Combined Robotic Training and tDCS in Chronic SCI

Study design: Using a within-subjects repeated measures design, up to 40 SCI participants
will be randomized to receive 6-week hand robotic training preceded by 20 min anodal 2mA tDCS
or sham (3 sessions/week, 18 sessions total). Clinical and functional scales, robotic
kinematics and neurophysiological data (TMS evaluation) will be collected before and after
the combined intervention period, and a month later (pre, post and follow up evaluations).
Randomization will be done using a randomized block design with a block size of 2. All
participants, raters, and experimenters will be blinded to treatment allocation.

AIM 1. To determine whether combining non-invasive brain stimulation (tDCS) and behavioral
training (robotics) in SCI can lead to functional improvement. The investigators hypothesize
that the group receiving the real stimulation will obtain a greater clinical improvement in
hand motor function. Using a within subjects repeated measures design, baseline clinical hand
function (Box and Blocks test) will be compared to post 6-week robotic training intervention,
and then a month later (follow up), each session preceded by real (2mA anodal M1) or sham
tDCS.

AIM 2. To examine the kinematic changes (from robotic measures) associated with the combined
training. Quantitative measurements obtained from robotics are highly sensitive, precise and
reliable. The investigators predict an enhancement of motor performance in all participants,
measured by 5 key parameters: mean speed, peak speed, smoothness, aim and deviation; with
greater improvements in the intervention group receiving the pre-conditioning effect of
transcranial stimulation. These data will identify features of motor control that underlie
improvements in clinical function, when comparing the two intervention groups.

AIM 3. To identify and compare the neurophysiological mechanisms (by TMS) associated with the
combined training. The relationship between clinical improvement in neurophysiological
measures pertaining to robotic motor training alone and combined with tDCS will be assessed.
Measuring changes in MEP amplitude of hand muscles before and after the training will
establish a) the plasticity associated with training alone and with supplementary brain
stimulation, b) the neurophysiological characteristics of patients who respond better to the
training. By understanding how brain excitability changes underpin motor dysfunction, and
motor recovery, interventions can be more effectively prescribed and prognoses established.

Inclusion Criteria:

- Tetraplegia (cervical lesion) with some degree of motor dysfunction in the hand
(ability to pick up at least 1 block on the Box and Blocks Test)

- Motor incomplete lesion (measured by the ASIA Impairment Scale, B, C, D)

- Chronic lesion (>6 months after the injury)

Exclusion Criteria:

- Motor and sensory complete lesion (AIS A)

- Presence of potential risk factor for brain stimulation (TMS and tDCS): history of
seizures, presence of surgically implanted foreign bodies such as a pacemaker, metal
plate in the skull, and metal inside the skull

- History of head trauma and/or cognitive deficit

- Medically unstable