HSC Section 6 Nov2016 Green Book

no clear consensus on how the diagnosis of VFP should be made in a given patient, and establishing one will be a challenge in the absence of tests or findings that are both reasonably specific and sensitive. Under these circum- stances, and given the frequency of asymmetric motion in the larynx, VFP is at risk of being diagnosed uncritically when no other obvious reason for a patient’s complaint is evident to the examiner. The survey format is subject to substantial recall bias and may give a false impression—likely falsely ele- vated—of the prevalence of paresis. This survey explic- itly did not distinguish between superior laryngeal nerve paresis and recurrent laryngeal nerve paresis, fre- quently separated in the literature, which may have caused surveyed physicians to assign less positive pre- dictive value to the signs under consideration than a more specific diagnosis. Reasons for the relatively rare use of LEMG were not investigated; these may have lit- tle to do with reservations regarding LEMG utility. Most importantly, the format of the survey necessarily does not well reflect the method of diagnosis of VFP in clini- cal practice. Such a diagnosis is rarely made on the basis of a single element of the evaluation or a single sign con- sidered by itself, but depends on an educated critical synthesis of the clinical evidence. Physicians may form an impression of the likelihood of a given diagnosis based on the history, which then informs the physical examination. In fact, the perceived likelihood of VFP based on symptoms and clinical evolution of the com- plaint may significantly affect the perceived positive pre- dictive value of a given laryngoscopic sign. Despite these limitations, this data may form a useful basis for further consideration of this challenging topic. CONCLUSION Surveyed laryngologists diagnose VFP frequently, relying principally on laryngeal strobovideolaryngoscopy to make the diagnosis. Among laryngoscopic signs, gross motion abnormalities were judged to have the highest positive predictive value for VFP, followed by abnormal- ities in the mucosal wave. Opinion varied most about the importance of these. LEMG was infrequently used to assess for VFP and was considered to have only moder- ate sensitivity for the diagnosis. Given the perceived clinical importance of VFP, directed investigation is nec- essary to refine diagnostic accuracy. BIBLIOGRAPHY 1. Sulica L., Vocal Fold Paresis: An Evolving Clinical Concept. Curr Otorhi- nolaryngol Rep 2013;1:158–162. 2. Koufman JA, Postma GN, Cummins MM, Blalock PD. Vocal fold paresis. Otolaryngol Head Neck Surg 2000;122:537–541. 3. Heman-Ackah YD, Barr A. Mild vocal fold paresis: understanding clinical presentation and electromyographic findings. J Voice 2006;20:269–281. 4. Rubin AD, Praneetvatakul V, Heman-Ackah Y, Moyer CA, Mandel S, Sataloff RT. Repetitive phonatory tasks for identifying vocal fold paresis. J Voice 2005;19:679–686. 5. Simpson CB, Cheung EJ, Jackson CJ. Vocal fold paresis: clinical and elec- trophysiologic features in a tertiary laryngology practice. J Voice 2009; 23:396–398. doi: 10.1016/j.jvoice.2007.10.011. 6. Belafsky PC, Postma GN, Reulbach TR, Holland BW, Koufman JA. Muscle tension dysphonia as a sign of underlying glottal insufficiency. Otolaryn- gol Head Neck Surg 2002;127:448–451.

TABLE III. Respondent Opinion Regarding Positive Predictive Value of Laryngoscopic Findings in VFP.

r

Examination finding

Average % Error

Slow/sluggish motion

74.9

3.0 22.8

Decreased VF adduction Decreased VF abduction

67.3 65.4

3.5 26.7 3.4 26.1

Decreased VF tone

61.1

3.5 26.3

Asymetric MW phase

60.2 60.1

4.1 31.3 4.0 30.8

Hemilarynx atrophy

Unilateral supraglottic hyperfunction

58.9

3.9 29.4

Glottic insufficiency

55.4 51.7

3.5 26.8 4.2 31.7

Asymetric MW amplitude

Asymetric MW frequency

48.6

4.0 30.6

VF height difference

43.5 42.9

3.8 28.6 3.6 27.8

Impairment of arytenoid rotation

Glottic axis deviation

41.3

3.8 29.3

Bilateral supraglottic hyperfunction

32.0 27.3

3.3 25

Presence of contact lesion

2.4 18.1

Presence of pseudocyst

22.3

2.8 21.4

MW 5 mucosal wave; VF 5 vocal fold; VFP 5 vocal fold paresis.

motion may be without clinical significance. Further, Roy et al. showed that laryngoscopic findings are not consistent from case to case, even in experimentally induced isolated unilateral superior laryngeal nerve palsy, a condition probably more homogeneous than that which presents clinically. 17 Respondents identified defi- cits of gross motion as having the highest positive pre- dictive value for VFP, despite reporting heavy reliance on stroboscopic examination in practice. This may reflect merely that stroboscopy is the standard clinical exami- nation for patients with a voice complaint in the special- ized practices of these physicians rather than the use of examination under stroboscopic light to identify VFP. Mucosal wave phase asymmetry was deemed the most useful stroboscopic sign, ranking only fifth in order of preference despite a report that identified it as correlat- ing very well with LEMG abnormalities. 7 Stroboscopic signs (phase, amplitude, and frequency) were also marked by the greatest divergence of opinion regarding significance, as reflected by the standard error. The few signs that have been the subject of systematic analysis in the literature, namely arytenoid rotation 8 and unilat- eral ventricular fold hyperfunction, 6 were not regarded as among the most useful. Reports have proposed a rela- tionship between contact lesions 9,10 and vocal fold pseu- docysts 11 and VFP. Despite this, respondents thought that the potential for VFP to be present when such lesions were identified was very low. Overall, this investigation reveals that paresis is fre- quently diagnosed and appears to be a significant clinical entity in laryngology practices. Diagnosis appears to be made on the basis of qualitative findings on laryngoscopy, principally deficits of gross vocal fold motion. Although stroboscopy is widely used, stroboscopic signs are not con- sidered the most reliable signs to identify VFP. Electro- physiologic testing is not used often. Plainly, there exists

Laryngoscope 125: April 2015

Wu and Sulica: Paresis Survey

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