We have recently reported that cognitive impairment occurred in 53.7% of patients with probable MS (evaluated within a mean of one month of the onset of new neurological symptoms). Verbal abilities and attention span were most frequently affected (43.3 and 41.8% respectively). An additional study demonstrated that MS patients within the first 5 years of disease onset presented attentional dysfunction only when the cognitive load of the attention task was high and when controlled information processing was required. This high rate of attention impairment found in MS patients early in the disease process may have a significant impact on quality of life and activities of daily living as attention is one of the most fundamental cognitive functions essential for normal daily activities and a requisite step towards conscious perception. Consequently, we suggest investigating whether treatment with Ritalin (methylphenidate) has an effect on patients.