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The Structural and Functional Mechanisms of Motor Recovery: Complementary use of Diffusion Tensor and Functional Magnetic Resonance Imaging in a Traumatic Injury of the Internal Capsule

CNS - Center for Neurological Studies > Support for DTI to Diagnose mTBI > The Structural and Functional Mechanisms of Motor Recovery: Complementary use of Diffusion Tensor and Functional Magnetic Resonance Imaging in a Traumatic Injury of the Internal Capsule

J Neurol Neurosurg Psychiatry. 1998 Dec;65(6):863-9.

 

The structural and functional mechanisms of motor recovery: complementary use of diffusion tensor and functional magnetic resonance imaging in a traumatic injury of the internal capsule.

 

Werring DJ, Clark CA, Barker GJ, Miller DH, Parker GJ, Brammer MJ, Bullmore ET, Giampietro VP, Thompson AJ.

 

NMR Research Unit, Institute of Neurology, London, UK.

 

 

OBJECTIVES: Recovery from focal motor pathway lesions may be associated with a functional reorganization of cortical motor areas. Previous studies of the relation between structural brain damage and the functional consequences have employed MRI and CT, which provide limited structural information. The recent development of diffusion tensor imaging (DTI) now provides quantitative measures of fiber tract integrity and orientation. The objective was to use DTI and functional MRI (fMRI) to determine the mechanisms underlying the excellent recovery found after a penetrating injury to the right capsular region.

 

METHODS: DTI and fMRI were performed on the patient described; DTI was performed

on five normal controls.

 

RESULTS: The injury resulted in a left hemiplegia which resolved fully over several weeks. When studied 18 months later there was no pyramidal weakness, a mild hemidystonia, and sensory disturbance. fMRI activation maps showed contralateral primary and supplementary motor cortex activation during tapping of each hand; smaller ipsilateral primary motor areas were activated by the recovered hand only. DTI disclosed preserved structural integrity and orientation in the posterior capsular limb by contrast with the disrupted structure in the anterior limb on the injured side.

 

CONCLUSIONS: The findings suggest that the main recovery mechanism was a preservation of the integrity and orientation of pyramidal tract fibers. The fMRI studies do not suggest substantial reorganization of the motor cortex, although ipsilateral pathways may have contributed to the recovery. The initial deficit was probably due to reversible local factors including oedema and mass effect; permanent damage to fiber tracts in the anterior capsular limb may account for the persistent sensory deficit. This study shows for the first time the potential value of combining fMRI and DTI together to investigate mechanisms of recovery and persistent deficit in an individual patient.

 

PMCID: PMC2170393

PMID: 9854962  [PubMed – indexed for MEDLINE]

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