Spasmodic Dysphonia Research Articles

Machine Learning Assessment of Spasmodic Dysphonia Based on Acoustical and Perceptual Parameters.

Adductor spasmodic dysphonia is a type of adult-onset focal dystonia characterized by involuntary spasms of laryngeal muscles. This paper applied machine learning techniques for the severity assessment of spasmodic dysphonia. To this aim, 7 perceptual indices and 48 acoustical parameters were estimated from the Italian word /a'jwɔle/ emitted by 28 female patients, manually segmented from a standardized sentence and used as features in two classification experiments. Subjects were divided into three severity classes (mild, moderate, severe) on the basis of the G (grade) score of the GRB scale. The first aim was that of finding relationships between perceptual and objective measures with the Local Interpretable Model-Agnostic Explanations method. Then, the development of a diagnostic tool for adductor spasmodic dysphonia severity assessment was investigated. Reliable relationships between G; R (Roughness); B (Breathiness); Spasmodicity; and the acoustical parameters: voiced percentage, F2 median, and F1 median were found. After data scaling, Bayesian hyperparameter optimization, and leave-one-out cross-validation, a k-nearest neighbors model provided 89% accuracy in distinguishing patients among the three severity classes. The proposed methods highlighted the best acoustical parameters that could be used jointly with GRB indices to support the perceptual evaluation of spasmodic dysphonia and provide a tool to help severity assessment of spasmodic dysphonia.

Motor neuron involvement threatens survival in spinocerebellar ataxia type 1.

Motor neuron involvement threatens survival in spinocerebellar ataxia type 1.

Laryngeal Imaging Study of Glottal Attack/Offset Time in Adductor Spasmodic Dysphonia during Connected Speech.

Adductor spasmodic dysphonia (AdSD) disrupts laryngeal muscle control during speech and, therefore, affects the onset and offset of phonation. In this study, the goal is to use laryngeal high-speed videoendoscopy (HSV) to measure the glottal attack time (GAT) and glottal offset time (GOT) during connected speech for normophonic (vocally normal) and AdSD voices. A monochrome HSV system was used to record readings of six CAPE-V sentences and part of the "Rainbow Passage" from the participants. Three raters visually analyzed the HSV data using a playback software to measure the GAT and GOT. The results show that the GAT was greater in the AdSD group than in the normophonic group; however, the clinical significance of the amount of this difference needs to be studied further. More variability was observed in both GATs and GOTs of the disorder group. Additionally, the GAT and GOT time series were found to be nonstationary for the AdSD group while they were stationary for the normophonic voices. This study shows that the GAT and GOT measures can be potentially used as objective markers to characterize AdSD. The findings will potentially help in the development of standardized measures for voice evaluation and the accurate diagnosis of AdSD.

A review of the peripheral proprioceptive apparatus in the larynx.

The larynx is an organ of the upper airway that participates in breathing, glutition, voice production, and airway protection. These complex functions depend on vocal fold (VF) movement, facilitated in turn by the action of the intrinsic laryngeal muscles (ILM). The necessary precise and near-instantaneous modulation of each ILM contraction relies on proprioceptive innervation of the larynx. Dysfunctional laryngeal proprioception likely contributes to disorders such as laryngeal dystonia, dysphagia, vocal fold paresis, and paralysis. While the proprioceptive system in skeletal muscle derived from somites is well described, the proprioceptive circuitry that governs head and neck structures such as VF has not been so well characterized. For over two centuries, researchers have investigated the question of whether canonical proprioceptive organs, muscle spindles, and Golgi tendon organs, exist in the ILM, with variable findings. The present work is a state-of-the-art review of the peripheral component of laryngeal proprioception, including current knowledge of canonical and possible alternative proprioceptive circuitry elements in the larynx.

Automated Creak Differentiates Adductor Laryngeal Dystonia and Muscle Tension Dysphonia.

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. 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. 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). 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. 3 Laryngoscope, 2023.

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

This study aims to analyze the impact of age and sex on botulinum neurotoxin (BoNT-A) dosing and outcomes in adductor spasmodic dysphonia (AdSD). 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. 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 meanBoNT-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). This study suggests that age and sex influence BoNT-A dosing and outcomes in AdSD.

Quantifying and Improving the Performance of Speech Recognition Systems on Dysphonic Speech.

This study seeks to quantify how current speech recognition systems perform on dysphonic input and if they can be improved. Experimental machine learning methods based on a retrospective database. Single academic voice center. A database of dysphonic speech recordings was created and tested against 3 speech recognition platforms. Platform performance on dysphonic voice input was compared to platform performance on normal voice input. A custom speech recognition model was trained on voice from patients with spasmodic dysphonia or vocal cord paralysis. Custom model performance was compared to base model performance. All platforms performed well on normal voice, and 2 platforms performed significantly worse on dysphonic speech. Accuracy metrics on dysphonic speech returned values of 84.55%, 88.57%, and 93.56% for International Business Machines (IBM) Watson, Amazon Transcribe, and Microsoft Azure, respectively. The secondary analysis demonstrated that the lower performance of IBM Watson and Amazon Transcribe was driven by performance on spasmodic dysphonia and vocal fold paralysis. Thus, a custom model was built to increase the accuracy of these pathologies on the Microsoft platform. Overall, the performance of the custom model on dysphonic voices was 96.43% and on normal voices was 97.62%. Current speech recognition systems generally perform worse on dysphonic speech than on normal speech. We theorize that poor performance is a consequence of a lack of dysphonic voices in each platform's original training dataset. We address this limitation with transfer learning used to increase the performance of these systems on all dysphonic speech.

Sensory processing in the auditory and olfactory domains is normal in laryngeal dystonia.

Abnormal sensory discriminatory processing has been implicated as an endophenotypic marker of isolated dystonia. However, the extent of alterations across the different sensory domains and their commonality in different forms of dystonia are unclear. Based on the previous findings of abnormal temporal but not spatial discrimination in patients with laryngeal dystonia, we investigated sensory processing in the auditory and olfactory domains as potentially additional contributors to the disorder pathophysiology. We tested auditory temporal discrimination and olfactory function, including odor identification, threshold, and discrimination, in 102 laryngeal dystonia patients and 44 healthy controls, using dichotically presented pure tones and the extended Sniffin' Sticks smell test protocol, respectively. Statistical significance was assessed using analysis of variance with non-parametric bootstrapping. Patients had a lower mean auditory temporal discrimination threshold, with abnormal values found in three patients. Hyposmia was found in 64 patients and anosmia in 2 patients. However, there were no statistically significant differences in either auditory temporal discrimination threshold or olfactory identification, threshold, and discrimination between the groups. A significant positive relationship was found between olfactory threshold and disorder severity based on the Burke-Fahn-Marsden dystonia rating scale. Our findings demonstrate that, contrary to altered visual temporal discrimination, auditory temporal discrimination and olfactory function are likely not candidate endophenotypic markers of laryngeal dystonia.

Use of Botulinum Toxin in Spasmodic Dysphonia: A Review of Recent Studies.

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.

Spasmodic Dysphonia

Spasmodic dysphonia (SD) is a chronic voice disorder characterized by excessive or inappropriate contraction of laryngeal muscles during speech. SD manifests as excessive glottic closure (adductor type) or sudden opening of the vocal folds (abductor type). Strained or strangled voice is the main symptom of adductor type SD, while abductor type SD presents with a breathy or absent voice. Adductor type SD accounts for 97% of all SD cases and 70% display abnormal contractions of extra laryngeal muscles. SD is currently understood to be a focal dystonia of inner laryngeal muscle during speech. Injection of botulinum toxin into laryngeal muscles is the primary treatment for SD, similar to other dystonia diseases. As the effects of botulinum toxin last for around three months, patients need repeated injections. There are two kind of surgical procedures which aim to achieve permanent emission, namely type 2 thyroplasty (TP2) and bilateral thyroarytenoid muscle myectomy (TAM). Both of these are effective and over 50% of patients can become symptom-free. However, in some cases, patient voices can become breathy and pitch ranges are reduced. For abductor type SD, there are no effective treatments apart from botulinum toxin injections into posterior cricoarytenoid muscles which open the vocal folds.

Anaesthetic Concerns in a Case of Spasmodic Dysphonia

Spasmodic dysphonia (SD) is a voice disorder resulting from involuntary laryngeal muscle movements. An anaesthesiologist might encounter patients with SD arriving for surgical treatment of the primary pathology or other surgical procedures. One must exercise caution while providing anaesthesia to such patients and consider any factor that may precipitate airway obstruction. Symptoms might get exacerbated following anaesthesia involving airway intervention that might warrant immediate airway control. Airway techniques that have minimal manipulation and vigilant observation of the patient for any symptom of airway compromise postextubation are recommended. SD, though manifesting just as a voice change, has a significant impact on anaesthesia management, and as an anaesthesiologist, one should be aware of its implications while handling these patients.

Clinical insights and challenges: A rare case report of Leigh syndrome

Leigh syndrome is a severe neurological disorder that impairs mobility and respiration, among other bodily functions. Progressive brain deterioration is what makes it distinctive. This case report describes a 10-monthold female child who displayed symptoms such as vibratory movements in the right upper and left lower limbs, failure to thrive, decreased activity, and vomiting after consuming supplemental feeds. Multiple clinical signs of Leigh syndrome, including missed developmental milestones and mild acute malnutrition, were identified during a physical examination. So the symptoms that led to the diagnosis of Leigh syndrome were quadriparesis, dystonia, intermittent stridor (laryngeal dystonia), and bulbar weakness. This was supported by various laboratory results and diagnostic procedures, including brain imaging. The treatment included pacitane, thiamine, biotin, l-carnitine, calcium + vitamin d3, and sodium benzoate as well as dietary assistance and other medicines. Leigh syndrome is an incredibly rare disorder that has major effects on those affected and often manifests in infancy or early childhood. It is characterized by things like vomiting, feeding issues, neurological impairments, and delays in development. Sadly, because Leigh syndrome is a degenerative condition, the outlook for those who have it is frequently bleak. In cases with Leigh syndrome, this case emphasizes the value of early diagnosis and interdisciplinary treatment. The patient was instructed to have additional testing such as an EEG and a disability evaluation. Healthcare professionals must be aware of the clinical manifestation and treatment of Leigh syndrome in order to give affected people and their families the right care and support.

Key Points in the Management of Spasmodic Dysphonia

Key Points in the Management of Spasmodic Dysphonia

DystoniaBoTXNet: Novel Neural Network Biomarker of Botulinum Toxin Efficacy in Isolated Dystonia.

Isolated dystonia is characterized by abnormal, often painful, postures and repetitive movements due to sustained or intermittent involuntary muscle contractions. Botulinum toxin (BoTX) injections into the affected muscles are the first line of therapy. However, there are no objective predictive markers or standardized tests of BoTX efficacy that can be utilized for appropriate candidate selection prior to treatment initiation. We developed a deep learning algorithm, DystoniaBoTXNet, which uses a 3D convolutional neural network architecture and raw structural brain magnetic resonance images (MRIs) to automatically discover and test a neural network biomarker of BoTX efficacy in 284 patients with 4 different forms of focal dystonia, including laryngeal dystonia, blepharospasm, cervical dystonia, and writer's cramp. DystoniaBoTXNet identified clusters in superior parietal lobule, inferior and middle frontal gyri, middle orbital gyrus, inferior temporal gyrus, corpus callosum, inferior fronto-occipital fasciculus, and anterior thalamic radiation as components of the treatment biomarker. These regions are known to contribute to both dystonia pathophysiology across a broad clinical spectrum of disorder and the central effects of botulinum toxin treatment. Based on its biomarker, DystoniaBoTXNet achieved an overall accuracy of 96.3%, with 100% sensitivity and 86.1% specificity, in predicting BoTX efficacy in patients with isolated dystonia. The algorithmic decision was computed in 19.2seconds per case. DystoniaBoTXNet and its treatment biomarker have a high translational potential as an objective, accurate, generalizable, fast, and cost-effective algorithmic platform for enhancing clinical decision making for BoTX treatment in patients with isolated dystonia. ANN NEUROL 2023;93:460-471.

Botulinum Neurotoxin Therapy in the Clinical Management of Laryngeal Dystonia.

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.

Detection of Neurogenic Voice Disorders Using the Fisher Vector Representation of Cepstral Features

Neurogenic voice disorders (NVDs) are caused by damage or malfunction of the central or peripheral nervous system that controls vocal fold movement. In this paper, we investigate the potential of the Fisher vector (FV) encoding in automatic detection of people with NVDs. FVs are used to convert features from frame level (local descriptors) to utterance level (global descriptors). At the frame level, we extract two popular cepstral representations, namely, Mel-frequency cepstral coefficients (MFCCs) and perceptual linear prediction cepstral coefficients (PLPCCs), from acoustic voice signals. In addition, the MFCC features are also extracted from every frame of the glottal source signal computed using a glottal inverse filtering (GIF) technique. The global descriptors derived from the local descriptors are used to train a support vector machine (SVM) classifier. Experiments are conducted using voice signals from 80 healthy speakers and 80 patients with NVDs (40 with spasmodic dysphonia (SD) and 40 with recurrent laryngeal nerve palsy (RLNP)) taken from the Saarbruecken voice disorder (SVD) database. The overall results indicate that the use of the FV encoding leads to better identification of people with NVDs, compared to the defacto temporal encoding. Furthermore, the SVM trained using the combination of FVs derived from the cepstral and glottal features provides the overall best detection performance.

Symptom Expression Across Voiced Speech Sounds in Adductor Laryngeal Dystonia

Differential diagnosis for adductor laryngeal dystonia (AdLD) is often carried out by comparing symptom expression during sentences with either all voiced or voiced and voiceless consonants. However, empirical research examining the effects of phonetic context on symptoms is sparse. The purpose of this study was to examine whether symptom probabilities varied across voiced speech segments in an all-voiced sentence, and whether this variability was systematic with respect to phonetic features. Eighteen speakers with AdLD read aloud a sentence comprised entirely of voiced speech sounds. Speech segment boundaries and AdLD symptoms (phonatory breaks, frequency shifts, and creak) were labeled separately, and speech segments were coded as symptomatic or asymptomatic based on their temporal overlap. Generalized linear mixed effects models with a binomial outcome variable were used to compare the probability of symptom expression across: 1) all speech segments in the sentence, and 2) four speech sound classes (vowels, approximants, nasals, and obstruents). Significant symptom variability was found across voiced speech segments in the sentence. Furthermore, the estimated probability of a symptom occurring on vowels and approximants was significantly greater than that of nasals and obstruents. These results indicate that AdLD symptoms are not uniformly distributed across voiced speech segments with systematic variation across speech sound classes.To explain these findings, future work should investigate how the complex interactions between the vocal tract articulators and glottal configurations may influence symptom expression in this population.

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

Despite many available patient-reported outcome measures (PROMs) for laryngeal movement disorders, there is a lack of patient input regarding which PROM most accurately and conveniently captures aspects related to their vocal disease. This study aimed to assess patients' preferences among a selection of voice-related PROMs (Voice Handicap Index-10 [VHI-10], OMNI-Vocal Effort Scale [OMNI-VES], Communicative Participation Item Bank-General Short Form [CPIB-10], and Visual Analog Scales [VAS]) within the laryngeal movement disorder population and investigate associations between selected instruments. Prior to botulinum toxin A injection, patients with laryngeal dystonia and/or essential tremor of the vocal tract were administered the VHI-10, OMNI-VES, CPIB-10, and three novel VAS questions in a randomized order. Patients rank ordered the four PROMs based on the PROMs' reflection of their voice problems. Pearson's correlation coefficients evaluated pairwise associations among PROM scores. Fisher's exact test compared the preferred PROM rankings. Seventy patients (53 female, mean age=60.7 years) participated. The VHI-10 and CPIB-10 were most preferred at 33.9% and 27.4% respectively. The OMNI-VES and VAS scales were less favored (19.4%, each). When analyzed by age ≥60 years, the CPIB-10 was most favored (33.3%), but for age <60 years, VHI-10 was most preferred (42.3%). There was a strong correlation between scores of all administered PROMs (strongest correlation between OMNI-VES and VAS, r= 0.8, p< 0.001; the weakest correlation between OMNI-VES and VHI-10, r= 0.6, p< 0.001). With an increasing trend in PROMs usage and a strong correlation between all evaluated outcome instruments, insight regarding patients' PROM preferences is an area for further consideration. NA Laryngoscope, 133:1448-1454, 2023.

Abnormal Laryngopharyngeal Sensation in Adductor Laryngeal Dystonia Compared to Healthy Controls.

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). 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. 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). 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. 2 Laryngoscope, 133:2271-2278, 2023.

Developing an Artificial Intelligence Tool to Predict Vocal Cord Pathology in Primary Care Settings.

Diagnostic tools for voice disorders are lacking for primary care physicians. Artificial intelligence (AI) tools may add to the armamentarium for physicians, decreasing the time to diagnosis and limiting the burden of dysphonia. Voice recordings of patients were collected from 2019 to 2021 using smartphones. The Saarbruecken dataset was included for comparison. Audio files were converted to mel-spectrograms using TensorFlow. Diagnostic categories were created to group pathology, including neurological and muscular disorders, inflammatory, mass lesions, and normal. The samples were further separated into sustained/a/and the rainbow passage. Two hundred three prospective samples and 1131 samples were used from the Saarbruecken database. The AI detected abnormal pathology with an F1-score of 98%. The artificial neural network (ANN) differentiated key pathologies, including unilateral paralysis, laryngitis, adductor spasmodic dysphonia (ADSD), mass lesions, and normal samples with 39%-87% F-1 scores. The Calgary database models had higher F-1 scores in a head-to-head comparison to the Saarbruecken and combined datasets (87% vs. 58% and 50%). The AI outperformed otolaryngologists using a standardized test set of recordings (83% compared to 55% ± 15%). An AI tool was created to differentiate pathology by individual or categorical diagnosis with high evaluation metrics. Prospective data should be collected in a controlled fashion to reduce intrinsic variability between recordings. Multi-center data collaborations are imperative to increase the prediction capability of AI tools for detecting vocal cord pathology. We provide proof-of-concept for an AI tool to assist primary care physicians in managing dysphonic patients. 3 Laryngoscope, 133:1952-1960, 2023.