title: Cerebrovascular reactivity in degenerative and vascular dementia: a transcranial Doppler study.
abstract: BACKGROUND
  An impairment of cerebral microvessels is reported both in normal ageing and in senescence-associated processes, as well as in Alzheimer's disease (AD) and vascular dementia (VaD). The aim of this study was to explore cerebral hemodynamics by transcranial Doppler in VaD and AD, compared with age-matched control subjects.
  
  
  METHODS
  Transcranial Doppler was investigated in all patients in the basal condition. Cerebral vasoreactivity to hyper- and hypocapnia was evaluated with CO2 mixture inhalation followed by hyperventilation.
  
  
  RESULTS
  We studied 60 AD and 58 VaD patients and 62 nondemented controls. Both AD and VaD subjects showed lower flow velocities (FV) and higher pulsatility indices (PI) as compared with controls. Lower total vasomotor reactivity and lower response to hypercapnia were observed in the AD and VaD groups as compared with controls. AD and VaD patients did not show significant differences in FV, PI values or cerebral vasoreactivity.
  
  
  CONCLUSIONS
  Reduced FV and increased PI with a significant vasoreactivity reduction in VaD and AD patients are indicators of impairment of cerebral microvasculature circulation in both diseases. The identification of vascular function impairment in all kinds of dementia could be of help in identifying patients who would thus benefit more from specific therapeutic approaches.
authors.affiliation: Department of Neurological Sciences, University of Rome, La Sapienza, Rome, Italy. edoardo.vicenzini@uniroma1.it
authors.forename: Edoardo
authors.initials: E
authors.lastname: Vicenzini
authors.forename: Maria Chiara
authors.initials: MC
authors.lastname: Ricciardi
authors.forename: Marta
authors.initials: M
authors.lastname: Altieri
authors.forename: Francesco
authors.initials: F
authors.lastname: Puccinelli
authors.forename: Novella
authors.initials: N
authors.lastname: Bonaffini
authors.forename: Vittorio
authors.initials: V
authors.lastname: Di Piero
authors.forename: Gian Luigi
authors.initials: GL
authors.lastname: Lenzi
mesh_terms: D000368:Aged; D000544:Alzheimer Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D000704:Analysis of Variance; D002560:Cerebrovascular Circulation; D015140:Dementia, Vascular / Q000000981:diagnostic imaging* / Q000503:physiopathology; D005260:Female; D007839:Functional Laterality; D006801:Humans; D008297:Male; D012307:Risk Factors; D017585:Ultrasonography, Doppler, Transcranial