Multiple sclerosis (MS) is a chronic autoimmune disease of the central nervous system (CNS) within different degrees of disability [1]. It affects over 2 million people worldwide [2].
Cortical affection in MS is associated with disease progression and cognitive impairment [3].
MS symptoms are inconsistent. They include fatigue, abnormal sensations such as paresthesia , muscle stiffness, tremor, numbness, dizziness, and even paralysis (usually in the legs) [5]. MS patients may be more likely to have hearing loss.
Event-related potentials (P300) showed abnormalities in MS patients suggesting impairment in cortical regions and dysfunction in cognitive processing, memory, attention, and auditory discrimination [7]. The mismatch negativity (MMN) is one of the cortical event-related evoked potentials. The MMN measure enables one to gain insights into the neurobiological substrate of central auditory processing, particularly into auditory memory, as well as into various attention-related processes controlling the access of auditory input to conscious perception and higher forms of memory [9-11]. About 40% to 70% of MS patients have varying degrees of cognitive impairment [12]. A study by Chinnadurai et al. [13] showed that cognitive fatigue is widely prevalent in MS and implies that MS may be a multifaceted entity. As the MS can affect cognitive abilities, it is assumed that the pre-attentive auditory responses could be affected in those patients.
Thus, the purpose of this study is to evaluate and measure the MMN test results as regards amplitude and latency in MS patients and to compare the results with average age and gender-matched control group < /p>