Motor recovery mechanism of diffuse axonal injury: a combined study of transcranial magnetic stimulation and functional MRI.
OBJECTIVE
The purpose of this study was to investigate the motor recovery mechanism following diffuse axonal injury (DAI) using transcranial magnetic stimulation (TMS) and functional MRI (fMRI).


METHODS
Twenty-six hands of 13 control subjects and 14 affected hands of 8 patients (two hemiparetics and six quadriparetics) were evaluated. All the patients were initially diagnosed with DAI and were evaluated after they had reached their maximal motor recovery. fMRI was performed at 1.5 T using a hand grasp-release movement paradigm and TMS was applied with a round coil over the vertex.


RESULTS
fMRI revealed that both normal subjects and patients with DAI showed increased contralateral primary sensori-motor cortex activation during affected hand movement. The motor evoked potentials (MEPs) of the patient group was slightly delayed in latency and significantly increased in duration and turns. The relative MEP amplitude, phase, and excitatory threshold were not significantly different between the groups.


CONCLUSIONS
These findings may indicate the heterogeneity of the axons in the recovery process of the corticospinal tract. It seems that the motor recovery in patients who had suffered DAI was attributable to the recovery of the corticospinal tract.
Jang
Sung Ho
SH
Department of Physical Medicine and Rehabilitation, College of Medicine, Yeungnam University, Republic of Korea.
Cho
Sang-Hyun
SH
Kim
Yun-Hee
YH
You
Sung H
SH
Kim
Seong Ho
SH
Kim
Oryong
O
Yang
Dong Suk
DS
Son
Su min
Sm
D000328:Adult; D020833:Diffuse Axonal Injury / Q000503:physiopathology* / Q000534:rehabilitation; D004574:Electromagnetic Fields; D019054:Evoked Potentials, Motor / Q000502:physiology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009048:Motor Skills / Q000502:physiology; D020127:Recovery of Function / Q000502:physiology*