Novel fMRI working memory paradigm accurately detects cognitive impairment in multiple sclerosis

• Published in: Multiple sclerosis 2017-05, Vol.23 (6), p.836-847
• Main Authors: Nelson, Flavia, Akhtar, Mohammad A, Zúñiga, Edward, Perez, Carlos A, Hasan, Khader M, Wilken, Jeffrey, Wolinsky, Jerry S, Narayana, Ponnada A, Steinberg, Joel L
• Format: Article
• Language: English
• Subjects: Adult; Brain Mapping - methods; Cognitive ability; Cognitive Dysfunction - diagnosis; Cognitive Dysfunction - diagnostic imaging; Cognitive Dysfunction - etiology; Cognitive Dysfunction - physiopathology; Cortex (motor); Female; Functional magnetic resonance imaging; Humans; Magnetic Resonance Imaging; Male; Memory; Memory, Short-Term - physiology; Mental task performance; Middle Aged; Motor Cortex - diagnostic imaging; Motor Cortex - physiopathology; Motor task performance; Multiple sclerosis; Multiple Sclerosis, Chronic Progressive - complications; Multiple Sclerosis, Chronic Progressive - physiopathology; Multiple Sclerosis, Relapsing-Remitting - complications; Multiple Sclerosis, Relapsing-Remitting - physiopathology; Neuroimaging; NMR; Nuclear magnetic resonance; Prefrontal cortex; Prefrontal Cortex - diagnostic imaging; Prefrontal Cortex - physiopathology; Short term memory; Supplementary motor area; Variance analysis; Young Adult
• ISSN: 1352-4585; 1477-0970
• DOI: 10.1177/1352458516666186

Background: Cognitive impairment (CI) cannot be diagnosed by magnetic resonance imaging (MRI). Functional magnetic resonance imaging (fMRI) paradigms, such as the immediate/delayed memory task (I/DMT), detect varying degrees of working memory (WM). Preliminary findings using I/DMT showed differences in blood oxygenation level dependent (BOLD) activation between impaired (MSCI, n = 12) and non-impaired (MSNI, n = 9) multiple sclerosis (MS) patients. Objectives: The aim of the study was to confirm CI detection based on I/DMT BOLD activation in a larger cohort of MS patients. The role of T2 lesion volume (LV) and Expanded Disability Status Scale (EDSS) in magnitude of BOLD signal was also sought. Methods: A total of 50 patients (EDSS mean (m) = 3.2, disease duration (DD) m = 12 years, and age m = 40 years) underwent the Minimal Assessment of Cognitive Function in Multiple Sclerosis (MACFIMS) and I/DMT. Working memory activation (WMa) represents BOLD signal during DMT minus signal during IMT. CI was based on MACFIMS. Results: A total of 10 MSNI, 30 MSCI, and 4 borderline patients were included in the analyses. Analysis of variance (ANOVA) showed MSNI had significantly greater WMa than MSCI, in the left prefrontal cortex and left supplementary motor area (p = 0.032). Regression analysis showed significant inverse correlations between WMa and T2 LV/EDSS in similar areas (p = 0.005, 0.004, respectively). Conclusion: I/DMT-based BOLD activation detects CI in MS. Larger studies are needed to confirm these findings.