Botulinum toxin treatment for adductor spasmodic dysphonia with EMG and endoscopic guidance

Background & Objective: Spasmodic dysphonia is idiopathic focal dystonia characterized by irregular contractions or postural disorders of the laryngeal muscles, resulting in abnormal speech. Progress in laryngoscopy has resulted in development of a precise technique of botulinum toxin (BTX) injection into the thyroarytenoid muscle under visual control. Methods: We used EMG and endoscopic guidance for BTX injection in adductor spasmodic dysphonia (AdSD). Results: Thirty eight patients with AdSD were injected with BTX in 84 treatment sessions. The voice handicap index (VHI) level of the patients were: severe (73.8%), moderate (26.2%) and mild (none). The average VHI score was 74.6 points. After 8 weeks of BTX treatment, the VHI level was: Severe (3.6%), moderate (10.8%), and mild (85.7%). The average VHI score was 27.7 points. The average values of jitter, shimmer and harmonic to noice ratio (HNR) improved statistically (p < 0.05). The incidence of side effects were: breathiness (17.9%), choking (15.5%); hoarseness (8.5%), and dysphagia (4.7%). Conclusions: Injection of BTX under both EMG and laryngoscopy guidance for treatment of adductor spasmodic dysphonia is an effective and safe treatment.

Neurogenic Laryngeal Disorders

The larynx is critical to performing complex tasks of airway protection, phonation, respiration, and deglutition. Various focal and systemic neurologic disorders impact the larynx, causing deficits that lead to dysfunction in voice, speech, breathing, and swallowing function. The most common hyperfunctional neurolaryngeal disorders include spasmodic dysphonia (laryngeal dystonia), essential vocal tremor, and muscle tension dysphonia. Some hypofunctional neurolaryngeal disorders include parkinsonian disorders, neuromuscular junction diseases, and myopathies. A multidisciplinary approach involving evaluation by neurologists, voice-trained otolaryngologists and speech-language pathologists is often key to diagnosis and treatment of these challenging and sometimes lifelong disorders. Botulinum toxin injection into the laryngeal musculature is currently the gold-standard treatment for both spasmodic dysphonia and vocal tremor. However, much research is being conducted to advance less invasive and more definitive medical and surgical treatment interventions. This review contains 3 figures, 11 videos, 6 tables and 29 references Keywords: laryngeal neurophysiology, laryngeal dystonia, adductor spasmodic dysphonia, abductor spasmodic dysphonia, essential vocal tremor, hyperfunctional voice disorders, hypofunctional voice disorders, botulinum toxin injection

Artificial Intelligence Application for Vocal Fold Disease Prediction Through Voice Recognition: Development and Usability Study (Preprint)

BACKGROUND Dysphonia influences the quality of life by interfering with communication. However, laryngoscopic examination is expensive and not readily accessible in primary care units. Experienced laryngologists are required to achieve an accurate diagnosis. OBJECTIVE This study sought to detect various vocal fold diseases through pathological voice recognition using artificial intelligence. METHODS We collected 29 normal voice samples and 527 samples of individuals with voice disorders, including vocal atrophy (n=210), unilateral vocal paralysis (n=43), organic vocal fold lesions (n=244), and adductor spasmodic dysphonia (n=30). The 556 samples were divided into two sets: 440 samples as the training set and 116 samples as the testing set. A convolutional neural network approach was applied to train the model and findings were compared with human specialists. RESULTS The convolutional neural network model achieved a sensitivity of 0.70, a specificity of 0.90, and an overall accuracy of 65.5% for distinguishing normal voice, vocal atrophy, unilateral vocal paralysis, organic vocal fold lesions, and adductor spasmodic dysphonia. Compared to human specialists, the overall accuracy was 58.6% and 49.1% for the two laryngologists, and 38.8% and 34.5% for the two general ear, nose, and throat doctors. CONCLUSIONS We developed an artificial intelligence-based screening tool for common vocal fold diseases, which possessed high specificity after training with our Mandarin pathological voice database. This approach has clinical potential to use artificial intelligence for general vocal fold disease screening via voice and includes a quick survey during a general health examination. It can be applied in telemedicine for areas that lack laryngoscopic abilities in primary care units.

Alternating Unilateral Versus Bilateral Injections of Botulinum Toxin for the Treatment of Adductor Spasmodic Dysphonia

Objective This study aimed to compare the long-term efficacy, durability, and dose and interval stability between alternating unilateral and bilateral injections of botulinum neurotoxin type A for the treatment of adductor spasmodic dysphonia. Study Design Retrospective cohort study. Setting Academic tertiary medical center. Methods A total of 137 patients (105 alternating unilateral and 32 bilateral injections) who were administered ≥5 injections of botulinum neurotoxin type A were included in this study. The mean dosage change, dose adjustment ratio (number of dose increases/total number of injections), and stability of treatment responses were compared between the alternating unilateral and bilateral injection groups. Results Long-term changes in the mean dosages for alternating unilateral (mean ± SD, –0.010 ± 0.048 IU) and bilateral (–0.042 ± 0.142 IU) injections did not differ between groups ( P = .225), suggesting that both methods follow a decreasing dosing trend over time. The dose adjustment ratio also did not differ between groups ( P = .077), although a longer average treatment interval ( P < .001) and duration of hoarse voice ( P = .045) were found in the bilateral injection group. The proportion of stable patients who did not increase injection dose and had regular follow-up did not differ between the groups. Conclusion Both alternating unilateral and bilateral injection methods showed a long-term decreasing dosing trend, with comparable levels of efficacy, durability, and stability for treating adductor spasmodic dysphonia. Our findings indicate that alternating unilateral injections can be routinely performed with fewer side effects, albeit at shorter treatment intervals, than bilateral injections.

An Auditory-Perceptual and Pupillometric Study of Vocal Strain and Listening Effort in Adductor Spasmodic Dysphonia

This study evaluated ratings of vocal strain and perceived listening effort by normal hearing participants while listening to speech samples produced by talkers with adductor spasmodic dysphonia (AdSD). In addition, objective listening effort was measured through concurrent pupillometry to determine whether listening to disordered voices changed arousal as a result of emotional state or cognitive load. Recordings of the second sentence of the “Rainbow Passage” produced by talkers with varying degrees of AdSD served as speech stimuli. Twenty naïve young adult listeners perceptually evaluated these stimuli on the dimensions of vocal strain and listening effort using two separate visual analogue scales. While making the auditory-perceptual judgments, listeners’ pupil characteristics were objectively measured in synchrony with the presentation of each voice stimulus. Data analyses revealed moderate-to-high inter- and intra-rater reliability. A significant positive correlation was found between the ratings of vocal strain and listening effort. In addition, listeners displayed greater peak pupil dilation (PPD) when listening to more strained and effortful voice samples. Findings from this study suggest that when combined with an auditory-perceptual task, non-volitional physiologic changes in pupil response may serve as an indicator of listening and cognitive effort or arousal.