ISSN:
1573-9686
Keywords:
Sinusoidal
;
CSF
;
Cerebrospinal fluid
;
System identification
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
,
Technology
Notes:
Abstract Cerebrospinal fluid dynamics have been studied in the past by analyses of responses to bolus, constant rate or constant pressure inputs. In this study, we present a method for analyzing CSF pressure responses to sinusoidal variation in the infusion rate. Infusion of artificial CSF into the cisterna magna of adult rats was modulated sinusoidally between 0 and 30 μl/min. The resulting sinusoidal variation in intracranial pressure was recorded on a strip chart recorder simultaneously with the infusion rate signal. The two signals were analyzed for peak-to-peak variation, mean value, and phase shift for input frequencies in the range of 0.0015 to 0.01 Hz (0.00942 to 0.0628 radians/sec). The system was analyzed at each mean infusion rate as a parallel resistance and compliance with a first order linear model. The resistance to CSF outflow was determined as the change in mean steady-state pressure divided by the change in mean infusion rate. The compliance was then obtained from the frequency dependent phase shift between input and output using the first-order linear model. Resistance values were lower for higher average infusion rates consistent with our previous work, while compliance remained constant over the measured pressure range.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02364084
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