Muscle Strain in Multiple Sclerosis Patients Measured by Ultrasound Speckle Tracking Technique

The primary study, as outlined in the original trial registration, aiming to use ultrasound speckle tracking (STU) to monitor muscle contractility in multiple sclerosis (MS) patients receiving vs. not receiving fampridine, as well as to relate these results to performance-based measures and biomarkers to explore disease progression and muscle activity, has been cancelled. Instead four exploratory studies that originate from the initial trial registration but with revised aims, outcome measures and time points, have been prepared - see the DEVIATIONS TO TRIAL PROTOCOL included in the Statistical Analysis Plan filed under "Document section" The detailed description that was included in the original trial registration: Despite effective treatments, the majority of multiple sclerosis (MS) patients experience difficulty in walking and the need of a walker or wheelchair. Since 2009, medical treatment of walking impairments has been possible with fampridine, which has proven effective at approximately 40% of patients. At present, the treatment is offered on the basis of a measurable improved walking function evaluated by simple performance-based walking tests. Multiple sclerosis patients, who do not have the sufficient gait function to complete these tests, may still benefit from fampridine treatment in other activities of daily life. However, these patients are currently not eligible for fampridine treatment due to current requirements of a measurable improved effect. Ultrasound speckle tracking (UST) is a non-invasive ultrasound technique, with the potential to directly analyze the muscle strain in the muscles. UST is designed for dynamic cardiac muscular examination, but can be used in a modified version for skeletal muscle examination. The technique has already been tested in a minor pilot study with MS patients. The objective of the present study is to use UST to monitor muscle strain in the weight-bearing and transfer-related muscles in MS patients who receive fampridine vs. patients who do not receive this treatment. Strain is evaluated over time during different isometric contractions. Furthermore, the relation between these results and the performance based measures of clinical function and biomarkers in blood and urine will be examined to explore disease progression and muscle activity. MS patients will be recruited from sclerosis clinics at Odense University Hospital (OUH), Esbjerg, Kolding and Sønderborg. All participants will undergo the existing standard practice for patients receiving fampridine treatment, including functional and neurological examination. In addition to the regular practice, participants will be offered UST, answer relevant questionnaires as well as the collection of blood- and urine samples (8 ml of blood and 10 ml of urine will be centrifuged and kept in 0.5 ml aliquots and stored in the already established biobank at the Department of Neurology, OUH. Participants will be tested at baseline (just before start of fampridine treatment), after 14 days of treatment and again one year after baseline. All three test sessions will include the above mentioned testing protocol. The primary end-point will be at one-year follow-up. A sub-group of 30 randomly selected participants will supplementary perform a 3-dimensional gait analysis in the motion laboratory. A list generated from 30 randomly found numbers from 1 to 60 will be used. In the motion laboratory, the outcomes: Kinematics, kinetics, gait summary measures and temporo spatial outcome measures will be generated. Participants, who respond to the fampridine after 14 days of treatment, will continue in the project as cases, whereas non-responders persist in the trial as an untreated control group. The study is approved by the Regional Committees on Health Research Ethics for Southern Denmark, project Identification: S-20170203. Sample size is based on previously published studies regarding effect of fampridine treatment as well as already detected differences in pilot data obtained from 2 MS patients and 4 healthy controls on m supraspinatus at 40% of maximal load. With an alpha value of p\<0.05 and a power of 0.80, sample size is 60. The study will be conducted in accordance to the Good Clinical Practice and the Declaration of Helsinki and has been approved by the National Committee on Health Research Ethics and the Danish Data Protection Agency. To our knowledge, this is the first study to evaluate muscle function in MS patients through muscle strain measured using UST as well as examine its correlation to biomarkers for disease progression and muscle activity. Consequently, the result of the present study could expand clinical guidelines for fampridine treatment in MS patients. Furthermore, UST could be implemented for clinical use in assessing muscle strength and treatment response and can ultimately be used to monitor disease progression in MS patients independent of fampridine treatment. The included analysis of blood and urine opens new opportunities for diagnostic and prognostic biomarkers. In addition to provide new knowledge of disease mechanisms, it may also serve as potential new targets for future treatments.