Table 3.
Flow velocities, cerebrovascular resistance, and cerebrovascular reserve capacity.
| Reference | Aim of study | Type of study | n MCI | n AD | n VD | N Controls | Parameters | Outcome |
|---|---|---|---|---|---|---|---|---|
| Asil and Uzuner (2005) | Assessment of CVRC in the occipital lobe in AD | Cross-sectional | 15 | 12 | 9 | Flow velocities in PCAs during eyes opened and eyes closed | No significant difference neither in flow velocities at rest nor at stimuli in three groups; decreased reactivity in VD at stimulus | |
| Bar et al. (2007) | CVRC in AD compared to VD and healthy controls, reactivity after ACHEI treatment | Cross-sectional Longitudinal | 17 | 17 | 20 | Flow velocities in MCA at rest and after CO2 inhalation in AD and VD repeated after 5 weeks of galantamine treatment | CVRC in MCA decreased in AD and VD in comparison to healthy controls, better CVRC after galantamine treatment on both AD and VD | |
| Caamano et al. (1993) | Comparison of flow velocities in MCA and BA in AD, VD and controls | Cross-sectional | 12 | 12 | 12 | Flow velocities in right and left MCA and BA | Decreased values in demented patients | |
| Claassen et al. (2009) | Assessment of cerebral hemodynamics impairment in early stage AD | Cross-sectional | 9 | 8 | Flow velocities in MCA, blood pressure, cerebrovascular resistance index | Significantly reduced flow velocities and increased resistance in AD | ||
| Ghorbani et al. (2010) | Assessment of the effect of Donepezil on cerebral blood flow velocity in AD patients | Longitudinal | 11 | Flow velocities in PCA and MCA at baseline, after 4 weeks of donepezil 5 mg and after another 4 weeks of donepezil 10 mg | Increase in PSV and MFV in MCA, and MFV and EDV in PCA after 10 mg treatment | |||
| Gucuyener et al. (2010) | CVRC in PCAs in AD compared to depressive pseudo-dementia | Cross-sectional | 11 | 13 | 10 | Flow velocities in both PCAs simultaneously; in steady state and after a visual stimulus | Lower flow velocities at rest and after stimulus in both AD and depressive pseudodementia then controls. CVRC impaired in AD, not in depressive pseudodementia | |
| Lee et al. (2007) | Assessment of CVRC in AD | Cross-sectional | 17 | 17 | Flow velocities and PI in MCA bilaterally in normal conditions and after 5 min of rebreathing | No difference in baseline MFV and PI between subjects and controls, CVRC significantly decreased on both sides in AD | ||
| Likitjaroen et al. (2009) | Comparison of CVRC in AD and VD | Cross-sectional | 9 | 9 | Flow velocities in MCA in normal conditions and after 1000 mg acetazolamide i.v. | Non-significantly better CVRC in AD than VD | ||
| Matteis et al. (1998) | Comparison of CVRC in AD and VD | Cross-sectional | 10 | 10 | 20 | Flow velocities in MCA during apnea, hand movement and verbal and design discrimination | CVRC to apnea lower in VD; hand movement – contralateral increase in flow in AD and controls, bilateral in VD; bilateral response on cognitive stimuli in AD and VD, corresponding side response in controls | |
| Provinciali et al. (1990) | Comparison of CVRC in AD, VD and controls | Cross-sectional | 20 | 20 | 25 | Flow velocities in MCA at rest, after hyperventilation, apnea and 5 min air rebreathing | Higher PI, lower velocity decrease in hyperventilation in both dementias; rest flow velocities and response to hypercapnia lower in VD than AD or controls | |
| Ries et al. (1993) | Utility of TCD in differentiation of AD and multi-infarct dementia | Cross-sectional | 24 | 17 | 64 | PSV and EDV in all large intracranial vessels bilaterally, pulse curve in MCA | No difference in PSV in all three groups, difference in MFV, EDV and effective pulsatility range in VD compared to AD or controls | |
| Roher et al. (2006) | Comparison of mean flow velocities and PI in intracranial arteries in AD and controls | Cross-sectional | 25 | 30 | Flow velocities in 16 different segments of circle of Willis | Higher PIs in AD, non-significantly lower mean flow velocities in AD | ||
| Roher et al. (2011) | Utility of TCD in diagnosing and preventing AD | Cross-sectional | 11 | 42 | 50 | Flow velocities in 16 different segments of circle of Willis | Significant difference in MFV and PI in left siphon, left ICA and right distal MCA between AD and controls | |
| Rosengarten et al. (2006) | Influence of ACHEI treatment on vasoregulation in AD | Longitudinal | 8 | 16 | Flow velocities in PCA and MCA in rest and at stimulation (text reading) at baseline, after 4 weeks of donepezil 5 mg and after another 4 weeks of donepezil 10 mg | Decrease in attenuation parameter after 10 mg in AD = dose dependent resolution of functional vascular deficit | ||
| Rosengarten et al. (2007) | Comparison of activation-flow coupling in AD, VD and controls | Cross-sectional | 15 | 10 | 15 | Flow velocities in PCA and MCA in rest and at stimulation (text reading) | Lower increase in PSV in VD | |
| Ruitenberg et al. (2005) | Correlation of flow velocities with cognitive decline and hippocampal atrophy | Cross-sectional | 13 | 1 | 1718 | Flow velocities in MCAs at rest and after 5 min of 5% CO2 | Greater PSV, MFV, EDV – less likely dementia and bigger hippocampus and amygdala No association of CVRC and presence of dementia | |
| Silvestrini et al. (2006) | Influence of cerebral hemodynamics alterations on the evolution of cognitive impairment | Longitudinal | 53 | Flow velocities in MCAs at rest and after breath-holding, time 0 and 12 month, during this time donepezil 5 mg daily for 3 month, then 10 mg daily | Positive correlation of neuropsychological tests changes with BHI, age and DM | |||
| Silvestrini et al. (2009), Stefani et al. (2009) | Comparison of cerebral hemodynamics in AD and controls | Cross-sectional | 40 | 40 | Flow velocities, PI and BHI in MCA | Lower MFV, higher PI and lower BHI in MCA in AD than in controls | ||
| Sun et al. (2007) | Changes in cerebral flow velocities in MCI and controls | Cross-sectional | 30 | 30 | Flow velocities in MCA, ACA, BA | Decreased PSV, MFV and EDV in MCA and ACA in MCI compared to controls | ||
| Vicenzini et al. (2007) | Comparison of flow velocities, PI and CVRC in AD, VD, and controls | Cross-sectional | 60 | 58 | 62 | Flow velocities in MCA in normal conditions, after hyperventilation and CO2 inhalation | Lower MFV, higher PI and lower CVRC in AD and VD compared to controls | |
| Viticchi et al. (2012) | Association of carotid atherosclerosis and cerebrovascular reserve capacity with the risk of conversion from MCI to AD | Longitudinal | 117 | 21 | IMT and plaques in CCA, BHI in MCAs | Association of higher IMT and lower BHI with faster progression from MCI to dementia |
ACA, anterior cerebral artery; ACHEI, acetylcholine esterase inhibitor; AD, Alzheimer’s disease; BA, basilar artery; CAA, cerebral amyloid angiopathy; CVRC, cerebrovascular reserve capacity; DM, diabetes mellitus; EDV, end diastolic velocity; ICA, internal carotid artery; MCA, middle cerebral artery; MCI, mild cognitive impairment; MFV, mean flow velocity; PCA, posterior cerebral artery; PI, pulsatility index; PSV, peak systolic velocity; VD, vascular dementia.