Impaired Object Handling during Bimanual Task Performance in Multiple Sclerosis

A novel tool for characterising upper limb function in progressive multiple sclerosis through kinematic assessment

INTRODUCTION

Current upper limb assessment methods in MS rely on measuring duration in tasks like the nine-hole peg test (9HPT). Kinematic techniques may provide a more useful measure of functional change in clinical and research practice. The aim of this study was to assess upper limb function prospectively in people with progressive MS using a kinematic 3D motion capture system and compare with current measures.

METHODS

42 people with progressive MS (PwPMS) and 15 healthy controls reached-and-grasped different objects whilst recorded by a kinematic assessment system. 9HPT, Expanded Disability Status Scale (EDSS), and patient reported outcome measures (PROs) were collected. All measures were taken at baseline for PwPMS and controls, and again at six months for PwPMS.

RESULTS

Relative to controls, PwPMS had significantly longer reaction (0.11 s, p < 0.05) and reach (0.25 s, p < 0.05) times. PwPMS took longer to pick-up (0.34 s, p < 0.05), move (0.14 s, p < 0.05), and place (0.18 s, p < 0.05) objects. PwPMS had lower peak velocities when reaching (7.4 cm/s, p < 0.05) and moving (7.3 cm/s, p < 0.05) objects. Kinematic assessment demonstrated consistent differences between PwPMS with mild and severe upper limb dysfunction as defined by PROs, which were not captured by 9HPT or EDSS in this group. PwPMS demonstrated altered grip apertures profiles, as measured by their ability to complete individual parts of the reach and grasp task, between the baseline and follow-up timepoints.

CONCLUSIONS

We have created and tested a novel upper limb function assessment tool which has detected changes and characteristics in hand function, not currently captured by the EDSS and 9HPT.

Pinch Strength Measurements in Adolescents With Pediatric Multiple Sclerosis

BACKGROUND

Multiple sclerosis (MS) is a degenerative disease with typical onset between 20 and 50 years of age. An increase in MS cases has been found in the adolescent US population. Adolescents require fine motor manipulation skills for their functional and academic performance. Deficits in the major components of manipulation skills may result in insufficient function. This study examined the 2-point, 3-point, and lateral pinch strength of adolescents diagnosed as having MS.

METHODS

Seventy-four adolescents, 37 with a diagnosis of relapsing-remitting MS and a control group of 37 age-matched peers, participated in this study. Data on 2-point, 3-point, and lateral pinch strength in both hands were collected using a pinch meter. Analyses of covariance were used to describe differences across the 2 groups, and effect sizes (Cohen d) were calculated by finding the mean difference between the study groups divided by the pooled SD.

RESULTS

A significant difference was found in the 2-point pinch strength of the right hand of participants with pediatric MS compared with age- and sex-matched control participants. There were no significant differences in 2-point pinch strength of the left hand or in 3-point or lateral pinch strength of the right and left hands.

CONCLUSIONS

Pinch grasp strength was differentially affected in adolescents with MS. Pinch strength should be assessed and considered in adolescents with MS for a better understanding of their functional performance of fine motor tasks in activities of daily living and academics.

Biosensing in multiple sclerosis

INTRODUCTION

The goal of using wearable biosensors in multiple sclerosis (MS) is to provide outcome metrics with higher sensitivity to deficits and better inter-test and inter-rater reliability than standard neurological exam bedside maneuvers. A wearable biosensor not only has the potential to enhance physical exams, but also offers the promise of remote evaluations of the patient either at home or with local non-specialist providers. Areas covered: We performed a structured literature review on the use of wearable biosensors in studies of multiple sclerosis. This included accelerometers, gyroscopes, eye-trackers, grip sensors, and multi-sensors. Expert commentary: Wearable sensors that are sensitive to change in function over time have great potential to serve as outcome metrics in clinical trials. Key features of generalizability are simplicity in the application of the device and delivery of data to the provider. Another important feature to establish is best sampling rate. Having too high of a sampling rate can lead to over-interpretation of noisy data On the other hand, a low sampling rate can result in an insensitive test thus missing subtle changes of clinical interest. Of most importance is to establish metrics derived from wearable devices that provide meaningful data in longitudinal studies.

Human-Human Handover Tasks and How Distance and Object Mass Matter

We investigated the coordination between two individuals during object handovers. Ten participants (eight males, two females; 26.0 ± 5.0 years, 72.7 ± 13.5 kg, 1.73 ± 0.8 m) arranged in pairs (a giver and a receiver), passed an object from the giver to the receiver at a self-selected speed. A motion capture system quantified the giver and the receiver's motion simultaneously. Three interpersonal distances and three object masses were chosen to study the handover. We hypothesized that (a) the handover occurs at half of the interpersonal distance between the giver and receiver and (b) the handover height depends on the objects' mass. Taken together, our results show that the handover strongly depends on the interpersonal distance between the giver and receiver, while object mass related only to handover duration.

Changes in Multidigit Synergies and Their Feed-Forward Adjustments in Multiple Sclerosis

The authors explored the changes in multidigit synergies in patients with multiple sclerosis (MS) within the framework of the uncontrolled manifold hypothesis. The specific hypotheses were that both synergy indices and anticipatory synergy adjustments prior to the initiation of a self-paced quick action would be diminished in the patients compared to age-matched controls. The MS patients and age-matched controls (n = 13 in both groups) performed one-finger and multifinger force production tasks involving both accurate steady-state force production and quick force pulses. The patients showed significantly lower maximal finger forces and a tendency toward slower force pulses. Enslaving was increased in MS, but only in the lateral fingers (index and little). Indices of multifinger synergies during steady-state force production were lower in MS, mainly due to the lower amount of intertrial variance that did not affect total force. Anticipatory synergy adjustments were significantly delayed in MS. The results show that MS leads to significant changes in multidigit synergies and feed-forward adjustments of the synergies prior to a quick action. The authors discuss possible contributions of subcortical structures to the impaired synergic control.