Motor and Physical Function Impairments as Contributors to Slow Gait Speed and Mobility Difficulty in Middle-Aged and Older Adults

Background Motor function impacts ability to perform daily activities and maintain independence. Yet, the interrelatedness of upper and lower extremity motor impairments and the magnitude of their contribution to slow gait and mobility difficulty are not well investigated. Methods Participants in the Baltimore Longitudinal Study of Aging (N=728, aged 50-99) completed motor and physical function tests including grip and knee extension strength, pegboard, finger tapping, standing balance, chair stands, fast-paced 400m walk, and usual gait speed. Slow gait was defined as usual gait speed <1.0m/s. Mobility difficulty was defined as self-reported difficulty walking ¼ mile or climbing stairs. Structural equation modeling (SEM) examined the interrelationships of motor measures and their contributions to slow gait and mobility difficulty, adjusting for demographics and comorbidities. Results Poorer manual dexterity (-0.571 standard deviation (SD) units, p<0.001) and lower muscle strength (upper and lower extremity) (-0.447 SD units, p=0.014) were most strongly associated with slow gait speed, followed by slower chair stand pace (-0.195 SD units, p=0.002) and greater lap time variation (0.102 SD units, p=0.028). Lower muscle strength (-0.582 SD units, p=0.001) was most strongly associated with mobility difficulty, followed by slower chair stand pace (-0.322 SD units, p<0.001), slower gait speed (-0.247 SD units, p<0.001), and poorer standing balance (-0.190 SD units, p=0.043). Conclusions Components of manual dexterity and strength were the strongest correlates of slow gait and mobility difficulty in mid-to-late life. Longitudinal studies examining relationships between changes in these motor parameters and mobility are needed to elucidate possible causal effects.

Adding up fine motor skills: developmental relations between manual dexterity and numerical abilities

We explore the relationship between mathematical skills and motor skills across three age groups of normally developing children. The existence of such a relationship is postulated in classical accounts of human development. In contemporary research, the existence of a relationship between motor development and the development of abstract concepts may form a crucial piece of evidence for theories of embodied cognition. Existing studies suggest a link between fine motor skills and various numerical and mathematical tasks in young children; however, there are few attempts to measure the strength of this relationship across different ages. We use a cross-sectional design to investigate the link between fine motor and mathematical skills in children in Kindergarten, 2nd grade, and 4th grade. The results show that correlational patterns vary in the three ages; while in Kindergarten manual dexterity of the dominant hand is related to math skills, in 2nd grade the manual dexterity of the nondominant hand is related to math skills, and finally, in 4th grade no such correlations are observable.

Robot-Assisted Upper Limb Training for Patients with Multiple Sclerosis: An Evidence-Based Review of Clinical Applications and Effectiveness

Upper extremities limitation is a common functional impairment in patients with Multiple Sclerosis (PwMS). Novel technological devices are increasingly used in neurorehabilitation to support motor function improvement and the quantitative assessment of motor performance during training in patients with neurological diseases. In this review, we systematically report the evidence on clinical applications and robotic-assisted arm training (RAT) in functional recovery in PwMS. PubMed/MEDLINE, the Cochrane Library, and the Physiotherapy Evidence Database (PEDro) databases were systematically searched from inception to March 2021. The 10-item PEDro scale assessed the study quality for the RCT, and the AMSTAR-2 was used to assess the quality of the systematic review. The 5-item Oxford CEBM scale was used to rate the level of evidence. A total of 10 studies (161 subjects) were included. The selected studies included one systematic review, four RCTs, one randomized crossover, and four case series. The RCTs were scored as high-quality studies, while the systematic review was determined to be of low quality. Shoulder range of motion, handgrip strength, and proximal arm impairment improved after RAT. Manual dexterity, arm function, and use in daily life also ameliorated arm function. The high clinical heterogeneity of treatment programs and the variety of robot devices affects the generalizability of the study results; therefore, we emphasize the need to standardize the intervention type in future studies that evaluate the role of robotic-assisted training in PwMS. Robot-assisted treatment seems safe and useful to increase manual dexterity and the quality of movement execution in PwMS with moderate to severe disability. Additional studies with an adequate sample size and methodological rigour are warranted to drive definite conclusions.

When Spinal Neuromodulation Meets Sensorimotor Rehabilitation: Lessons Learned From Animal Models to Regain Manual Dexterity After a Spinal Cord Injury

Electrical neuromodulation has strongly hit the foundations of spinal cord injury and repair. Clinical and experimental studies have demonstrated the ability to neuromodulate and engage spinal cord circuits to recover volitional motor functions lost after the injury. Although the science and technology behind electrical neuromodulation has attracted much of the attention, it cannot be obviated that electrical stimulation must be applied concomitantly to sensorimotor rehabilitation, and one would be very difficult to understand without the other, as both need to be finely tuned to efficiently execute movements. The present review explores the difficulties faced by experimental and clinical neuroscientists when attempting to neuromodulate and rehabilitate manual dexterity in spinal cord injured subjects. From a translational point of view, we will describe the major rehabilitation interventions employed in animal research to promote recovery of forelimb motor function. On the other hand, we will outline some of the state-of-the-art findings when applying electrical neuromodulation to the spinal cord in animal models and human patients, highlighting how evidences from lumbar stimulation are paving the path to cervical neuromodulation.

Motor skills predict adaptive behavior in autistic children and adolescents

There is a well-documented difference between IQ and adaptive behavior scores in autism, with autistic children having lower adaptive behavior scores than would be predicted based on their IQ scores. Differences in motor skills may explain the variability in their adaptive behavior scores. The current study examined how motor skills might explain autistic individuals’ low adaptive behavior scores and which individual components of IQ (i.e., verbal comprehension and perceptual reasoning) and motor skills (i.e., manual dexterity, aiming and catching, and balance) may drive this effect. We examined the relationships between IQ, motor skills, calibrated severity, and adaptive behavior scores in 45 autistic children and adolescents. We found a significant difference in the full-scale IQ and the adaptive behavior scores indicating that our participants’ adaptive behavior scores were lower than would be expected given their full-scale IQ. We investigated whether motor skills predicted adaptive behavior in autistic children and adolescents and found that motor skills scores were related to adaptive behavior scores. To further investigate these relationships, we examined how individual components of IQ and motor skills predicted adaptive behavior scores in autistic children and adolescents. Our results indicated that manual dexterity scores were related to adaptive behavior scores. These findings clearly illustrate the need for further understanding of autistic individuals’ difficulties with adaptive behavior and the potential role of motor skill difficulties that may underlie these difficulties.

Improvement in Fine Manual Dexterity in Children with Spinal Muscular Atrophy Type 2 after Nusinersen Injection: A Case Series

Although nusinersen has been demonstrated to improve motor function in patients with spinal muscular atrophy (SMA), no studies have investigated its effect on fine manual dexterity. The present study aimed to investigate the ability of nusinersen to improve fine manual dexterity in patients with SMA type 2. A total of five patients with SMA type 2 were included. The Hammersmith Functional Motor Scale (expanded version) (HFMSE) and Purdue Pegboard (PP) tests were used to evaluate gross motor function and fine manual dexterity, respectively, until 18 months after nusinersen administration. HFMSE scores improved by 3–10 points (+13–53%) in all patients following nusinersen administration. PP scores also improved in all patients, from 4 to 9 points (+80–225%) in the preferred hand and from 3 to 7 points (+60–500%) in the non-preferred hand. These results suggest that nusinersen treatment improved both gross motor function and fine manual dexterity in children with SMA type 2. Addition of the PP test may aid in evaluating the fine manual dexterity essential for activities of daily living in these patients.