Cerebral blood flow velocity changes to visual stimuli in patients with multiple sclerosis

We assessed the blood flow velocity (BFv) changes to visual stimuli using transcranial Doppler (TCD) in patients with multiple sclerosis (MS) during an exacerbation period by means of vasoneuronal coupling. Eighty-four patients (19 men, 75 women) and 45 healthy subjects (14 men, 31 women) were studied. Both posterior cerebral arteries (PCAs) were simultaneously monitored by TCD sonography during 10 cycles of 20 s eyes open observing complex moving visual images, and 20 s eyes closed at the end of every cycle. TCD sonography was performed at least at the first 2 days of exacerbation. Mean cerebral BFv throughout the procedure (p=0.003, p=0.001; right and left sides, respectively), velocity at rest (p=0.001, p<0.001), and velocity at stimulation (p=0.021, p=0.01) on both PCAs were significantly lower in patients than controls. However, BFv changes to visual stimulation on both sides were significantly higher in patients (p=0.01, p=0.031) compared to controls. There were negative correlations between P100 latencies and relative blood flow changes on both sides, but it was not significant on the left side. These results may suggest that patients with MS during exacerbation have more reactive vessels in the posterior circulation and! or more reactive neurons in the occipital cortex.