Effect of orthostatic hypotension on sustained attention in patients with autonomic failure.
BACKGROUND
Orthostatic hypotension has been associated with impaired cognitive function, but cognitive function during orthostatic hypotension has hardly been studied. We studied the effect of orthostatic hypotension, induced by head-up tilt (HUT), on sustained attention in patients with autonomic failure.


METHODS
We studied the sustained attention to response task (SART) in the supine position and during HUT in 10 patients with autonomic failure and 10 age-matched and sex-matched controls. To avoid syncope, the tilting angle was tailored to patients to reach a stable systolic blood pressure below 100 mm Hg. Controls were all tilted at an angle of 60°. Cerebral blood flow velocity, blood pressure and heart rate were measured continuously.


RESULTS
In patients, systolic blood pressure was 61.4 mm Hg lower during HUT than in the supine position (p<0.001). Patients did not make more SART errors during HUT than in the supine position (-1.3 errors, p=0.3). Controls made 2.3 fewer errors during SART in the HUT position compared to the supine position (p=0.020). SART performance led to an increase in systolic blood pressure (+11.8 mm Hg, p=0.018) and diastolic blood pressure (+5.8 mm Hg, p=0.017) during SART in the HUT position, as well as to a trend towards increased cerebral blood flow velocity (+3.8 m/s, p=0.101).


CONCLUSIONS
Orthostatic hypotension in patients with autonomic failure was not associated with impaired sustained attention. This might partly be explained by the observation that SART performance led to a blood pressure increase. Moreover, the upright position was associated with better performance in controls and, to a lesser extent, also in patients.
Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands Department of Gerontology and Geriatrics, Leiden University Medical Center, Leiden, The Netherlands.
P
P
van Vliet
Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands.
A D
AD
Hilt
Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands SEIN-Stichting Epilepsie Instellingen Nederland, Heemstede, The Netherlands.
R D
RD
Thijs
Department of Neurology, Leiden University Medical Center, Leiden, The Netherlands.
J G
JG
van Dijk
D000328:Adult; D001288:Attention; D001342:Autonomic Nervous System Diseases / Q000150:complications / Q000523:psychology*; D001794:Blood Pressure; D002560:Cerebrovascular Circulation; D005260:Female; D006339:Heart Rate; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D011930:Reaction Time; D012791:Shy-Drager Syndrome / Q000150:complications / Q000523:psychology*; D016683:Supine Position; D018667:Tilt-Table Test
AUTONOMIC; COGNITION