TY - GEN
T1 - Efficacy of using mean arterial blood pressure sequence for linear modeling of cerebral autoregulation
AU - Gehalot, Piyush
AU - Zhang, Rong
AU - Mathew, Aby
AU - Behbehani, Khosrow
PY - 2005
Y1 - 2005
N2 - Linear autoregressive (ARX) models are often used to describe the dynamic cerebral autoregulation in humans by relating cerebral blood flow velocity (CBFV) to beat-to-beat mean arterial blood pressure (MABP). For linear model estimation it is required that the input be persistently exciting. This study aimed to establish if the MABP is adequately persistently exciting for estimating to yield a linear model. Using ARX models with MABP as input and CBFV as output, linear models for 11 healthy normal subjects in supine position were obtained. The order of the models was allowed to vary between 1 to 10. For each subject, the model with the least mean squared error (MSE) value was selected, called Ma. Ma was then treated as the unknown model of the cerebral autoregulation to be estimated. Ma was separately subjected to the measured MABP as well as a pseudo random binary sequence (PRBS) to estimate two ARX models for it. The resulting estimates of Ma with the lowest MSE were selected as Me1 and Me2, respectively. With the measured MABP as input, the MSE values between the resulting output of M e1 and Me2 and the measured CBFV were calculated. These MSE values were compared to the MSE value previously obtained for Ma to determine if Me1 that was obtained using MABP can estimate CBFV with the same level of accuracy as Me2. This analysis was carried out both with the traditional 6 minutes data and was repeated by dividing the 6 minutes of data into four 1.5 minute sections, a total of 5 comparisons. The analysis showed that the computed MSE values for Ma, Me1 and M e2 were the same for each subject, irrespective of the duration of the data set used for the study. However, the orders of the models were not identical. For each of the three models the average MSE value for 11 subjects was 0.0200 for 6 minutes, 0.0235 for first 1.5 minute and 0.0263, 0.0278 and 0.0255 for second, third and fourth 1.5 minutes, respectively. Results suggest that 1.5 minutes of MABP sequence is adequate as input for estimating linear models of cerebral autoregulation.
AB - Linear autoregressive (ARX) models are often used to describe the dynamic cerebral autoregulation in humans by relating cerebral blood flow velocity (CBFV) to beat-to-beat mean arterial blood pressure (MABP). For linear model estimation it is required that the input be persistently exciting. This study aimed to establish if the MABP is adequately persistently exciting for estimating to yield a linear model. Using ARX models with MABP as input and CBFV as output, linear models for 11 healthy normal subjects in supine position were obtained. The order of the models was allowed to vary between 1 to 10. For each subject, the model with the least mean squared error (MSE) value was selected, called Ma. Ma was then treated as the unknown model of the cerebral autoregulation to be estimated. Ma was separately subjected to the measured MABP as well as a pseudo random binary sequence (PRBS) to estimate two ARX models for it. The resulting estimates of Ma with the lowest MSE were selected as Me1 and Me2, respectively. With the measured MABP as input, the MSE values between the resulting output of M e1 and Me2 and the measured CBFV were calculated. These MSE values were compared to the MSE value previously obtained for Ma to determine if Me1 that was obtained using MABP can estimate CBFV with the same level of accuracy as Me2. This analysis was carried out both with the traditional 6 minutes data and was repeated by dividing the 6 minutes of data into four 1.5 minute sections, a total of 5 comparisons. The analysis showed that the computed MSE values for Ma, Me1 and M e2 were the same for each subject, irrespective of the duration of the data set used for the study. However, the orders of the models were not identical. For each of the three models the average MSE value for 11 subjects was 0.0200 for 6 minutes, 0.0235 for first 1.5 minute and 0.0263, 0.0278 and 0.0255 for second, third and fourth 1.5 minutes, respectively. Results suggest that 1.5 minutes of MABP sequence is adequate as input for estimating linear models of cerebral autoregulation.
KW - ARX estimation
KW - Cerebral autoregulation
KW - Linear models
KW - Mean arterial blood pressure
UR - http://www.scopus.com/inward/record.url?scp=33846923793&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33846923793&partnerID=8YFLogxK
U2 - 10.1109/iembs.2005.1615760
DO - 10.1109/iembs.2005.1615760
M3 - Conference contribution
AN - SCOPUS:33846923793
SN - 0780387406
SN - 9780780387409
T3 - Annual International Conference of the IEEE Engineering in Medicine and Biology - Proceedings
SP - 5619
EP - 5622
BT - Proceedings of the 2005 27th Annual International Conference of the Engineering in Medicine and Biology Society, IEEE-EMBS 2005
PB - Institute of Electrical and Electronics Engineers Inc.
T2 - 2005 27th Annual International Conference of the Engineering in Medicine and Biology Society, IEEE-EMBS 2005
Y2 - 1 September 2005 through 4 September 2005
ER -