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Comprehensive Bifurcation Analysis
in a Neuromuscularly-Controlled
In Vivo Canine Larynx

Juergen Neubauer and Dinesh K. Chhetri

Simon Levin MCMSC @ ASU
Head and Neck Surgery @ UCLA

ICVPB Salt Lake City, 2014

Supported by NIH RO1 DC011300


Complete description of the vocal fold dynamics in an in vivo model


Neuro-muscular control of F0, loudness, voice quality, pathologies

Dynamic equivalence of larynges of different species

Model validation

Bifurcation analysis in in vivo dog experiment

Phonation onset, a Hopf bifurcation during air flow ramp

Observed bifurcations

Hopf bifurcation

Subharmonic bifurcation

Frequency jumps

Secondary Hopf bifurcation

Sudden transition to chaotic vibrations

Bifurcations induced by neuromuscular control

Computer-controlled, automated pulse train sequences (1500 ms)

Bifurcations induced by air flow ramp

Computer-controlled linear flow ramp -- Increasing subglottal pressure

Left-right asymmetric stimulation

right SLN versus left SLN, constant mid RLN

Agonist-antagonist imbalance

TA versus trunk RLN (LCA/IA), constant No SLN

F0 for SLN-TA-trunk RLN manipulation

chest and falsetto-like clusters at phonation onset

Tight experimental control. Fast and automated setup and experiments.

In vivo dog model
Extensive control and
recording infrastructure

Computer-controlled, automated sequences of nerve stimulation pulse trains (8 nerves)

Rapid setup

Binary search for threshold of nerve excitation (one threshold in 10 seconds)

Fast experiments: New recording every 5 seconds

High speed video: prephonatory posturing, vocal fold vibration

5:20 min for 64 stimulation conditions

Replication possible!

First take ---- Second take

Left recurrent nerve paralysis: both SLN versus right RLN

Complete bifurcation behavior provides a metric to compare dynamical systems

Metric to measure dynamical equivalence of different larynes: human, dog, bats, etc

Metric to evaluate intervention procedures for voice pathologies: implants, arytenoid adduction, injection