The Rat as a Potential Animal Model for Dysphonia. (23rd August 2013)

• Record Type: Journal Article
• Authors: Zolkind, Paul A.; Last, Jordan; Shuminov, Oktay; Silverman, Joshua B.; Sundaram, Krishnamurthi; Stewart, Mark; Kollmar, Richard
• Is Part Of: Otolaryngology--head and neck surgery. Volume 149(2013)Supplement 2
• Page Start: P210
• Page End: P210
• Publication Date: 2013-08-23
• Subjects: Head -- Surgery -- Periodicals; Neck -- Surgery -- Periodicals; Otolaryngology -- Periodicals; 617.51
• DOI: 10.1177/0194599813496044a206
• Languages: English
• ISSNs: 0194-5998

Abstract

Abstract : Objectives: Dysphonia, or hoarseness, is the primary complaint of patients with unilateral vocal‐fold paralysis due to damage to the recurrent laryngeal nerve (RLN). Animal models for RLN injury exist but are generally limited to histological, endoscopic, and electrophysiological approaches. As a step towards using the rat as a model system for dysphonia, we have characterized ultrasonic vocalizations in healthy adult animals. Methods: Ultrasonic vocalizations were evoked individually from adult male Sprague‐Dawley rats by manual stroking on two different days one month apart. The vocalizations were visualized and recorded by using an ultrasound microphone attached to a computer. Parameters such as duration, amplitude, pitch, and entropy were measured for each vocalization as well as the preceding silent period with Sound Analysis Pro 2011 software. Results: For a total of 980 vocalizations from five rats, the following parameter values (mean ± standard deviation) were obtained: duration, 14 ± 10 msec; amplitude, 13 ± 6 relative units; pitch, 57 ± 7 kHz; and entropy, ‐3.9 ± 1.0. No differences were noticed among animals or days. However, the vocalizations were distinct from the background noise during the preceding silent period: amplitude, ‐1.4 ± 2.9 relative units; pitch, 42 ± 6 kHz; and entropy, ‐1.2 ± 0.9. Virtually none of the vocalizations were located in the 20‐kHz band associated with distress. Conclusions: Ultrasound vocalizations can be recorded from adult rats easily and reliably. The features of the vocalizations are consistent among individuals and over time. Experiments with RLN‐lesioned animals are now underway.