New Studies Aim to Provide Non-Invasive, Accessible Therapies for People with Spinal Cord Injury

As post-doctoral fellows in Shepherd Center’s Hulse Spinal Cord Injury Lab – fresh from obtaining their doctorates in basic science research – Jennifer Iddings, Ph.D., and Stephen Estes, Ph.D., have the opportunity to apply their strong scientific expertise while gaining skills needed for studying humans. They are both leading studies that aim to refine and enhance current therapies used for people who have sustained a spinal cord injury (SCI). One study will focus on enhancing upper-extremity movement, while the other study will address improvements in walking function.

Enhancing Corticospinal Excitability to Improve Functional Recovery

With funding through a grant from the Craig H. Nielsen Foundation, Dr. Iddings is leading a study that will compare two types of non-invasive brain stimulation – transcranial direct current stimulation (tDCS) and transcranial pulsed current stimulation (tPCS). The study will determine which type of stimulation has a greater influence on the brain’s response to arm and hand training, with the goal of improving upper-extremity function in people with a cervical spinal cord injury. Prior laboratory research has shown that tDCS – a type of stimulation in which continuous, low-intensity current is applied to the scalp to excite the brain areas controlling movement – improves upper-extremity function in people with SCI. A recent study in non-injured individuals showed that tPCS – a type of stimulation in which low-intensity current is applied to the scalp in pulses rather than continuously – may have a larger effect on neural excitability than tDCS. This approach has not yet been tested in people with SCI, but Dr. Iddings’ study will change that.

“We want to determine whether one type of stimulation more robustly enhances the excitability of the motor cortex – the region of the brain that controls voluntary movements – to increase communication between the brain and spinal cord. Our goal is to begin optimizing non-invasive brain stimulation for use as a neurorehabilitation tool in persons with SCI,” Dr. Iddings says.

For this study, participants will receive individual sessions of each type of stimulation – tDCS, tPCS and a sham control, while participating in arm and hand training. During stimulation, two sponge electrodes, pads that transmit the electrical current from the stimulator, placed on the participant’s head will apply low-level electrical stimulation to the scalp for 30 minutes to increase excitability in the regions of the brain that control arm and hand function. These brain changes are aimed at improving the effectiveness of arm and hand training, which involves tasks such as grasping, moving and releasing objects. For each session, the type of stimulation or the location of the stimulation electrodes will be modified to determine the effect of these parameters on brain excitability and upper-extremity function.

“We’re hopeful the study will provide us with valuable information on which of these two types of non-invasive brain stimulation is most effective, as well as the best site of electrode placement,” Dr. Iddings explains. “This study will lay the groundwork for future research investigating the use of non-invasive brain stimulation as an adjunct to rehabilitation for functional restoration in persons with SCI.”

Participant recruitment will begin in fall 2017. Participants must:

• Be 18 to 65 years of age
• Have a cervical (neurological level C1-C8) SCI occurring more than six months ago
• Have any severity classification (ASIA/ISNCSCI A, B, C, D)
• Have self-reported functional limitation in at least one upper limb
• Have the ability to voluntarily move a thumb or index finger (visible twitch) of both upper limbs
• Have the ability and willingness to consent to participate in the study and authorize the use of their protected health information

For more information or to express interest in participating, contact Jennifer Iddings, Ph.D., at 404-367-1239 or jennifer_iddings@shepherd.org.

Combined Influence of Transcutaneous Spinal Cord Stimulation and Locomotor Training on Spasticity and Walking Outcomes after Spinal Cord Injury

Dr. Estes is leading a study – funded by the Wings for Life Spinal Cord Research Foundation – that tests a novel way to increase the effectiveness of locomotor training for improving walking function. Locomotor training may work to improve neural pathways that are damaged following a spinal cord injury (SCI) by repetitively stimulating the muscles and nerves in the lower body. Locomotor training sessions can be conducted using specialized body-weight-supported harness systems, treadmills or walking over-ground. Either a specially trained team or a robotic system may help move the participant’s legs to walk. The goal of this training is to improve walking quality, speed and distance, as well as decrease the use of assistive devices. The therapy in Dr. Estes’ study combines locomotor training with non-invasive, spinal cord stimulation called transcutaneous spinal cord stimulation.

Research shows that locomotor training can improve over-ground walking in persons with a motor incomplete SCI. By adding transcutaneous spinal cord stimulation to locomotor training, Dr. Estes’ research aims to further improve walking function in persons with motor incomplete SCI. He also hopes to reduce involuntary muscle activity, called spasticity, which affects 70 to 80 percent of people with SCI.

“Depending on the individual, spasticity can be good or bad,” Dr. Estes says. “But we see that it can impede functional goals in people with a spinal cord injury, and is often poorly managed by drug treatments alone, which is why we want to find a way to reduce it.”

““Following a spinal cord injury, the loss of input from the brain to the spinal cord can lead to an imbalance in the spinal cord circuitry that is important for motor control – both voluntary and involuntary,” Dr. Estes explains. “Our thought is that by stimulating nerve fibers leading into the spinal cord using transcutaneous spinal cord stimulation, we can rebalance the circuitry, resulting in reduced spasticity and improved walking function.”

During the study, participants will undergo clinical assessments, as well as analyses of muscle activity for four weeks while participating in standard locomotor training with their physical therapist three days a week. For the first two weeks, all participants will receive standard locomotor training only. The last two weeks of locomotor training will include the addition of spinal cord stimulation provided through a transcutaneous electrical nerve stimulation (TENS) unit. Some participants will receive sham stimulation as part of a randomly preassigned control group.

This study is a pragmatic clinical trial where standard treatment practices are directed by a physical therapist in a clinical setting.

“If the addition of transcutaneous spinal cord stimulation reduces spasticity and improves walking function, the combination of the therapies can be more quickly integrated into the clinical setting”, Dr. Estes notes.

Participants must:

• Be 18 to 65 years of age
• Be enrolled in Spinal Cord Injury Day Program at Shepherd Center
• Have at least mild spasticity affecting the lower-extremity muscles
• Be able to stand for at least one minute using the upper extremities for balance only
• Have a spinal cord injury, completed inpatient rehabilitation and have been discharged to home
• Have the ability and willingness to consent and authorize the use of their private health information

For more information or to express interest in participating, please contact Stephen Estes, Ph.D., at stephen_estes@shepherd.org or call 404-603-4967.

For more information on current research studies at Shepherd Center, visit here.

Written by Kerry Ludlam