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Laryngeal dystonia (LD) is an isolated, task‐specific, focal dystonia characterized by intermittent spasms of laryngeal muscles impairing speech production. Although recent studies have demonstrated neural alterations in LD, the consistency of findings across studies is not well‐established, limiting their translational applicability. We conducted a systematic literature search to identify studies reporting stereotactic coordinates of peak structural and functional abnormalities in LD patients compared to healthy controls, followed by a coordinate‐based activation likelihood estimation meta‐analysis. A total of 21 functional and structural neuroimaging studies, including 31 experiments in 521 LD patients and 448 healthy controls, met the study inclusion criteria. The multimodal meta‐analysis of these studies identified abnormalities in the bilateral primary motor cortices, the left inferior parietal lobule and striatum, the right insula, and the supplementary motor area in LD patients compared to healthy controls. The meta‐analytical findings reinforce the current view of dystonia as a neural network disorder and consolidate evidence for future investigations probing these targets with new therapies. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The article discusses a case report of a 45-year-old male patient with abductor laryngeal dystonia (ABLD) who underwent pallidal deep brain stimulation (DBS) surgery. ABLD is a rare subtype of laryngeal dystonia characterized by breathy breaks during speech. The patient experienced immediate and remarkable efficacy of DBS, with full recovery from symptoms without recurrence. The study highlights the potential of pallidal DBS as a highly effective treatment for ABLD, offering new insights into the management of this challenging condition. [Extracted from the article]

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 [ABSTRACT FROM AUTHOR]

Objectives: Adult‐onset idiopathic laryngeal dystonia (LD) can be associated with the risk of spread to muscles in the body. Subjects with extralaryngeal onset of dystonia have exhibited spread to the larynx. Previous studies analyze the spread of other dystonias but emphasis has not been placed on LD. The objective was to identify demographic and clinical factors contributing to the spread of dystonia to and from the larynx. Methods: Data were obtained from the Dystonia Coalition (DC)‐patients from 49 international clinical centers. Clinical and demographic data was taken from 143 out of 409 patients with diagnosed LD. Patient criteria included adult‐onset LD diagnosed on exam with no co‐morbid neurologic conditions and no dystonia in other locations. Results: Among the 143 patients, 94 (65.7%) patients were diagnosed with focal laryngeal onset, with the remainder having extralaryngeal onset. Family history and age at study were statistically significant indicators of a patient developing laryngeal versus extralaryngeal onset of dystonia. Among the laryngeal onset group, 21 cases (22.3%) had an average time of 5.81 ± 5.79 years to spread from diagnosis, most commonly to neck (61.9%). Among extralaryngeal onset patients, mean time of larynx spread was 7.92 ± 7.737 years, most commonly to neck (22.7%). Conclusions: Our data indicates approximately a quarter of patients with laryngeal‐onset dystonia will exhibit spread. There were no demographic or clinical factors that were statistically predictive of the likelihood of spread from larynx. Patients with dystonia elsewhere in the body should be counseled on the possibility of spread to larynx, and vice versa. Level of Evidence: 4 Laryngoscope, 134:2295–2299, 2024 [ABSTRACT FROM AUTHOR]

Abductor laryngeal dystonia (ABLD) is a rare neurological voice disorder which results in sporadic opening of the vocal folds during speech. Etiology is unknown, and to date there is no identified effective behavioral treatment for it. It is hypothesized that LSVT LOUD®, which was developed to treat dysphonia secondary to Parkinson's disease, may have application to speakers with ABLD to improve outcomes beyond that with botulinum neurotoxin (BoNT) treatment alone. The participant received one injection of BoNT in each vocal fold 2 to 3 months prior to initiating intensive voice therapy via teletherapy. Objective measures of vocal loudness (dB sound pressure level), maximum phonation time, and high/low pitch frequency (Hz) were recorded in all treatment sessions and follow-up sessions. Over the course of treatment, the participant showed steady gains in phonation time, volume, pitch range, and vocal quality with a substantial reduction in aphonic voice breaks by the end of the treatment program. Perceptual symptoms of ABLD were nearly undetectable by the participant and the clinicians up to 12 months posttreatment, with no additional BoNT injections. The results suggest that LSVT LOUD® following BoNT was effective, with long-lasting improvement in vocal function, for this speaker with ABLD. [ABSTRACT FROM AUTHOR]

Simple Summary: In this review, the endeavor is to compile the most significant findings related to the interconnection among various autonomic centers that regulate the autonomic activity of the central nervous system. These centers appear to play a crucial role in the control of vocal emissions in mammals, including humans. Specifically, the aim is to comprehend and delineate the intricate neural networks involved in this functional relationship. This will allow us to describe how these structures, traditionally associated with cardiorespiratory control, also play a crucial role in the regulation of vocalization. In humans, speech is a complex process that requires the coordinated involvement of various components of the phonatory system, which are monitored by the central nervous system. The larynx in particular plays a crucial role, as it enables the vocal folds to meet and converts the exhaled air from our lungs into audible sounds. Voice production requires precise and sustained exhalation, which generates an air pressure/flow that creates the pressure in the glottis required for voice production. Voluntary vocal production begins in the laryngeal motor cortex (LMC), a structure found in all mammals, although the specific location in the cortex varies in humans. The LMC interfaces with various structures of the central autonomic network associated with cardiorespiratory regulation to allow the perfect coordination between breathing and vocalization. The main subcortical structure involved in this relationship is the mesencephalic periaqueductal grey matter (PAG). The PAG is the perfect link to the autonomic pontomedullary structures such as the parabrachial complex (PBc), the Kölliker–Fuse nucleus (KF), the nucleus tractus solitarius (NTS), and the nucleus retroambiguus (nRA), which modulate cardiovascular autonomic function activity in the vasomotor centers and respiratory activity at the level of the generators of the laryngeal-respiratory motor patterns that are essential for vocalization. These cores of autonomic structures are not only involved in the generation and modulation of cardiorespiratory responses to various stressors but also help to shape the cardiorespiratory motor patterns that are important for vocal production. Clinical studies show increased activity in the central circuits responsible for vocalization in certain speech disorders, such as spasmodic dysphonia because of laryngeal dystonia. [ABSTRACT FROM AUTHOR]

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 UC Christus 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. [ABSTRACT FROM AUTHOR]

Laryngeal dystonia is a debilitating disorder of voicing in which the laryngeal muscles are intermittently in spasm resulting in involuntary interruptions during speech. The central pathophysiology of laryngeal dystonia, underlying computational impairments in vocal motor control, remains poorly understood. Although prior imaging studies have found aberrant activity in the CNS during phonation in patients with laryngeal dystonia, it is not known at what timepoints during phonation these abnormalities emerge and what function may be impaired. To investigate this question, we recruited 22 adductor laryngeal dystonia patients (15 female, age range = 28.83-72.46 years) and 18 controls (eight female, age range = 27.40-71.34 years). We leveraged the fine temporal resolution of magnetoencephalography to monitor neural activity around glottal movement onset, subsequent voice onset and after the onset of pitch feedback perturbations. We examined event-related beta-band (12-30 Hz) and high-gamma-band (65-150 Hz) neural oscillations. Prior to glottal movement onset, we observed abnormal frontoparietal motor preparatory activity. After glottal movement onset, we observed abnormal activity in the somatosensory cortex persisting through voice onset. Prior to voice onset and continuing after, we also observed abnormal activity in the auditory cortex and the cerebellum. After pitch feedback perturbation onset, we observed no differences between controls and patients in their behavioural responses to the perturbation. But in patients, we did find abnormal activity in brain regions thought to be involved in the auditory feedback control of vocal pitch (premotor, motor, somatosensory and auditory cortices). Our study results confirm the abnormal processing of somatosensory feedback that has been seen in other studies. However, there were several remarkable findings in our study. First, patients have impaired vocal motor activity even before glottal movement onset, suggesting abnormal movement preparation. These results are significant because (i) they occur before movement onset, abnormalities in patients cannot be ascribed to deficits in vocal performance and (ii) they show that neural abnormalities in laryngeal dystonia are more than just abnormal responses to sensory feedback during phonation as has been hypothesized in some previous studies. Second, abnormal auditory cortical activity in patients begins even before voice onset, suggesting abnormalities in setting up auditory predictions before the arrival of auditory feedback at voice onset. Generally, activation abnormalities identified in key brain regions within the speech motor network around various phonation events not only provide temporal specificity to neuroimaging phenotypes in laryngeal dystonia but also may serve as potential therapeutic targets for neuromodulation.

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Background: There are several widely used clinical rating scales for documenting the severity and distribution of various types of dystonia. Objectives: The goal of this study was to evaluate the performance of the most commonly used scales in a large group of adults with the most common types of isolated dystonia. Methods: Global Dystonia Rating Scale (GDRS) and the Burke‐Fahn‐Marsden Dystonia Rating Scale (BFM) scores were obtained for 3067 participants. Most had focal or segmental dystonia, with smaller numbers of multifocal or generalized dystonia. These scales were also compared for 209 adults with cervical dystonia that had Toronto Western Spasmodic Torticollis Rating Scale (TWSTRS) scores and 210 adults with blepharospasm that had Blepharospasm Severity Scale (BSRS) scores. Results: There were strong correlations between the GDRS and BFM total scores (r = 0.79) and moderate correlations for their sub scores (r > 0.5). Scores for both scales showed positive skew, with an overabundance of low scores. BFM sub‐scores were not normally distributed, due to artifacts caused by the provoking factor. Relevant sub‐scores of the GDRS and BFM also showed moderate correlations with the TWSTRS (r > 0.5) for cervical dystonia and the BSRS (r > 0.5) for blepharospasm. Conclusions: The BFM is more widely used than the GDRS, but these results suggest the GDRS may be preferable for focal and segmental dystonias. The overabundance of very low scores for both scales highlights challenges associated with discriminating very mild dystonia from other abnormal movements or variants of normal behavior. [ABSTRACT FROM AUTHOR]

Laryngeal dystonia (LD), known or termed as spasmodic dysphonia, is a rare movement disorder with an unknown cause affecting the intrinsic laryngeal muscles. Neurophysiological studies point to perturbed inhibitory processes, while conventional genetic studies reveal fragments of genetic architecture in LD. The study's aims are to (1) describe transcranial magnetic stimulation (TMS) methodology for studying the functional integrity of the corticospinal tract by stimulating the primary motor cortex (M1) for laryngeal muscle representation and recording motor evoked potentials (MEPs) from laryngeal muscles; (2) evaluate the results of TMS studies investigating the cortical silent period (cSP) in LD; and (3) present the standard treatments of LD, as well as the results of new theoretical views and treatment approaches like repetitive TMS and laryngeal vibration over the laryngeal muscles as the recent research attempts in treatment of LD. Neurophysiological findings point to a shortened duration of cSP in adductor LD and altered cSP duration in abductor LD individuals. Future TMS studies could further investigate the role of cSP in relation to standard laryngological measures and treatment options. A better understanding of the neurophysiological mechanisms might give new perspectives for the treatment of LD. [ABSTRACT FROM AUTHOR]

Objective: The purpose of this study was to determine whether automated estimates of vocal creak would differentiate speakers with adductor laryngeal dystonia (AdLD) from speakers with muscle tension dysphonia (MTD) and speakers without voice disorders. Methods: Sixteen speakers with AdLD, sixteen speakers with MTD, and sixteen speakers without voice disorders were recorded in a quiet environment reading aloud a standard paragraph. An open‐source creak detector was used to calculate the percentage of creak (% creak) in each of the speaker's six recorded sentences. Results: A Kruskal‐Wallis one‐way analysis of variance revealed a statistically significant effect of group on the % creak with a large effect size. Pairwise Wilcoxon tests revealed a statistically significant difference in % creak between speakers with AdLD and controls as well as between speakers with AdLD and MTD. Receiver operating characteristic curve analyses indicated that % creak differentiated AdLD from both controls and speakers with MTD with high sensitivity and specificity (area under the curve statistics of 0.94 and 0.86, respectively). Conclusion: Percentage of creak as calculated by an automated creak detector may be useful as a quantitative indicator of AdLD, demonstrating the potential for use as a screening tool or to aid in a differential diagnosis. Level of Evidence: 3 Laryngoscope, 133:2687–2694, 2023 [ABSTRACT FROM AUTHOR]

This postmarketing surveillance study was conducted to evaluate the safety and effectiveness of onabotulinumtoxinA in Japanese patients with laryngeal dystonia (LD). Patients receiving onabotulinumtoxinA for the first time were enrolled and observed for up to 12 months following the first injection. Safety assessment included adverse drug reactions (ADRs), and effectiveness assessments included the Voice Handicap Index-10 (VHI-10) and physician's global assessment (PGA). ADRs were observed in 48 (5.8%) of 834 patients in the safety analysis set, including dysphonia in 43 (5.2%) patients and dysphagia in 7 (0.8%) patients. The change in total VHI-10 score (mean) in 790 patients included in the effectiveness analysis set showed that improvement in adductor LD peaked at 2 months after the first injection, while patients with abductor or mixed LD showed a gradual attenuation of effect 2–4 weeks post-injection. The change in total VHI-10 score in subsequent injections was generally similar to that following the first injection. The overall effectiveness rate according to the PGA was 93.4% (738/790 patients). The results demonstrate that onabotulinumtoxinA is a well-tolerated and effective treatment for LD in real-world clinical practice. [ABSTRACT FROM AUTHOR]

Background/Objectives: Laryngeal sensory abnormality has been implicated as a component of adductor laryngeal dystonia (AdLD). The study objective was to assess laryngopharyngeal sensation in AdLD utilizing a calibrated, tactile aesthesiometer to deliver differential stimuli to lateral pyriform sinus (LPS), aryepiglottic fold (AEF), and false vocal fold (FVF). Methods: Patients with known Botox‐responsive AdLD underwent sensory testing using a previously‐validated methodology involving calibrated tactile stimuli (6–0, 5–0, 4.5–0, 4–0 nylon monofilaments). Laryngeal adductor reflex (LAR) and participant‐rated perceptual strength of stimulI were evaluated. Responses were compared to normative controls (n = 33). Two‐samples, Mann–Whitney and Fisher exact tests compared mean strength ratings and LAR between AdLD and control groups. Mixed‐effects logistic regression and linear models assessed association of filament size, stimulus site, age, sex, and LD status on LAR and perceptual strength rating respectively. Results: Thirteen AdLD patients (nine women, mean age 60+/−15 years) completed testing. Average LAR response rates were higher amongst all filament sizes in AdLD versus controls at LPS (56.3% vs. 35.7%) and AEF (96.1% vs. 70.2%) with comparable rates at FVF (90.2% vs. 91.7%). AdLD had 3.3 times the odds of observed LAR compared to controls (p = 0.005), but differences in subjective detection of stimuli, perceptual strength ratings, and cough/gag rates were insignificant on multivariate modeling (p > 0.05). Conclusions: This is the first study to objectively assess laryngopharyngeal sensation in AdLD. Findings demonstrated increased laryngopharyngeal sensation in AdLD compared to controls. The identification of increased laryngeal hypersensitivity in these patients may improve understanding of AdLD pathophysiology and identify future targets for intervention. Level of Evidence: 2 Laryngoscope, 133:2271–2278, 2023 [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Laryngeal dystonia is a potentially disabling task specific dystonia primarily affecting speech. The evaluation and diagnosis of laryngeal dystonia remain challenging, and often require a multi‐disciplinary approach, involving collaboration among speech language pathologists, neurologists and laryngologists (1–5). It is crucial to correctly differentiate between the types of laryngeal dystonia due to the distinct therapeutic approaches and responses to botulinum toxin therapy or speech therapy. For educational purposes, we have divided laryngeal dystonia into two main types: adductor and abductor dystonia. In this article, we describe a series of examination techniques that can assist movement disorders neurologists diagnosing this condition, and appropriately differentiating the most common forms of laryngeal dystonia. [ABSTRACT FROM AUTHOR]

Spasmodic dysphonia (SD) is considered a rare focal laryngeal dystonia characterized by task-specific voice dysfluency resulting from selective intrinsic laryngeal musculature hyperfunction. Symptoms may be attenuated by a sensory trick. Although SD can be seen at times in generalized dystonia syndrome, it is typically a sporadic phenomenon, and the involvement of the laryngeal adductor muscles is more common than that of the abductor muscles. This research reviews the literature for the pathogenesis, clinical characteristics, treatment options, and current management methods of SD. Technological advances have enabled clinicians to better understand the connection between laryngeal function and dysfunction. Refinements in imaging and genetic investigation techniques have helped better understand the underlying mechanisms of this neurolaryngology disorder. Currently, the standard of care for SD is the symptomatic management of botulinum toxin (BT) chemodenervation. This is supported by a large body of literature attesting to its efficacy in many different research studies, particularly in the uncomplicated adductor form of the disorder. Efforts towards surgical treatment predate the development of BT treatment by a decade, but the long-term efficacy has not been proven and, further research is expected. Symptom relief in patients with abductor SD and dystonia with tremors after surgical and BT treatments and those in patients remains suboptimal. [ABSTRACT FROM AUTHOR]

Laryngeal dystonia (LD), or spasmodic dysphonia (SD), is a chronic, task-specific, focal movement disorder affecting the larynx. It interferes primarily with the essential functions of phonation and speech. LD affects patients' ability to communicate effectively and significantly diminishes their quality of life. Botulinum neurotoxin was first used as a therapeutic agent in the treatment of LD four decades ago and remains the standard of care for the treatment of LD. This article provides an overview of the clinical application of botulinum neurotoxin in the management of LD, focusing on the classification for this disorder, its pathophysiology, clinical assessment and diagnosis, the role of laryngeal electromyography and a summary of therapeutic injection techniques, including a comprehensive description of various procedural approaches, recommendations for injection sites and dosage considerations. [ABSTRACT FROM AUTHOR]

Purpose: Traditional vocal fold pathology recognition typically requires expertise of laryngologists and advanced instruments, primarily through direct visualization. This study aims to augment this conventional paradigm by introducing a parallel diagnostic procedure. Our objective is to harness a machine-learning algorithm designed to discern intricate patterns within patients' voice recordings to distinguish not only between healthy and hoarse voices but also among various specific disorders., Materials and Methods: We employed a machine-learning algorithm, utilizing transfer learning on the HuBERT model with Saarbruecken Voice Database samples. The study was conducted in two stages: a binary classifier distinguishes healthy and hoarse voices, while a subsequent multi-class classifier identifies specific voice disorders. Data from 2103 sessions, including over 25,000 components, representing diverse pathologies and healthy individuals, was analyzed. The models were trained, validated, and tested with a focus on robustness and accuracy in diagnosis., Results: The binary classifier achieved 82 % accuracy in distinguishing healthy from pathological voices. The multi-class algorithm which aims to identify specific laryngeal disorders obtained the highest accuracy (>93 %) for Laryngeal Dystonia. Noteworthy is the persistent challenge posed by Laryngeal Dystonia, a condition lacking a definitive diagnostic modality., Conclusions: Our findings demonstrate the feasibility of utilizing machine-learning algorithms to process voice samples, categorizing them into distinct pathologies. This approach holds potential for enhance patient triage, streamline diagnostics, and elevate overall patient care. Particularly valuable for challenging diagnoses, such as Laryngeal Dystonia, this method underscores the transformative role of machine learning in optimizing healthcare practices., Competing Interests: Declaration of competing interest This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Acute dystonia is a neurological condition characterized by involuntary muscle contractions that can affect various parts of the body. It is commonly triggered by the use of antipsychotic medications, especially within the first few days after administration. Respiratory acute laryngeal dystonia, a particularly severe form of this condition and a very subtype of laryngeal dystonia, can lead to respiratory distress and airway obstruction if not promptly treated. This case report describes a 23-year-old male who developed acute laryngeal dystonia within 24 hours of receiving haloperidol for agitation. The patient presented with hoarseness, difficulty swallowing, and progressive respiratory distress, eventually requiring emergent intubation due to airway compromise. This case underscores the need for healthcare providers to recognize and promptly manage rare but potentially life-threatening side effects of antipsychotic medications. Particular attention must be directed toward patients with risk factors for developing extrapyramidal reactions. Early intervention is crucial to prevent progression to airway obstruction and respiratory failure., Competing Interests: Human subjects: Consent for treatment and open access publication was obtained or waived by all participants in this study. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Guani et al.)

Objective: Creak is an acoustic feature found to discriminate speakers with adductor laryngeal dystonia (AdLD) from typical speakers with outstanding diagnostic accuracy. Yet creak is also used by typical speakers as a phrase-boundary marker. This study aims to compare the prevalence of creak across estimated breath groups in speakers with AdLD and controls to delineate physiological mechanisms underlying creak in AdLD., Methods: Thirty-four speakers read aloud the first paragraph of the Rainbow Passage (17 diagnosed with AdLD and 17 with no history of voice complaints). "Breath-like" pauses were defined as any in which technicians audibly heard a pause and all pauses >500 ms. For each phoneme, the time preceding the next breath-like pause was calculated, and the probability of creak occurrence was calculated. A generalized linear mixed-effects model was performed to determine the relationship between creak and time preceding a breath-like pause., Results: Inter-rater and intrarater reliability of technicians were excellent. There was a statistically greater probability of creak in the AdLD group compared to controls (22% vs. 5%) and a statistically greater probability of creak as speakers approached a breath-like pause in both groups. The interaction between the time preceding a breath-like pause and group was significant, with a stronger relationship between the time preceding a breath-like pause and creak for control speakers (P < 0.001)., Conclusions: Creak is more prevalent in speakers with AdLD and may not only be related to respiratory phrasing but possibly in response to or because of the hyperadduction of the vocal folds during a laryngeal spasm., Lay Summary: The probability of creak occurring was greater towards the end of estimated breath groups in speakers with and without AdLD; however, for speakers with AdLD, creak was more prominent across the entire breath group., Competing Interests: Declaration of Competing Interest Cara E. Stepp has received consulting fees from Altec, Inc./Delsys, Inc., companies focused on developing and commercializing technologies related to human movement. Stepp’s interests were reviewed and are managed by Boston University in accordance with their conflict-of-interest policies. The other authors have declared that no other competing interests existed at the time of submission., (Copyright © 2024 The Voice Foundation. All rights reserved.)

Focal laryngeal dystonia (LD) is a rare, idiopathic disease affecting the laryngeal musculature with an unknown cause and clinically presented as adductor LD or rarely as abductor LD. The most effective treatment options include the injection of botulinum toxin (BoNT) into the affected laryngeal muscle. The aim of this narrative review is to summarize the patho-neuro-physiological and genetic background of LD, as well as the standard recommended therapy (BoNT) and pharmacological treatment options, and to discuss possible treatment perspectives using neuro-modulation techniques such as repetitive transcranial magnetic stimulation (rTMS) and vibrotactile stimulation. The review will present two LD cases, patients with adductor and abductor LD, standard diagnostic procedure, treatments and achievement, and the results of cortical excitability mapping the primary motor cortex for the representation of the laryngeal muscles in the assessment of corticospinal and corticobulbar excitability. [ABSTRACT FROM AUTHOR]

Laryngeal Botulinum Toxin injection (LBTX) in the adductor musculature is the current therapy for Adductor Spasmodic Dysphonia. This study explores nonbiological factors that can affect the patient experience during this procedure and their association with better or worse self-reported effectiveness. A 14 item survey was used to evaluate the patient experience in patients who had undergone LBTX in Mayo Clinic Jacksonville, Florida, during 2019. Information from the survey, previous medical history, and demographic data were collected, and a descriptive analysis was performed. Of the 36 patients who participated, the mean age was 65 years and a female predominance was found (66%). The average age at onset of symptoms was 57 years, and voice tremor was associated with 36.1% of patients. Preprocedure education was recognized as a factor affecting outcomes in 87% of patients; 11 patients reported that body position used during the injection could affect the results. Pain or stress experienced at the time of procedure was referred in one-third of patients as an influencing factor too. This study has shown that nonpharmacological factors such as education before the procedure, body position, pain, and stress sensation before LBTX may have a role in the botulinum toxin effect on Adductor Spasmodic Dysphonia patients. This study is the first to describe these variables qualitatively, and further studies may help to improve the patient experience and outcome of LBTX around the world. [ABSTRACT FROM AUTHOR]

Objective: Non-motor symptoms (NMS) have been identified in some focal adult-onset dystonia. In the present study we aimed to evaluate the presence of NMS in patients with spasmodic dysphonia (SD), a focal action-induced dystonia that affects intrinsic laryngeal muscle control.Methods: Seventeen SD patients and 17 control subjects not significantly different in age and sex were evaluated for the presence of NMS. Additionally, voice handicap index (VHI-10), reflux symptom index, neuropsychiatric symptoms and QoL were assessed by validated scales and questionnaires.Results: Patients' group significantly differed from control group in mild depressive symptoms (4.35 ± 3.9 vs. 1.47 ± 2; p=0.01), insomnia (35.3% vs. 14.7%; p=0.016), smell and taste loss (11.8% vs. 0%; p=0.033), swallowing difficulties (17.6% vs. 0%; p=0.007) and throat pain (17.6% vs. 0%; p=0.007). In the group of SD, there was no correlation between voice perception evaluated by VHI-10, number of NMS or QoL.Conclusion: Patients with SD have a greater burden of depressive, smell, taste, and sleep NMS than control subjects. [ABSTRACT FROM AUTHOR]

Objective: Adductor laryngeal dystonia (AdLD) disrupts fine motor movements of vocal folds during speech, resulting in a strained, broken, and strangled voice. Laryngeal high-speed videoendoscopy (HSV) in connected speech enables the direct visualization of detailed laryngeal dynamics, hence, it can be effectively used to study AdLD. The current study utilizes HSV to investigate supraglottic laryngeal tissue maneuvers obstructing the view of the vocal folds, in AdLD and normophonic speakers during connected speech. Characterizing the laryngeal maneuvers in these groups can facilitate a deeper understanding of the normophonic voice physiology and AdLD voice pathophysiology., Methods: HSV data were obtained from six normophonic speakers and six patients with AdLD during production of connected speech. Three experienced raters visually analyzed the data to determine laryngeal tissues leading to obstructions of vocal folds in HSV images. The raters recorded the duration of each obstruction and indicated the specific tissue(s) leading to the obstruction. After the completion of their individual visual analysis, the raters came to consensus about their observations and measurements., Results: Statistical analysis indicated that AdLD patients exhibited higher occurrences of vocal fold obstructions and longer durations of obstructions compared with the normophonic group. Similar obstruction types were found in both groups, with the epiglottis being the primary site of obstruction for both. Participants with AdLD displayed significantly elevated occurrences of sphincteric compression resulting in vocal fold obstruction., Conclusion: HSV can be used to study the movements of laryngeal tissues in detail during connected speech. The analysis of supraglottic laryngeal tissue dynamics in speech can help us characterize the AdLD pathophysiology. The study's findings regarding the tissues implicated in obstructions may potentially inform the development of patient-specific therapeutic strategies targeting individual control over specific laryngeal muscles during phonation and speech production., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Objective: Laryngeal dystonia (LD), previously termed spasmodic dysphonia, is an isolated focal dystonia that involves involuntary, uncontrolled contractions of the laryngeal muscles during speech. It is a severely disabling condition affecting patients' work and social lives through prevention of normal speech production. Our understanding of the pathophysiology of LD and available therapeutic options are currently limited. The aim of this short review is to provide an up-to-date summary of what is known about the central mechanisms and the pathophysiology of LD., Methods: A systematic review of the literature was performed searching Embase, CINHAL, Medline, and Cochrane with the cover period January 1990-October 2023 with a search strategy (("Laryngeal dystonia" OR "Spasmodic dysphonia") AND ("Central Mechanism" OR "Pathophysiology")). Original studies involving LD patients that discussed central mechanisms and/or pathophysiology of LD were chosen., Results: Two hundred twenty-six articles were identified of which 27 articles were included to formulate this systematic review following the screening inclusion and exclusion criteria. LD is a central neurological disorder involving a multiregional altered neural network. Affected neural circuits not only involve the motor control circuit, but also the feedforward, and the feedback circuits of the normal speech production neural network, involving higher-order planning, somatosensory perception and integration regions of the brain., Conclusion: Speech production is a complex process, and LD is a central neurological disorder involving multiregional neural network connectivity alteration reflecting this. Neuromodulation targeting the central nervous system could therefore be considered and explored as a new potential therapeutic option for LD in the future, and should assist in elucidating the underlying central mechanisms responsible for causing the condition., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Laryngeal botulinum toxin injection is an important treatment modality for spasmodic dysphonia and other laryngeal disorders. We sought to compare usage patterns of laryngeal botulinum toxin injections for voice disorders and to identify and quantify inefficiencies and barriers in providing this treatment. A 26 item survey was written and approved for distribution by the American Academy of Otolaryngology-Head and Neck Surgery and the National Spasmodic Dysphonia Association. It was distributed to Otolaryngologists who perform laryngeal botulinum toxin injections via the e-mail lists of the National Spasmodic Dysphonia Association provider database, American Academy of Otolaryngology-Head and Neck Surgery Voice Committee and the American Laryngological Association Neurolaryngology Study Group. There were 81 survey participants who collectively reported performing >1700 laryngeal botulinum toxin injections for voice disorders monthly (Mean = 21.5 pts/month). Regarding botulinum toxin A (BtxA) vial use, 54% of participants reported using multiple doses per vial for different patients during a single clinic day, while 14% reported using pharmacy predrawn single use aliquots. A combination of usage practices was reported by 7% of participants. Using an individual vial per patient and discarding the unused remainder was reported by 26% of participants with an associated annual cost in wasted BtxA of $84,300 per physician. There is wide variation in injection practices regarding management of BtxA vials and adherence to an individual vial per patient policy is associated with significant waste of health care resources. Alternative approaches to BtxA vial use could positively impact health care resource utilization. [ABSTRACT FROM AUTHOR]

This systematic review aims to identify instruments used to evaluate treatment outcomes for people with spasmodic dysphonia. Electronic database (PubMed, Cochrane Library, Embase, and CINAHL) searches and hand-searching identified studies that evaluated treatment approaches for spasmodic dysphonia which included pre and post outcome data. A total of 4714 articles were retrieved from searching databases; 1165 were duplicates. Titles and abstracts of 3549 were screened, with 171 being selected for full-text review. During full-text review, 101 articles were deemed suitable for inclusion. An additional 24 articles were identified as suitable for inclusion through hand-searching of reference lists. Data was extracted from 125 studies, identifying 220 outcome measures. As per the World Health Organization's International Classification of Functioning (ICF), the majority measured body functions (n = 212, 96%). Outcomes that explored communication and participation in everyday life and attitudes towards communication (ie, activity and participation domains) were infrequent (n = 8; 4%). Quality of life, a paradigm outside of the scope of the ICF, was also captured by four outcome measures. No instruments evaluating communication partners' perspectives were identified. Currently there is no unified approach to the measurement of outcomes in SD treatment research. Development and implementation of a core outcome set is recommended to facilitate improved understanding of the efficacy of current and new treatment options. [ABSTRACT FROM AUTHOR]

Acute laryngeal dystonia (ALD) is a rare side effect of antipsychotic medications, but it is a life-threatening condition. We are introducing the case of a 49-year-old Saudi single male, who has been known to have schizophrenia for the last 20 years. He developed three attacks of acute laryngeal dystonia owing to different antipsychotic medications. The first was because of haloperidol on a dose of 20 mg a day. After being treated for dystonia and stabilized physically, the patient received oral aripiprazole at a dose of 10 mg a day. Unfortunately, he developed acute laryngeal dystonia, and treatment had to be discontinued. The third attack of dystonia was two months later because of the use of olanzapine in a dose of only 5 mg/day. The patient was finally stabilized on quetiapine with no more side effects. This case highlights the importance of careful monitoring of patients who are receiving antipsychotic medications, even newer ones, to avoid, or treat, such a rare but serious side effect early., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2024, Ibn Auf et al.)

Background and Objectives: Laryngeal dystonia (LD) is a focal dystonia affecting adductor and/or abductor muscles of the larynx. It can be isolated or may spread to extra laryngeal muscles. The aim of this study was to report the characteristics of LD over time in a large single-center study with a long follow-up., Methods: Retrospective review of patients with LD referred to our institution between 1991 and 2021. Demographic data, time to diagnosis, type of LD, follow-up and spread of dystonia [SD] were recorded. Risk factors for spread of dystonia during follow-up were analyzed., Results: Over the 30-year period, 516 patients (77.3 % female, median age 50 years, range 5-87 years) were analyzed. Three hundred and fifteen patients (61 %) had adduction laryngeal dystonia, 136 patients (26.4 %) had abduction laryngeal dystonia, 46 patients (8.9 %) had adductor respiratory laryngeal dystonia, 12 patients (2.3 %) had mixed laryngeal dystonia, and seven patients (1.4 %) had singer's laryngeal dystonia. A previous history of dystonia was found in 47 patients (9.1 %). A laryngeal tremor was found in 68 patients (13.2 %). Since the onset of symptoms, LD was diagnosed after a median of 3 years (IQR: 1.0, 7.0). SD occurred in 55 patients (10.7 %) after a median time of 4 year (IQR: 1.5, 13.0). Patients with mixed laryngeal dystonia had higher probability of SD (p = 0.018)., Discussion: This study reports a large European study of LD, with a long follow-up. SD occurred in 10.5 % of patients. Patients with mixed laryngeal dystonia had a higher probability of SD. A close follow-up may be recommended for patients with mixed laryngeal dystonia., Competing Interests: Declaration of competing interest G. Dupuch reports no disclosures relevant to the manuscript. M. Mailly reports no disclosures relevant to the manuscript. J. Guillaume reports no disclosures relevant to the manuscript. M. Daval reports no disclosures relevant to the manuscript. D. Ayache reports no disclosures relevant to the manuscript. D. Brasnu reports no disclosures relevant to the manuscript. Data collected for the study, including individual participant data and a data dictionary defining each field in the set, will be made available to others. All other data will be made available. These data will be available with publication. The data will be made available at guillaume.dupuch1@gmail.com (first author email address)., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objective: The main objective of this study was to compare the demographic and clinical characteristics of patients with laryngeal dystonia (LD), dystonic tremor (DT), and vocal tremor (VT)., Study Design: This was a retrospective longitudinal study., Methods: Data analysis from every patient diagnosed with LD, DT, or VT from January 1, 2010, to September 30, 2022, at a tertiary hospital center. Differential diagnosis between these entities was clinical (clinical history, voice assessment, and endoscopy) and confirmed by laryngeal electromyography., Results: A total of 87 patients were included in this study: 50 patients with LD, 23 with DT, and 14 with VT. Age at diagnosis was significantly lower in patients with LD, with a mean age of 56.2 years when compared to DT (67.6 years; P = 0.002) and VT (70.5 years; P = 0.009). Furthermore, VT had a higher female prevalence (92.9%) when compared with LD (52%; P = 0.011). LD was mainly adductor, with only two patients diagnosed with abductor LD, and DT was adductor in every case. Tremor direction in patients with VT was horizontal in 50% and mixed (horizontal + vertical) in 50%, while in DT was mixed in 65.2% and horizontal in 34.8%. LD was more commonly an isolated laryngeal movement disorder (78%) when compared to DT (47.8%; P = 0.015) or VT (28.5%; P < 0.001), which were more often secondary to generalized neurological disorders. There were no differences between groups on Voice Handicap Index-10, self-reported grade of dysphonia on a visual analogic scale (0-10), maximum phonation time, and G, R, B, A, and I in the GRBAS-I scale at diagnosis (P > 0.05). S was significantly higher in LD when compared to VT (P < 0.001) and nonsignificantly higher than in DT (P = 0.075)., Conclusions: LD, DT, and VT seem to be different entities with different demographics and clinical characteristics., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper. The authors have no conflicts of interest to declare., (Copyright © 2023 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

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., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

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., (Copyright © 2023 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Outcome assessment in laryngeal dystonia is hindered by lack of consensus on a core set of outcome measures to quantify treatment effect and disease severity on quality of life. Potential outcome measure domains include objective voice, clinician reported, and patient reported outcome measures (PROMs) for determining treatment success and longitudinal disease tracking. We aim to determine correlations between a selections of outcome measure tools following Botulinum toxin injection., Methods: A selection of instruments were administered to assess adductor laryngeal dystonia patient outcomes before and after Botulinum toxin injection. Voice samples recorded using a cellular telephone application were used for objective acoustic measures (CPPS, acoustic voice quality index) and speech language pathologist perceptual analysis (CAPE-V). Additionally, patients completed a PROMs battery consisting of the Voice Handicap Index-10, Communicative Participation Item Bank-10, OMNI-Vocal Effort Scale, 3 visual analog scale (VAS) questions. Changes in these outcome measures pre-post treatment were compared between each other and with a global rating of change questionnaire (GRCQ) using Spearman's rank correlation coefficients., Results: Twenty six patients (20 female, mean age 57.7 years) participated. Using an anchor based GRCQ, patients reported Botox efficacy was the only outcome measure found to have significant correlation (r = 0.54, P = 0.022); all other outcome measures did not meet statistically significant correlation. Amongst the selected outcome tools, several moderate-strong correlations were identified, largely for outcome measures within the same domain. Most notable were correlations between the patient reported OMNI-VES and VAS questions (r > 0.68, P < 0.05), clinician CAPE-V strain and overall severity (r = 0.900, P < 0.001), and acoustic voice quality index with sustained vowel CPPs (r = -0.797, P = 0.002)., Conclusion: Correlation between outcome measures instruments used for patients with adductor laryngeal dystonia requires further attention. Weak correlations with an anchor based GRCQ were found for this study's selected outcome instruments. A select number of correlations were found between outcome instruments within each of the individual outcome measure domains (patient perception, clinical perception, objective acoustics), but there was largely a lack of correlation found for instruments between these three separate domains., (Copyright © 2023 The Voice Foundation. Published by Elsevier Inc. All rights reserved.)

Spasmodic dysphonia (SD), also known as laryngeal dystonia, is a neurological voice disorder that causes involuntary spasms of the vocal cord muscles. This impacts speech to varying degrees and results in strained and strangled voice quality, as in adductor spasmodic dysphonia, or weak, quiet, and breathy, as in abductor spasmodic dysphonia. While there is currently no cure for SD, voice therapy and chemodenervation with botulinum toxin (btx) injections remain the mainstay of management. Surgery may be performed in some cases; however, btx injections are widely used to treat both adductor and abductor forms of SD. While btx injections may show vocal improvement in both types of SD, results can depend on several factors such as the general health of the patient, onset and severity of the condition, dosage, interval between injections, and expertise of the practitioner. While many studies have documented the efficacy of btx for improving vocal symptoms in individuals with SD, this review aims to discuss some of those studies from the last 10 years., Competing Interests: The authors have declared that no competing interests exist., (Copyright © 2023, Khan et al.)

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., (Copyright © 2023. Published by Elsevier Inc.)

Objectives: Demonstrate an understanding of incobotulinumtoxinA efficacy in the treatment of adductor spasmodic dysphonia (SD). Understand that incobotulinumtoxinA can successfully be used as an alternative to onabotulinumtoxinA and for secondary non-responders., Methods: We conducted a prospective open-label trial from 2016 until 2019 regarding the use of incobotulinimtoxinA for the treatment of adductor spasmodic dysphonia. Exclusion criteria included pregnant/nursing women, botulinum toxin for other indications, known allergy, neuromuscular or systemic diseases, use of aminoglycoside antibiotics, substance abuse, litigation regarding prior therapy, or other confounding conditions. Sixty-four injection sessions with completed with sixteen patients who were enrolled in the study and underwent EMG-guided incobotulinumtoxinA injections to the thyroarytenoid (TA) muscle using a hollow monopolar Teflon-coated needle via a trans-cricothyroid membrane approach. Dosages to each TA muscle were recorded and patients completed a Voice Handicap Index-10 (VHI-10), a validated worksheet regarding their perceived percent of normal function (PNF) following treatment, and a side effect profile. Outcomes were analyzed using the paired t-test., Results: For primary transitioners to incobotulinimtoxinA, VHI-10 scores and best percent normal function did not significantly change. For non-responders, VHI-10 decreased from 32.5 on Botox to 19.5 on incobotulinimtoxinA and best PNF increased from 37.6 to 90 %, which was statistically significant. Transient side effects included breathiness., Conclusions: Our study demonstrates that incobotulinimtoxinA may be used successfully for adductor SD either as first line treatment or in secondary non-responders to onabotulinumtoxinA., (Copyright © 2022. Published by Elsevier Inc.)