title: Modeling the relationship among gray matter atrophy, abnormalities in connecting white matter, and cognitive performance in early multiple sclerosis.
abstract: OBJECTIVE
  Quantitative assessment of clinical and pathologic consequences of white matter abnormalities in multiple sclerosis is critical in understanding the pathways of disease. This study aimed to test whether gray matter atrophy was related to abnormalities in connecting white matter and to identify patterns of imaging biomarker abnormalities that were related to patient processing speed.
  
  
  METHODS
  Image data and Symbol Digit Modalities Test scores were collected from a cohort of patients with early multiple sclerosis. The Network Modification Tool was used to estimate connectivity irregularities by projecting white matter abnormalities onto connecting gray matter regions. Partial least-squares regression quantified the relationship between imaging biomarkers and processing speed as measured by the Symbol Digit Modalities Test.
  
  
  RESULTS
  Atrophy in deep gray matter structures of the thalami and putamen had moderate and significant correlations with abnormalities in connecting white matter (r = 0.39-0.41, P < .05 corrected). The 2 models of processing speed, 1 for each of the WM imaging biomarkers, had goodness-of-fit (R(2)) values of 0.42 and 0.30. A measure of the impact of white matter lesions on the connectivity of occipital and parietal areas had significant nonzero regression coefficients.
  
  
  CONCLUSIONS
  We concluded that deep gray matter regions may be susceptible to inflammation and/or demyelination in white matter, possibly having a higher sensitivity to remote degeneration, and that lesions affecting visual processing pathways were related to processing speed. The Network Modification Tool may be used to quantify the impact of early white matter abnormalities on both connecting gray matter structures and processing speed.
authors.affiliation: From the Departments of Radiology (A.F.K., M.D., A.R.) The Brain and Mind Research Institute (A.F.K., A.R., S.A.G.), Weill Cornell Medical College, New York, New York. amk2012@med.cornell.edu.
authors.forename: A F
authors.identifier: http://orcid.org/0000-0002-5050-8342
authors.initials: AF
authors.lastname: Kuceyeski
authors.affiliation: Neurology (W.V., E.M., C.B., K.F., S.A.G.).
authors.forename: W
authors.initials: W
authors.lastname: Vargas
authors.affiliation: From the Departments of Radiology (A.F.K., M.D., A.R.).
authors.forename: M
authors.initials: M
authors.lastname: Dayan
authors.affiliation: Neurology (W.V., E.M., C.B., K.F., S.A.G.).
authors.forename: E
authors.initials: E
authors.lastname: Monohan
authors.affiliation: Neurology (W.V., E.M., C.B., K.F., S.A.G.).
authors.forename: C
authors.initials: C
authors.lastname: Blackwell
authors.affiliation: From the Departments of Radiology (A.F.K., M.D., A.R.) The Brain and Mind Research Institute (A.F.K., A.R., S.A.G.), Weill Cornell Medical College, New York, New York.
authors.forename: A
authors.initials: A
authors.lastname: Raj
authors.affiliation: Neurology (W.V., E.M., C.B., K.F., S.A.G.).
authors.forename: K
authors.initials: K
authors.lastname: Fujimoto
authors.affiliation: Neurology (W.V., E.M., C.B., K.F., S.A.G.) The Brain and Mind Research Institute (A.F.K., A.R., S.A.G.), Weill Cornell Medical College, New York, New York.
authors.forename: S A
authors.initials: SA
authors.lastname: Gauthier
mesh_terms: D000328:Adult; D001284:Atrophy / Q000473:pathology; D001921:Brain / Q000473:pathology*; D003071:Cognition / Q000502:physiology; D003072:Cognition Disorders / Q000209:etiology / Q000473:pathology; D005260:Female; D066128:Gray Matter / Q000473:pathology*; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods; D008297:Male; D008875:Middle Aged; D008959:Models, Neurological; D009103:Multiple Sclerosis / Q000150:complications / Q000473:pathology*; D066127:White Matter / Q000473:pathology*