title: Neural correlates of alerting and orienting impairment in multiple sclerosis patients.
abstract: BACKGROUND
  A considerable percentage of multiple sclerosis patients have attentional impairment, but understanding its neurophysiological basis remains a challenge. The Attention Network Test allows 3 attentional networks to be studied. Previous behavioural studies using this test have shown that the alerting network is impaired in multiple sclerosis. The aim of this study was to identify neurophysiological indexes of the attention impairment in relapsing-remitting multiple sclerosis patients using this test.
  
  
  RESULTS
  After general slowing had been removed in patients group to isolate the effects of each condition, some behavioral differences between them were obtained. About Contingent Negative Variation, a statistically significant decrement were found in the amplitude for Central and Spatial Cue Conditions for patient group (p<0.05). ANOVAs showed for the patient group a significant latency delay for P1 and N1 components (p<0.05) and a decrease of P3 amplitude for congruent and incongruent stimuli (p<0.01). With regard to correlation analysis, PASAT-3s and SDMT showed significant correlations with behavioral measures of the Attention Network Test (p<0.01) and an ERP parameter (CNV amplitude).
  
  
  CONCLUSIONS
  Behavioral data are highly correlated with the neuropsychological scores and show that the alerting and orienting mechanisms in the patient group were impaired. Reduced amplitude for the Contingent Negative Variation in the patient group suggests that this component could be a physiological marker related to the alerting and orienting impairment in relapsing-remitting multiple sclerosis. P1 and N1 delayed latencies are evidence of the demyelination process that causes impairment in the first steps of the visual sensory processing. Lastly, P3 amplitude shows a general decrease for the pathological group probably indexing a more central impairment. These results suggest that the Attention Network Test give evidence of multiple levels of attention impairment, which could help in the assessment and treatment of relapsing-remitting multiple sclerosis patients.
authors.affiliation: Experimental Psychology Department, Faculty of Psychology, University of Seville, Seville, Spain.
authors.forename: Manuel
authors.initials: M
authors.lastname: Vázquez-Marrufo
authors.affiliation: Experimental Psychology Department, Faculty of Psychology, University of Seville, Seville, Spain.
authors.forename: Alejandro
authors.initials: A
authors.lastname: Galvao-Carmona
authors.affiliation: Laboratory for Clinical Neuroscience, Centre of Biomedical Technology (CTB), Technical University of Madrid (UPM), Madrid, Spain.
authors.forename: Javier J
authors.initials: JJ
authors.lastname: González-Rosa
authors.affiliation: Experimental Psychology Department, Faculty of Psychology, University of Seville, Seville, Spain.
authors.forename: Antonio R
authors.initials: AR
authors.lastname: Hidalgo-Muñoz
authors.affiliation: Multiple Sclerosis Unit, Virgen Macarena Hospital, Seville, Spain.
authors.forename: Mónica
authors.initials: M
authors.lastname: Borges
authors.affiliation: Multiple Sclerosis Unit, Virgen Macarena Hospital, Seville, Spain.
authors.forename: Juan Luis
authors.initials: JL
authors.lastname: Ruiz-Peña
authors.affiliation: Multiple Sclerosis Unit, Virgen Macarena Hospital, Seville, Spain.
authors.forename: Guillermo
authors.initials: G
authors.lastname: Izquierdo
mesh_terms: D000328:Adult; D001288:Attention; D005071:Evoked Potentials; D005260:Female; D006801:Humans; D008297:Male; D009103:Multiple Sclerosis / Q000503:physiopathology*; D009483:Neuropsychological Tests; D009949:Orientation; D012008:Recurrence