Dynamic cerebral autoregulation is impaired in glaucoma

Objectives: Autonomic and endothelial dysfunction is likely to contribute to the pathophysiology of normal pressure glaucoma (NPG) and primary open angle glaucoma (POAG). Although there is evidence of vasomotor dysregulation with decreased peripheral and ocular blood flow, cerebral autoregulation (CA) has not yet been evaluated. The aim of our study was to assess dynamic CA in patients with NPG and POAG. Materials and Methods: In 10 NPG patients, 11 POAG patients and 11 controls, we assessed the response of cerebral blood flow velocity (CBFV) to oscillations in mean arterial pressure (MAP) induced by deep breathing at 0.1 Hz. CA was assessed from the autoregressive cross-spectral gain between 0.1 Hz oscillations in MAP and CBFV. Results: 0.1 Hz spectral powers of MAP did not differ between NPG, POAG and controls; 0.1 Hz CBFV power was higher in patients with NPG (5.68 +/- 1.2 cm(2) s(-2)) and POAG (6.79 +/- 2.1 cm(2) s(-2)) than in controls (2.40 +/- 0.4 cm(2) s(-2)). Furthermore, the MAP-CBFV gain was higher in NPG (2.44 +/- 0.5 arbitrary units [a.u.]) and POAG (1.99 +/- 0.2 a.u.) than in controls (1.21 +/- 0.1 a.u.). Conclusion: Enhanced transmission of oscillations in MAP onto CBFV in NPG and POAG indicates impaired cerebral autoregulation and might contribute to an increased risk of cerebrovascular disorders in these diseases. (C) 2004 Elsevier B.V. All rights reserved.