Affiliations: Department of Physical Medicine and Rehabilitation,
School of Medicine, Yeungnam University, 317-1 Daemyungdong, Namku, Taegu,
705-717, Republic of Korea. Tel.: +82 053 620 3269; Fax: +82 53 625 3508;
E-mail: {strokerehab,shahn}@hanmail.net | Physical Therapy Program, Hampton University, Phoenix
Hall 219B, Hampton, VA 23668, USA. Tel.: +1 757 727 5623; Fax: +1 757 728 6546;
E-mail: sung.you@hamptonu.edu | Human Motor Control Section, National Institue of
Neurological Disorders and Stroke Medical Building 10, Room 5N226, MSC 1428,
Bethesda, MD 20892, USA. Tel.: +1 301 496 9526; Fax: +1 301 480 2286; E-mail:
hallettm@ninds.nih.gov | Department of Physical Therapy, Graduate School of
Rehabilitation Science Daegu University, 317-1 Daemyungdong, Namku, Taegu,
705-717, Republic of Korea. Tel.: +82 53 620 3275; Fax: +83 53 620 3278;
E-mail: kxhpt@lycos.co.kr
Note: [] Corresponding author
Abstract: Purpose: Recovery mechanisms supporting upper extremity motor
recovery following stroke are well established, but cortical mechanism
associated with lower extremity motor recovery is unknown. The aim of this
study was to assess cortical reorganization associated with lower extremity
motor recovery in a hemiparetic patient. Methods: Six control subjects and a 17 year-old woman with left
intracerebral hemorrhage due to an arterio-venous malformation rupture were
evaluated. The motor function of the paretic (left) hip and knee had recovered
slowly to the extent of her being able to overcome gravity for 10 months after
the onset of stroke. However, her paretic upper extremity showed no significant
motor recovery. Blood oxygenation level dependent (BOLD) functional MRI at 1.5
Tesla was used to determine the acutual location of cortical activation in the
predefined regions of interest. Concurrently, Diffusion Tensor Imaging (DTI) in
combination with a novel 3D-fiber reconstruction algorithm was utilized to
investigate the pattern of the corticospinal pathway connectivity between the
areas of the motor stream. All subjects' body parts were secured in the scanner
and performed a sequential knee flexion-extension with a predetermined angle of
0–60° at 0.5 Hz. Results: Controls showed anticipated activation in the contralateral
sensorimotor cortex (SM1) and the descending corticospinal fibers stemming from
motor cortex. In contrast to control normal subjects, the stroke patient showed
fMRI activation only in the unaffected (right) primary SM1 during either
paretic or nonparetic knee movements. DTT fiber tracing data showed that the
corticospinal tract fibers were found only in the unaffected hemisphere but not
in the affected hemisphere.
