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Titolo:
Predicting cerebral blood flow response to orthostatic stress from restingdynamics: effects of healthy aging
Autore:
Narayanan, K; Collins, JJ; Hamner, J; Mukai, S; Lipsitz, LA;
Indirizzi:
Hebrew Rehabil Ctr Aged, Res & Training Inst, Boston, MA 02131 USA Hebrew Rehabil Ctr Aged Boston MA USA 02131 ng Inst, Boston, MA 02131 USA Boston Univ, Ctr BioDynam, Boston, MA 02215 USA Boston Univ Boston MA USA02215 Univ, Ctr BioDynam, Boston, MA 02215 USA Boston Univ, Dept Biomed Engn, Boston, MA 02215 USA Boston Univ Boston MAUSA 02215 v, Dept Biomed Engn, Boston, MA 02215 USA Beth Israel Deaconess Med Ctr, Gerontol Div, Boston, MA 02215 USA Beth Israel Deaconess Med Ctr Boston MA USA 02215 v, Boston, MA 02215 USA Harvard Univ, Sch Med, Div Aging, Boston, MA 02215 USA Harvard Univ Boston MA USA 02215 Sch Med, Div Aging, Boston, MA 02215 USA
Titolo Testata:
AMERICAN JOURNAL OF PHYSIOLOGY-REGULATORY INTEGRATIVE AND COMPARATIVE PHYSIOLOGY
fascicolo: 3, volume: 281, anno: 2001,
pagine: R716 - R722
SICI:
0363-6119(200109)281:3<R716:PCBFRT>2.0.ZU;2-R
Fonte:
ISI
Lingua:
ENG
Soggetto:
FREQUENCY-DOMAIN ANALYSIS; SPONTANEOUS FLUCTUATIONS; PRESSURE; AUTOREGULATION; VELOCITY; HUMANS; RESISTANCE;
Keywords:
autoregulation; transfer function; hypotension; pulsatility; vascular stiffness;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
21
Recensione:
Indirizzi per estratti:
Indirizzo: Lipsitz, LA Hebrew Rehabil Ctr Aged, Res & Training Inst, 1200 Ctr St, Boston, MA 02131 USA Hebrew Rehabil Ctr Aged 1200 Ctr St Boston MA USA 02131 31 USA
Citazione:
K. Narayanan et al., "Predicting cerebral blood flow response to orthostatic stress from restingdynamics: effects of healthy aging", AM J P-REG, 281(3), 2001, pp. R716-R722

Abstract

The transfer function relating arterial pressure (AP) to cerebral blood flow velocity (CBFV) during resting conditions has been used to predict the CBFV response to hypotension. We hypothesized that this approach could predict the CBFV response to posture change in elderly individuals if impaired autoregulation allowed changes in AP to be passively transferred to CBFV. AP(Finapres) and CBFV (middle cerebral artery transcranial Doppler) were measured in 10 healthy young (age 24 +/- 1 yr) and 10 healthy elderly (age 72 /- 3 yr) subjects during 5 min of quiet sitting and 1 min of active standing while breathing was paced at 0.25 Hz. Transfer functions between AP and CBFV changes during sitting were estimated from each fall waveform in both low-frequency (LF; 0.05-0.2 Hz) and heartbeat-frequency (HBF; 0.7-1.4 Hz) ranges. The impulse-response function was used to compute changes in CBFV during posture change. The LF transfer function did not predict orthostatic changes in CBFV in either group, suggesting normal cerebral autoregulation. In the HBF range, the prediction was high in elderly (R = 0.65 +/- 0.23) but not young subjects (R = 0.19 +/- 0.35; P < 0.003, young vs. elderly). Thus rapidly acting regulatory mechanisms that reduce the transmission of beat-to-beat changes in AP to CBFV may be engaged during posture change in young but not elderly subjects.

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Documento generato il 25/11/20 alle ore 07:19:40