Neural Correlates of Alerting and Orienting Impairment in Multiple Sclerosis Patients

Abstract

BackgroundA 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.ResultsAfter 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).ConclusionsBehavioral 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.

Event-Related Potentials for the Study of Cognition

“…These results were also in accordance with neuropsychological scores from atentional tests [26] (see Figure 4). …”

“…Our group has referred in some studies to alterations of the amplitude (decrease) and latency (increase) of P3 in multiple sclerosis [79,80] (see Figure 8). Comi et al [81] has shown that a longer latency in P3 may be related to demyelination.…”

Contingent Negative Variation Is Associated with Cognitive Dysfunction and Secondary Progressive Disease Course in Multiple Sclerosis

“…However, our RRMS patients had a longer disease course and slightly lower EDSS score than the patients in their study, suggesting the presence of differences between the patient characteristics and that some of our RRMS patients might be similar to the BMS patients in the study of Gonzalez-Rosa et al 29 Furthermore, other limiting factors such as methodological differences (differences in stimulus paradigms, interstimulus durations, or in the methods used to analyze waveforms), and a small number of patients in the latter study may account for the discrepant findings. In another recent study, Vázquez-Marrufo et al 30 reported that CNV amplitudes were significantly lower in RRMS patients than in controls in central and frontal electrodes during an Attention Network Test using central and spatial cueing; they found a trend toward decreased amplitude that did not reach to statistical significance when a cue was not used. They interpreted these results as impairment in the central cueing mechanism and also a worse orienting response.…”

Emotionserkennung, Theory of Mind und Empathie bei Multipler Sklerose

“…Obwohl die Genauigkeit sich nicht zwischen Patienten und gesunden Kontrollen unterschied, waren die Patienten langsamer. Diese beobachtbare Verlangsamung dürfte jedoch kein Defizite in der Emotionserkennung sein, sondern eine generelle Verlangsamung der Arbeitsgeschwindigkeit, ein häufiges Symptom bei MS [87], oder eine altersbezogene Verlangsamung [88], da die gesunden Kontrollen signifikant jünger als die Patienten waren.…”

“…Überdies leiden MS Patienten häufig an kognitiven Symptomen [30,87,144] und signifikante Korrelationen wurden zwischen der sozialkognitiven Leistungsfähigkeit und verschiedenen nicht-sozialkognitiven Fähigkeiten gefunden, wie Aufmerksamkeit, Arbeitsgeschwindigkeit, Arbeitsgedächtnis, Lernen und exekutiven Funktionen [5,69,76,84,86,100,101,[104][105][106][107]. Die Untersuchung nicht sozialkognitiver Fähigkeiten in zukünftigen Studien könnte ihr Verhältnis zur sozialen Kognition besser verständlich machen.…”