CURRENT RESEARCH

Accelerometry Following Brachial Plexus Injury

A critical concept in brachial plexus surgical reconstruction is the accurate assessment of functional outcomes. The current standard for motor outcome assessment is clinician-elicited, outpatient clinic-based, serial evaluation of range of motion and muscle power. However, discrepancies exist between such clinical measurements and actual patient-initiated use. We are employing emerging technology in the form of accelerometry-based motion detectors to quantify real-world arm use after brachial plexus surgery. Currently, we are utilizing wrist accelerometry to measure arm use after brachial plexus reconstructive surgery in children (collaboration with the Brachial Plexus Program of Michigan Medicine) and adults (collaboration with Chang Gung Memorial Hospital). Furthermore, we are investigating the relationship between accelerometry data and patient-reported perceptions of function in these populations.

Balance and Postural Deficits Following Peripheral Nerve Injury

Unilateral upper limb peripheral nerve injury may affect the ability of an individual to appropriately control lower limb posture. We are examining balance changes in children with neonatal brachial plexus palsy (NBPP) as well as adults with acquired upper limb peripheral nerve injury in order to determine if asymmetric arm use following injury poses a challenge to postural control in these populations.

Sensorimotor Assessment and Function Following Peripheral Nerve Injury

We have developed a new tactile device which assesses the ability of individuals to “make sense” of what they feel through tactile feedback. This allows one to assess higher order processing of somatosensory feedback, separate from tactile registration which is assessed using standard tactile assessment techniques (e.g. monofilament testing). We have also developed a visually-guided grip force system which can quantify a number of force measures including force preparation time as well as dynamic and static force control. In collaboration with the Department of Neurosurgery of Michigan Medicine, we have examined somatosensory and motor function in children with NBPP and adults with acquired upper limb peripheral nerve injury. In children with NBPP we have found that both position sense (Brown et al., 2013) and tactile acuity (Brown et al., 2016) are impaired despite the widely-held clinical view that recovery of sensory function exceeds motor function recovery. We are also investigating the ability to reach and maintain low levels of grip force in children with NBPP using the novel grip force software.

Home Training Programs to Improve Upper Limb Function

We are addressing the need for non-surgical therapies which focus on movement-based training. This work is based on past research in the lab examining movement-based training in adults with cerebral palsy (Brown et al., 2010, 2011) and stroke (Langan et al., 2013). Preliminary results indicate that upper limb function can be improved in NBPP, years after the initial insult (Brown et al., 2015). Additionally, we have collaborated with the Meals on Wheels program of Ann Arbor to create a home-based training program focused on improving hand function and quality of life using an intergenerational approach. Currently, we are implementing a novel home-based training program aiming to improve sensory and motor function of the upper limb in young adults with NBPP.

Hand Function in Older Adults

In collaboration with the Brain and Behavior Lab of the School of Kinesiology, we have investigated the relationship between parietal and motor functional connections in older adults. Additionally, we are examining currently available hand assessment tools for older adults and their efficacy. Finally, we are testing the feasibility of using a commercially available board game to assess hand and arm function in a healthy older adult population.

PREVIOUS RESEARCH

Upper Limb Function in Breast Cancer Survivors with Lymphedema:

Using techniques to assess upper limb function in peripheral nerve injury, we are examining deficits in arm use patients who have developed lymphedema following surgery for breast cancer. Typically, therapy for these patients focus at shoulder/upper arm function and little is known regarding the effects of limited/painful movement on distal function involving the hand. This study is in collaboration with Dr. Kathy Van Poznak, Dept. of Internal Medicine-Hematology and Oncology. Most recently, we are investigating the use of tri-axial accelerometry to remotely monitor patient-initiated arm movement following surgery for peripheral nerve injury or breast cancer. The goal is to develop algorithms to identify specific activities of daily living from acceleration data obtained over several days of recording.

Factors Affecting Upper Limb Position Sense:

We have conducted a number of studies examining upper limb position sense including factors such as development (Goble et al., 2005), aging (Adamo et al., 2007, 2009; Wright et al., 2011; Goble et al.., 2012; Schaap et al., 2015), limb asymmetries (Goble et al., 2006, 2010; Goble and Brown, 2007, 2008a, b, 2009, 2010), handedness (Goble et al., 2009), skill level, limb immobilization, and menstrual cycle-related sex hormones. We have also examined proprioceptive acuity in children (Goble et al., 2009) and adults (Langan et al., 2014) and in neonatal brachial plexus palsy (Brown et al., 2013).

Sensorimotor Control in Older Adults:

Previous studies have examined limb-posture coordination in healthy older adults (Huang et al., 2013, 2015) as well as proprioceptive acuity (Adamo et al., 2007, Schaap et al., 2015) including the effects of physical activity on position sense (Adamo et al., 2009). Current work focuses age-related changes in hand function regarding the effects of cognitive loading on grip force control.