"Balance, Gait, and Motion Analysis in Multiple Sclerosis"

Three-dimensional gait and balance analysis will be performed using a Vicon Nexus version 2.16 motion-capture system (12 Vero cameras, 200 Hertz [Hz]) synchronized with two Bertec force plates (1000 Hz). Reflective markers will record spatial coordinates for gait speed, step length, joint angles, and Center-of-Pressure (CoP) displacement. This setup enables precise kinetic and kinematic quantification of balance and gait parameters and allows correlation with clinical functional tests in individuals with Multiple Sclerosis (MS).

The mini Balance Evaluation Systems Test (mini-BESTest) assesses dynamic postural control across four domains: anticipatory adjustments, reactive responses, sensory orientation, and dynamic gait. It includes 14 items scored on a 3-point scale (0 = severe impairment, 2 = normal performance); total = 28. Higher scores indicate better balance. It is validated and reliable for detecting fall risk in neurological populations, including Multiple Sclerosis and its Greek cross-cultural adaptation has further confirmed the scale's reliability and validity within Greek-speaking clinical cohorts.

The Functional Gait Assessment (FGA) evaluates dynamic balance and gait adaptability under varying conditions. It consists of 10 walking tasks (e.g., head turns, obstacle negotiation, pivot turns), each rated 0-3 (0 = severe impairment, 3 = normal). Total = 30; higher scores indicate better functional gait performance and lower fall risk. Demonstrates strong reliability and validity in neurological and Multiple Sclerosis populations living. The Greek version of the scale will be employed in the present study.

The Fall Efficacy Scale-International (FES-I) assesses fear of falling and confidence in performing daily activities. It consists of 16 self-report items, each rated 1-4 (1 = not at all concerned, 4 = very concerned). Total score 16-64, with higher scores indicating greater fear of falling. The Greek validated version will be used. It is reliable and widely applied in Multiple Sclerosis and older-adult populations.

The Short Physical Performance Battery (SPPB) evaluates lower-limb function through three components: (1) standing balance, (2) 4-meter gait speed, and (3) repeated chair stands. Each component is scored 0-4 based on performance time or ability, for a maximum total of 12 points. Higher scores indicate better physical performance. The SPPB is validated for assessing mobility, endurance, and fall risk in individuals with Multiple Sclerosis.

The 2-Minutes Walk Test (2MWT) measures walking endurance and fatigue by recording the total distance walked in 2 minutes on a flat 12-meter walkway at a self-selected pace. Results are expressed in meters. Higher distances reflect better walking endurance and lower fatigue. The test is validated for patients with Multiple Sclerosis and correlates with physical fitness and perceived fatigue.

The Fatigue Severity Scale (FSS) quantifies perceived fatigue through 9 self-report items, each scored 1-7 (1 = strongly disagree, 7 = strongly agree). The mean of all items represents the final score; higher values indicate greater fatigue severity. It is reliable, simple, and sensitive to changes in energy levels in Multiple Sclerosis and other neurological populations.

The modified Ashworth Scale (mAS) assesses muscle tone and spasticity during passive movement of specific joints. Each muscle group is rated on a 6-point ordinal scale (0 = no increase in tone; 1, 1+, 2, 3, 4 = progressively increasing resistance or rigidity). Higher scores indicate greater spasticity. The scale demonstrates strong intra- and inter-rater reliability in Multiple Sclerosis.