Nociceptive Pain in Neuromuscular Disorders - Low Interventional Pilot Study to Assess Musculoskeletal Pain in Neuromuscular Disorders (NMD)

The explorative, cross-sectional low-interventional pilot study evaluates the prevalence, severity and quality of musculoskeletal nociceptive pain in participants with defined neuromuscular disorders (NMD). Adult participants with the following neuromuscular disorders will be included: histologically confirmed inclusion body myositis (IBM), genetically confirmed late-onset Pompe disease (LOPD), genetically confirmed spinal muscular atrophy type 3 (SMA3), genetically confirmed facio-scapulo-humeral muscle dystrophy (FSHD) and genetically confirmed myotonic dystrophy type 1 or type 2 (DM1, DM2). 20 healthy participants will be enrolled as a control group. The Beck depression inventory fast screen (BDI-FS) will be used as a screening. If there is a possibility of major depression (with a BDI ≥4), patients will be excluded from the study. So only patients with BDI-FS score ≤3 at screening will be enrolled. Patients will be asked to complete the following validated disease-related and quality-of-life questionnaires: German Pain Inventory (module A and abbreviated module S and L and V), Brief Pain Inventory (BPI) and Fatigue Severity and Disability Scale (FSS). Demographic and disease related data will be obtained. A neuromuscular examination will be conducted. A clinical evaluation of muscle strength using the MRC-Scale (Medical Research Council-Scale) will be performed on both sides deltoid muscles, biceps brachii muscles, triceps brachii muscles, hip flexors, hip extensors, quadriceps femoris muscles, foot extensor and foot flexor muscles as well as axial muscles and neck flexors and extensors. The Quick Motor Function Test (QMFT) with 16 items will be performed to assess muscle and movement functions of the participants. To ensure a high level of objective measurement, muscle strength will also be assessed by using handheld dynamometry. The following muscle groups will be tested: arm abduction, elbow flexion, elbow extension, hip flexion, hip extension, knee extension, knee flexion, foot extension, foot flexion. A six-minute-walk test (6MWT) will be performed once. Additionally, first signs of muscle pain or muscle cramps will be recorded (including the quality and intensity of pain). The Borg scale to rate dyspnea will be administered before starting the 6MWT and after completing the 6MWT. For diagnosis of myofascial pain, a Pressure Pain Threshold test by using a pressure algometer is included for the trapezius, deltoid and supraspinatus muscles, the rectus femoris muscles, and the tibialis anterior muscles until the patient feels any sensation of pain. Measurement of muscle stiffness, muscle tone, relaxation periods and viscoelasticity of selected muscles will be assessed by a myotonometer. Data collected in this study will be reported using summary tables, figures, and patient data listings. Differences between the patients and the healthy volunteers will be analyzed.