The motor-evoked potentials elicited from the deltoid muscle by transcranial magnetic stimulation with a standardized facilitation: the potential diagnostic utility for C5 radiculopathy

Development of a Computer Vision-Based Muscle Stimulation Method for Measuring Muscle Fatigue during Prolonged Low-Load Exposure

Measuring muscle fatigue is one essential and standard method to quantify the ergonomic risks associated with prolonged low-load exposure. However, measuring muscle fatigue using EMG-based methods has shown conflicting results under low-load but sustained work conditions, e.g., prolonged sitting. Muscle stimulation technology provides an alternative way to estimate muscle fatigue development during such work conditions by monitoring the stimulation-evoked muscle responses, which, however, could be restricted by the accessibility and measurability of targeted muscles. This study proposes a computer vision-based method to overcome such potential restrictions by visually quantifying the muscle belly displacement caused by muscle stimulation. The results demonstrate the ability of the developed computer vision-based stimulation method to detect muscle fatigue from prolonged low-load tasks. Current results can be used as a foundation to develop a sensitive and reliable method to quantify the adverse effects of the daily low-load sustained condition in occupational and nonoccupational settings.

Clinical and Neurophysiological Changes after Targeted Intrathecal Injections of Bone Marrow Stem Cells in a C3 Tetraplegic Subject

High-level quadriplegia is a devastating condition with limited treatment options. Bone marrow derived stem cells (BMSCs) are reported to have immunomodulatory and neurotrophic effects in spinal cord injury (SCI). We report a subject with complete C2 SCI who received three anatomically targeted intrathecal infusions of BMSCs under a single-patient expanded access investigational new drug (IND). She underwent intensive physical therapy and was followed for >2 years. At end-point, her American Spinal Injury Association Impairment Scale (AIS) grade improved from A to B, and she recovered focal pressure touch sensation over several body areas. We conducted serial neurophysiological testing to monitor changes in residual connectivity. Motor, sensory, and autonomic system testing included motor evoked potentials (MEPs), somatosensory evoked potentials (SSEPs), electromyography (EMG) recordings, F waves, galvanic skin responses, and tilt-table responses. The quality and magnitude of voluntary EMG activations increased over time, but remained below the threshold of clinically obvious movement. Unexpectedly, at 14 months post-injury, deep inspiratory maneuvers triggered respiratory-like EMG bursting in the biceps and several other muscles. This finding means that connections between respiratory neurons and motor neurons were newly established, or unmasked. We also report serial analysis of MRI, International Standards for Neurological Classification of SCI (ISNCSCI), pulmonary function, pain scores, cerebrospinal fluid (CSF) cytokines, and bladder assessment. As a single case, the linkage of the clinical and neurophysiological changes to either natural history or to the BMSC infusions cannot be resolved. Nevertheless, such detailed neurophysiological assessment of high cervical SCI patients is rarely performed. Our findings indicate that electrophysiology studies are sensitive to define both residual connectivity and new plasticity.