Asymptomatic Progressive Multifocal Leukoencephalopathy Associated with Natalizumab: Diagnostic Precision with MR Imaging.

PURPOSE: To determine diagnostic precision with magnetic resonance (MR) imaging of the brain, the most predictive MR imaging features, and the added value of comparison with previous data for the diagnosis of asymptomatic progressive multifocal leukoencephalopathy (PML) associated with natalizumab (NTZ). MATERIALS AND METHODS: This retrospective study was approved by the institutional review board, and written informed consent was obtained. Eleven consecutive patients with multiple sclerosis (MS) who had received a definitive diagnosis of asymptomatic NTZ-associated PML (NTZ PML, 18 brain lesions) underwent 3-T MR imaging. The control group included 40 patients with MS but without PML who were treated with NTZ. Three readers independently performed blinded analysis of MR images. First, the readers were asked to detect NTZ PML lesions without comparing current images with previously obtained MR imaging data by evaluating MR images for the following features: U fiber and/or cortex involvement, lesion signal intensity and borders, and occurrence of punctate lesions. Second, they reassessed NTZ PML lesions with all the previous MR imaging data available. Diagnostic precision with MR imaging was assessed with and without comparison with previously obtained data. Logistic regression analyses were performed to identify the association of MR imaging features with NTZ PML. RESULTS: Overall interobserver agreement was good (κ = 0.76; 95% confidence interval [CI]: 0.71, 0.81). Hyperintensity on diffusion-weighted images and involvement of U fibers were the most predictive features (odds ratio, 33.7; 95% CI: 4.9, 229.7 [P < .0001] and odds ratio, 8.7; 95% CI: 1.2, 61.4 [P = .03], respectively), while punctate lesions were exclusively observed in patients with NTZ PML. Comparison with previous MR imaging data improved specificity of MR imaging for the detection of NTZ PML lesions (from 88% to 100%, P = .05). CONCLUSION: Recognition of the most predictive imaging features and comparison with previous MR imaging data may facilitate the detection of asymptomatic NTZ PML.

Does fatigue complaint reflect memory impairment in multiple sclerosis?

Background and Purpose. Fatigue and memory impairment are common symptoms in multiple sclerosis (MS) and both may interact with cognition. This can contribute to making a complaint misrepresentative of the objective disorder. We sought to determine whether fatigue complaint in MS reflects memory impairment and investigated whether patients' subjective fatigue is associated with memory complaint. Methods. Fifty MS patients complaining of fatigue underwent subjective assessment of fatigue and memory complaint measured using self-assessment scales. Cognitive functions were assessed using a battery of neuropsychological tests, including a test of verbal episodic memory, the selective reminding test (SRT). Correlations were studied between subjective fatigue, memory complaint, and performance in verbal episodic memory. Results. Depression score, psychotropic and/or antiepileptic drug use, Expanded Disability Status Scale (EDSS) score, and MS form were confounding factors. After adjusting for these confounding factors, neither fatigue complaint nor memory complaint was correlated with SRT performance. Subjective fatigue was significantly associated with memory complaint. Conclusion. Although complaint of fatigue in MS was correlated with memory complaint, subjective fatigue was not the expression of memory impairment.