Neurovascular coupling in patients with relapsing-remitting multiple sclerosis.

OBJECTIVES: Also to the inflammatory demyelinating lesions and degenerative process, altered cerebrovascular reactivity or neurovascular coupling (NVC) might be considered as playing another role in the pathogenesis of multiple sclerosis. The objective of this study is to assess the NVC of patients with relapsing-remitting multiple sclerosis (RRMS) during the acute exacerbation period.

PATIENTS AND METHODS: Four hundred fifty-eight patients with RRMS and 160 healthy subjects were screened for this study during the last 14 years. We performed transtemporal transcranial Doppler recordings from the P2-segments of both posterior cerebral arteries simultaneously during simple or complex visual stimulation. The NVC was defined as a relative increase of the blood flow velocities as a percentage change of the baseline values during visual stimulation.

RESULTS: The NVC to simple visual stimulation was significantly higher in the patients on both sides (37.2±13.5% and 36.0±14.8%; right and left side, respectively) from those of the controls (30.9±9.9% and 30.0±8.8%; right and left side, respectively) (p<0.01). Similarly, the NVC to complex visual stimulation was significantly higher in the patients (43.3±14.1% and 41.7±13.5%; right and left side, respectively) from those of the controls (38.6±14.2% and 37.6±14.1%; right and left side, respectively) (p<0.05).

CONCLUSION: Our results suggest that patients with RRMS during exacerbation period have more reactive neurovascular units in the occipital cortex.