Interplay of Cerebral Autoregulation and Neurovascular Coupling evaluated by Functional Transcranial Doppler in different orthostatic conditions

• Tipo: Artigo em Revista Científica Internacional
• Data: 2007

Autores

Elsa Azevedo (Autor) FMUP; Rosengarten B (Autor) Outra; Rosa Santos (Autor) Outra; João Freitas (Autor) FMUP; Kaps M (Autor) Outra

Revista

Título: Journal of Neurology

Vol. 254 Nº 2

Páginas: 236-241

ISSN: 0340-5354

Editora: Springer Nature

Indexação

Pubmed / Medline

Classificação Científica

CORDIS: Ciências da Saúde > Neurociências > Neurologia

Outras Informações

Resumo (PT): Background Adequate cerebral blood flow (CBF) is mainly governed by neurovascular coupling (NC) which adapts local CBF to underlying cortical activity, and cerebral autoregulation (CA) that tends to maintain constant CBF despite changes in arterial blood pressure (BP). Since it was suggested that resistance vessels play an important role on both mechanisms, we investigated their regulative interplay by performing a functional transcranial Doppler (f-TCD) test under different orthostatic conditions. Methods Fifteen healthy volunteers performed a visual readind test stimulation task after stabilized in sitting, supine and upright position on a tilt table. Simultaneously, BP and heart rate (HR) were recordrd by a photoplethysmographic method and CBF velocity was measured with TCD in left posterior cerebral artery, and, as a reference, also in right middle cerebral artery. Evoked flow velocity (FV) responses were evaluated by a control system approach for systolic and diastolic data. Paramaters studied were baseline FV with eyes closed, stable FV under stimulation (gain), oscilatory feature (natural frequency) and damping (attenuation) of the control system model, rate time, and also systolic and diastolic BP and HR. ANOVA test was used for comparing the values of variables in different postural settings, inferring statistical significance at a p < 0,05 level. Results Although there was a significant variation on the different orthostatic conditions in systolic (p = 0,027) and diastolic (p = 0,001) BP and HR (p = 0,0001), there was no significant change in the basal or evoked CBF velocities. Conclusions An intact CA compensates the different orthostatic conditions completely thus allowing an independent rwegulation of NC according to the metabolic needs of cortical stimulation

Idioma: Português

Tipo (Avaliação Docente): Científica