Hemodynamics in neurodegenerative diseases

Contribution of small vessel disease to vascular cognitive impairment and dementia is the most studied issue in last years. The prevalence of dementia is rising over the coming decades and the interest in the role of brain vessels in neurodegeneration is increasing as well. Cerebral vasomotor reactivity (CVMR) is the basis for blood flow regulation in response to changes in its metabolic status and is it has been shown to be impaired particularly in Alzheimer's disease (AD), small vessels disease. The vascular damage, both cause and effect of the amyloid deposition in the brain and in the vessel wall in some of the degenerative diseases, alter the wall compliance, thus affecting the cerebral hemodynamic function. We investigated hemodynamic characteristics (Mean Flow Velocity, Pulsatility Index and Breath Holding Index) by Trans Cranial Doppler in patients hospitalized for the evaluation of neurodegenerative diseases such as Parkinson's disease (PD), fronto temporal dementia (FTD), mild cognitive impairment (MCI), Lewy body disease (LBD) and vascular dementia (VAD). Demographic characteristics, vascular risk factors, presence of focal neurological signs MRI, cerebrospinal fluid proteins dosages (tau, phospho‐tau and β‐amyloid) were collected. BHI was clearly impaired in AD patients with respect to other groups of patients and positively correlated with β‐amyloid levels. No correlation between hemodynamic parameters and cerebrospinal fluid proteins was found in the other groups of patients. CVMR impairment at baseline was correlated with the disease progression in AD. We found an association between CVMR impairment and β‐amyloid cerebrospinal fluid levels in amyloid related degenerative disease. These results reinforce the awareness that alterations of endogenous amyloid processing are directly involved in the neurodegenerative mechanisms as well as the impairment of CVMR. In “amyloid” neurodegenerative diseases, CVMR could be a functional alternative marker of state and stage disease in AD patients.