Lesion Load of the Corticospinal Tract Predicts Motor Impairment in Chronic Stroke

• Published in: Stroke (1970) Vol. 41; no. 5; pp. 910 - 915
• Main Authors: Zhu, Lin L., Lindenberg, Robert, Alexander, Michael P., Schlaug, Gottfried
• Format: Journal Article
• Language: English
• Published: Hagerstown, MD Lippincott Williams & Wilkins 01.05.2010
• Subjects: Adult; Aged; Biological and medical sciences; Brain - pathology; Chronic Disease; Diffusion Tensor Imaging - methods; Female; Headache. Facial pains. Syncopes. Epilepsia. Intracranial hypertension. Brain oedema. Cerebral palsy; Humans; Male; Medical sciences; Middle Aged; Motor Skills Disorders - etiology; Motor Skills Disorders - pathology; Nervous system (semeiology, syndromes); Neurology; Predictive Value of Tests; Pyramidal Tracts - pathology; Stroke - complications; Stroke - pathology; Vascular diseases and vascular malformations of the nervous system; Cartography; Stroke; Nervous system diseases; motor recovery; Cardiovascular disease; Cerebral disorder; Diffusion tensor imaging; Vascular disease; Chronic; lesion mapping; corticospinal tract; Central nervous system disease; Cerebrovascular disease
• ISSN: 0039-2499; 1524-4628; 1524-4628
• DOI: 10.1161/STROKEAHA.109.577023

Background and Purpose— Previous studies have shown motor impairment after a stroke relates to lesion size and location, but unexplained variability in recovery still exists. In this study, we used lesion-mapping techniques in combination with diffusion tensor imaging to quantitatively test the hypothesis that motor recovery in patients with chronic stroke is inversely related to the proportion of the corticospinal tract (CST) affected by the lesion. Methods— We studied 50 patients with chronic stroke, all of whom presented with moderate to severe motor impairments in the acute stage, using high-resolution anatomic MRI. We evaluated the degree of motor impairment with the Upper Extremity module of the Fugl-Meyer Assessment. To analyze the relationship between CST damage and impairment scores, we calculated a CST-lesion load for each patient by overlaying the patient’s lesion map with a probabilistic tract derived from diffusion tensor images of age-matched healthy subjects. Results— CST-lesion load was a significant predictor of motor deficit. Infarct size, despite correlating with motor scores, did not significantly predict impairment. Conclusions— Our results show the degree of functional motor deficit after a stroke is highly dependent on the overlap of the lesion with the CST and not lesion size per se. In the future, automated calculation of CST-lesion load may allow more precise prediction of motor impairment after stroke.