Quantitative laryngeal electromyography parameters may correlate with improved outcomes following botulinum toxin injection for spasmodic dysphonia

Abstract

Background Despite use of qualitative laryngeal electromyography (LEMG) guided botulinum toxin A (BoNT‐A) injection for treatment of adductor spasmodic dysphonia (AdSD), unsatisfactory injections and complete “misses” remain problematic. We aimed to determine if the quantitative LEMG measure of number of small segments (NSS) correlates with voice outcomes following (BoNT‐A injection for AdSD. Methods Automated quantitative LEMG analysis was performed during electromyography (EMG) ‐guided BoNT‐A injection into the thyroarytenoid‐lateral cricoarytenoid muscle complex for treatment of AdSD. Pre‐injection phonatory NSS values were correlated with clinical voice outcomes and patient reported injection results. Results Quantitative LEMG measures were obtained for 45 AdSD patients (28 female, mean age 60.8 ± 12.8 years) during EMG‐guided BoNT‐A injection. Mean sampled NSS during phonation immediately prior to BoNT‐A injection was 524 ± 323 (range: 2–904). Mean follow up was 36.5 ± 9.4 days; one patient was lost to follow‐up. In comparison to their previous BoNT‐A injection, the current injection was rated as worse, same, and better by 13 (29.5%), 25 (56.8%), and 6 (13.6%) patients, respectively. All 4 (9.1%) patients with NSS < 200 rated their BoNT‐A injection result as worse than previous, and change in Voice Handicap Index‐10 (VHI‐10) scores were worse or without change. Conclusions Aiming for an NSS value greater than 200 during phonation prior to BoNT‐A toxin injection for AdSD may reduce unfavorable voice outcomes.

Exploring Patient's Preference of Patient‐Reported Outcome Measures in Laryngeal Movement Disorders

“…21 Patient recall bias is a potential confounder, because they have seen the VHI-10 previously or if they participated in previous research studies. 28 These patients do complete the VHI-10 (among other PROMs) at their initial, multi-disciplinary evaluation. However, patients receiving BoNT-A injections do not routinely complete any PROMs at subsequent visits for their BoNT-A injections.…”

“…Finally, the most preferred PROM was the VHI‐10, which is acknowledged as a PROM created and validated by study team members and used routinely in clinical care 21 . Patient recall bias is a potential confounder, because they have seen the VHI‐10 previously or if they participated in previous research studies 28 . These patients do complete the VHI‐10 (among other PROMs) at their initial, multi‐disciplinary evaluation.…”