Induced unilateral vocal fold paralysis and recovery rapidly modulate brain areas related to phonatory behavior: a case study.
BACKGROUND
Peripheral and behavioral effects of voice disorders are well documented in the literature; yet, there is little information regarding the central neural biomarkers and mechanisms underlying these disorders. Understanding the details of brain function changes in disordered voice production is a critical factor for developing better treatment strategies that result in more robust patient outcomes.


OBJECTIVE
To examine a model of induced unilateral vocal fold paralysis (iUVFP) to demonstrate and characterize the form of activity changes within central mappings of the larynx to the induced paralysis. The induced paralysis model allowed the participant to serve as his or her own control when comparing baseline results of normal voice with results during the paralysis and subsequent recovery.


METHODS
Prospective, case-study design.


METHODS
Functional magnetic resonance imaging was used to examine central laryngeal representations during three time points: pre-iUVFP, during iUVFP, and postrecovery from iUVFP. iUVFP was induced using a lidocaine with epinephrine nerve block unilaterally. Percent changes in blood oxygenation level-dependent (BOLD) activity served as the dependent variable.


RESULTS
Results indicated an overall reduced activity level in sensorimotor, subcortical, and cerebellar regions during paralysis. Recovery from paralysis led to augmented responses, particularly in sensory, association, and cerebellar zones.


CONCLUSIONS
The decrease in activity during iUVFP and the significantly increased activity during the recovery phase likely represent immediate neuroplastic events occurring within minutes of nerve blockade. Recovery-related changes in the BOLD response are hypothesized to be associated with a recalibration of the system after return of normal laryngeal function.
Department of Rehabilitation Sciences, College of Health Sciences, University of Kentucky, Lexington, Kentucky, USA.
Ashwini
A
Joshi
Yang
Y
Jiang
Joseph C
JC
Stemple
Sanford M
SM
Archer
Richard D
RD
Andreatta
D000368:Aged; D000779:Anesthetics, Local / Q000008:administration & dosage; D001696:Biomechanical Phenomena; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping / Q000379:methods; D025461:Feedback, Physiological; D006801:Humans; D007823:Laryngeal Nerves / Q000503:physiopathology*; D007828:Laryngoscopy; D007830:Larynx / Q000503:physiopathology*; D008012:Lidocaine / Q000008:administration & dosage; D008279:Magnetic Resonance Imaging; D008297:Male; D009407:Nerve Block; D009434:Neural Pathways / Q000503:physiopathology; D009473:Neuronal Plasticity; D010699:Phonation; D011446:Prospective Studies; D020127:Recovery of Function; D013997:Time Factors; D014741:Video Recording; D014826:Vocal Cord Paralysis / Q000139:chemically induced / Q000503:physiopathology*; D014833:Voice Quality
D000779:Anesthetics, Local; D008012:Lidocaine