26 Phase Coherence Between Cardiovascular Oscillations in Malaria …
417
for real-time techniques for noninvasive malaria diagnosis an active area of research.
Based on our findings, a cut-off was established in line with differences in cardiovascular dynamics between malarias and healthy non-malaria, with a classification
accuracy of 88% (Table 26.2). Early cases of non-febrile malaria, where subjects had
started taking antimalarial or antipyretic drugs, were also considered as malaria in
this study, due to its similarity to febrile malaria in terms of blood properties: the
cytoadherence and microvasculature characteristics, including the increased stiffness
of the membrane of an infected erythrocytes and their abnormal tendency to stick to
endothelial cells lining the blood vessels. Consistent with this similarity, no significant differences were found in mean blood flow recorded from the extremities of
the body, or in respiratory rate, between febrile malaria and non-febrile malaria. In
addition, there was no significant difference in the blood flow or IHF dynamics in
any of the six frequency intervals between febrile and non-febrile malaria. On the
contrary, febrile malaria and non-febrile malaria differed mainly in terms of their
mean skin temperature and IHF.
In summary, this study demonstrated changes in both the average values and
oscillatory components of cardiovascular dynamics in malaria, in comparison with
healthy non-malaria subjects, providing a better understanding of the cardiovascular
physiology of malaria. A diagnostic cut-off for the early distinction between malaria
and non-malaria is presented, based on differences observed in both IHF, blood flow
and IHF dynamics, extracted through wavelet based analysis and nonlinear mode
decomposition. Whilst this approach looks promising, as it has potential for identifying malaria noninvasively within a short period of time, future studies are needed
to compare the physical findings in malaria with those in other febrile infections.
Acknowledgements We are grateful to the participants who generously volunteered to be measured in this project. The work was supported by the Engineering and Physical Sciences Research
Council (UK) Grant No. EP/M006298/1, the Tertiary Education Trust Fund (Nigeria), the Petroleum
Technology Development Fund (Nigeria) under Grant No. PTDF/ED/OSS/PHD/1120/17, and the
Joy Welch Educational Charitable Trust (UK).
References
1. Y.A. Abdulhameed, Nonlinear cardiovascular oscillatory dynamics in malaria. Ph.D. thesis,
Lancaster University (2020)
2. O.O. Aina, C.O. Agomo, Y.A. Olukosi, H.I. Okoh, B.A. Iwalokun, K.N. Egbuna, A.B. Orok,
O. Ajibaye, V.N. Enya, S.K. Akindele et al., Malariometric survey of Ibeshe community in
Ikorodu, Lagos state: dry season. Malar. Res. Treat. 2013 (2013)
3. A. Bandrivskyy, A. Bernjak, P.V.E. McClintock, A. Stefanovska, Wavelet phase coherence
analysis: Application to skin temperature and blood flow. Cardiovasc. Engin. 4(1), 89–93
(2004)
4. S.C. Beards, G.M. Joynt, J. Lipman, Hæmodynamic and oxygen transport response during
exchange transfusion for severe falciparum malaria. Postgrad. Med. J. 70(829), 801–804 (1994)
5. A. Bernjak, J. Cui, S. Iwase, T. Mano, A. Stefanovska, D.L. Eckberg, Human sympathetic
outflows to skin and muscle target organs fluctuate concordantly over a wide range of timevarying frequencies. J. Physiol. (London) 590(2), 363–375 (2012)
417
for real-time techniques for noninvasive malaria diagnosis an active area of research.
Based on our findings, a cut-off was established in line with differences in cardiovascular dynamics between malarias and healthy non-malaria, with a classification
accuracy of 88% (Table 26.2). Early cases of non-febrile malaria, where subjects had
started taking antimalarial or antipyretic drugs, were also considered as malaria in
this study, due to its similarity to febrile malaria in terms of blood properties: the
cytoadherence and microvasculature characteristics, including the increased stiffness
of the membrane of an infected erythrocytes and their abnormal tendency to stick to
endothelial cells lining the blood vessels. Consistent with this similarity, no significant differences were found in mean blood flow recorded from the extremities of
the body, or in respiratory rate, between febrile malaria and non-febrile malaria. In
addition, there was no significant difference in the blood flow or IHF dynamics in
any of the six frequency intervals between febrile and non-febrile malaria. On the
contrary, febrile malaria and non-febrile malaria differed mainly in terms of their
mean skin temperature and IHF.
In summary, this study demonstrated changes in both the average values and
oscillatory components of cardiovascular dynamics in malaria, in comparison with
healthy non-malaria subjects, providing a better understanding of the cardiovascular
physiology of malaria. A diagnostic cut-off for the early distinction between malaria
and non-malaria is presented, based on differences observed in both IHF, blood flow
and IHF dynamics, extracted through wavelet based analysis and nonlinear mode
decomposition. Whilst this approach looks promising, as it has potential for identifying malaria noninvasively within a short period of time, future studies are needed
to compare the physical findings in malaria with those in other febrile infections.
Acknowledgements We are grateful to the participants who generously volunteered to be measured in this project. The work was supported by the Engineering and Physical Sciences Research
Council (UK) Grant No. EP/M006298/1, the Tertiary Education Trust Fund (Nigeria), the Petroleum
Technology Development Fund (Nigeria) under Grant No. PTDF/ED/OSS/PHD/1120/17, and the
Joy Welch Educational Charitable Trust (UK).
References
1. Y.A. Abdulhameed, Nonlinear cardiovascular oscillatory dynamics in malaria. Ph.D. thesis,
Lancaster University (2020)
2. O.O. Aina, C.O. Agomo, Y.A. Olukosi, H.I. Okoh, B.A. Iwalokun, K.N. Egbuna, A.B. Orok,
O. Ajibaye, V.N. Enya, S.K. Akindele et al., Malariometric survey of Ibeshe community in
Ikorodu, Lagos state: dry season. Malar. Res. Treat. 2013 (2013)
3. A. Bandrivskyy, A. Bernjak, P.V.E. McClintock, A. Stefanovska, Wavelet phase coherence
analysis: Application to skin temperature and blood flow. Cardiovasc. Engin. 4(1), 89–93
(2004)
4. S.C. Beards, G.M. Joynt, J. Lipman, Hæmodynamic and oxygen transport response during
exchange transfusion for severe falciparum malaria. Postgrad. Med. J. 70(829), 801–804 (1994)
5. A. Bernjak, J. Cui, S. Iwase, T. Mano, A. Stefanovska, D.L. Eckberg, Human sympathetic
outflows to skin and muscle target organs fluctuate concordantly over a wide range of timevarying frequencies. J. Physiol. (London) 590(2), 363–375 (2012)