pattern (episodic or chronic). A total of 213 consecutive headache patients were studied. Most patients had episodic migraine (116); 37 had tension-type headache. Overall, 156 patients had episodic headache forms, and 57 had chronic forms. As far as allodynia, 93 were non-allodynic; 120 presented allodynic symptoms during their headaches. No significant difference was found between allodynic and non-allodynic patients neither if studied in a whole group (t test, P = 0.10 NS) nor when patients were evaluated comparing different subgroups on the basis of headache type, and of the episodic/chronic pattern. Our results suggest that the presence/absence of allodynia may not be influenced by the psychological profile.

Use of Lidocaine Patches for Neuropathic Pain in a Comprehensive Cancer Centre

There are few reports of the use of the lidocaine 5% patch (L5%P) for neuropathic pain (NP) in the cancer patient. Within a comprehensive cancer centre, L5%P has been prescribed by the Pain and Palliative Care Service (Peter McCallum Cancer Centre, East Melbourne, Victoria, Australia) for selected patients with NP since 2001. To retrospectively audit the use of L5%P within a comprehensive cancer centre. All L5%P prescriptions up to January 2009 were listed and patient medical records were searched to determine neuropathic pain syndromes treated, the presence of allodynia, previous analgesic medications, treatment duration and outcome. L5%P was prescribed for 97 patients, most frequently for persistent postsurgical NP (n=26), postherpetic neuralgia (n=24) and cancer-related NP (n=18). Six patients had no history of cancer and two patients never applied L5%P. Reviewers classed L5%P analgesic efficacy as 'potent' in 38% of patients with postherpetic neuralgia, 35% of patients with postsurgical pain, 27% of patients with NP after other treatments for cancer and 12% of patients with NP attributed to cancer alone. Allodynia featured in at least 60% of patients. Where allodynia was present, the efficacy of L5%P was assessed as 'potent' in 38% and 'partial' in 24%, but 'ineffective' in 26%, and 'causing worse pain' in 3.4% of patients. Treatment duration extended longer than one month in 52 patients, longer than two months in 29 patients and longer than one year in 13 patients. Therapy was ceased due to skin irritation in seven patients. The outcomes in relation to other reports are discussed. The present data support trials of L5%P for cancer patients with NP syndromes associated with allodynia.

Migraine, allodynia, and implications for treatment

Allodynia--perception of pain from non-noxious stimuli--is a common clinical feature in various pain syndromes. The significance for migraine has increasingly been recognized and the pathophysiology has been investigated in detail. Allodynia is a marker for sensitization of central trigeminal neurons. Intensity and persistence of allodynic symptoms are a function of duration of migraine attacks, frequency of attacks, and migraine history. It has been hypothesized that treatment success with triptans may be severely impaired in the presence of allodynia. However, randomized controlled trials did not confirm that. Treatment with cyclooxygenase inhibitors and dihydroergotamine does not seem to be limited by allodynia; these medications may be able to reverse allodynia. Data on the new class of calcitonin-gene related-peptide antagonists are not yet available. Additional and more refined randomized controlled trials, focusing on methodological issues pertaining to the determination of allodynia, are warranted to resolve the true relationship between allodynia and treatment response. Regardless--based on available randomized controlled trials--the recommendation prevails to initiate abortive treatment as soon as possible after attack onset when pain is still mild.

Personality profile and allodynic migraine

Migraine is known to be associated to particular psychological features. Cutaneous allodynia is a painful sensation or discomfort induced by a non-noxious stimulus, and is a frequent complaint during migraine attacks. The aim of this study was to compare the personality profile of allodynic and non-allodynic migraineurs to identify possible relationships between psychological aspects and the presence of allodynia. The Symptom Check List 90-R (SCL90R), a 90-item self-report psychological symptom inventory, was used to investigate the psychological profile of our patients. The presence of allodynia was assessed by a set of semi-structured questions that investigated if the patient experienced abnormal scalp sensitiveness and/or discomfort during headache episodes. Twenty-five nonallodynic patients and 38 allodynic migraineurs were studied. No significant difference was found between the two groups in any area of the personality profile. The psychological profile seems not to affect the presence/absence of cutaneous allodynia in migraine patients. This reinforces the hypothesis that allodynia is a "somatic" symptom, not modified by psychological aspects.

Identifying Cutaneous Allodynia in Chronic Migraine Using a Practical Clinical Method

Cutaneous allodynia is common in migraine. In the majority of previous studies on allodynia in migraine, only patients with episodic migraine (EM) were included. Little is known on patterns of allodynia in chronic migraine (CM). Since the presence of allodynia is associated with a poor response to triptans, a clinically practical method to test migraine patients for allodynia would be useful to the clinician. The aim of this study was to assess the prevalence of dynamic mechanical (brush) allodynia (BA) in CM, using a clinically practical method. Eighty-nine CM patients were prospectively recruited. Patients were given a structured questionnaire regarding demographic data and migraine characteristics. Allodynia was tested using a 10 x 10-cm gauze pad to brush various areas of the skin lightly. The prevalence of BA in the entire study population and in different patient subgroups was calculated. BA was present in 42.7% (38/89) of the patients. The presence of allodynia was unrelated to age, disease duration or to the occurrence of an acute headache exacerbation at the time of testing. Allodynia was positively associated with a history of migraine aura. BA was most common in the cephalic area, but was also seen in cervical dermatomes. BA is common in CM and, unlike in EM, is not significantly affected by the occurrence of an acute headache exacerbation. This suggests that central trigeminovascular neurons are chronically sensitized in patients experiencing migraine headache >15 days per month. The testing of BA in the clinical setting is possible using a simple and brief approach. It allows the clinician to determine whether the patient is sensitized, a diagnosis that affects treatment decisions.

Early treatment of migraine attacks with triptans: a strategy to enhance outcomes and patient satisfaction?

Treating migraine attacks early with triptans may be more effective than late triptan administration. However, in published studies, the definition of ‘early’ varied (in terms of time, pain intensity or presence of allodynia) or was unclear. Therefore, clear clinical indications have not been established. Appropriately designed trials to address this issue remain a priority. Early triptan treatment may also have disadvantages, including inadvertent treatment of tension-type headaches and danger of medication overuse. At present, only those migraineurs with rapid pain worsening, high pain recurrence rate and clinical indications of allodynia should be encouraged to take triptans as quickly as possible. This recommendation implies a requirement for patient education and the need to carefully tailor treatment to individual needs.

Efficacy of salmon calcitonin in complex regional pain syndrome (type 1) in addition to physical therapy

The aim of the study was to assess the efficacy of salmon calcitonin, which was suggested as effective in the treatment of complex regional pain syndrome type 1 (CRPS 1). Patients who had suffered trauma to their upper extremities and developed CRPS 1 were included into this randomised, controlled single-blind study. The diagnosis was made according to the clinical examination and scintigraphy. The evaluation parameters were: pain [visual analogue scale (VAS)], the angle of dorsiflexion (DF) and palmar flexion (PF) of the wrist, distance between the fingertip and distal palmar crease (FT-DPC), allodynia, hyperalgesia and trophic changes. One group received paracetamol 1500 m/day and the other group salmon calcitonin 200 IU/day for 2 months. All of the patients participated in a physical therapy and exercise programme. A total of 35 patients were divided into two groups, who were found to be similar for age, body mass index, period of trauma, period of rest in a plaster splint or bandage, the duration of symptoms, VAS, DF and PF angle, FT-DPC, presence of allodynia, hyperalgesia and trophic changes (p>0.05). The control examination showed similar results for allodynia, hyperalgesia and trophic changes, whereas remarkable improvement was observed in the rest of the parameters within groups. On the other hand, between the two groups there was no significant difference in any of the parameters (p>0.05) This randomised, single-blind study showed that all of the patients with acute CRPS 1 in their upper extremities after trauma, who were treated with either paracetamol or calcitonin along with physical therapy, recovered in all parameters significantly, but without any difference between groups. We can conclude that calcitonin does not make any favourable contribution in the treatment of patients with acute CRPS 1; physical therapy combined with only a simple analgesic is an efficient means of therapy.

MIGRAINE PATHOPHYSIOLOGY

MIGRAINE PATHOPHYSIOLOGY

Painless Electrodiagnostic Current Perception Threshold and Pain Tolerance Threshold Values in CRPS Subjects and Healthy Controls: A Multicenter Study

The purpose of this study is to evaluate both painless and painful sensory transmission in patients with Complex Regional Pain Syndrome (CRPS) using the automated electrodiagnostic sensory Nerve Conduction Threshold (sNCT) test. This test generates reliable, painless Current Perception Threshold (CPT) and atraumatic Pain Tolerance Threshold (PTT) measures. Standardized CPT and PTT measures using constant alternating current sinusoid waveform stimulus at 3 different frequencies 5 Hz, 250 Hz, and 2 kHz (Neurometer CPT/C Neurotron, Inc. Baltimore, MD) were obtained from CRPS subjects at a distal phalange of the affected extremity and at an ipsilateral asymptomatic control site. Matched sites were tested on healthy subjects. Detection sensitivities for an abnormal PTT and CPT test were calculated based on specificity of 90% as determined from data obtained from healthy controls. A Spearman rank correlation was used to test for a significant association between presence of allodynia and an abnormal PTT or CPT at any frequency tested. Thirty-six CRPS subjects and 57 healthy controls were tested. The highest detection sensitivity of the PTT test from symptomatic test sites was 63% for the finger and 71% for the toe. PTT abnormalities were also detected, to a lesser degree, at the asymptomatic control site (41% finger control site, 16% toe control site). The highest CPT detection sensitivity at the symptomatic site was 37% for the finger site and 53% for the toe site. CPT abnormalities were also detected at the asymptomatic control site (29% finger control site, 37% toe control site). Eighty-six percent of the CRPS subjects had either a PTT or CPT abnormality at any frequency at the symptomatic site. There was a significant correlation between presence of allodynia and presence of an abnormal CPT and PTT, respectively (P < .01). The correlation coefficient was lower for CPT than for PTT, ie, 0.34 versus 0.6 for the finger and 0.48 versus 0.67 for the toe, respectively. In studied CRPS patients an abnormal PTT was detected with higher sensitivity than an abnormal CPT. Assessing PTT may become a useful electrodiagnostic quantitative sensory test for diagnosing and following the course of neuropathic pain conditions.

A peripheral mononeuropathy in rat that produces disorders of pain sensation like those seen in man

A peripheral mononeuropathy was produced in adult rats by placing loosely constrictive ligatures around the common sciatic nerve. The postoperative behavior of these rats indicated that hyperalgesia, allodynia and, possibly, spontaneous pain (or dysesthesia) were produced. Hyperalgesic responses to noxious radiant heat were evident on the second postoperative day and lasted for over 2 months. Hyperalgesic responses to chemogenic pain were also present. The presence of allodynia was inferred from the nocifensive responses evoked by standing on an innocuous, chilled metal floor or by innocuous mechanical stimulation, and by the rats' persistence in holding the hind paw in a guarded position. The presence of spontaneous pain was suggested by a suppression of appetite and by the frequent occurrence of apparently spontaneous nocifensive responses. The affected hind paw was abnormally warm or cool in about one-third of the rats. About one-half of the rats developed grossly overgrown claws on the affected side. Experiments with this animal model may advance our understanding of the neural mechanisms of neuropathic pain disorders in humans.