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.

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

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

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

Vocal Parameters and Self-Perception in Individuals With Adductor Spasmodic Dysphonia.

OBJECTIVE: The study aimed to compare and correlate perceptual-auditory analysis of vocal parameters and self-perception in individuals with adductor spasmodic dysphonia before and after the application of botulinum toxin. STUDY DESIGN: This is a prospective cohort study. METHODS: Sixteen individuals with a diagnosis of adductor spasmodic dysphonia were submitted to the application of botulinum toxin in the thyroarytenoid muscle, to the recording of a voice signal, and to the Voice Handicap Index (VHI) questionnaire before the application and at two time points after application. Two judges performed a perceptual-auditory analysis of eight vocal parameters with the aid of the Praat software for the visualization of narrow band spectrography, pitch, and intensity contour. RESULTS: Comparison of the vocal parameters before toxin application and on the first return revealed a reduction of oscillation intensity (P = 0.002), voice breaks (P = 0.002), and vocal tremor (P = 0.002). The same parameters increased on the second return. The degree of severity, strained-strangled voice, roughness, breathiness, and asthenia was unchanged. The total score and the emotional domain score of the VHI were reduced on the first return. There was a moderate correlation between the degree of voice severity and the total VHI score before application and on the second return, and a weak correlation on the first return. CONCLUSIONS: Perceptual-auditory analysis and self-perception proved to be efficient in the recognition of vocal changes and of the vocal impact on individuals with adductor spasmodic dysphonia under treatment with botulinum toxin, permitting the quantitation of changes along time.

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.