Distonía laríngea post COVID-19: reporte de dos casos y posible explicación fisiopatogénica

La distonía laríngea (DL), también conocida como disfonía espasmódica, es un desorden focal tarea-específico del movimiento, que afecta primariamente la producción de la voz. Los movimientos distónicos de las cuerdas vocales producen fenómenos diferentes, especialmente quiebres o interrupciones vocales y tensión en el tipo de distonía laríngea aductora (DLAD), e interrupciones y soplo o segmentos áfonos en el tipo abductor (DLAB). Más del 80% de pacientes sufren de DLAD o DEAD (disfonía espasmódica aductora). Dos pacientes de sexo femenino desarrollaron DL un mes después de haber contraído una infección del tracto respiratorio superior causada por COVID-19. Ambas presentaron distonía laríngea de tipo aductor. En el análisis acústico de la vocal /a/ sostenida se han observado quiebres o interrupciones, cambios frecuenciales y aperiodicidad. El rango de habla fue estudiado en ambas pacientes mediante el fonetograma, dando un resultado alterado. Posiblemente la inflamación de los nervios periféricos de la laringe, causada por COVID-19, produjo una alteración sensitiva con una respuesta mal adaptativa en estas pacientes con una base genética quizás predisponente. O la activación inmunológica, o la invasión del germen a través de la vía retrógrada alteraron las redes neuronales involucradas en la génesis de la DL.

Laryngeal dystonia (LD), also known as spasmodic dysphonia, is a task-specific focal movement disorder, primarily affecting voice production. The dystonic movements of the vocal folds result in a varied phenomenology, typically hard vocal breaks and strain in the adductor-type laryngeal dystonia (ADLD), and breathy breaks or aphonia in the abductor-type laryngeal dystonia (ABLD). More than 80% of patients have suffered from ADLD. Two female patients developed LD a month after presenting an upper respiratory tract infection by COVID-19. They had the adductor-type laryngeal dystonia. Through the acoustic study of the vowel /a/ breaks, frequency changes and aperiodicity were observed. Speech was studied using the phonetogram, and the range of speech is altered in both patients. The inflammation of the peripheral nerves of the larynx by COVID-19 produced a sensory alteration, with a maladaptive response in these patients, who perhaps had predisposing genetic basis, or the immunological activation or the invasion of the germ by retrograde pathway altered the neuronal networks involved in the genesis of LD.

Demographic and clinical characteristics of our patients diagnosed with laryngeal dystonia.

PURPOSE: Laryngeal dystonia (LD) is a focal dystonia affecting laryngeal musculature with no known etiology or cure. The present study evaluated the sociodemographic and clinical features of patients diagnosed with LD. MATERIALS AND METHODS: All patients diagnosed with LD at our University Hospital's Ear, Nose, and Throat Department between January 2017 and July 2023 were retrospectively analyzed. The study included 43 patients. RESULTS: Out of the 43 patients, 19 (44%) were male. At the time of diagnosis, the mean age of the patients was 35.1 years (ranging from 17 to 65 years). The mean elapsed time between the first symptom onset and the first diagnosis was 49.2 months (min. 4 months, max. 240 months). Of the participants, 94% had adductor-type LD. None of the patients had a family history of LD. Of the patients, 9 (20%) experienced a life-altering event or trauma just before the onset of symptoms. All patients who consumed alcohol reported symptom relief with alcohol intake. A total of 67.6% of patients stated that their symptoms were triggered by stress. All of our patients received at least one Botulinum toxin injection, with an average of 2.75 dosages per patient. CONCLUSION: The gender distribution was approximately equitable between males and females. There was a tendency for men to receive a diagnosis earlier than women following the manifestation of symptoms. A significant number of patients associate the emergence of their symptoms with a stressful event or traumatic experience. This study represents the initial investigation into the sociodemographic characteristics of patients within the Turkish population.

Intractable Aspiration Treated With Laryngectomy After SLAD-R Surgery: A Case Report.

A variety of surgical treatment options exist for adductor spasmodic dysphonia (ADSD) with selective adductor recurrent laryngeal nerve denervation and reinnervation (SLAD-R) being one of the more popular. We present a case of bilateral vocal fold paralysis (BVFP) for SLAD-R resulting in the need for total laryngectomy. We suggest BVFP is more common than reported and that we all must insure optimal long term follow up of our surgical patients. Laryngoscope, 2024.

Genetic Update and Treatment for Dystonia.

A neurological condition called dystonia results in abnormal, uncontrollable postures or movements because of sporadic or continuous muscular spasms. Several varieties of dystonia can impact people of all ages, leading to severe impairment and a decreased standard of living. The discovery of genes causing variations of single or mixed dystonia has improved our understanding of the disease's etiology. Genetic dystonias are linked to several genes, including pathogenic variations of VPS16, TOR1A, THAP1, GNAL, and ANO3. Diagnosis of dystonia is primarily based on clinical symptoms, which can be challenging due to overlapping symptoms with other neurological conditions, such as Parkinson's disease. This review aims to summarize recent advances in the genetic origins and management of focal dystonia.

Voice Therapy Outcome Post Transoral Thyroarytenoid Myoneurectomy in Adductor Spasmodic Dysphonia: A Case Series.

OBJECTIVES: Postoperative evaluations of patients, who undergo of transoral thyroarytenoid myoneurectomy using CO2 laser for the treatment of Adductor Spasmodic Dysphonia (ASD), reveal some residual laryngeal symptoms such as intermittent spasms, vocal effort, and stiffness in laryngeal muscles which can be identified on videolaryngo-stroboscopy (VLS) by patterns of Muscle Tension Dysphonia (MTD) and mucosal wave, and as deviations in acoustic perceptual measures. This study aims to document these vocal symptoms observed postoperatively, and most importantly highlight the need for voice therapy postoperatively and report the short-term vocal outcomes post-therapy. STUDY DESIGN: Retrospective case series. METHOD: The case series includes five patients, three females and two males, in the age range of 40 to 76years, who underwent transoral thyroarytenoid myoneurectomy using CO2 laser for severe ASD. The assessment protocol to document pretherapy (3-week postop) and post-therapy (after 1month of therapy) findings included VLS, Maximum Phonation Time (MPT), VHI-10 GRBAS, and Multi-Dimensional Voice Profile (MDVP) (acoustic voice analysis). Voice therapy regimen included Resonant Voice Therapy, semi-occluded vocal tract exercises, Vocal Function Exercises, and/or breath support exercises customized for individual symptoms. RESULT: MTD of varying grades, MPT less than 10 seconds, deviant F0, mild to moderate degrees of perceptually rough and predominantly strained voice were noted in the pretherapy evaluation. Following 1month of voice therapy, changes noted were a reduction in strained and rough voice quality and an increase in MPT and muscle tension. Improvement of almost all parameters of MDVP tended towards normative as compared to pretherapy including F0. CONCLUSION: Voice therapy initiated at the earliest recovery stage postoperatively does lead to positive short-term vocal outcomes in patients with severe ASD. It is necessary to have long-term follow-ups and aim for the maintenance of satisfactory vocal outcomes.

Tremor Makes a Difference: A Comparative Study of the Demographics and Treatment Outcomes in Patients With Adductor Spasmodic Dysphonia With or Without Vocal Tremor.

OBJECTIVES: This study aims to evaluate the demographic differences between those with adductor spasmodic dysphonia with vocal tremor (AdSD(+)VT) and those without vocal tremor (AdSD(-)VT) and to analyze their response to treatment with botulinum neurotoxin (BoNT-A). STUDY DESIGN: Retrospective cohort study. METHODS: A database review of all spasmodic dysphonia patients treated with BoNT from 1989 to 2018 at the Mayo Clinic in Arizona was performed. Only patients who had received ≥4 injections of BoNT-A for AdSD were included. Patients were divided into two cohorts: those with coexistent vocal tremor (AdSD(+)VT) and those without vocal tremor (AdSD(-)VT). RESULTS: The final analysis included 398 patients, with 210 AdSD(+)VT patients (53%) and 188 AdSD(-)VT patients (47%). The length of follow-up and median number of treatments were similar between cohorts. AdSD(+)VT patients were more likely to be female (P < 0.001), and older at onset (P < 0.001) and first injection (P < 0.001). The mean maximal benefit was significantly lower for the AdSD(+)VT cohort (P < 0.01), however the mean length of benefit was similar (P = 0.70). CONCLUSIONS: Demographic differences exist between AdSD(+)VT and AdSD(-)VT patients. AdSD(+)VT patients benefit from BoNT-A treatment; however, our analysis suggests that the degree of their maximal benefit is less than in those without VT.

Comparison of the efficacy and adverse effects of unilateral or bilateral botulinum toxin injections for adductor spasmodic dysphonia: a systematic review and meta-analysis.

PURPOSE: This study aims to aggregate and analyze existing clinical evidence to compare the efficacy and adverse effects of unilateral or bilateral botulinum toxin injections for the treatment of adductor spasmodic dysphonia (ADSD). METHODS: Reports from non-randomized controlled trials and cohort studies pertaining to the efficacy and adverse effects of unilateral and bilateral botulinum toxin injections for ADSD were identified and retrieved from four electronic databases from inception to July 2023. The meta-analysis employed fixed or random effects models to assess pooled relative risks (RR), mean differences (MDs), and standard mean differences (SMDs) with their corresponding 95% confidence intervals (CIs). RESULTS: We included two non-randomized controlled trials and seven cohort studies comprising 854 total patients. Meta-analysis of the included studies showed that bilateral botulinum toxin injections associated with a longer duration of vocal improvement (MD = - 2.89, 95% CI - 3.13 to - 2.65, I2 = 0%, P < 0.00001). However, bilateral botulinum toxin injections associated with an increase in adverse effects, including a longer duration of breathy voice quality (SMD = - 0.51, 95% CI - 0.79 to - 0.22, I2 = 35%, P = 0.0005) and a higher occurrence of swallowing difficulties (RR = 0.46, 95% CI 0.35 to 0.11, I2 = 0%, P < 0.00001). CONCLUSION: Bilateral botulinum toxin injections for ADSD showed a longer duration of vocal improvement, a longer breathy voice duration and a higher dysphagia occurrence and duration than unilateral injections.

Spasmodic Dysphonia Patients' Perception of Pain with Botulinum Toxin Injections.

OBJECTIVES: To evaluate spasmodic dysphonia patients' perception of pain associated with laryngeal botulinum toxin (BTX) injections and to determine factors associated with higher pain scores relative to other included patients. METHODS: Prospective cohort study. Adult patients with adductor spasmodic dysphonia that presented to a tertiary laryngology practice for BTX injections were recruited from March to July 2022. Patients completed the visual analog scale (VAS) pre-procedure to quantify predicted pain. Ten minutes post-procedure they completed VAS and the short form McGill Pain Questionnaire (SF-MPQ). Factors that may affect pain were extracted from charts. Descriptive statistics, univariate, and multivariate analyses were conducted (alpha = 0.05). RESULTS: One hundred and nineteen patients were included (63 ± 14 yo, 26% Male). SF-MPQ reported mild pain (4.12 ± 4.05 out of 45) with a pain intensity of none to mild (0.70 ± 0.89 out of 5). Bilateral injections yielded significantly higher SF-MPQ scores (5.19 ± 4.66) than unilateral injections (3.30 ± 3.30) (p = 0.012). There was a significant VAS reduction from pre 28.9 ± 24.6 mm (out of 10 mm) to post 24.5 ± 22.3 (p < 0.001). On multiple regression analyses, receiving a bilateral injection significantly (p < 0.05) contributed to a model that predicted higher pre-VAS (p = 0.013). Bilateral injections (p < 0.05) and higher VHI-10 (p < 0.05) contributed to a model that predicted higher total SF-MPQ (p = 0.001) and affective SF-MPQ (p = 0.001) scores. Not being a professional voice user (PVU) significantly (p < 0.05) contributed to a model that predicted higher post-VAS (p = 0.008) scores. CONCLUSIONS: BTX injections were well tolerated with low pain scores. Factors associated with higher relative predicted or experienced pain included bilateral versus unilateral injection, PVU status, and higher VHI-10. LEVEL OF EVIDENCE: 4 Laryngoscope, 134:240-246, 2024.

Improved vocal quality and decreased vocal effort after botulinum toxin treatment for laryngeal dystonia.

OBJECTIVES: Laryngeal dystonia (LD) is characterized by irregular and involuntary task-specific spasms of the intrinsic laryngeal muscles. There is no curative treatment for it, however, laryngeal botulinum neurotoxin injections (BoNT-I) are considered the standard of care therapy. This study aims to characterize the population of LD patients and to assess the results of laryngeal BoNT-I. METHODS: A Retrospective cohort study was conducted. Medical records were reviewed for all the patients with LD diagnosis seen in the Voice Unit of the Red de Salud UCChristus between January 2013 and October 2021. Biodemographic, clinical and treatment data were collected. Additionally, a telephonic survey was completed by the patients that underwent laryngeal BoNT-I, including self-reported voice outcomes and Voice Handicap Index 10 (VHI-10). RESULTS: Of the 34 patients with LD included in the study, 23 received a total of 93 laryngeal BoNT-I and 19 completed the telephone survey. The majority (97%) of the injections corresponded to patients with adductor LD and 3% to abductor LD. Patients received a median of 3 (1-17) injections, with a more frequent cricothyroid approach (94.4%), while the thyrohyoid approach accounted for 5.6% of cases. Most injections were bilateral (96.8%). A significant improvement in the vocal quality and effort was noted after the last injection and the overall BoNT-I treatment (P < 0.001). Similarly, the VHI-10 score improved from a median of 31 (7-40) to 2 (0-19) (P < 0.001) after the last injection. A post-treatment breathy voice was reported in 95% of patients, and dysphagia to liquids and solids in 68% and 21%, respectively. CONCLUSIONS: Laryngeal BoNT-I is an effective treatment for LD, achieving an improvement in self-reported vocal quality and VHI-10 scores, and a reduction of the self-reported vocal effort. Adverse effects are mild in the majority of cases, constituting a safe and effective therapy for these patients.

Botulinum toxin injection for abductor spasmodic dysphonia under cervical ultrasonography guidance.

Ultrasound (US) imaging effectively provides real-time anatomical information for clinical examinations. In otolaryngology, US imaging can visualize laryngeal muscles as well as cervical muscles. Here we present the case where US imaging was used while injecting botulinum toxin (BT) for the treatment of abductor spasmodic dysphonia, which provided definite results. We could visualize not only the injection pathway but also the infiltration of the BT solution into the posterior cricoarytenoid muscles. Therefore, our laryngeal US imaging is useful for both improving the success rate and avoiding injection complications of BT.

Analgesia in Transcutaneous Laryngeal Botulinum Toxin Injections: A Randomized Crossover Trial.

OBJECTIVES: There is an absence of data in the literature regarding methods to improve the patient experience during the performance of awake in-office laryngeal injections. This study sought to evaluate whether the use of local anesthetic or a vibrating instrument decreased overall pain experienced by patients with laryngeal dystonia, frequently referred to as spasmodic dysphonia (SD), undergoing transcervical botulinum toxin injections. METHODS: This was an unblinded, prospective randomized control trial with a crossover design where each patient received transcutaneous transcricothyroid injection of botulinum toxin with alternating use of no anesthesia, local anesthesia (2% lidocaine in 1:100,000 epinephrine), and vibrating instrument in three consecutive laryngeal injections to treat adductor SD. Patients were randomized to the order they received these treatments. Patients measured pain on a 0-10 visual analogue scale (VAS) and selected their preferred technique after receiving all three analgesic modalities. RESULTS: Thirty-two patients completed the study. There was no statistically significant difference in pain between the three analgesic techniques (p = 0.38). The most preferred analgesic technique was the vibrating wand (44% (14/32)). Lidocaine was the second most preferred (37% (12/32)) and 19% (6/32) of patients preferred nothing. When combining the wand and nothing groups, 63% of patients preferred one of these two methods (95% exact CI: 44%-79%). CONCLUSION: There was no statistically significant difference in median pain experienced by patients during laryngeal botulinum toxin injection between these different analgesic modalities. More than half of the patients selected a preference for a technique that did not include lidocaine. This data supports individualization of analgesia during transcutaneous laryngeal injections. LEVEL OF EVIDENCE: 2 Laryngoscope, 134:2277-2281, 2024.

Reliability of Phonemically Loaded Sentences in Spanish for Identifying Laryngeal Dystonia by Non-Spanish Speaking Speech-Language Pathologists.

INTRODUCTION: Laryngeal dystonia (LD) is a focal dystonia affecting the intrinsic laryngeal muscles. Clinical diagnosis requires subjective evaluation by experienced clinicians and is primarily based on auditory-perceptual assessment. Several speech tasks are widely accepted to elicit diagnosis specific auditory-perceptual symptoms of glottal stops in adductor LD or breathy breaks in abductor LD in spoken English. With the growing Spanish speaking population in the US and lack of Spanish speech tasks to assist in identifying LD in Spanish speaking subjects, assessing the reliability of phonemically loaded sentences in Spanish for use by non-Spanish speaking providers is critical. The first aim of this study was to develop and assess the reliability of a set of Spanish language phonemically loaded sentences designed to elicit signs and symptoms of LD. The second aim was to determine the effectiveness of non-Spanish speaking speech-language pathologists (SLPs) in identifying LD in Spanish speaking subjects using these stimuli. METHODS: Phonemically loaded sentences were developed for this study following current guidelines for assessment of LD. Voice samples were obtained from native Spanish speaking individuals. Participant-speakers included 20 people with LD and 20 people without LD who served as controls. All participant-speakers were assessed by a Spanish-speaking laryngologist. Audio samples were presented to non-Spanish speaking SLPs with expertise in working with people with LD who served as raters and classified the samples as either presence or absence of LD. Kappa and the intra-class correlation coefficient were calculated and mixed effects logistic regression was used for prediction. RESULTS: The inter and intra-rater reliability indicated statistically significant agreement. Sensitivity, specificity, and predictive values for the diagnosis of LD by the raters were overall strong. CONCLUSIONS: Findings demonstrate that non-Spanish speaking SLPs with expertise in the assessment and treatment of LD can reliably identify the presence of LD using Spanish language stimuli in Spanish-speaking individuals. This study supports the use of newly developed Spanish language phonemically loaded voiced and voiceless sentences by English speaking clinicians as an effective tool for identifying LD in Spanish speakers, perhaps mitigating diagnostic delays experienced by patients with LD.

Vocal Vibration Opening Onset Position Abnormality in Patients With Adductor Spasmodic Dystonia by Using High-Speed Endoscopy.

OBJECTIVE: To analyze vocal fold vibration onset in patients with adductor laryngeal dystonia (ADLD) by analyzing vocal vibration opening onset position (VVOOP). STUDY DESIGN: Case-control study SETTING: A voice center. METHODS: Eleven patients with ADLD diagnosed in our voice center were enrolled in the ADLD group. Eleven healthy subjects matched by exact age and gender to the ADLD patients were selected as the control group. All subjects underwent laryngeal high-speed video endoscopy. VVOOP and its change were assessed by two otolaryngologists. The multiline video kymography was used to analyze the open quotient (OQ) and standard deviation of OQ. RESULTS: VVOOP had more than one position in 54.6% (6/11) of the patients with ADLD, which was higher than the control group (P < 0.05). VVOOP appeared in the front of the vocal fold in 54.6% (6/11) of patients with ADLD and in the back of the vocal fold in 81.8% (9/11) of patients with ADLD. VVOOP can be abnormal in 90.9% (10/11) of patients with ADLD, and the rate of VVOOP abnormality was higher than that of the control group (P < 0.05). Of 11, 6 (54.6%) patients with ADLD had a variable VVOOP; the variability rate of VVOOP was higher than that in the control group (P < 0.05). OQ and OQ standard deviation in the ADLD group were significantly greater than in the control group (P < 0.05). CONCLUSIONS: In patients with ADLD, vocal fold vibration was irregular, and VVOOP was abnormal and had a variable position and could reflect variability of the vocal vibration. LEVEL OF EVIDENCE: Level 4.

Probing the inhibitory motor circuits in adductor laryngeal dystonia during a dystonia-unrelated task.

BACKGROUND: The pathophysiology of adductor laryngeal dystonia (AdLD) remains unknown; however, there is growing evidence that dystonia is associated with disruptions in the inhibitory regulation of sensorimotor cortical areas. Using functional MRI (fMRI) and transcranial magnetic stimulation (TMS) complementarily, we previously demonstrated an overly activated laryngeal motor cortex and revealed correlations between blood-oxygen-level dependent (BOLD) activation and intracortical inhibition in a phonation (dystonia-related) task in adductor laryngeal dystonia (AdLD). OBJECTIVE: Here, we aimed to characterize the brain-based findings in the primary motor cortex (M1) during a dystonia-unrelated (finger tapping) task in AdLD and controls (CTL). METHODS: We examined the between-group differences in task-dependent BOLD activation and intracortical inhibition, measured by the TMS-evoked cortical silent period (cSP), in the M1. The correlations between fMRI and TMS responses were assessed. RESULTS: There is more broadly dispersed BOLD activation, not confined to the hand motor cortex, and reduced intracortical inhibition in AdLD compared to CTL. Further, there are more positive correlations between cSP and BOLD activation in a task unrelated to dystonic symptoms in AdLD compared with CTL. This is in contrast to our previous work that demonstrated fewer positive correlations in AdLD during a dystonic phonation task. CONCLUSIONS: In unaffected musculature activation, there is dispersed BOLD activation that is correlated with intracortical inhibition suggesting a possible compensatory strategy in the non-dystonic muscles.

Adult-onset focal dystonias: To lump or split.

The adult-onset focal dystonias are a group of clinically heterogeneous disorders that affect different regions of the body. Although they affect different regions with different clinical manifestations, there is evidence that etiopathogenesis is shared at the anatomical, physiological, and genetic levels. However, there is also evidence that etiopathogenesis varies. This chapter summarizes the evidence for lumping or splitting these apparently different clinical phenotypes. It also includes some potential explanations to explain the similarities and differences.

Comparison of Botulinum Toxin Injections and Type 2 Thyroplasty for Adductor Spasmodic Dysphonia.

OBJECTIVES: Injection of botulinum toxin type A (BTX) into intrinsic laryngeal muscles is the current gold standard therapy for adductor spasmodic dysphonia (AdSD). However, a surgical procedure could potentially offer more stable and long-lasting voice quality to AdSD patients. Here, we report the long-term results of type 2 thyroplasty (TP2) with TITANBRIDGE® (Nobelpharma, Tokyo, Japan) compared with those of BTX injections. METHODS: In total, 73 AdSD patients visited our hospital between August 2018 and February 2022. Patients were provided the option of BTX injections or TP2. They were assessed via the Voice Handicap Index (VHI)-10 before treatments and at scheduled clinical follow-ups at 2, 4, 8, and 12 weeks for BTX and at 4, 12, 26, and 52 weeks for TP2. RESULTS: Overall, 52 patients selected the BTX injection and had a pre-injection mean VHI-10 score of 27.3 ± 8.8. Following injections, the scores significantly improved to 21.0 ± 11.1, 18.6 ± 11.5, and 19.4 ± 11.7 at 2, 4, and 8 weeks, respectively. There were no significant differences between the pre-injection scores and the 12-week scores (21.5 ± 10.7). Alternately, 32 patients opted to be treated with TP2 and had a pre-treatment mean VHI-10 score of 27.7. All patients reported an improvement in their symptoms. Additionally, the mean VHI-10 score significantly improved to 9.9 ± 7.4 at 52 weeks following treatment. There was a significant difference between the two treatment groups at 12 weeks. Some patients received both treatments. CONCLUSION: These preliminary results provide important insights into the value of TP2 as a potential permanent treatment for AdSD patients. LEVEL OF EVIDENCE: 3 Laryngoscope, 133:3443-3448, 2023.

Cannabinoid Use in the Treatment of Laryngeal Dystonia and Vocal Tremor: A Pilot Investigation.

OBJECTIVES/HYPOTHESIS: Laryngeal dystonia and vocal tremor can be debilitating conditions with suboptimal treatment options. Botulinum toxin chemodenervation is typically the first-line treatment and is considered the gold standard. However, patient response to botulinum toxin varies widely. There is anecdotal evidence for the use of cannabinoids in treating laryngeal dystonia with a scarcity of research investigating this potential treatment option. The primary objective of this study is to survey patients with laryngeal dystonia and vocal tremor to gauge how some people are using cannabinoids to treat their condition and to ascertain patient perceptions of cannabinoid effectiveness. STUDY DESIGN: This is a cross-sectional survey study. METHODS: An eight-question anonymous survey was distributed to people with abductor spasmodic dysphonia adductor spasmodic dysphonia, vocal tremor, muscle tension dysphonia, and mixed laryngeal dystonia via the Dysphonia International (formerly National Spasmodic Dysphonia Association) email listserv. RESULTS: 158 responses: 25 males and 133 females, (mean [range] age, 64.9 [22-95] years). 53.8% of participants had tried cannabinoids for the purposes of treating their condition at some point, with 52.9% of this subset actively using cannabis as part of their treatment. Most participants who have used cannabinoids as a treatment rank their effectiveness as somewhat effective (42.4%) or ineffective (45.9%). Participants cited a reduction in voice strain and anxiety as reasons for cannabinoid effectiveness. CONCLUSIONS: People with laryngeal dystonia and/or vocal tremor currently use or have tried using cannabinoids as a treatment for their condition. Cannabinoids were better received as a supplementary treatment than as a stand-alone treatment.

Significance of age and sex in botulinum neurotoxin dosing for adductor spasmodic dysphonia.

Objectives: This study aims to analyze the impact of age and sex on botulinum neurotoxin (BoNT-A) dosing and outcomes in adductor spasmodic dysphonia (AdSD). Methods: A database review of all spasmodic dysphonia patients treated with BoNT from 1989 to 2018 at the Mayo Clinic in Arizona was performed. Only patients who had received ≥4 injections of BoNT-A for AdSD were included. Patients were divided into two cohorts to analyze age, with an age of first treatment cutoff of 60 years. Patients were divided into male and female cohorts to analyze sex. Results: The final analysis included 398 patients. The mean dose of BoNT-A per treatment was significantly higher in the younger cohort (4.4 vs. 3.9 units, p = 0.048). The mean maximal benefit was similar (72% vs. 70%, p = 0.48); however, the mean length of benefit was significantly shorter in younger patients (3.0 vs. 3.6 months, p < 0.01). The mean BoNT-A dose was significantly higher in the female cohort (4.2 vs. 3.6 units, p = 0.02). The mean maximal benefit was similar (69% vs. 75%, p = 0.58), as was the mean length of benefit (3.2 vs. 3.5 months, p = 0.11). Conclusions: This study suggests that age and sex influence BoNT-A dosing and outcomes in AdSD.

The Cortical Silent Period in the Cricothyroid Muscle as a Neurophysiologic Feature for Dystonia Observation: E-Field-Navigated Transcranial Magnetic (TMS) Study.

The cortical silent period (cSP) is a period of electrical silence following a motor-evoked potential (MEP) in the electromyographic signal recorded from a muscle. The MEP can be elicited by transcranial magnetic stimulation (TMS) over the primary motor cortex site corresponding with the muscle. The cSP reflects the intracortical inhibitory process mediated by GABAA and GABAB receptors. The study aimed to investigate the cSP in the cricothyroid (CT) muscle after applying e-field-navigated TMS over the laryngeal motor cortex (LMC) in healthy subjects. Then, a cSP as a neurophysiologic feature for laryngeal dystonia was observed. We applied a single-pulse e-field-navigated TMS to the LMC over both hemispheres with hook-wire electrodes positioned in the CT muscle in nineteen healthy participants, which triggered the elicitation of contralateral and ipsilateral corticobulbar MEPs. The subjects were engaged in a vocalization task, and then we assessed the following metrics: LMC intensity, peak-to-peak MEP amplitude in the CT muscle, and cSP duration. The results showed that the cSP duration from the contralateral CT muscle was distributed from 40 ms to 60.83 ms, and from the ipsilateral CT muscle, from 40 ms to 65.58 ms. Also, no significant difference was found between the contralateral and ipsilateral cSP duration (t(30) = 0.85, p = 0.40), MEP amplitude in the CT muscle (t(30) = 0.91, p = 0.36), and LMC intensity (t(30) = 1.20, p = 0.23). To conclude, the applied research protocol showed the feasibility of recording LMC corticobulbar MEPs and observing the cSP during vocalization in healthy participants. Furthermore, an understanding of neurophysiologic cSP features can be used to study the pathophysiology of neurological disorders that affect laryngeal muscles, such as laryngeal dystonia.