Poor dynamic balance, such as poor walking stability, is a hallmark of multiple sclerosis. Instrumental measures of local dynamic stability (LDS, e.g. short-term Lyapunov’s exponents, sLyEs) are genuine measures of walking stability and increasingly used as dynamic balance indicators. The current work aims to investigate if people with multiple sclerosis (PWMS) with no clinical evidence of gait impairment suffer poor LDS of gait. Eighty PWMS with minimal impairment (EDSS≤2.5) and twenty controls completed the Six Minutes Walking Test (6MWT) at their maximum speed, wearing inertial sensors. sLyEs were calculated from trunk vertical, mediolateral and anteroposterior (sLyEAP) acceleration. PWMS also completed a full clinical assessment including gait, balance and fatigue. Gait speed was lower in PWMS than controls (-15%), while sLyEs were larger in PWMS (+12%), even when adjusting for the different gait speed. High sLyEAP was associated with low gait speed, high impact of disease (including high fatigue) and poor balance, the three variables returned by a principal component analysis of the dataset of clinical measures. PWMS suffer poor LDS of gait, as indicated by large sLyEs. The association between high sLyEAP and poor balance supports the validity of sLyEAP as a dynamic balance measure. The inverse relationship between sLyEAP and gait speed is in line with the view that good balance is decisive for high gait speed. Finally, these findings are in line with the vicious circle linking poor balance and fatigue in PWMS, with fatigue worsening balance and poor balance leading to fatigue.

The balance of people with multiple sclerosis (PwMS) is commonly assessed during neurological examinations through clinical Romberg and tandem gait tests that are often not sensitive enough to unravel subtle deficits in early-stage PwMS. Inertial sensors (IMUs) could overcome this drawback. Nevertheless, IMUs are not yet fully integrated into clinical practice due to issues including the difficulty to understand/interpret the big number of parameters provided and the lack of cut-off values to identify possible abnormalities. In an attempt to overcome these limitations, an instrumented modified Romberg test (ImRomberg: standing on foam with eyes closed while wearing an IMU on the trunk) was administered to 81 early-stage PwMS and 38 healthy subjects (HS). To facilitate clinical interpretation, 21 IMU-based parameters were computed and reduced through principal component analysis into two components, sway complexity and sway intensity, descriptive of independent aspects of balance, presenting a clear clinical meaning and significant correlations with at least one clinical scale. Compared to HS, early-stage PwMS showed a 228% reduction in sway complexity and a 63% increase in sway intensity, indicating, respectively, a less automatic (more conscious) balance control and larger and faster trunk movements during upright posture. Cut-off values were derived to identify the presence of balance abnormalities and if these abnormalities are clinically meaningful. By applying these thresholds and integrating the ImRomberg test with the clinical tandem gait test, balance impairments were identified in 58% of PwMS versus the 17% detected by traditional Romberg and tandem gait tests. The higher sensitivity of the proposed approach would allow for the direct identification of early-stage PwMS who could benefit from preventive rehabilitation interventions aimed at slowing MS-related functional decline during neurological examinations and with minimal modifications to the tests commonly performed.

Limited longitudinal studies have been conducted on gait impairment progression overtime in non-disabled people with multiple sclerosis (PwMS). Therefore, a deeper understanding of gait changes with the progression of the disease is essential. The objective of the present study was to describe changes in gait quality in PwMS with a disease duration ≤ 5 years, and to verify whether a change in gait quality is associated with a change in disability and perception of gait deterioration. We conducted a multicenter prospective cohort study. Fifty-six subjects were assessed at baseline (age: 38.2 ± 10.7 years, Expanded Disability Status Scale (EDSS): 1.5 ± 0.7 points) and after 2 years, participants performed the six-minute walk test (6MWT) wearing inertial sensors. Quality of gait (regularity, symmetry, and instability), disability (EDSS), and walking perception (multiple sclerosis walking scale-12, MSWS-12) were collected. We found no differences on EDSS, 6MWT, and MSWS-12 between baseline and follow-up. A statistically significant correlation between increased EDSS scores and increased gait instability was found in the antero-posterior (AP) direction (r = 0.34, p = 0.01). Seventeen subjects (30%) deteriorated (increase of at least 0.5 point at EDSS) over 2 years. A multivariate analysis on deteriorated PwMS showed that changes in gait instability medio-lateral (ML) and stride regularity, and changes in ML gait symmetry were significantly associated with changes in EDSS (F = 7.80 (3,13), p = 0.003, R² = 0.56). Moreover, gait changes were associated with a decrease in PwMS perception on stability (p < 0.05). Instrumented assessment can detect subtle changes in gait stability, regularity, and symmetry not revealed during EDSS neurological assessment. Moreover, instrumented changes in gait quality impact on subjects’ perception of gait during activities of daily living.

Background and purpose: Upper limb (UL) function is often affected in people with multiple sclerosis (PwMS) and is typically assessed through objective measures, including the Nine Hole Peg Test (9‐HPT), Box and Block Test (BBT), and Hand Grip Strength (HGS). It is important to include the subjective perspective of PwMS in the assessment. This study aims to evaluate associations between Manual Ability Measure‐36 (MAM‐36) and 9‐HPT, BBT, and HGS in MS.Methods: The cross‐sectional study included five Italian centers. Inclusion criteria were age ≥ 18 years, MS diagnosis, and stable disease course. Exclusion criteria were bilateral UL paralysis, and concomitant orthopedic or neurological diseases.Results: A total of 199 PwMS were included: 128 female, mean age = 50.7 ± 13.0 years, 119 relapsing–remitting MS (RRMS), 31 primary and 49 secondary progressive MS, mean disease duration = 14.0 ± 10.4, years, mean Expanded Disability Status Scale (EDSS) = 4.6 ± 2.0.The MAM‐36 showed small correlations with 9‐HPT, BBT, and HGS. Correlations between MAM‐36 and 9‐HPT and BBT were highest among subjects with EDSS ≥ 6 and progressive MS. MAM‐36 and HGS showed the highest correlations in subjects with EDSS ≤ 5 and RRMS. Combining 9‐HPT and HGS provided the strongest predictive power over the MAM‐36.Conclusions: Correlations between objective measures and MAM‐36 were small to moderate, meaning that objective measures do not match subjects' perception of UL function. The combination of 9‐HPT and HGS measures can help improve the assessment of UL function in activities of daily living.