Background: Neonatal brachial plexus palsy (NBPP) results in muscle weakness and impaired somatosensory function of the arm. Current functional assessment is primarily based on clinician-elicited measurements including muscle strength and range of motion. To what extent these measures are representative of real-world arm movement is unclear. Objective: To determine the feasibility of using body-worn accelerometers to remotely assess arm movements in children with NBPP. Design: Prospective criterion validity study of accelerometry versus clinician assessment. Setting: Academic medical center. Participants: Nine adolescents with NBPP and nine age-and gender-matched control adolescents participated in the study. All were enrolled in school and participated in community activities.Interventions: Not applicable. Methods: Standard clinician-elicited measurements were collected. For assessing spontaneous arm movements, participants wore activity monitors during all waking hours for 7 days. Results were expressed as ratios of affected to unaffected arm motion for duration and magnitude and correlated with traditional clinic-based assessments. Spearman correlations were used to determine relationships between accelerometry results and traditional assessments. A p value <.05 was considered statistically significant. Main Outcome Measurements: Accelerometry measurements of arm motion and traditional clinical assessments. Results: Compared to control ratios, duration of arm movement and magnitude ratios were reduced in the NBPP group, particularly for arm magnitude due to reduced affected arm movement and an increase in unaffected arm movement. Ratios were highly correlated with shoulder function and, to a lesser extent, with elbow function. Conclusion: Real-world arm use is an appropriate outcome measure that reflects functional recovery. This study demonstrates the feasibility of wearable technology to quantify duration and intensity of spontaneous arm movement in children with NBPP. Accelerometry also allows for the association between traditional clinician-elicited assessment measures and spontaneous arm movements, demonstrating the importance of the shoulder as a focus of treatment in NBPP.

Age-related changes in cortico-cortical connectivity in the human motor network in older adults are associated with declines in hand dexterity. Posterior parietal cortex (PPC) is strongly interconnected with motor areas and plays a critical role in many aspects of motor planning. Functional connectivity measures derived from dual-site transcranial magnetic stimulation (dsTMS) studies have found facilitatory inputs from PPC to ipsilateral primary motor cortex (M1) in younger adults. In this study, we investigated whether facilitatory inputs from PPC to M1 are altered by age. We used dsTMS in a conditioning-test paradigm to characterize patterns of functional connectivity between the left PPC and ipsilateral M1 and a standard pegboard test to assess skilled hand motor function in 13 young and 13 older adults. We found a PPC-M1 facilitation in young adults but not older adults. Older adults also showed a decline in motor performance compared to young adults. We conclude that the reduced PPC-M1 facilitation in older adults may be an early marker of age-related decline in the neural control of movement.

Background The ability to grasp and manipulate objects is essential for performing activities of daily living. However, there is limited information regarding age-related behavioral differences in hand sensorimotor function due, in part, to the lack of assessment tools capable of measuring subtle but important differences in hand function. The purpose of this study was to demonstrate performance differences in submaximal force control and tactile pattern recognition in healthy older adults using two custom-designed sensorimotor assessment tools. Methods Sensorimotor function was assessed in 13 healthy older adults (mean age 72.2 ±5.5y, range: 65-84y) and 13 young adults (mean age 20 ±1.4y, range: 19-23y). Clinical assessments included the Montreal Cognitive Assessment (MoCA), monofilament testing, maximum voluntary contraction (MVC), and Grooved Pegboard Test. Sensorimotor assessments included submaximal (5, 20% MVC) grip force step-tracking and tactile pattern recognition tasks. Results Clinical assessments revealed no or minimal group differences in MVC, monofilament thresholds, and MoCA. However, sensorimotor assessments showed that older adults took longer to discriminate tactile patterns and had poorer accuracy than young adults. Older adults also produced submaximal forces less smoothly than young adults at the 20% force level while greater variability in force maintenance was seen at 5% but not 20% MVC. Conclusions These results demonstrate the ability to integrate higher-order tactile information and control low grip forces is impaired in older adults despite no differences in grip strength or cognition. These findings underscore the need for more sensitive evaluation methods that focus on sensorimotor ability reflective of daily activities.

Aging is associated with a decline in hand muscle strength, dexterity, and tactile perception, leading to difficulties in activities of daily living and reduced independence (Millan-Calenti et al., 2010). However, current assessments do not adequately capture sensorimotor skills that underlie everyday activities such as dressing and food preparation. This study examined the ability of two novel assessment devices to detect age-related changes in hand force control and tactile pattern discrimination. Sensorimotor function was assessed in 13 healthy older adults (mean age 72.2 +/- 5.5y) and 13 young adults (mean age 20 +/- 1.4y). Maximum grip force (MVC), tactile sensation, and hand dexterity were measured using standard clinical techniques. Novel assessments consisted of submaximal (5-20% MVC) grip force tracking and computer-controlled tactile pattern recognition. Monofilament testing of tactile sensation was normal in the older group. In contrast, both the accuracy and speed associated with identifying tactile patterns was significantly worse in older (p&lt;0.001) compared to young adults for both hands. While maximum grip force was similar in both groups, the ability to smoothly produce (p&lt;0.05) and maintain (p&lt;0.02) low grip force levels was compromised in older adults. Manual dexterity (Grooved Pegboard test) was significantly reduced in the older group (p&lt;0.001) regardless of hand. These results indicate that the ability to extract meaningful information from tactile feedback and control low levels of force - aspects of fine hand control associated with activities of daily living – are impaired in older adults and underscore the need for more sensitive measures of hand function.

Homebound older adults represent an understudied population who are at greater risk of losing hand strength and manipulation skills that, in turn, can lead to increased disability and cognitive declines (Dayanidhi and Valero-Cuevas, 2014). The Hands and Health at Home program was developed through a partnership with the University of Michigan’s School of Kinesiology and Michigan Medicine’s Ann Arbor Meals on Wheels program to demonstrate the feasibility of an intergenerational approach to address unmet needs of Meals on Wheels recipients. Undergraduate movement science student trainers were paired with a client who they visited twice weekly for 5 weeks. Students received training, including mock training scenarios, from an interprofessional team with backgrounds in social work, nursing, and neurorehabilitation. Home training protocols were developed using commercially available games and occupational therapy tools with the aim of improving hand function and facilitating socialization. Pre- and post-assessments included hand strength and dexterity, and client-reported measures of physical function and self-efficacy. Feedback from clients and students was overwhelmingly positive with several students indicating that the experience had stimulated interest in pursuing gerontology careers. Changes in quantitative assessments were variable across clients although pinch strength increased significantly in the non-dominant hand (p&lt;0.02) and was predictive of measures of self-efficacy (r=.78, p&lt;0.02). To our knowledge, this pilot program is the first of its kind and demonstrates the value of an intergenerational approach aimed at improving quality of life in Meals on Wheels clients, and may be of benefit for other underserved older members of the community.