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E20 2012 ACRM–ASNR Annual Conference Abstracts

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Objective: To determine the feasibility of combining transcranialirect current stimulation (tDCS) of the lower extremity (LE) motorortex with novel locomotor training to facilitate gait and neuroplastichange in subjects with chronic stroke. Methodology: Double-blind,andomized controlled study. We enrolled 10 subjects with chronic stroke;utpatient rehabilitation setting. Subjects were stratified according toaseline LE motor function then randomized to either active tDCS (20in; 2mA) or sham tDCS for 12 sessions over one month. Both groups

articipated in identical locomotor training following each tDCS session.raining protocol (robot-assisted treadmill (Lokomat)) was designed toarness corticospinal neuroplasticity. Primary Outcome Measure: 10-eter Walk Test (10MWT). Other Outcome Measures: Functionalmbulation Category (FAC), Timed Up and Go (TUG), Berg Balancecale (BBS), Stroke Impact Scale-16 (SIS); cortical excitability (transcra-ial magnetic stimulation (TMS)). Results: Eight subjects completed the

study (four men; mean age 67.8 years; mean years post-stroke: four).ANOVA trended towards improvement for both groups. Active tDCSgroup showed more marked improvement than sham in all measures(FAC p�0.028; 10 MWT p�0.19; TUG p�0.066; SIS p�0.062) exceptBBS (p�0.919). TMS recruitment curves demonstrated increased corticalexcitability at completion and one-month follow-up. ImportantFindings: It is feasible to combine tDCS targeting the LE motor cortexwith novel locomotor training. It appears that tDCS has the potential toimprove gait in chronic stroke. Our novel locomotor training also appearsto enhance corticospinal excitability. Results warrant larger studies apply-ing tDCS and locomotor training, particularly regarding stroke survivorswith low ambulation. Key Words: Stroke; Motor function; Neurosci-ence; Rehabilitation.

Poster 21Callosal Sensory Fibre Integrity is Reduced in the Chronic Phaseof Stroke. Cameron Scott Mang (Brain Behaviour Laboratory,Department of Rehabilitation Sciences, Faculty of Medicine, Uni-versity of British Columbia, Vancouver, BC, Canada).

Disclosure: None disclosed.Objectives: To characterize microstructural fiber integrity of sen-

sorimotor regions of the corpus callosum (CC) in individuals withchronic stroke. The secondary objective was to evaluate relationshipsbetween CC integrity and upper extremity motor performance. Wehypothesized that the integrity of CC sensorimotor regions would bereduced in individuals with chronic stroke compared to age-matchedcontrols and that CC integrity would relate to upper extremity motorperformance. Design: Single-blinded survey controlled study. Setting:

niversity of British Columbia Brain Behaviour Laboratory and 3TRI Research Centre. Participants: Thirteen individuals with middle

erebral artery chronic stroke and thirteen age- and gender-matchedealthy controls. Participants were recruited through volunteerampling. Interventions: Not applicable. Main Outcome Measures:he primary outcome measure was fractional anisotropy (FA) of aross-section of the sensorimotor regions of the CC obtained fromiffusion tensor imaging. The secondary outcome measure was boxnd block test (BBT) score to evaluate upper extremity motor perfor-ance. Multivariate analysis of variance evaluated differences in FA

etween stroke and healthy groups. Correlational analyses were con-ucted for upper extremity motor performance and FA. Results: In thetroke group FA was reduced in the sensory (CI95%: 0.044–0.141,�0.001), but not motor (CI95%: �0.015–0.057, p�0.236), region ofhe CC. A significant correlation between CC sensory region FA andBT performance was observed across all participants (R2�0.222,�0.023). Conclusions: Reduced integrity of callosal sensory fibersay contribute to motor deficits in chronic stroke. Future research is

eeded to determine how CC sensory region integrity influencesnterhemispheric interactions post-stroke. Key Words: Stroke; Motorunction; Neuroscience; Rehabilitation.

oster 22ptimizing Transcranial Direct Current Stimulation for Motor Recov-

ry From Severe Post-Stroke Hemiparesis: Early Results From an On-

rch Phys Med Rehabil Vol 93, October 2012

oing Clinical Trial. Kenneth Chelette, Cheryl Carrico, Laurieichols, Lumy Sawaki (University of Kentucky, Lexington, KY).

isclosure: Transcranial Direct Current Stimulation.Objective: To determine the best electrode configuration for trans-

cranial direct current stimulation (tDCS), a non-invasive brain stimu-lation technique, to enhance upper extremity (UE) motor function insubjects with severe post-stroke hemiparesis. Design: Randomized,double-blind, placebo-controlled clinical trial. Setting: Outpatientrehabilitation. Participants: Here, we present data from 26 of (pro-jected) 44 chronic stroke subjects with severe UE motor deficit (i. e,virtually no wrist and hand movement). Interventions: Subjects wereassigned to one of four groups: (1) anodal tDCS to excite ipsilesionalhemisphere, (2) cathodal tDCS to inhibit contralesional hemisphere,(3) dual: a simultaneous combination of anodal and cathodal tDCS,(4) sham tDCS. All subjects participated in 10 treatment sessionsconsisting of tDCS followed by three hours of occupational therapy.Main Outcome Measures: Primary outcome measure: Fugl-MeyerAssessment. Secondary Outcome Measures: Action Research ArmTest and Stroke Impact Scale. Evaluations were performed at baselineand post-intervention. Results: Preliminary results indicate substan-tially greater improvement in the cathodal group than in other groups.Conclusions: Our results differ from findings in subjects with mildhemiparesis. This disparity may be due to the larger lesions of subjectswith severe hemiparesis which may change tDCS current flow comparedto subjects with mild hemiparesis. Furthermore, in subjects with severehemiparesis, comparatively less ipsilesional neuronal substrate may beavailable for stimulation. Therefore, the anodal and the dual configura-tions, which rely on ipsilesional stimulation, may not prove optimal. KeyWords: Stroke; Motor function; Neuroscience; Rehabilitation.

Poster 23Correlating Electrophysiology and Metabolic Profiles to AssessMotor Impairment After Stroke. Paul W. Jones (University ofKentucky, Lexington, KY).

Disclosure: None disclosed.Objective: To correlate metabolic, anatomical, and electrophysiolog-

ical measurements of the primary motor (M1) and somatosensory (S1)cortices to identify potential mechanisms underlying motor deficits afterstroke. Design: Single time-point case series study. Setting: Laboratorybased study in the Brain Behaviour Lab and MRI Research Centre at theUniversity of British Columbia. Participants: Population-based sampleof 15 individuals (aged 50-75) with chronic stroke affecting unilateralmotor or sensorimotor systems. Interventions: Single and paired-pulsetranscranial magnetic stimulation (TMS) to assess primary motor corticalexcitability in both cerebral hemispheres. Single voxel magnetic reso-nance spectroscopy (MRS) positioned over M1 and S1 in both theipsilesional and contralesional hemispheres to characterize metabolicchanges after stroke. Main Outcome Measures: For metabolic mea-sures, absolute concentration (mmol/kg) of glutamate, creatine, N-acety-laspartate, choline and myo-inositol were quantified in both affected andunaffected hemispheres. Electrophysiology measurements of motorevoked potentials (MEPs) were collected using surface electromyographyplaced over the flexor carpi radialis of both arms. Results: Preliminarydata shows a significant decrease in glutamate concentration (affected,6.91(�/� 0.17) mmol/kg; unaffected, 7.47(�/�0.17) mmol/kg) coupled

ith altered cortical excitability in the stroke affected hemisphere. Con-lusions: Initial findings indicate altered cortical excitability may beelated to a decrease in the facilitatory neurotransmitter glutamate in thetroke affected hemisphere. Further study will provide a more compre-ensive understanding of the metabolic consequences of stroke and howhey relate to motor deficits. In turn this knowledge may be used toenerate novel therapeutic approaches. Key Words: Stroke; Motor

function; Neuroscience; Rehabilitation.

Poster 24Ipsilesional White Matter Integrity Predicts Implicit MotorLearning. Katlyn Brown (University of British Columbia, Van-

couver, BC, Canada).