Publisher Correction: Neuromodulation of lumbosacral spinal networks enables independent stepping after complete paraplegia.

In the version of this article originally published, Dimitry G. Sayenko's affiliations were not correct. The following affiliation for this author was missing: Department of Neurosurgery, Center for Neuroregeneration, Houston Methodist Research Institute, Houston, TX, USA. This affiliation has been added for the author, and the rest of the affiliations have been renumbered accordingly. The error has been corrected in the HTML and PDF versions of this article.

Neuromodulation of lumbosacral spinal networks enables independent stepping after complete paraplegia.

Spinal sensorimotor networks that are functionally disconnected from the brain because of spinal cord injury (SCI) can be facilitated via epidural electrical stimulation (EES) to restore robust, coordinated motor activity in humans with paralysis1-3. Previously, we reported a clinical case of complete sensorimotor paralysis of the lower extremities in which EES restored the ability to stand and the ability to control step-like activity while side-lying or suspended vertically in a body-weight support system (BWS)4. Since then, dynamic task-specific training in the presence of EES, termed multimodal rehabilitation (MMR), was performed for 43 weeks and resulted in bilateral stepping on a treadmill, independent from trainer assistance or BWS. Additionally, MMR enabled independent stepping over ground while using a front-wheeled walker with trainer assistance at the hips to maintain balance. Furthermore, MMR engaged sensorimotor networks to achieve dynamic performance of standing and stepping. To our knowledge, this is the first report of independent stepping enabled by task-specific training in the presence of EES by a human with complete loss of lower extremity sensorimotor function due to SCI.

Electrical Neuromodulation of the Respiratory System After Spinal Cord Injury.

Spinal cord injury (SCI) is a complex and devastating condition characterized by disruption of descending, ascending, and intrinsic spinal circuitry resulting in chronic neurologic deficits. In addition to limb and trunk sensorimotor deficits, SCI can impair autonomic neurocircuitry such as the motor networks that support respiration and cough. High cervical SCI can cause complete respiratory paralysis, and even lower cervical or thoracic lesions commonly result in partial respiratory impairment. Although electrophrenic respiration can restore ventilator-independent breathing in select candidates, only a small subset of affected individuals can benefit from this technology at this moment. Over the past decades, spinal cord stimulation has shown promise for augmentation and recovery of neurologic function including motor control, cough, and breathing. The present review discusses the challenges and potentials of spinal cord stimulation for restoring respiratory function by overcoming some of the limitations of conventional respiratory functional electrical stimulation systems.

Enabling Task-Specific Volitional Motor Functions via Spinal Cord Neuromodulation in a Human With Paraplegia.

We report a case of chronic traumatic paraplegia in which epidural electrical stimulation (EES) of the lumbosacral spinal cord enabled (1) volitional control of task-specific muscle activity, (2) volitional control of rhythmic muscle activity to produce steplike movements while side-lying, (3) independent standing, and (4) while in a vertical position with body weight partially supported, voluntary control of steplike movements and rhythmic muscle activity. This is the first time that the application of EES enabled all of these tasks in the same patient within the first 2 weeks (8 stimulation sessions total) of EES therapy.

Review of Epidural Spinal Cord Stimulation for Augmenting Cough after Spinal Cord Injury.

Spinal cord injury (SCI) remains a debilitating condition for which there is no cure. In addition to loss of somatic sensorimotor functions, SCI is also commonly associated with impairment of autonomic function. Importantly, cough dysfunction due to paralysis of expiratory muscles in combination with respiratory insufficiency can render affected individuals vulnerable to respiratory morbidity. Failure to clear sputum can aggravate both risk for and severity of respiratory infections, accounting for frequent hospitalizations and even mortality. Recently, epidural stimulation of the lower thoracic spinal cord has been investigated as novel means for restoring cough by evoking expiratory muscle contraction to generate large positive airway pressures and expulsive air flow. This review article discusses available preclinical and clinical evidence, current challenges and clinical potential of lower thoracic spinal cord stimulation (SCS) for restoring cough in individuals with SCI.

Assessing the temporal relationship between cognition and gait: slow gait predicts cognitive decline in the Mayo Clinic Study of Aging.

BACKGROUND: The association between gait speed and cognition has been reported; however, there is limited knowledge about the temporal associations between gait slowing and cognitive decline among cognitively normal individuals. METHODS: The Mayo Clinic Study of Aging is a population-based study of Olmsted County, Minnesota, United States, residents aged 70-89 years. This analysis included 1,478 cognitively normal participants who were evaluated every 15 months with a nurse visit, neurologic evaluation, and neuropsychological testing. The neuropsychological battery used nine tests to compute domain-specific (memory, language, executive function, and visuospatial skills) and global cognitive z-scores. Timed gait speed (m/s) was assessed over 25 feet (7.6 meters) at a usual pace. Using mixed models, we examined baseline gait speed (continuous and in quartiles) as a predictor of cognitive decline and baseline cognition as a predictor of gait speed changes controlling for demographics and medical conditions. RESULTS: Cross-sectionally, faster gait speed was associated with better performance in memory, executive function, and global cognition. Both cognitive scores and gait speed declined over time. A faster gait speed at baseline was associated with less cognitive decline across all domain-specific and global scores. These results were slightly attenuated after excluding persons with incident mild cognitive impairment or dementia. By contrast, baseline cognition was not associated with changes in gait speed. CONCLUSIONS: Our study suggests that slow gait precedes cognitive decline. Gait speed may be useful as a reliable, easily attainable, and noninvasive risk factor for cognitive decline.

Limb immobilization and corticobasal syndrome.

BACKGROUND: Recently, we evaluated two patients with corticobasal syndrome (CBS) who reported symptom onset after limb immobilization. Our objective was to investigate the association between trauma, immobilization and CBS. METHODS: The charts of forty-four consecutive CBS patients seen in the Mayo Clinic Alzheimer Disease Research Center were reviewed with attention to trauma and limb immobilization. RESULTS: 10 CBS patients (23%) had immobilization or trauma on the most affected limb preceding the onset or acceleration of symptoms. The median age at onset was 61. Six patients manifested their first symptoms after immobilization from surgery or fracture with one after leg trauma. Four patients had pre-existing symptoms of limb dysfunction but significantly worsened after immobilization or surgery. CONCLUSIONS: 23 percent of patients had immobilization or trauma of the affected limb. This might have implications for management of CBS, for avoiding injury, limiting immobilization and increasing movement in the affected limb.