Nerve ultrasound in Friedreich's Ataxia: enlarged nerves as a biomarker of disease severity.

OBJECTIVE: In Friedreich's ataxia research, the focus is on discovering treatments and biomarkers to assess disease severity and treatment effects. Our study examines high-resolution nerve ultrasound in these patients, seeking correlations with established clinical markers of disease severity. METHOD: Ten patients with Friedreich's Ataxia underwent a comprehensive clinical assessment with established scales (SARA, FARS, mFARS, INCAT, ADL 0-36, IADL). Additionally, they underwent nerve conduction studies and high-resolution nerve ultrasound. Quantitative evaluation of nerve cross-sectional area, conducted at 24 nerve sites using high-resolution nerve ultrasound, was compared with data obtained from 20 healthy volunteers. RESULTS: All the patients had a severe sensory axonal neuropathy. High-resolution nerve ultrasound showed significant increase, in cross sectional area, of median and ulnar nerves at the axilla and arm. The cumulative count of affected nerve sites was directly associated with clinical disability, as determined by SARA, FARS, mFARS, ADL 0-36, and INCAT score, while displaying an inverse correlation with IADL. CONCLUSIONS: Our study shows that high-resolution ultrasound reveals notable nerve abnormalities, primarily in the upper limbs of patients diagnosed with Friedreich's Ataxia. The observed correlation between these nerve abnormalities and clinical disability scales indicates the potential use of this technique as a biomarker for evaluating disease severity and treatment effects. SIGNIFICANCE: Nerve Ultrasound is a potential biomarker of disease severity in Friedreich's Ataxia.

Predicting value for incomplete recovery in Bell's palsy of facial nerve ultrasound versus nerve conduction study.

OBJECTIVE: This longitudinal study aims at assessing the predictive value of facial nerve high-resolution ultrasound (HRUS) for incomplete clinical recovery in patients with Bell's palsy, the most common facial nerve disease. METHODS: We prospectively enrolled 34 consecutive patients with Bell's palsy. All patients underwent neurophysiological testing (including facial nerve conduction study) and HRUS evaluations 10-15 days (T1), one month (T2), and three months (T3) after the onset of Bell's palsy. Patients who did not experience complete recovery within three months were also evaluated after six months (T4). We have then compared the accuracy of HRUS with that of the facial nerve conduction study in predicting incomplete clinical recovery at three and six months. RESULTS: At T1, the facial nerve diameter, as assessed with HRUS, was larger on the affected side than on the normal side, particularly in patients with incomplete recovery at T2, T3 and T4. ROC curve analysis, however, showed that the facial nerve diameter at T1 had a lower predictive value than the facial nerve conduction study for an incomplete clinical recovery at three (T3) and six (T4) months. Still, the facial nerve diameter asymmetry, as assessed with HRUS, had a relatively high negative predictive value (thus indicating a strong association between normal HRUS examination and a good prognosis). CONCLUSIONS: Although HRUS shows abnormally increased facial nerve diameter in patients in the acute phase of Bell's palsy, the predictive value of this technique for incomplete clinical recovery at three and six months is lower than that of the nerve conduction study. SIGNIFICANCE: Nerve ultrasound has a low predictive value for incomplete clinical recovery in patients with Bell's Palsy.

Modulation of the spinal N13 SEP component by high- and low-frequency electrical stimulation. Experimental pain models matter.

OBJECTIVE: The N13 component of somatosensory evoked potential (N13 SEP) represents the segmental response of cervical dorsal horn neurons. Neurophysiological studies in healthy participants showed that capsaicin-induced central sensitization causes an increase of the N13 SEP amplitude. Consequently, in human research, this spinal component may serve as a valuable readout of central sensitization. In this study, we wanted to verify if the sensitivity of the N13 SEP for detecting central sensitization is consistent across different experimental pain models inducing central sensitization and secondary hyperalgesia, namely high and low-frequency electrical stimulation (HFS and LFS). METHODS: In 18 healthy participants, we recorded SEP after bilateral ulnar nerve stimulation before and after secondary hyperalgesia was induced through HFS and LFS applied on the ulnar nerve territory of the hand of one side. The area of secondary hyperalgesia was mapped with a calibrated 128-mN pinprick probe, and the mechanical pain sensitivity with three calibrated 16-64-256-mN pinprick probes. RESULTS: Although both HFS and LFS successfully induced secondary hyperalgesia only LFS increased the amplitude of the N13 SEP. CONCLUSIONS: These findings suggest that the sensitivity of the N13 SEP for detecting dorsal horn excitability changes may critically depend on the different experimental pain models. SIGNIFICANCE: Our results indicate that LFS and HFS could trigger central sensitization at the dorsal horn level through distinct mechanisms, however this still needs confirmation by replication studies.

Clinical criteria and diagnostic assessment of fibromyalgia: position statement of the Italian Society of Neurology-Neuropathic Pain Study Group.

BACKGROUND: The role of central and/or peripheral nervous system dysfunction is basically fundamental in fibromyalgia. AIM: The aim of this position statement on behalf of the Neuropathic Pain Study Group of the Italian Society of Neurology is to give practical guidelines for the clinical and instrumental assessment of fibromyalgia (FM) in the neurological clinical practice, taking into consideration recent studies. METHODS: Criteria for study selection and consideration were original studies, case-controls design, use of standardized methodologies for clinical practice, and FM diagnosis with ACR criteria (2010, 2011, 2016). RESULTS: ACR criteria were revised. For diagnostic procedure of small-fiber pathology, 47 studies were totally considered. Recent diagnostic criteria should be applied (ACR, 2016). A rheumatologic visit seems mandatory. The involvement of small fibers should request at least 2 among HRV + SSR and/or laser-evoked responses and/or skin biopsy and/or corneal confocal microscopy, eventually followed by monitoring of metabolic and/or immunological/ and or/paraneoplastic basis, to be repeated at 1-year follow-up. CONCLUSIONS: The correct diagnostic approach to FM could promote the exclusion of the known causes of small-fiber impairment. The research toward common genetic factors would be useful to promote a more specific therapeutic approach.

How different experimental models of secondary hyperalgesia change the nociceptive flexion reflex.

OBJECTIVE: In this neurophysiological study in healthy humans, we assessed how central sensitization induced by either high-frequency stimulation (HFS) or topical capsaicin application modulates features of the RIII reflex response. The ability of these stimuli to engage the endogenous pain modulatory system was also tested. METHODS: In 26 healthy participants we elicited an RIII reflex using suprathreshold stimulation of the sural nerve. Subsequently HFS or capsaicin were applied to the foot and the RIII reflex repeated after 15 minutes. Contact heating of the volar forearm served as the heterotopic test stimulus to probe activation of the endogenous pain modulatory system. RESULTS: HFS significantly reduced the pain threshold by 29% and the RIII reflex threshold by 20%. Capsaicin significantly reduced the pain threshold by 17% and the RIII reflex threshold by 18%. Both HFS and capsaicin left RIII reflex size unaffected. Numerical Rating Scale (NRS) pain scores elicited by the heterotopic noxious heat stimulus were unaffected by capsaicin and slightly increased by HFS. CONCLUSIONS: HFS and capsaicin similarly modulated the pain threshold and RIII reflex threshold, without a concomitant inhibitory effect of the endogenous pain modulatory system. SIGNIFICANCE: Our neurophysiological study supports the use of the RIII reflex in investigating central sensitization in humans.

EGFR mutation subtypes and response to immune checkpoint blockade treatment in non-small-cell lung cancer.

BACKGROUND: Although EGFR mutant tumors exhibit low response rates to immune checkpoint blockade overall, some EGFR mutant tumors do respond to these therapies; however, there is a lack of understanding of the characteristics of EGFR mutant lung tumors responsive to immune checkpoint blockade. PATIENTS AND METHODS: We retrospectively analyzed de-identified clinical and molecular data on 171 cases of EGFR mutant lung tumors treated with immune checkpoint inhibitors from the Yale Cancer Center, Memorial Sloan Kettering Cancer Center, University of California Los Angeles, and Dana Farber Cancer Institute. A separate cohort of 383 EGFR mutant lung cancer cases with sequencing data available from the Yale Cancer Center, Memorial Sloan Kettering Cancer Center, and The Cancer Genome Atlas was compiled to assess the relationship between tumor mutation burden and specific EGFR alterations. RESULTS: Compared with 212 EGFR wild-type lung cancers, outcomes with programmed cell death 1 or programmed death-ligand 1 (PD-(L)1) blockade were worse in patients with lung tumors harboring alterations in exon 19 of EGFR (EGFRΔ19) but similar for EGFRL858R lung tumors. EGFRT790M status and PD-L1 expression did not impact response or survival outcomes to immune checkpoint blockade. PD-L1 expression was similar across EGFR alleles. Lung tumors with EGFRΔ19 alterations harbored a lower tumor mutation burden compared with EGFRL858R lung tumors despite similar smoking history. CONCLUSIONS: EGFR mutant tumors have generally low response to immune checkpoint inhibitors, but outcomes vary by allele. Understanding the heterogeneity of EGFR mutant tumors may be informative for establishing the benefits and uses of PD-(L)1 therapies for patients with this disease.

Current and Innovative Pharmacological Options to Treat Typical and Atypical Trigeminal Neuralgia.

Trigeminal neuralgia is a representative neuropathic facial pain condition, characterised by unilateral paroxysmal pain in the distribution territory of one or more divisions of the trigeminal nerve, triggered by innocuous stimuli. A subgroup of patients with trigeminal neuralgia [TN (previously defined as atypical TN)] also suffer from concomitant continuous pain, i.e. a background pain between the paroxysmal attacks. The aim of this review is to provide current, evidence-based, knowledge about the pharmacological treatment of typical and atypical TN, with a specific focus on drugs in development. We searched for relevant papers within PubMed, EMBASE, the Cochrane Database of Systematic Reviews and the Clinical Trials database (ClinicalTrials.gov), taking into account publications up to February 2018. Two authors independently selected studies for inclusions, data extraction, and bias assessment. Carbamazepine and oxcarbazepine are the first-choice drugs for paroxysmal pain. When sodium channel blockers cannot reach full dosage because of side effects, an add-on treatment with lamotrigine or baclofen should be considered. In patients with atypical TN, both gabapentin and antidepressants are expected to be efficacious and should be tried as an add-on to oxcarbazepine or carbamazepine. Although carbamazepine and oxcarbazepine are effective in virtually the totality of patients, they are responsible for side effects causing withdrawal from treatment in an important percentage of cases. A new, better tolerated, Nav1.7 selective state-dependent, sodium channel blocker (vixotrigine) is under development. Future trials testing the effect of combination therapy in patients with TN are needed, especially in patients with concomitant continuous pain and in TN secondary to multiple sclerosis.

A pain in the skin. Regenerating nerve sprouts are distinctly associated with ongoing burning pain in patients with diabetes.

BACKGROUNDS: Patients with diabetic polyneuropathy commonly suffer from ongoing burning pain and dynamic mechanical allodynia. In this clinical and skin biopsy study, we aimed at assessing how intraepidermal regenerating nerve sprouts are associated with these two types of pain. METHODS: We consecutively enrolled 85 patients with diabetic polyneuropathy. All patients underwent skin biopsy at the distal leg. Intraepidermal nerve fibres were immunostained with the anti-protein gene product 9.5 (PGP9.5) to quantify all intraepidermal nerve fibres, and the growth-associated protein 43 (GAP43) to quantify regenerating nerve sprouts. RESULTS: We found that the GAP43-stained intraepidermal nerve fibre density and the ratio GAP43/PGP9.5 were significantly higher in patients with ongoing burning pain than in those without. The area of receiver operating characteristic (ROC) curve for the ratio GAP43/PGP9.5 was 0.74 and yielded a sensitivity and specificity for identifying ongoing burning pain of 72% and 71%, respectively. Conversely, although the density of PGP9.5 and GAP43 intraepidermal nerve fibre was higher in patients with dynamic mechanical allodynia than in those without, this difference was statistically weak and the ROC curve analysis of skin biopsy variables for this type of pain failed to reach the statistical significance. CONCLUSION: Our clinical and skin biopsy study showed that ongoing burning pain was strongly associated with regenerating sprouts, as assessed with GAP43 immunostaining. This finding improves our understanding on the mechanisms underlying neuropathic pain in patients with diabetic polyneuropathy and suggests that the GAP43/PGP 9.5 ratio might be used as an objective marker for ongoing burning pain due to regenerating sprouts. SIGNIFICANCE: Our skin biopsy study showing that regenerating sprouts, as assessed with GAP43-staining, were strongly associated with ongoing burning pain, improves our knowledge on the mechanisms underlying neuropathic pain in patients with diabetes.

A longitudinal study of painless and painful intercostobrachial neuropathy after breast cancer surgery.

Intercostobrachial neuropathy, often resulting in neuropathic pain, is a common complication of breast cancer surgery. In this 1-year longitudinal study, we aimed at seeking information on the frequency, clinical features, and course of painless and painful intercostobrachial neuropathy. We enrolled 40 women previously undergoing breast cancer surgery. In these patients, we collected, at 3, 6 and 12 months after surgery, clinical and quantitative sensory testing (QST) variables to diagnose intercostobrachial neuropathy, DN4 questionnaire to identify neuropathic pain, Neuropathic Pain Symptom Inventory to assess the different neuropathic pain symptoms, the Beck Depression Inventory to assess depressive symptoms, and SF36 to assess quality of life and Patient Global Impression of Change. Clinical and QST examination showed an intercostobrachial neuropathy in 23 patients (57.5%). Out of the 23 patients, five experienced neuropathic pain, as assessed with clinical examination and DN4. Axillary surgery clearance was associated with an increased risk of intercostobrachial neuropathy. Whereas sensory disturbances improved during the 1-year observation, neuropathic pain did not. Nevertheless, Beck Depression Inventory, SF36, and the Patient Global Impression of Change scores significantly improved over time. Our study shows that although intercostobrachial neuropathy is a common complication of breast cancer surgery, neuropathic pain affects only a minor proportion of patients. After 1 year, sensory disturbances partially improve and have only a mild impact on mood and quality of life.

Author Correction to: L-Acetyl-carnitine in Patients with Carpal Tunnel Syndrome: Effects on Nerve Protection, Hand Function and Pain.

In the original publication the name of third author was incorrectly published.

Identifying neuropathic pain in patients with multiple sclerosis: a cross-sectional multicenter study using highly specific criteria.

BACKGROUND: Pain is a common and heterogeneous complication of multiple sclerosis (MS). In this multicenter, cross sectional study, we aimed at investigating the prevalence of pain in MS using highly specific criteria for distinguishing the different types of pain. MATERIALS AND METHODS: After a structured interview, in patients with pain, clinical examination and DN4 questionnaire were used for distinguishing neuropathic and nociceptive pain. In subjects with neuropathic pain, the Neuropathic Pain Symptom Inventory was used for differentiating neuropathic pain symptoms. RESULTS: We enrolled 1249 participants (832 F, 417 M, mean age 33.9 years, mean disease duration 8 years, mean EDSS 3.2); based on clinical evaluation and DN4 score 429 patients (34.34%) were classified with pain (470 pain syndromes): 286 nociceptive pain syndromes and 184 neuropathic pain syndromes. Multivariate analysis showed that pain was associated with age, gender and disease severity and that neuropathic pain was distinctly associated with EDSS. CONCLUSIONS: Our study, providing definite information on the prevalence, characteristics and variables associated with neuropathic pain due to MS, shows that a more severe disease course is associated with a higher risk of neuropathic pain. Our findings might, therefore, provide a basis for improving the clinical management of this common MS complication.

Skin denervation does not alter cortical potentials to surface concentric electrode stimulation: A comparison with laser evoked potentials and contact heat evoked potentials.

BACKGROUND: In the neurophysiological assessment of patients with neuropathic pain, laser evoked potentials (LEPs), contact heat evoked potentials (CHEPs) and the evoked potentials by the intraepidermal electrical stimulation via concentric needle electrode are widely agreed as nociceptive specific responses; conversely, the nociceptive specificity of evoked potentials by surface concentric electrode (SE-PREPs) is still debated. METHODS: In this neurophysiological study we aimed at verifying the nociceptive specificity of SE-PREPs. We recorded LEPs, CHEPs and SE-PREPs in eleven healthy participants, before and after epidermal denervation produced by prolonged capsaicin application. We also used skin biopsy to verify the capsaicin-induced nociceptive nerve fibre loss in the epidermis. RESULTS: We found that whereas LEPs and CHEPs were suppressed after capsaicin-induced epidermal denervation, the surface concentric electrode stimulation of the same denervated skin area yielded unchanged SE-PREPs. CONCLUSION: The suppression of LEPs and CHEPs after nociceptive nerve fibre loss in the epidermis indicates that these techniques are selectively mediated by nociceptive system. Conversely, the lack of SE-PREP changes suggests that SE-PREPs do not provide selective information on nociceptive system function. SIGNIFICANCE: Capsaicin-induced epidermal denervation abolishes laser evoked potentials (LEPs) and contact heat evoked potentials (CHEPs), but leaves unaffected pain-related evoked potentials by surface concentric electrode (SE-PREPs). These findings suggest that unlike LEPs and CHEPs, SE-PREPs are not selectively mediated by nociceptive system.

L-Acetyl-carnitine in Patients with Carpal Tunnel Syndrome: Effects on Nerve Protection, Hand Function and Pain.

BACKGROUND AND AIM: L-Acetyl-carnitine (LAC) exerts an energetic effect on nerves and muscles. Recently, preclinical experiments have demonstrated a central anti-nociceptive action. OBJECTIVE: Our objective was to assess the effects of LAC on neuroprotection, pain, and function in carpal tunnel syndrome (CTS), a very frequent chronic compressive neuropathy. METHODS: In a multicentre, examiner-blinded, clinical and neurophysiological 4-month study, we enrolled 82 patients and examined 120 hands with CTS of mild to moderate severity. Patients were assessed at baseline and 10, 60 and 120 days after treatment with LAC 500 mg twice daily (BID). All patients underwent a conduction study of the median nerve, the Boston Carpal Tunnel Questionnaire (BCTQ) and the Neuropathic Pain Symptom Inventory (NPSI). The primary endpoint was the sensory conduction velocity (SCV) of the median nerve. RESULTS: The primary endpoint was met, with significant improvement of the SCV (P < 0.0001). All sensory neurophysiological measures also significantly improved. BCTQ score changed significantly (P < 0.0001), with a greater improvement in the symptom component. Nine of the NPSI types of pain, particularly squeezing and pressure pain and pain evoked by pressure, showed a significant reduction (P < 0.0001). CONCLUSIONS: Our clinical and neurophysiological study indicated that 4 months of treatment with LAC exerted a neuroprotective effect. LAC reduced pain in patients with mild and moderate CTS, a result that is possibly due to both its neuroprotective action and its central anti-nociceptive properties. Clinical Trials Registration code: EudraCT 2014-002289-62.

Pain-motor integration in the primary motor cortex in Parkinson's disease.

BACKGROUND: In Parkinson's disease (PD), the influence of chronic pain on motor features has never been investigated. We have recently designed a technique that combines nociceptive system activation by laser stimuli and primary motor cortex (M1) activation through transcranial magnetic stimulation (TMS), in a laser-paired associative stimulation design (Laser-PAS). In controls, Laser-PAS induces long-term changes in motor evoked potentials reflecting M1 long-term potentiation-like plasticity, arising from pain-motor integration. OBJECTIVE: We here examined the possible influence of chronic pain on motor responses to Laser-PAS in patients with PD, with and without chronic pain. METHODS: We compared motor responses to Laser-PAS in healthy subjects and in patients with PD, with and without chronic pain. RESULTS: Unlike controls, we found reduced responses to Laser-PAS in patients with PD, with and without pain. Patients off and on dopaminergic therapy had similar responses to Laser-PAS. When comparing responses to Laser-PAS in patients with and without pain, the two patients' subgroups had similar abnormalities. When we compared patients with pain in the body region investigated with Laser-PAS, with those with pain in other body regions, we found prominent changes in patients with homotopic pain. Finally, when comparing Laser-PAS with the original PAS protocol, which combines electric peripheral nerve stimuli and TMS, in patients without pain and those with homotopic pain, we found similar responses to both techniques in patients without pain, whereas Laser-PAS induced greater abnormalities than PAS in patients with pain. CONCLUSIONS: In PD, chronic pain degrades response to Laser-PAS through abnormal pain-motor integration.

Depressive Symptoms Correlate with Disability and Disease Course in Multiple Sclerosis Patients: An Italian Multi-Center Study Using the Beck Depression Inventory.

BACKGROUND: Depression occurs in about 50% of patients with multiple sclerosis. The aims of this study was to investigate the prevalence of depressive symptoms in a multicenter MS population using the Beck Depression Inventory II (BDI II) and to identify possible correlations between the BDI II score and demographic and clinical variables. METHODS: Data were collected in a multi-center, cross-sectional study over a period of six months in six MS centers in Italy using BDI II. RESULTS: 1,011 MS patients participated in the study. 676 subjects were female, with a mean age of 34 years (SD 10.8), mean EDSS of 3.3 (0-8.5) and mean disease duration of 10.3 years (range 1-50 years). 668 (%) subjects scored lower than 14 on the BDI II and 343 (33.9%) scored greater than 14 (14 cut-off score). For patients with BDI>14 multivariate analysis showed a significant difference between EDSS and disease course. BDI II scores for subjects with secondary progressive (SP) MS were significantly different from primary progressive (PP) patients (p < 0.001) but similar to relapsing-remitting (RR) patients. Considering subjects with moderate to severe depressive symptoms (BDI II score from 20-63), in relation to disease course, 11.7% (83/710) had RR MS, 40.7% (96/236) SP and 13.6% (6/44) PP. CONCLUSIONS: Using the BDI II, 30% of the current sample had depressive symptoms. BDI II score correlates with disability and disease course, particularly in subjects with SP MS. The BDI II scale can be a useful tool in clinical practice to screen depressive symptoms in people with MS.

EAN guidelines on central neurostimulation therapy in chronic pain conditions.

BACKGROUND AND PURPOSE: Our aim was to update previous European Federation of Neurological Societies guidelines on neurostimulation for neuropathic pain, expanding the search to new techniques and to chronic pain conditions other than neuropathic pain, and assessing the evidence with the Grading of Recommendations, Assessment, Development and Evaluation (GRADE) system. METHODS: A systematic review and meta-analysis of trials published between 2006 and December 2014 was conducted. Pain conditions included neuropathic pain, fibromyalgia, complex regional pain syndrome (CRPS) type I and post-surgical chronic back and leg pain (CBLP). Spinal cord stimulation (SCS), deep brain stimulation (DBS), epidural motor cortex stimulation (MCS), repetitive transcranial magnetic stimulation (rTMS) and transcranial direct electrical stimulation (tDCS) of the primary motor cortex (M1) or dorsolateral prefrontal cortex (DLPFC) were assessed. The GRADE system was used to assess quality of evidence and propose recommendations. RESULTS: The following recommendations were reached: 'weak' for SCS added to conventional medical management in diabetic painful neuropathy, CBLP and CRPS, for SCS versus reoperation in CBLP, for MCS in neuropathic pain, for rTMS of M1 in neuropathic pain and fibromyalgia and for tDCS of M1 in neuropathic pain; 'inconclusive' for DBS in neuropathic pain, rTMS and tDCS of the DLPFC, and for motor cortex tDCS in fibromyalgia and spinal cord injury pain. CONCLUSIONS: Given the poor to moderate quality of evidence identified by this review, future large-scale multicentre studies of non-invasive and invasive neurostimulation are encouraged. The collection of higher quality evidence of the predictive factors for the efficacy of these techniques, such as the duration, quality and severity of pain, is also recommended.

An observational study assessing peripheral neuropathy related to multiple myeloma.

We aimed at assessing the prevalence of peripheral neuropathy in newly diagnosed, treatment-naïve patients with multiple myeloma. We enrolled 153 patients with multiple myeloma at initial diagnosis. All patients underwent neurological examination and nerve conduction study. Patients with suspected pure small fiber neuropathy underwent skin biopsy. Of the 153 patients included in this study, 7.2 % had a multiple myeloma-related neuropathy. All patients suffered from a distal symmetric sensory peripheral neuropathy, associated with age (P = 0.04). Our study on prevalence rate of multiple myeloma-related peripheral neuropathy might provide a basis for improving the clinical management of this condition.

Central sensitization as the mechanism underlying pain in joint hypermobility syndrome/Ehlers-Danlos syndrome, hypermobility type.

BACKGROUND: Patients with joint hypermobility syndrome/Ehlers-Danlos syndrome, hypermobility type (JHS/EDS-HT) commonly suffer from pain. How this hereditary connective tissue disorder causes pain remains unclear although previous studies suggested it shares similar mechanisms with neuropathic pain and fibromyalgia. METHODS: In this prospective study seeking information on the mechanisms underlying pain in patients with JHS/EDS-HT, we enrolled 27 consecutive patients with this connective tissue disorder. Patients underwent a detailed clinical examination, including the neuropathic pain questionnaire DN4 and the fibromyalgia rapid screening tool. As quantitative sensory testing methods, we included thermal-pain perceptive thresholds and the wind-up ratio and recorded a standard nerve conduction study to assess non-nociceptive fibres and laser-evoked potentials, assessing nociceptive fibres. RESULTS: Clinical examination and diagnostic tests disclosed no somatosensory nervous system damage. Conversely, most patients suffered from widespread pain, the fibromyalgia rapid screening tool elicited positive findings, and quantitative sensory testing showed lowered cold and heat pain thresholds and an increased wind-up ratio. CONCLUSIONS: While the lack of somatosensory nervous system damage is incompatible with neuropathic pain as the mechanism underlying pain in JHS/EDS-HT, the lowered cold and heat pain thresholds and increased wind-up ratio imply that pain in JHS/EDS-HT might arise through central sensitization. Hence, this connective tissue disorder and fibromyalgia share similar pain mechanisms. WHAT DOES THIS STUDY ADD?: In patients with JHS/EDS-HT, the persistent nociceptive input due to joint abnormalities probably triggers central sensitization in the dorsal horn neurons and causes widespread pain.

How to diagnose neuropathic pain? The contribution from clinical examination, pain questionnaires and diagnostic tests.

Patients with peripheral and central nervous system diseases may suffer from different types of pain, namely nociceptive, neuropathic and mixed pain. Although in some cases, the distinction between these types of pain is clinically evident, yet in some patients an accurate differential diagnosis requires dedicated clinical examination, screening questionnaires and diagnostic techniques some of which are available only in specialized pain centres. This review briefly addresses the currently agreed definitions of the different types of pain and shows how clinical examination, pain questionnaires and diagnostic tests can help the clinicians in identifying neuropathic pain.