Bachground and Aim: The involvement of central auditory nervous system is relatively prevalent in patients suffering from multiple sclerosis (MS). To understand cortex function and to investigate cognitive impairment, event related potential is considered as a valuable tool. This study was aimed to compare the amplitude and latency of the event related potentials of P300 in MS patients and normal individuals.
Methods: This cross sectional study was conducted on 21 MS patients and 27 normal cases aged 18-50 years. Auditory P300 was recorded with oddball paradigm, using two tone burst stimuli (1000 and 2000).
Results: In MS patients, mean latencies were significantly longer (p<0.001) and mean amplitude were significantly lower (p<0.001), in both males and females. Sex did not affect P300 latencies and amplitudes significantly.
Conclusion: MS patients show some degree of event related potential abnormalities. Combination of auditory P300 and neuropsychological tests may be useful to investigate cognitive impairment in MS patients.

Background and Aim: Multiple sclerosis (MS) is characterized with inflammation, demyelization and gliosis. It may be relapsing, remitting, or progressive. Cognitive impairment is relatively prevalent in patients wit h multiple sclerosis and as duration of disease is longer as cognition impairment is more. To understand the cognitive impairment, event related potential can be considered as a valuable tool. This study aimed to investigate the influence of duration of disease and expanded disability status scale (EDSS) on the amplitude and latency of the event related potentials of P300 in patients with multiple sclerosis.

Methods: In this cross-sectional and non-intervention study, 21 patients with multiple sclerosis with mean age of 27.8 with SD 7.1 years (between 18 to 50 years) were enrolled. The patients were selected randomly. The correlation of P300 event-related potential and oddball paradigm was assessed, using two 1000 and 2000 Hz tone burst stimulus.

Results: There was a significant correlation between the latency of P300 wave and duration of disease and expanded disability status scale (p < 0.05) there was high correlation in both electrode sites (r>0.50). The correlation of amplitude of P300 and duration of disease and expanded disability status scale was not significant (p>0.05).

Conclusion: Significant correlation between the latency of P300 and the duration of multiple sclerosis and expanded disability status scale can be a sign of central nervous system changes. Besides, there is a relation between physical disability and cognitive impairments.