Biomarkers
offer significant potential for diagnosis and treatment
of complex disorders such as asthma, epilepsy, autism, Parkinson’s,
and Alzheimer’s, as well as many others. In many cases, however,
there is little consensus on what an appropriate biomarker would be.
Consequently, biomarker identification is an important area of research
for which a link between physiological measurements and the presence/absence
or severity of a disorder can be established. This is nontrivial due
to both the curse of dimensionality and because the number of measurements
per trial often exceeds the number of trial participants. Overfitting
of potential biomarkers is thus a significant problem that needs to
be addressed. This paper highlights similarities between the biomarker
identification problem and the parameter estimation problem, more
specifically the regularization used for avoiding overfitting. Parallels
between the underlying methodologies are pointed out and opportunities
for advancing the systems’ concepts are discussed. Finally,
a candidate biomarker for diagnosis of autism spectrum disorder is
identified from a data set comprising metabolic measurements from
four separate clinical trials to illustrate the procedure outlined
in this work.