Panerai RB et al Intersubject TFA coherence analysis in studies of CA clean version R1.pdf (727.79 kB)
Download file

Inter-subject analysis of transfer function coherence in studies of dynamic cerebral autoregulation

Download (727.79 kB)
journal contribution
posted on 22.02.2019, 12:10 by RB Panerai, VJ Haunton, JS Minhas, TG Robinson
Objective: The gain and phase of the arterial blood pressure (BP)-cerebral blood flow velocity (CBFV) relationship, assessed by transfer function analysis (TFA), are widely used dynamic cerebral autoregulation (CA) metrics, but their reliability depend on the statistical significance of the magnitude squared coherence (MSC) function. We tested a new approach, based on inter-subject data, to estimate the confidence limits of MSC. Approach: Five minute beat-to-beat time series of mean arterial BP (MAP, Finometer) and CBFV (transcranial Doppler) were used for intra-subject (MAP and CBFV from same subject) and inter-subject (BP and CBFV swapped between subjects) estimates of MSC. The 95% confidence limit of MSC was obtained by non-parametric methods for the cases of single frequency harmonics in the range [0.02-0.50 Hz], and also from the mean value of all possible frequency intervals in this range. Main results: Intra-subject estimates of MSC were obtained from 100 healthy subjects (48 female, age range: 21-82 years old) allowing calculation of 9,900 inter-subject estimates, with 95% confidence limits in excellent agreement with classical values derived from surrogate random data. Confidence limits of MSC, derived from mean values, decreased asymptotically to around 0.16 with the increasing number of harmonics averaged. Significance: Replacing estimates of MSC at a single frequency harmonic by the mean calculated over the range [0.02-0.30 Hz] could lead to more robust studies of dynamic CA with greater acceptance of recordings, an important consideration in clinical studies where measurements tend to be more susceptible to noise and artefacts. .

Funding

Supported by EPSRC grant EP/K041207/1.

History

Citation

Physiol Meas, 2018, 39 (12)

Author affiliation

/Organisation/COLLEGE OF LIFE SCIENCES/School of Medicine/Department of Cardiovascular Sciences

Version

AM (Accepted Manuscript)

Published in

Physiol Meas

Publisher

IOP Publishing

eissn

1361-6579

Acceptance date

15/11/2018

Copyright date

2018

Publisher version

https://iopscience.iop.org/article/10.1088/1361-6579/aaf160/meta

Notes

The file associated with this record is under embargo until 12 months after publication, in accordance with the publisher's self-archiving policy. The full text may be available through the publisher links provided above.

Language

en