Standardized Stimulation Protocols Are Needed for Comparable Analysis of Pain-related Evoked Potentials (PREP)

Objective: Pain-related evoked potentials (PREP) are increasingly used to investigate nociception and small-fibre function. Due to lack of a standard stimulation protocol, it is unclear whether results from studies using different protocols are comparable. Aim of the study was to assess the influence of different stimulation parameters on N1P1-amplitudes, N1-latencies and PREP-induced pain intensity. Methods: In a cross-over design we examined 31 healthy volunteers using four different stimulation protocols (number of stimulation electrodes 1 vs. 3, stimulus durations 200 µs vs. 500 µs) in a randomized order. Statistics: paired t-test, ANOVA, correlation analyses. Results: Longer stimulus duration induced higher N1P1-amplitudes (p<0.05) and higher pain intensity (p<0.001). Stimulation with 3 electrodes lead to a lower pain intensity (p<0.01), whereas the N1P1-amplitude and stimulus intensity at twofold of individual pain remained unaffected by the number of electrodes. Also, there was no relation between stimulus intensities and N1P1-amplitudes (one electrode: r=0.079; p=0.646, three electrodes: r=-0.10, p=0.70) was observed. N1-latencies remained comparable between the four protocols.Conclusions and Significance: The use of different stimulation protocols for PREP is limited by relevant differences in the N1P1-amplitudes and evoked pain intensities. Standard consented stimulation protocols are needed to allow data comparison between different labs and studies.

Review of Mechanisms, Pharmacological Management, Psychosocial Implications, and Holistic Treatment of Pain in Fabry Disease

Fabry disease is a progressive X-linked lysosomal storage disease caused by a mutation in the GLA gene, encoding the lysosomal hydrolase α-galactosidase A. The consequent reduced enzyme activity results in the toxic accumulation of glycosphingolipids, particularly globortriaosylceramide (Gb3 or GL3), in blood vessels, renal epithelia, myocardium, peripheral nervous system, cornea and skin. Neuropathic pain is the most common manifestation of Fabry disease and can be extremely debilitating. This often develops during childhood and presents with episodes of burning and sharp pain in the hands and feet, especially during exercise and it is worse with increased heat or fever. It is thought to be due to ischaemic injury and metabolic failure, leading to the disruption of neuronal membranes and small fibre neuropathy, caused by a reduced density of myelinated Aδ and unmyelinated C-fibres and alterations in the function of ion channels, mediated by Gb3 and lyso Gb3. It is important to confirm small fibre neuropathy before any Fabry disease treatment modality is considered. There is a clinical need for novel techniques for assessing small fibre function to improve detection of small fibre neuropathy and expand the role of available therapies. The current Fabry disease guidelines are in favour of pharmacological management as the first-line treatment for pain associated with Fabry disease. Refractory cases would benefit from a rehabilitation approach with interdisciplinary input, including medical, physiotherapy and psychological disciplines and including a Pain Management Programme.

Quantitative sensorische Testung im Rahmen neuropathischer Schmerzen und ihre Bedeutung für die Physiotherapie

Zusammenfassung Hintergrund Neuropathische Schmerzsyndrome zeichnen sich durch hohe Chronifizierungsraten sowie lange und intensive Schmerzepisoden aus. Ein treffsicheres Erkennen stellt eine Grundkompetenz von Physiotherapeuten dar, ermöglicht eine ursachengerechte Therapie und kann die Entstehung von Folgeschäden verhindern. Die quantitative sensorische Testung (QST) wird im medizinischen Rahmen als Ergänzung zur klinischen Sensibilitätsprüfung eingesetzt, konnte inzwischen eine beachtliche Stellung in der Forschung einnehmen, wird in der klinischen Praxis jedoch weniger häufig eingesetzt. Fragestellung Welchen Mehrwert hat die QST in der Untersuchung neuropathischer Schmerzen? Was sind die Ursachen für die begrenzte klinische Anwendung der QST? Was sind potenzielle Wege für einen erfolgreichen Übertrag der QST in die physiotherapeutische Praxis? Methode Literaturrecherche im Zuge einer Bachelorarbeit Physiotherapie. Ergebnisse Als valides Untersuchungsinstrument, das zur Evaluierung des gesamten somatosensorischen Profils geeignet ist, bietet die QST vor allem im Bereich der Small-fibre-Neuropathien einen erheblichen Vorteil gegenüber konventionellen Testverfahren. Diese kleinen Fasern scheinen insbesondere in der Frühphase von Neuropathien betroffen zu sein und können über konventionelle Testverfahren nicht evaluiert werden. Das macht den Einsatz von Teilaspekten der QST zu einem nützlichen Instrument für Physiotherapeuten und medizinisches Personal, was besonders in der Früherkennung von Neuropathien von großem Nutzen ist. Diskussion Trotz des bestehenden großen Nutzens existieren bis dato noch Limitationen, die den klinischen Routineeinsatz der QST behindern. Einige davon können durch exakte Testausführungen und Vorkehrungen bis zu einem gewissen Grad überwunden werden, andere, für die Klinik hochrelevante Bereiche wie die hohen Anschaffungskosten der Geräte und der hohe zeitliche Aufwand der Durchführung konnten bislang noch nicht zufriedenstellend gelöst werden. Weniger umfassende Testprotokolle sowie die Entwicklung handlicher und kostengünstiger Testgeräte könnten diesbezüglich erste Lösungsansätze darstellen. Die Ergänzung der konventionellen Bedside-Untersuchung um Testungen zur Wärmesensibilität und Schmerzschwellenbestimmung kann eine weitere Möglichkeit darstellen, um den dargestellten Mehrwert der QST in den klinischen Alltag zu integrieren. Schlussfolgerung Die QST steuert einen wesentlichen Beitrag zur Untersuchung und Diagnose von Neuropathien bei. Physiotherapeuten sind dazu angehalten, Teilaspekte aus der QST in eine standardmäßige Untersuchung zu implementieren, um sowohl in der Früherkennung als auch in der Behandlung positiv einzuwirken.

A Retrospective Analysis of Pain Etiology in Middle-Aged Patients with Peripheral Neuropathy

Background and Objectives: Correct assessment and a multidisciplinary approach appear to be extremely important in preventing peripheral neuropathy and its complications. The purpose of this study was to find the correlations and dissimilarities between different types of peripheral neuropathy, the occurrence of pain, and laboratory results. Materials and Methods: This retrospective study assessed 124 patients who were hospitalized in our neurology department due to various types of sensory or motor disturbances. The patients were eventually diagnosed with peripheral neuropathy, based on the electrophysiological study, anamnesis, physical examination, and laboratory results. The whole group was subjected to statistical analysis. Results: The mean age of patients was over 56 years, with a slight woman predominance. A statistically significant (p < 0.05) relationship between the place of residence and gender was seen, where more men than women live in the rural area, while more women than men live in the urban area. Most often we observed symmetric, sensorimotor, demyelinating, inflammatory, and chronic neuropathy. More than 40% of patients reported pain. A statistically significant correlation between the evolution/severity and the occurrence of pain was seen in subacute type (p < 0.05) and small fibre neuropathy (p < 0.01). Conclusions: A higher incidence of peripheral neuropathy in middle-aged people will become essential in the aging society with lifestyle and chronic disorders. Peripheral neuropathy is slightly more common in women than men and its occurrence may be influenced by work performed or internal and external factors. In the study group, more than 40% of patients reported pain, therefore the pain measurement for each patient should be implemented and repeated at every visit. An assessment of sodium level and, in women, markers of neuroinflammation level in the various types of peripheral neuropathy may be an interesting direction for the future.

Paraproteinaemic neuropathy: MGUS and beyond

Paraproteinaemic neuropathies comprise a heterogeneous group of neuro-haematological conditions with some distinct neurological, haematological and systemic phenotypes. The spectrum of disease varies from mild to severe, indolent to rapidly progressive and from small fibre sensory involvement to dramatic sensorimotor deficits. The haematological association may be overlooked, resulting in delayed treatment, disability, impaired quality of life and increased mortality. However, the presence of an irrelevant benign paraprotein can sometimes lead to inappropriate treatment. In this review, we outline our practical approach to paraproteinaemic disorders, discuss the utility and limitations of diagnostic tests and the distinctive clinical phenotypes and touch on the complex multidisciplinary management approaches.