Jessica Maria D'Amico

• BSc, PhD
• Scientific Program Lead at Glenrose Rehabilitation Hospital University of Alberta

Cervical spinal cord injury (SCI) leads to permanent impairment of arm and hand functions. Here we conducted a prospective, single-arm, multicenter, open-label, non-significant risk trial that evaluated the safety and efficacy of ARCEX Therapy to improve arm and hand functions in people with chronic SCI. ARCEX Therapy involves the delivery of exter...

Objective: In adults with cervical spinal cord injury (SCI), transcutaneous spinal stimulation (scTS) has improved upper extremity strength and control. This novel noninvasive neurotherapeutic approach combined with training may modulate the inherent developmental plasticity of children with SCI, providing even greater improvements than training o...

Conclusion: Sub-threshold thoracolumbar tSCS facilitates recovery of trunk sensorimotor function in individuals with chronic SCI. Improvements required at least 60 tSCS-ABT sessions, with further exposure to tSCS facilitating continued improvements in function. These findings demonstrate that prolonged training with tSCS-ABT is an effective neuromo...

Objective: Spinal cord injury (SCI) is classified as complete or incomplete depending on the extent of sensorimotor preservation below the injury level. However, individuals with complete SCIs can voluntarily activate paralyzed lower limb muscles alone or by engaging non-paralyzed muscles during neurophysiological assessments, indicating the presen...

Objective: To examine the efficacy, dosing, and safety profiles of intrathecal and oral baclofen in treating spasticity after spinal cord injury (SCI). Data sources: PubMed and Cochrane Databases were searched between 1970-2018 with keywords baclofen, spinal cord injury and efficacy. Study selection: The database search yielded 588 sources and...

Purpose: To investigate how quadriceps muscle fatigue affects power production over the extension and flexion phases and muscle activation during maximal cycling. Methods: Ten participants performed 10-s maximal cycling efforts without fatigue and after 120 bilateral maximal concentric contractions of the quadriceps muscles. Extension power, flexio...

In children with spinal cord injury (SCI), scoliosis due to trunk muscle paralysis frequently requires surgical treatment. Transcutaneous spinal stimulation enables trunk stability in adults with SCI and may pose a non-invasive preventative therapeutic alternative. This non-randomized, non-blinded pilot clinical trial (NCT03975634) determined the s...

Voluntary force declines during sustained, maximal voluntary contractions (MVC) due to changes in muscle and central nervous system properties. Central fatigue, an exercise-induced reduction in voluntary activation, is influenced by multiple processes. Some may occur independent of descending voluntary drive. To differentiate the effects associated...

Objective The importance of subcortical pathways to functional motor recovery after spinal cord injury (SCI) has been demonstrated in multiple animal models. In the current study, we sought to evaluate descending interlimb influence on lumbosacral motor excitability after chronic SCI in humans. Methods Ulnar nerve stimulation and transcutaneous el...

Plasticity can be induced at human corticospinal-motoneuronal synapses by delivering repeated, paired stimuli to corticospinal axons and motoneurones in a technique called paired corticospinal-motoneuronal stimulation (PCMS). To date, the mechanisms of the induced plasticity are unknown. To determine whether PCMS-induced plasticity is dependent on...

Paired corticospinal-motoneuronal stimulation (PCMS), which delivers repeated pairs of transcranial magnetic stimuli (TMS) and maximal motor nerve stimuli, can alter corticospinal transmission to low threshold motoneurones in the human spinal cord. To determine whether similar changes occur for high threshold motoneurones, we tested whether maximal...

Non-invasive, weak direct current stimulation can induce changes in excitability of underlying neural tissue. Many studies have used transcranial direct current stimulation to induce changes in the brain, however more recently a number of studies have used transcutaneous spinal direct current stimulation to induce changes in the spinal cord. This s...

Dataset for study 2. (XLSX)

Dataset for study 1. (XLSX)

Key points: In the adult turtle spinal cord, action potential generation in motoneurones is inhibited by spillover of serotonin to extrasynaptic serotonin 1A (5-HT1A ) receptors at the axon initial segment. We explored whether ingestion of the 5-HT1A receptor partial agonist, buspirone, decreases motoneurone excitability in humans. Following inges...

Background: Cervical trans-spinal direct current stimulation (tsDCS) is a relatively new technique that reportedly modifies muscle responses to motor cortical stimulation1,2; however it is not known whether neural changes occur within the spinal cord. Here we tested H-reflexes as well as muscle responses to subcortical cervicomedullary stimulation...

Introduction: Intense descending drive in the adult turtle spinal cord results in serotonin spillover to the axon hillock of the motoneurones. This activates inhibitory 5HT1A receptors and hence, inhibits action potential generation(1). This mechanism has been proposed to contribute to central fatigue. In this study we examined whether activation o...

Introduction: Substantial decreases in the net power produced at the ankle joint during plantar flexion have been associated with large reductions in crank power during the course of a maximal cycling exercise. However, it remains unclear if fatigue of the ankle plantar flexor (APF) muscles causes this reduction in ankle joint power and subsequentl...

Objective To determine if sleep bruxism is associated with abnormal physiological tremor of the jaw during a visually-guided bite force control task. Methods Healthy participants and patients with sleep bruxism were given visual feedback of their bite force and asked to trace triangular target trajectories (duration = 20s, peak force < 35% maximu...

The state of areflexia and muscle weakness that immediately follows a spinal cord injury (SCI) is gradually replaced by the recovery of neuronal and network excitability, leading to both improvements in residual motor function and the development of spasticity. In this review we summarize recent animal and human studies that describe how motoneurons...

In animals, sodium and calcium-mediated persistent inward currents (PICs), which produce long-lasting periods of depolarization during low synaptic drive, can be activated in trigeminal motoneurons following the application of the monoamine serotonin. Here we examined if PICs are activated in human trigeminal motoneurons during voluntary contractio...

Activation of receptors for serotonin (5HT1) and noradrenaline (α2) on primary afferent terminals and excitatory interneurons reduces transmission in spinal sensory pathways. Loss or reduction of descending sources of serotonin and noradrenaline after spinal cord injury (SCI) and the subsequent reduction of 5HT1/α2-receptor activity contributes, in...

In animals, the recovery of motoneuron excitability in the months following a complete spinal cord injury is mediated, in part, by increases in constitutive serotonin (5HT2) and noradrenaline (α1) receptor activity, which facilitates the reactivation of calcium-mediated persistent inward currents (CaPICs) without the ligands serotonin and noradrena...

Loss of descending serotonergic innervation after spinal cord injury (SCI) results in disinhibition of sensory transmission and contributes to the development of spasticity after injury. A prevalent feature that emerges after chronic injury in both rats and humans is the production of long (~ 1s) excitatory postsynaptic potentials (EPSPs) in motone...

The recovery of motoneuron excitability and the development of muscle spasms after SCI are mediated by the re-emergence of sodium/calcium persistent inward currents (PICs), despite the loss/reduction of serotonin (5HT) that facilitates the PIC. Here we examined if, like in animal models, PICs in humans are facilitated by constitutively-activated 5H...

Sensory afferent transmission and associated spinal reflexes are normally inhibited by serotonin (5-HT) derived from the brain stem. Spinal cord injury (SCI) that eliminates this 5-HT innervation leads to a disinhibition of sensory transmission and a consequent emergence of unusually long polysynaptic excitatory postsynaptic potentials (EPSPs) in m...

The brain stem provides most of the noradrenaline (NA) present in the spinal cord, which functions to both increase spinal motoneuron excitability and inhibit sensory afferent transmission to motoneurons (excitatory postsynaptic potentials; EPSPs). NA increases motoneuron excitability by facilitating calcium-mediated persistent inward currents (Ca...

Muscle paralysis after spinal cord injury is partly caused by a loss of brainstem-derived serotonin (5-HT), which normally maintains motoneuron excitability by regulating crucial persistent calcium currents. Here we examine how over time motoneurons compensate for lost 5-HT to regain excitability. We find that, months after a spinal transection in...

Recruitment and repetitive firing of spinal motoneurons depend on the activation of persistent inward calcium and sodium currents (PICs) that are in turn facilitated by serotonin and norepinephrine that arise primarily from the brain stem. Considering that in rats motoneuron PICs are greatly facilitated by increasing the presynaptic release of nore...