About the PhD thesis

Over the past thirty years, the methods for evaluating vestibular
function have developed immensely, and multiple new diagnostic tools
have entered clinical practice. Assessment of the cervical vestibular
evoked myogenic potentials (cVEMP) is one of these that has become
part of the standard test battery in most Danish vestibular clinics,
where it is used, among other purposes, to guide cochlear implantation
side selection in adults across Scandinavia.

Despite this central role, key assumptions behind clinical use of
cVEMP have not been sufficiently examined. In particular, it is
commonly assumed that cVEMP responses are both reliable and
selectively reflect saccular function. This PhD thesis investigates and
challenges both assumptions across three studies.

The first two studies report findings from a test-retest experiment
conducted in a clinical cohort of cochlear implant candidates. Results
showed substantial inconsistency in cVEMP outcomes between two
test sessions, indicating that single-session cVEMP assessments in
adult cochlear implant candidates are unlikely to provide reliable
information for individual-level decisions. More broadly, these findings
suggest that the reliability of cVEMP assessments in a specific clinical
context cannot be presumed without empirical support.

The third study presents a critical review of the scientific literature
related to the origin of the cVEMP response. This study finds that the
available evidence does not support a confident and specific attribution
to any single vestibular organ. In particular, the widespread
assumption that cVEMP responses selectively reflect saccular
function appears insufficiently substantiated by the collective evidence
base.

Al together, the results of this thesis suggest that cVEMP assessments
may be less robust than commonly assumed, both in terms of
measurement stability and physiological specificity. This raises
important questions about the basis for widespread clinical application
and highlights the need for a more cautious interpretation of their
outcomes.