Characterization of Upper Limb Impairments at Body Function, Activity, and Participation in Persons With Multiple Sclerosis by Behavioral and EMG Assessment: A Cross-Sectional Study

[Multidisciplinary and multimodal rehabilitation care for patients suffering from multiple sclerosis]

The support provided at the Germaine-Revel medical center in the Rhône region involves assessing the patient as a whole, which is a key aspect of implementing personalized rehabilitation focused on one or more objectives. The team offers multidisciplinary and multimodal care, because the clinical symptoms of people with multiple sclerosis are very varied: they can include neuromotor, neurosensory, neurosensory and cognitive disorders, as well as bladder and bowel and genital disorders.

Upper Limb Sensory-Motor Control During Exposure to Different Mechanical Environments in Multiple Sclerosis Subjects With No Clinical Disability

Multiple sclerosis (MS) is an autoimmune and neurodegenerative disease resulting in motor impairments associated with muscle weakness and lack of movement coordination. The goal of this work was to quantify upper limb motor deficits in asymptomatic MS subjects with a robot-based assessment including performance and muscle synergies analysis. A total of 7 subjects (MS: 3 M−4 F; 42 ± 10 years) with clinically definite MS according to McDonald criteria, but with no clinical disability, and 7 age- and sex-matched subjects without a history of neurological disorders participated in the study. All subjects controlled a cursor on the computer screen by moving their hand or applying forces in 8 coplanar directions at their self-selected speed. They grasped the handle of a robotic planar manipulandum that generated four different environments: null, assistive or resistive forces, and rigid constraint. Simultaneously, the activity of 15 upper body muscles was recorded. Asymptomatic MS subjects generated less smooth and less accurate cursor trajectories than control subjects in controlling a force profile, while the end-point error was significantly different also in the other environments. The EMG analysis revealed different muscle activation patterns in MS subjects when exerting isometric forces or when moving in presence of external forces generated by a robot. While the two populations had the same number and similar structure of muscle synergies, they had different activation profiles. These results suggested that a task requiring to control forces against a rigid environment allows better than movement tasks to detect early sensory-motor signs related to the onset of symptoms of multiple sclerosis and to differentiate between stages of the disease.

Performance of Activities of daily living in people with multiple sclerosis

OBJECTIVE

Multiple sclerosis (MS) may result in activity and participation limitations, including the performance of activities of daily living (ADL). This study aims at systematically investigate ADL performance by using Assessment of Motor and Process Skills (AMPS) in people with MS (PwMS) of all disease types and within the Kurtzke Expanded Disability Status Scale (EDSS) range from 1.0 - 8.0.

METHODS

Eight multiple sclerosis (MS) centres participated in data collection of a consecutive sample of PwMS. Participants were referred for assessment to occupational therapy (OT) by treating physician or recruited from neurology department in each hospital and assessed by EDSS and AMPS. The AMPS is an observational, criterion referenced ADL assessment, providing values for a person's ADL performance in terms of motor and process skills. Criterion referenced cut-off scores were established at 2.0 for motor skills and at 1.0 for process skills and both values above the cut-off score indicate competent (independent, safe, efficient and effortless) ADL performance. Process skills refer to the act of carrying out a series of actions and is summarized in terms of efficiency, like initiating without pauses, continuing actions through to completion, performing actions in logical order (sequences), choosing, and completing the task as planned (heeds).

RESULTS

Two hundred and ten PwMS were recruited (48 +/- 13 years of age, 145 women/65 men, average disease duration was 11.8 +/- 9.6 years, average EDSS was 4.8+/-1.8). Average motor skills score was 1.01+/- 1.12 (indicating need for assistance with evidence of increased clumsiness/physical effort) and average process skills score was 1.02 +/- 0.66 (risk zone, questionable efficiency and more likely to need assistance). Overall, motor skills and process skills decreased with increasing EDSS score. No need for assistance in motor skills was indicated in subjects with lower EDSS scores (1.0 - 2.5). In higher EDSS group (≥4.5), 57% of subjects needed assistance in motor skills and 27% in process skills. The competency in process skills was either questionable or reduced within all EDSS scores. However, 33-38% of subjects with higher EDSS scores (6.0-8.5) showed competent performance in process skills. Overall correlation between motor and process scores was moderate (r = 0.56, p<0.0001), but no significant relationships between motor and process skills were found in the lower EDSS (1-2.5) and high EDSS scores (8-8.5). Further, EDSS and disease type were significant predictors, explaining 52.7% of motor skills and 22.3% of process skills performance.

CONCLUSION

Problems in ADL performance were found in EDSS categories 1.0 to 8.0 and in all disease types, therefore it is advisable to screen all PwMS for ADL deficits and provide relevant rehabilitation interventions.

A comparison of upper limb function in subjects with multiple sclerosis and healthy controls using an inertial measurement unit

Upper limbs (UL) dysfunction is frequent in people with Multiple Sclerosis (PwMS). Several objective measures of UL function are proposed; however, their use is mostly confined to assess subjects with mild-to-moderate disability and requires fine motor skills, often impaired in high disability level subjects. Thus, a tool to score UL function in the advanced disease stage is lacking. The aim of the study is to analyse and compare UL unilateral and bilateral movements of healthy control (HC) and PwMS, at different disability levels, using an instrumented version (Inertial Measurement Unit, IMU) of the 15-seconds finger-to-nose test (FNT). Each movement cycle was segmented in going/adjusting/returning phases. The inter-hand interval (IHI) allowed assessing bilateral coordination (i.e. synchrony) in each phase. The larger IHI, the more severe the bilateral coordination impairment is. After stratifying PwMS for disability level (PwMS_LOW, Expanded Disability Status Scale, EDSS≤5.5 and PwMS_HIGH, EDSS≥6), the ANOVA on IHI showed significant differences between PwMS and HC (p<0.001) in all phases. However, only the going phase IHI showed significantly higher asynchrony in PwMS_HIGH than PwMS_LOW and HC (p<0.001) and no differences between PwMS_LOW and HC. The going phase IHI seems to be a clinical marker specific for high disability level PwMS. These findings suggest inertial sensors during FNT could be an easy-to-use method for a more detailed quantitative characterization of UL function in PwMS also in subjects with EDSS greater than 6.

Abnormal motor surround inhibition associated with cortical and deep grey matter involvement in multiple sclerosis

OBJECTIVE

Motor surround inhibition (mSI) is a physiological mechanism that contributes to hand movement control by focusing voluntary movement. Growing evidence suggests that hand movement control is impaired in multiple sclerosis. The aim of the study was to evaluate mSI in MS and to investigate the brain structures involved in mSI in multiple sclerosis.

METHODS

We recruited 33 patients and 23 controls. To investigate mSI, we delivered transcranial magnetic single pulses during index finger flexion. Motor evoked potentials were recorded and first dorsal interosseous ("active muscle") and from the abductor digiti minimi ("surround muscle"). mSI was expressed as the ratio between Motor evoked potentials recorded from the surround muscle during movement and at rest. Participants underwent a magnetic resonance study.

RESULTS

Patients had impaired mSI as compared with controls. Magnetic resonance showed that basal ganglia had smaller volumes and higher mean diffusivity than controls. Impaired mSI correlated with primary motor cortex and basal ganglia involvement in multiple sclerosis.

CONCLUSION

Altered mSI in multiple sclerosis is related to cortical and subcortical grey matter involvement.

SIGNIFICANCE

Our study provides the first demonstration of a pathophysiological mechanism underlying hand movement control dysfunction in multiple sclerosis. mSI represents a new therapeutic target of multiple sclerosis rehabilitative approaches.

Visualizing and Evaluating Finger Movement Using Combined Acceleration and Contact-Force Sensors: A Proof-of-Concept Study

The 10-s grip and release is a method to evaluate hand dexterity. Current evaluations only visually determine the presence or absence of a disability, but experienced physicians may also make other diagnoses. In this study, we investigated a method for evaluating hand movement function by acquiring and analyzing fingertip data during a 10-s grip and release using a wearable sensor that can measure triaxial acceleration and strain. The subjects were two healthy females. The analysis was performed on the x-, y-, and z-axis data, and absolute acceleration and contact force of all fingertips. We calculated the variability of the data, the number of grip and release, the frequency response, and each finger’s correlation. Experiments with some grip-and-release patterns have resulted in different characteristics for each. It was suggested that this could be expressed in radar charts to intuitively know the state of grip and release. Contact-force data of each finger were found to be useful for understanding the characteristics of grip and release and improving the accuracy of calculating the number of times to grip and release. Frequency analysis suggests that knowing the periodicity of grip and release can detect unnatural grip and release and tremor states. The correlations between the fingers allow us to consider the finger’s grip-and-release characteristics, considering the hand’s anatomy. By taking these factors into account, it is thought that the 10-s grip-and-release test could give us a new value by objectively assessing the motor functions of the hands other than the number of times of grip and release.

Effects of Transcranial Direct Current Stimulation on Hand Dexterity in Multiple Sclerosis: A Design for a Randomized Controlled Trial

BACKGROUND

Cerebellar and motor tracts are frequently impaired in multiple sclerosis (MS). Altered hand dexterity constitutes a challenge in clinical practice, since medical treatment shows very limited benefits in this domain. Cerebellar control is made via several cerebellocortical pathways, of which the most studied one links the cerebellum to the contralateral motor cortex via the contralateral ventro-intermediate nucleus of the thalamus influencing the corticospinal outputs. Modulating the activity of the cerebellum or of the motor cortex could be of help.

METHOD

The main interest here is to evaluate the efficacy of transcranial direct current stimulation (tDCS), a noninvasive brain stimulation technique, in treating altered dexterity in MS. Forty-eight patients will be recruited in a randomized, double-blind, sham-controlled, and crossover study. They will randomly undergo one of the three interventions: anodal tDCS over the primary motor area, cathodal tDCS over the cerebellum, or sham. Each block consists of five consecutive daily sessions with direct current (2 mA), lasting 20 min each. The primary outcome will be the improvement in manual dexterity according to the change in the time required to complete the nine-hole pegboard task. Secondary outcomes will include fatigue, pain, spasticity, and mood. Patients' safety and satisfaction will be rated.

DISCUSSION

Due to its cost-effective, safe, and easy-to-use profile, motor or cerebellar tDCS may constitute a potential tool that might improve dexterity in MS patients and therefore ameliorate their quality of life.