Objectives
Supraglottic structures can act as a sound source in both pathological and healthy
voice production. In pathological voices it may form part of the voice production, be a
presenting symptom, or may constitute a substitutional phonation. A recent taxonomy
proposes 4 dimensions, including distinct phenotyping, vibrational strategies, level of
control, and number of vibrating sources to distinguish supraglottic sound sources in
healthy voices, yet differences and similarities between healthy and unhealthy
involvement of supraglottic sound sources remain unclear.
Methods
A case series of 6 patients identified as involving vibrations in supraglottic structures
during routine clinical practice were included and discussed according to the
supraglottic sound source taxonomy dimensions. Patients were assessed using
stroboscopy, electroglottography, and acoustic measures during sustained vowel tasks
and continuous speech tasks at a comfortable pitch.
Results
Beyond supplementary and substitutional strategies for involving supraglottic sound
sources, pathological voices may also recruit supraglottic structures in a compensatory
manner allowing for improved vocal fold entrainment. The compensatory strategy
comes in two forms, one in cases where the pathology necessitating supraglottic
sound source involvement is irreversible (e.g. following extensive cordectomy) and one
where the pathology is reversible (e.g. following medialisation laryngoplasty procedure
for unilateral paralysis).
Accordingly, supraglottic vibrations can be separated into an integrative taxonomy that
outlines supplementary, compensatory, or substitutional functions of vibration with
further dimensions related to intentional or unintentional level of control, mono-source
or multi-source number of supraglottic sound sources, and distinction of the involved
supraglottic phenotypes. Previously identified distinct phenotypes were determined in
the studied population according to the anatomical vibration source, including
ventricular fold vibrations, arytenoid against arytenoid vibrations, cuneiform/arytenoid
against epiglottis vibrations, and vibrations in the aryepiglottic free edge along with
large vocal fold amplitude of vibrations. The study proposes hypotheses as to
differences between healthy and pathological use of supraglottic vibrations along
dimensions of laryngeal, respiratory, and resonatory technical ability and control.
Conclusion
The study presents the first integrative systematic supraglottic vibration taxonomy
including phenotyping for both pathological and healthy voice. Diagnostic, surgical,
rehabilitative, and pedagogical relevance is discussed.