Wallerian degeneration of the corticofugal tracts in chronic stroke: a pilot study relating diffusion tensor imaging, transcranial magnetic stimulation, and hand function.
OBJECTIVE
This study tested the hypothesis that degeneration of the corticofugal tracts (CFTs) is related to poor functional outcome in the upper limb after stroke.


METHODS
. The authors used diffusion tensor imaging to determine the degree of white matter integrity of the CFT (FA(AH/UH)) in chronic stroke patients and controls. The functional integrity of the corticospinal pathway was examined using transcranial magnetic stimulation. Recruitment curves and silent period duration were measured. The relationship between FA(AH/UH) and functional outcome of the upper limb was also assessed using a battery of upper limb function tests.


RESULTS
In patients, FA( AH/UH) correlated positively with the slope of recruitment curves (RC(AH/UH)) and grip strength. FA(AH/UH) also correlated negatively with the silent period duration (SP(AH/UH)). According to the FA(AH/UH), patients were also classified into groups with minimal or extensive Wallerian degeneration (WD). Patients with more extensive WD had poorer grip strength, dexterity, and range of movement.


CONCLUSIONS
The authors' results suggest that structural and functional integrity of the CFT is essential to maintain function of the upper limb after stroke.
Lindberg
Påvel G
PG
Department of Neuroscience, Uppsala University Hospital, Uppsala, Sweden. Pavel.Lindberg@rehab.uu.se
Skejø
Pernille H B
PH
Rounis
Elisabeth
E
Nagy
Zoltan
Z
Schmitz
Christina
C
Wernegren
Helena
H
Bring
Annika
A
Engardt
Margareta
M
Forssberg
Hans
H
Borg
Jörgen
J
D000328:Adult; D000368:Aged; D002908:Chronic Disease; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006225:Hand / Q000294:innervation / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D011237:Predictive Value of Tests; D011712:Pyramidal Tracts / Q000473:pathology* / Q000503:physiopathology; D020127:Recovery of Function; D020521:Stroke / Q000473:pathology* / Q000503:physiopathology; D050781:Transcranial Magnetic Stimulation; D014855:Wallerian Degeneration / Q000473:pathology* / Q000503:physiopathology