Usefulness of mismatch negativity for simple cognitive dysfunction assessment in multiple sclerosis patients

• Published in: Multiple sclerosis Vol. 14; p. S257
• Main Authors: Hainque, E, Daniel, F, Lebrun, N, Etard, O, Defer, G
• Format: Journal Article
• Language: English
• Published: 01-09-2008
• ISSN: 1352-4585

Background: Cognitive disturbances are an important and frequent complain of multiple sclerosis (MS) patients and must be evaluated for different reasons (impact on quality of life, socio-professional activities...). Classical cognitive evaluations are relatively time consuming and not easily repeatable and would be suggested to patients after a first short and simple screening. The usefulness of Event-related potential (ERPs) especially the P300 component was often reported in the literature but to our knowledge only one study 0ung et al. 2006) explored correlations between pre-attention and mismatch negativity (MMN) component. Objective: To estimate the usefulness of MMN for detecting early cognitive dysfunction in MS. Methods: This work allows the inclusion of 30 MS patients and 30 healthy subjects with normal auditory evoked potentials. All of them will be assessed for attention and memory using computerized attention tests, Paced Auditory Serial Attention Test (PASAT), Digit Spans and California Verbal Learning Task (CVLT) and ERPs elicited using a passive oddball paradigm in auditory modality. N1 and P2 components will be recorded and MMN component will be calculated as the potential difference between deviant and standard stimuli. Amplitudes, latencies and areas in both groups will be compared using Kruskal-Wallis and Chi2 tests with a significant level at p<0.05. Results: Today 24 MS patients and 30 healthy subjects were included. Preliminary analysis of ERPs on 18 patients (age: 47 plus or minus 12,1, disease duration: 9,5 plus or minus 7,29, Expanded Disability Status Scale (EDSS): 3,31 plus or minus 2,87) and 29 healthy subjects (age: 35,9 plus or minus 9,95) showed that MMN were detected in 96,6% of healthy subjects against 77,8% of patients (p<0.05). The comparison of N1 and P2 components in both groups didn't show any significant difference. In addition, MS patients showed significant reduced MMN amplitudes whatever age, EDSS or disease durations. Conclusions: MMN amplitude reduction suggests pre-attention dysfunctions and could represent an objective index of cognitive dysfunction. Complete data for the whole group of patients and correlations between cognitive scores and ERPs components will be presented during the meeting.