Functional electrical stimulation in spinal cord injury:: from theory to practice

Electrical stimuli in the central nervous system microenvironment

Electrical stimulation to manipulate the central nervous system (CNS) has been applied as early as the 1750s to produce visual sensations of light. Deep brain stimulation (DBS), cochlear implants, visual prosthetics, and functional electrical stimulation (FES) are being applied in the clinic to treat a wide array of neurological diseases, disorders, and injuries. This review describes the history of electrical stimulation of the CNS microenvironment; recent advances in electrical stimulation of the CNS, including DBS to treat essential tremor, Parkinson's disease, and depression; FES for the treatment of spinal cord injuries; and alternative electrical devices to restore vision and hearing via neuroprosthetics (retinal and cochlear implants). It also discusses the role of electrical cues during development and following injury and, importantly, manipulation of these endogenous cues to support regeneration of neural tissue.

Gait recovery in a girl with ischemic spinal cord stroke

BACKGROUND AND PURPOSE

This case report describes an aggressive, task-specific program for the recovery of gait in a girl with a spinal cord stroke.

CASE DESCRIPTION

The 11-year-old girl sustained a spinal cord stroke resulting in a T4 motor-incomplete lesion. Therapy was initiated 6 months after onset when she was not ambulating.

INTERVENTION

The focus of all interventions was on the restoration of gait. Locomotor treadmill training and over ground walking were the primary practice interventions. Walking was facilitated by orthoses, neuromuscular electrical stimulation, laser treatments, and strengthening. Treatment continued for 18 months.

OUTCOMES

At the conclusion of therapy, the client was able to walk independently in the community with a single ankle foot orthosis and reverse rolling walker.

DISCUSSION

The outcome was not anticipated for this client, given the type and level of her injury and the delay in starting gait training.

Functional electrical stimulation as a component of activity-based restorative therapy may preserve function in persons with multiple sclerosis

OBJECTIVE

To examine the effect of functional electrical stimulation (FES) cycling on disability progression in persons with multiple sclerosis (MS).

DESIGN

Retrospective cohort, 40 participants with mean follow-up of 15 months. Setting International Center for Spinal Cord Injury at Kennedy Krieger Institute in Baltimore, a rehabilitation referral center.

PARTICIPANTS

Forty consecutive persons with MS undergoing rehabilitation from 2007 to 2011, with at least two evaluations based on the International Standards for Neurological Classification of Spinal Cord Injury (ISNCSCI). Interventions FES cycling as part of activity-based restorative therapy interventions.

OUTCOME MEASURES

Change in Expanded Disability Status Scale (EDSS) and ISNCSCI motor, light touch, and pin prick scores from baseline to latest evaluation.

RESULTS

In 71% of patients, activity-based rehabilitation included FES cycling. There was no disability progression on the EDSS. Lower extremity motor scores improved or stabilized in 75% of patients with primary progressive MS (PPMS), 71.4% with secondary progressive MS (SPMS), and 54.5% with relapsing remitting MS (RRMS). Among patients with improved or stabilized lower extremity motor function, PPMS recorded a mean 9% improvement, SPMS 3% and RRMS 6%. In PPMS, use of FES showed trend towards improvement in motor scores (P = 0.070).

CONCLUSIONS

FES as part of activity-based rehabilitation may help preserve or improve neurological function in patients with MS.

Inflammation-mediating cytokine response to acute handcycling exercise with/without functional electrical stimulation-evoked lower-limb cycling

This feasibility study compared the plasma inflammation-mediating cytokine response to an acute bout of handcycling (HC) with and without the addition of functional electrical stimulation (FES)-evoked lower-limb cycling. On two separate occasions, five recreationally active, community-based participants with motor complete paraplegia (thoracic 5- 7) performed 30 min HC and hybrid exercise (HYB) at a fixed power output. Venous blood samples were collected at rest, immediately postexercise, 1 h postexercise (post+1) and 2 h postexercise (post+2). Plasma interleukin (IL)-6, IL-10, IL-1 receptor antagonist (IL-1ra), adrenaline, and cortisol concentrations were determined via enzyme-linked immunoassay. Plasma IL-6 concentrations were significantly (p < 0.04) elevated (~2.5-fold) at post+1 and post+2 in HYB only. A small (0.5-fold), nonsignificant (p > 0.05) increase in IL-6 was observed at post+1 in HC, with concentrations significantly higher in HYB at post+2 (p < 0.02). Plasma IL-1ra was unaffected in both trials. Although not reaching statistical significance (p = 0.15), a ~1-fold increase in IL-10 concentration was seen in HYB at post+2. In contrast, increases in adrenaline (p < 0.04) and cortisol (p = 0.08) were observed immediately postexercise in HC and HYB. Initial findings suggest paralyzed skeletal muscle releases IL-6 in response to FES-evoked contractions. HYB may provide a greater anti-inflammatory potential in individuals with a thoracic spinal cord injury compared with HC alone.

Improving the Efficiency of Electrical Stimulation Activities After Spinal Cord Injury

In order to enhance spinal cord injury (SCI) rehabilitation programs using neuromuscular electrical stimulation (NMES) and functional electrical stimulation (FES) it is important to examine the manner in which muscle fibers are recruited and the dose-response relationship. A review of the literature suggests that premature force decline and early fatigue with NMES and FES activities may be alleviated with decreased current frequency and increased current intensity. Dose-response relationships with NMES and FES are dependent on the goals of interest as reversing muscle atrophy can be achieved with activities 2-3 times per week for 6 or more weeks while increasing bone mass is more limited and requires more intense activity with greater exercise frequency and duration, e.g., 3-5 days per week for at least 6-12 months. The best known protocol to elicit neurological improvement is massed practice activities-based restorative therapies (ABRT) (3-5 h per day for several weeks).