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.

Impacto en la calidad de vida del tratamiento de disfonía espasmódica aductora con toxina botulínica A / Impact on the quality of life of the treatment of adductor spasmodic dysphonia with botulinum toxin A

Introducción. La distonía laríngea o disfonía espasmódica se caracteriza por con-tracciones involuntarias de los músculos laríngeos internos que se desencadenan al hablar, siendo la forma aductora la más frecuente. La inyección de toxina botulínica es el manejo de elección. Para evaluar la respuesta a la terapia existen varios instru-mentos validados, uno de ellos es el cuestionario Voice Handicap Index-10 (VHI-10). El objetivo de este estudio es caracterizar a los pacientes con disfonía espasmódica aductora y evaluar el impacto de la toxina en su calidad de vida.Método. Éste se centró en un estudio retrospectivo descriptivo en pacientes adultos con diagnóstico de disfonía espasmódica aductora tratados con toxina botulínica A, en el Hospital Clínico Universidad de Chile (HCUC), en el periodo comprendido en-tre 2013 y 2021. El mismo permitió la obtención de los datos epidemiológicos de los pacientes, a quienes se les solicitó responder la encuesta VHI-10 previo y posterior a un mes de cada inyección de la toxina.Resultados. Se incluyeron 55 pacientes (218 procedimientos). La dosis promedio utilizada fue de 9,18 UI con un intervalo promedio de 7,4 meses. El puntaje VHI-10 promedio en la evaluación inicial fue de 29,4 y posinfiltración de 14,96, siendo esta diferencia significativa (p < 0,000001). En nuestra serie casi un tercio tiene asociada alguna patología neurológica, y se reportó un 3,67% de complicaciones leves y transitorias.Conclusión. La disfonía espasmódica aductora tiene un gran impacto en la calidad de vida de los pacientes, que se reduce significativamente mediante la inyección de toxina botulínica A, procedimiento que ha demostrado ser seguro y eficaz

Introduction. Laryngeal dystonia or spasmodic dysphonia is characterized by in-voluntary contractions of internal laryngeal muscles that are triggered when speak-ing, being the adductor form the most frequent. Botulinum toxin injection is the management of choice. There are several validated instruments to assess response to therapy, one of them is the Voice Handicap Index-10 (VHI-10) questionnaire. The objective of this study is to characterize patients with adductor spasmodic dysphonia and evaluate the impact of the toxin in their quality of life.Method. A descriptive retrospective study was carried out in adult patients with a diagnosis of adductor spasmodic dysphonia treated with botulinum toxin A, between 2013-2021 at the Hospital Clínico Universidad de Chile. The epidemiological data of the patients and the VHI-10 survey were obtained before and after one month of each toxin injection was requested.Results. 55 patients (218 procedures) were included. The average dose used was 9.18 IU with an average interval of 7.4 months. The average VHI-10 score in the initial evaluation was 29.4 and post-infiltration was 14.96, being this difference sig-nificant (p <0.000001). In our series, almost a third had an associated neurological pathology, and 3.67% of mild and transitory complications were reported.Conclusion. Adductor spasmodic dysphonia has a great impact on the quality of life of patients, which is significantly reduced by injecting botulinum toxin A, a pro-cedure that has been shown to be safe and effective

Differential Diagnosis between Neurogenic and Functional Dysphonia

Voice disorder is classified into three categories, structural, neurogenic and functional dysphonia. Neurogenic dysphonia refers to a disruption in the nerves controlling the larynx. Common examples of this include complete or partial vocal cord paralysis, spasmodic dysphonia. Also it occurs as part of an underlying neurologic condition such as Parkinson's disease, myasthenia gravis, Lou Gehrig's disease or disorder of the central nervous system that causes involuntary movement of the vocal folds during voice production. Functional dysphonia is a voice disorder in the absence of structual or neurogenic laryngeal characteristics. A near consensus exist that Muscle tension dysphonia (MTD) is functional voice disorder wherein hyperfunctional laryngeal muscle activity whereas Spasmodic dysphonia (SD) is neurogenic, action-induced focal laryngeal dystonia including several subtype. Both Adductor type spasmodic dysphonia (AdSD) and MTD may be associated with excessive supraglottic contraction and compensation, resulting in a strained voice quality with spastic voice breaks. It makes these two disorders extremely difficult to differentiate based on clinical interpretation alone. Because treatment for AdSD and MTD are quite different, correct diagnosis is important. Clinician should be aware of the specific vocal characteristics of each disease to improve therapeutic outcome.

Differentiation of Adductor-Type Spasmodic Dysphonia from Muscle Tension Dysphonia Using Spectrogram

BACKGROUND AND OBJECTIVES: Adductor type spasmodic dysphonia (ADSD) is neurogenic disorder and focal laryngeal dystonia, while muscle tension dysphonia (MTD) is caused by functional voice disorder. Both ADSD and MTD may be associated with excessive supraglottic contraction and compensation, resulting in a strained voice quality with spastic voice breaks. The aim of this study was to determine the utility of spectrogram analysis in the differentiation of ADSD from MTD. MATERIALS AND METHODS: From 2015 through 2017, 17 patients of ADSD and 20 of MTD, underwent acoustic recording and phonatory function studies, were enrolled. Jitter (frequency perturbation), Shimmer (amplitude perturbation) were obtained using MDVP (Multi-dimensional Voice Program) and GRBAS scale was used for perceptual evaluation. The two speech therapist evaluated a wide band (11,250 Hz) spectrogram by blind test using 4 scales (0–3 point) for four spectral findings, abrupt voice breaks, irregular wide spaced vertical striations, well defined formants and high frequency spectral noise. RESULTS: Jitter, Shimmer and GRBAS were not found different between two groups with no significant correlation (p>0.05). Abrupt voice breaks and irregular wide spaced vertical striations of ADSD were significantly higher than those of MTD with strong correlation (p < 0.01). High frequency spectral noise of MTD were higher than those of ADSD with strong correlation (p < 0.01). Well defined formants were not found different between two groups. CONCLUSION: The wide band spectrograms provided visual perceptual information can differentiate ADSD from MTD. Spectrogram analysis is a useful diagnostic tool for differentiating ADSD from MTD where perceptual analysis and clinical evaluation alone are insufficient.

Characteristics of Adduct Spasmodic Dysphonia and Muscle Tension Dysphonia Using Spectrogram / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Adduct spasmodic dysphonia (ADSD) is a neurogenic and focal laryngeal dystonia resulting in a strained voice quality with spastic voice breaks. While muscle tension dysphonia (MTD) is caused by functional voice disorders, its symptoms are similar to those of ADSD. Because the approaches of treatment for ADSD and MTD are radically different, accurate evaluations are necessary for precise diagnosis. A spectrogram analysis for differentiating ADSD from MTD provides differentiations on four spectral findings (abrupt voice breaks, irregular wide-spaced vertical striations, well-defined formants and high-frequency spectral noise). The aim of this study was to evaluate if the spectrogram could provide detailed information on the visual characteristics that distinguish ADSD and MTD. SUBJECTS AND METHOD: 11 female patients of ADSD and 13 female patients of MTD who were diagnosed by laryngoscope and stroboscope from 2009 through 2012 were selected for this study. The speech samples of subjects were obtained using Computerized Speech Lab. The two speech therapists evaluated a wide-band (300 Hz) spectrogram by blind test using 4 scales (0-3 point) for four spectral findings. RESULTS: Abrupt voice breaks and irregular wide-spaced vertical striations of ADSD were significantly higher than those of MTD. Well-defined formants and high-frequency spectral noise were not found significantly different between two groups. CONCLUSION: The spectrograms provided visual perceptual information needed to differentiate ADSD from MTD. Voice therapy to reduce hypertension could be considered for patients of ADSD with excessive formants and noise. If spectrogram analysis were used along with other assessments, it would be more useful in distinguishing ADSD from MTD.

Voice Characteristics of Adductor Spasmodic Dysphonia before and after Botulinum Toxin-A Injection / 대한이비인후과학회지

BACKGROUND AND OBJECTIVES: Botulinum toxin type A (BTX-A) injection is well known for its effectiveness in the treatment of "Spasmodic dysphonia". However, studies on the efficacy of BTX-A injection have not been attempted in Korea. Therefore, this study was carried out to investigate the effects of BTX-A. SUBJECTS AND METHOD: The study examined 12 female patients with 'adductor spasmodic dysphonia'. Objective assesments included aerodynamic analysis and electoroglottography (EGG) of each patient before and after BTX-A. Subjective assessments included using the Korean-version of Voice Handicap Index-30 (KVHI-30) and a patient self-rating scale. RESULTS: Aerodynamic analysis revealed that only maximum phonation time (MPT) was significantly shortened after the injection of BTX-A (p<0.05). In the EGG, the mean frequency distribution was significantly increased, while the mean amplitude and the mean closed quotient distribution were significantly decreased (p<0.05). The KVHI-30 and patient self-rating scale scores were significantly decreased (p<0.01) as well, demonstrating the effects of BTX-A on the quality of life. CONCLUSION: Our results show the effects of BTX-A objectively by comparing voice characteristics, which were measured through EGG before and after BTX-A injection, as well as by determining aerodynamic characteristics. The subjective self-assessment on the quality of life is significant as it may serve as a clinically relevant measure. This study may be helpful in elucidating treatment efficacy of BTX-A in many ways.

Anatomic direction of entry for botulinum toxin injection to treat the adductor spasmodic dysphonia in Thais.

Background: Botulinum toxin injections into the thyroarytenoid (TA) muscle of the larynx is the most popular treatment for adductor spasmodic dysphonia. Injection is usually done by percutaneous transcricothyroid membrane with either electromyography (EMG) or fiberoptic laryngoscopy (FOL) to verify placement of the needle within the TA muscle. This procedure requires a working knowledge of three-dimensional anatomy of the larynx to establish the direction for the accurate placement of the needle. Objective: Find out the appropriate angles and depth of the needle for placement of percutaneous transcricothyroid membrane method of botulinum toxin injection by means of studying the larynges of Thai cadavers. Methods: The descriptive study was performed in 45 Thai freshly thawed cadavers. The angle of the needle from midline sagittal plane, the angle in superior relation to tracheal plane, and the depth from midline cricothyroid (CT) membrane to midlength of TA muscle were measured from the two views of photographs, anteroposterior and lateral. Results: The mean angle of 24.2±6.76ο (mean±SD) from the midline sagittal plane in male and 24.9±7.6ο in female were worked out. A mean angle in superior relation to the tracheal plane was 47.7±7.8ο and 51.4±9.6ο in male and female, respectively. The mean depth was 1.7±0.2 and 1.4±0.1 cm in male and female, respectively. Conclusion: The mean angles and depth of the needle insertion from the midline of CT membrane to the center of TA muscle in Thai laryngeal specimens were evaluated. These values were different from the studies in Caucasians, but it could provide a direct relationship to the build of the races. This knowledge may help laryngologists do this procedure more accurately with better outcome, especially in hospitals that have no EMG or FOL guide.

Spasmodic Dysphonia / 대한이비인후과학회지

Spasmodic dysphonia is a primary task specific focal dystonia affecting the laryngeal muscle during speech. Adductor spasmodic dysphonia (ADSD) affects close to 90% of spasmodic dysphonia patients is characterized by voice breaks during vowels during speech due to intermittent hyperadduction of the vocal folds. Abcuctor spasmodic dysphonia (ABSD) is relatively rare and involves intermittent voiceless voice breaks due to prolonged voiceless consonants before initiation of the following vowels. Treatment for spasmodic dysphonia has been aimed at denervation or adjustment of the larynx to prevent the uncontrolled spasms in the laryngeal muscles from interfering with voice production. As a result there is a risk-benefit ratio in that the denervation must be adequate to reduce the detection of symptoms whereas at the same time not producing aphonia, breathiness and swallowing difficulties. This article summarizes the pathogenesis, diagnosis and treatment of the spasmodic dysphonia.

Comparación de los trastornos de la voz con el Voice Handicap Inventory Index / Comparing voice pathologies with the Voice Handicap Inventory: is a weighting factor required?

El Voice Handicap Inventory/Index (VHI) es un instrumento difundido para medir la calidad de vida relacionada con los trastornos de la voz. Sin embargo, la literatura muestra que el VHI no es apropiado para comparar distintas enfermedades. Nosotros intentamos entender el punto de vista personal del paciente que respondía agregando a cada ítem del VHI una medida de su importancia. Por ende, proponemos un factor de ponderación/corrección que parece facilitar la comparación de las enfermedades. Dado que el apoyo financiero gubernamental o de los terceros pagadores a menudo se basa en tablas y figuras, puede ser de interés disponer de una herramienta que compare la gravedad de estos trastornos, es decir, las diferentes categorías de las enfermedades de la voz.

The Voice Handicap Inventory/Index (VHI) is a widespread instrument for measuring the disease specific quality oflife related to voice disorders. Literature has shown, however, that the VHI is not suitable for comparing various pathologies. We tried to gain insight in theresponder’s personal view by adding a measure ofimportance to each VHI item. Hence we propose aweighting/correction factor which seems to facilitate comparing pathologies. As financial support by the government or third party payers often is based on tablesand figures, a tool for comparing the seriousness of diseases, i.e. different categories of voice pathologies, can be interesting.

The vocal rehabilitation training for patients with spasmodic dysphonia / 中华物理医学与康复杂志

Objective To explore the effect of vocal rehabilitation training on patients with spasmodic dys-phonia. Methods Thirty-six patients with spasmodic dysphonia were recruited, and psychotherapy, acupuncture,respiratory and vocal training were performed according to the patients condition to improve the coordination of the vo-cal organs. Interventions were also employed to convert the patients reverse or high locational pattern of respiration in-to the normal associated chest and abdomen respiration, so as to reduce the tone of the laryngeal muscle. ResultsSatisfactory effects were achieved by the rehabilitation training. 30 out of 36 cases recovered and the other 6 cases im-proved. Conclusion It indicated that the comprehensive vocal rehabilitation should be adopted for the treatment ofpatients with spasmodic dysphonia.

Effect of Botulinum Toxin Injection in Patients with Adductor Spasmodic Dysphonia / 대한이비인후과학회지

In the treatment of spasmodic dysphonia, local injection of botulinum toxin A has been reported to be successful. The treatment of adductor type spasmodic dysphonia using botulinum toxin type A was conducted in 31 patients. These patients were given toxins in the vocal fold(s), unilaterally or bilaterally, under telelaryngoscopic guidance with 23 gauge scalp needle attached by laryngeal forceps. Before the above procedure, laryngeal anesthesia was done with 2% pontocain instillation. Among the 31 patients, 30 patients were given the toxin successfully. Telephone interview were made at 2 weeks and then at 4 weeks post injection. Among the above 30 patients, 90% reported that the injection was of significant benefit. The functional status of the patient's disorder was classified into four grades. The mean pre-injection grade for the patients in this study was 2.10 and it was significantly lowered to 1.13 after the injection(p<0.01). As a self assessment method, the patients were asked to rate their voice on a scale of 100. In this study, the mean pre-injection score was 40 and it was significantly improved to 69.8 after the injection(p<0.01). In conclusion, botulinum toxin injection using telelaryngoscope is a safe and effective method for the treatment of adductor type spasmodic dysphonia.